Morris, L.A; Miller, R.E. 1994. Evidence for Long ·
CHAPTER ...1
Tenn Productivity Change as Provided by Field
Trials. In: Dyck, W.J.; Cole, D. W.;· Comerford,
N.B., comps., eds. Impacts ofForest Harvesting
on Long- Tenn Site Productivity. London;
·
Chapman and Hall: 41-:30.
P R 0 VID ED BY FIELD TRIALS
EVIDENCE FOR LONG-TERM PRODUCTIVITY CHANGE AS PROVIDED BY FIELD TRIALS
L.A. -tORRIS
Warne!! School of Fores t Rc!sources. University of Georgia
Athens. GA
30602.
R".E. :.rrLLER
USA
·
USDA Forl!st Savic(!, PJcific :\onh west Rc! e:rch S tJtion
3625 93A\'e, SW. Oly m pia . WA 93512. uSA
INTROOCCTION
In lhe
p::.st two dl!c ades , considerJble e mphasis has been plac ed on d e ve lopi ng
computer models
th at can be used to predict effects of m
agement pract ices on
long - te rm forest productivity ( l, 2. 3. 4 ]. Although the v::tlue of s uc h models as
exploratory rese:rch tool c; is widely recognized, ac ceptan ce of their predic te d
:
changes in fo res t growth is limited. All models incorporate current understanding
of forest grow ch . and produce results that are on ly as reliable
as
th is understand­
ing. B ecause our understanding of factors affec ting forest growth is incomplete,
results
from carefully c ontrolled field trials, rather than mode! s . provide the more
convinc ing evidence of productivity change.
In this chapter, we review the best avail able field e v idenc e for change s in long·
tenn
site produc tiv ity associated wir.h harvest and regenerati on activities. This
idence i ncl udes comparisons of growth in successive rotations
ev­
an the same plots,
results from matched plots. and analy ses of con trol led treatment e xperimen ts. We
begin by discussin g assumptions required in analyses of1ong- term field trials and
by offering minimum criteria that should be met before acce pti ng results fr9m field
:'· .
·.···
j•,
42
£ ,idetice[or fong-temt produc::\•iry changes
trinfs as re!inbie evidence for productivity change. We then evaluate evidence for
productivity ch:mge Jssocinted with the to!lowing manngement activities: use o
monocultures or restricted species. harvest utiiiz:nion and nuuienc re:novJJ, slnsr
disposal. and ame!iomtive tre=.trnenc.s inc!uding nutriems and t illage
_
ASSU 1PTTONS IN LONG-TER ·( FIELD TRIAL RESEARCH
Producth·ity Components
There is ;1o generlll y agreed upon usJg•.! for the tc:nns forest pr od uc ii vit y ilnd :;i 1c
oroduc:ivitv. While some aut hors tre:H these as inte:-c!1Jn - e:blc tcm1s. othc:.
.
J.uthors dr::.w disiincrions. F'or?sr proclucth•iry is the more gt.!nt!:-:1
tc!rm
t.videly use::i by foresters. boc:nisi5. ecologists, and wildlife scie:1tists.
atHJ i
fc refers
tc
growth and maincc::1ance of Jll or Jny pan of the Jssembl:ge of pl:nts Jnd animJI
char. exist !n forestS Jt scJies th<lt rJnge from micrcplots co er11ire ecosystems. [r
cantr::tst. sire productivity gene:::lly has a more limited scJic :md us::tge. [tis us.:!c
by soii scientists and foresters when referring to the growth or c::pacity of a sit-:
to grow trees at the scale of individu:1! forest stands.
Tr::tdicionally, productivity is .:!:<p ressed as a function of b iotic factors (spccic.s.
genotype) and abiotic factors (soil cond itions , slo91!. precipitation). For the pur­
ose of evaluating long-tenn site productivity, these factors
divided \nco four components:
lane pocemial, c!im:ue,
.lfc
more convenientl:­
soil capacity, Jnd catJ.­
s tro phe thac differ in deg r ee co which they are .controlled or assumed constll1t
ir:
long te rm studies (Table 3.1 ) As defined in Chapter 2, "sire quality'' i s decerrninec
-
.
by climate and soil properties (i.e., ca pacity) and is the major focus of long-tern:
site productivity studies.
The first component. plane potentia!, indudes major factors
manipufnced by
forest management: tree species. genotype, stoc!dng, and quality and q uanti ty o{
competing vegetation. Although t.his com ponen t
:
. .
productivity
as
has a majo r influence on forest
me:J.Sured by timber or fiber yield, its influence relates more tc
utilization and allocation of site resources to t.he desired prod u c es
change in resources.
th:1n co Iong-terrr.
Plane poce:ttia! is not necessariiy related to tong-term site
pr odu ctivity For instance, a dec:ease in the c::oacitv of a site to oroduce biomass
.
.
'
.
Assumprions in long-rerm field rrial research
43
TAnLEJ.l Factors affecting stand productivity, by groups subject to different le vels of con!Iol in long-term studies. Factors associated with soil capacity arc of prime importance ior C\'Jfuating long-term changes in site productivity associ:ucd with har\'cst Jlld associated practices. GROUP VARIABLES
Plant Potential
Species. genotype, stocl:ing,
plant competition
E..\PERIMENTAL CONTROL
age.
1inimi7.c differences among ··rotations''
and trc:ltmcnts
unless
part of
c:�pcrimcmat treatmems
Climate Soil ClpaC:ty Temperature. precipitation,
Diifcrcnccs rcmo\'cd by co-variance
humidity, growing season length.
lnalyscs for succc$sivc rotations:
atmospheric tr:!Mfcrs and
lssumcd not to interact with experimental
pollution. sunlight
trc:;;tmcms in lield studies
Soil dcrth. rooting \'Olumc :111d
rc trictions, org nic m:ttter
E. pc:imcmal manipulation and
mc::;,sun:mcnt
content. water-holding c:lpucity,
nutrient $torngc. nutrh:nt
mincr:�fiz tion. nd avail;,biiity
Catastroph�.: llurrit::lllt! dam:!gc. \'Oicanic :lcti\'ity. c:mcmc cJrly/l tc ircl!7.t! or drought. insect or i..li$c se epidemics nlll .moci:ucd with tre:umcnts c:m be masked by eliminating species that compete with crop trees. A major
effort in productivity research is to control plant factors so that measurements of
tree height, stand volume, or stand basal area will provide a reliable index of site
productivity and change.
The second component includes climatic influences. For most field trials of
tong-term site productivity, climate is largely ignored in analyses because:
the tong
1) over
tenn, climate is assumed to average out (i.e., years of good and poor
:]}:7:;. fied by management activities at a specific site. Although evidence for global
!I�i�::. .. climate chnnge is increasing, comparisons among management treaunents within
i�%; ·a.ro.tation remain valid, providing treaunenrs do not interact with these broad-scale
§.Iii{ cli'inatic conditi ons. In contrast, changing climatic conditions severely limit our
growth contribute to observed growth); and 2) climate is not controlled or modi­
awi .
·r§f.+.
ability to assess site productivity changes among successive rotations.
l i.
.,s . The third omponent, soil capacity, includes those factors that detennine .the
ability of soil to provide support, water, and nutrients required by trees. This
· m:.z..
.
.
!". capacity is maintained through the activities .of a broad range of soil biota that
•. ·'.t
.::::_:., :
·
E ·idence jar lang-rerm producrivicy changes
44 conuibuce co deve!opment of soil
suucrure., d
omposition of organic matter, and
nutrient minera.lization :md cr.:msfonmuion. This component is tile main thrust of
most long-tenn
site produc tivity rese:J.rch. In theory, effects of management
p rac tic es on soil can be assessed inde penden dy of tree growth measurements. fr:
p ractice. however, such plant-independent
evafu::uian of soil cJpaci ty is difficul:
and provides only circumsmntiaf evidenc e of productivity chnnge. No c urrent ly
available soil ex
md biologicJ.l
c !ion or bioassay can reliably index the com plex so i l ch emi s try
activity that lffect m ine ralization and availabilily of nutrients.
co ndition s for root growth. For these reasons. soil cJpncity in forestry
:tnc
mus:
ulti m me!y be evaluated by me:1suremenc of tree growth.
The nn:1l c ompo nent. c:lt.ilstr ophe, plays an essential role in de ermining
the structure and p roducti v ity of forest stJnds. Same t.:Jtastrophic events like
hurric:mes and volc:mic l!ruptions are beyond our control and cJ.n destroy tie!c
tri al s. S uc!1 disJsters seldom affect fidd-uial results becJuse the tri::ll is disc:.rde(:
when such events occu r. Other cJ.tastrophes. like insect and diseJse cpid e mic .
be rela ted
m :1 :·
ca. or ind uced by, forest practices hence these should not be ignored o:
d ismissed as random infl uences without investigation.
Acceptable F c!d-Trial EYidence for Productivity Change
Worldwide, numerous studies have been estab li shed to evaluate changes in site
productivity resulting from forest management ac tivities . Although such studie:
i
have provided useful insight about seedling establishment. stand growth, nutrier.
II ;
.
·(' !
I
I
:; :I
i
.:I,
..
.
•t ,. it
.
il
:1
:i
·it
,,
l!
·:
.:
n
:i
;
·•
::
I'I ;II
!j
;l
( :1
1.n
: !l
II· :i
ac cumulation and cycling, and the role of insects and d ise:lS e , they have gener:1il;
failed to provid e
an answer to t.he central question: How do specific m.anagemen
activities affect long-cenn site productiviry? To be acceptable evidence fa:
a change
in long-term site productivity, three conditions must be met. Erst
d ifferences in tree growth must be attribu tab le to d ifferences
in site condition
r.tt.her chan to d ifferences in resource allocation among target and non-targe
species or to differences in plan t potentiaL Seco nd, growth results must be
available
far a suffic ient duration of time so !.hat the influence of ephemera.
differences in initial site conditions has dim in i sh ed and so that the capacity of th::
site to support tree growth is stressed. Fin all y, adequate e perimen tal control mus
e ist. We shall address each condition in more detaiL
t\ssumprions in
long-1erm field :rial research
Sdecring Growr!t Measures: The degree to which
a
45
site c:m supply physical
support., water, and nutrients to trees, and the xte:1t to which tree roots can grow
through the soil to utilize these resources, dete:mines the capacity of a si te for tree
growth. Theoretically, site productivity can be evaluated by any measure that
accurately reflecrs changes in these conditions. The merits of using net prim:uy
productivity (NPP), the tot:J.I carbon fixed in org anic matter min u s respiration
losses, as a measure of site productivity change has been discussed
(5).
This
measure cle:lf!y has value in ecological studies; however. from a practical
st.:J.ndpoinr. measurement of NPP is unwork:lble in long-tetm studies of forest
management. Complete characteriz:J.tion of net primary productivity is difficult
J.nu subject to large measurement etTor, partic'Jlarly where changes in species
composition are involved. Hence, most l ong · \enn studies in forestry rely on
growth of the target tree species for Jssessing changes in site productivity. Site
index (or height growth) has been the mosr c:;mmonly used measure because
height is readilv measured and relative!v less sensitive to stand conditions than
-
"
.
.
other parameters. Stand b a sal arealnd bole ,·ciume growth or biomass lccumu­
lation provide more cornprehensi\·e measures of st.1Ild growth , but these can only
be reliably interpreted where growth differenc s are not Strongly con founded by
differences in stand conditions.
Defining U111g-Term Response:
A second major consideration for evaluating
results from field trials of long-term productivity involves the definition of "long­
term." Many management practices have short-term impacts on stand or site
conditions that are ephemeral and poorly related to long-term site productivity.
..
....
.
Control of herbac.eous competition, for example. often promotes rapid tree growth
;_:; : in· young stands but has little influence on growth following crown closure
��<
.
:-!.,.
(except, of cour e. in the case of nitrogen-fixing plants). When competition
·.fr:; control does not result in su bsequent accelerated erosion or nutrient loss, it largely
: .
·affects tree growth through changes in resource allocation to trees, rather than
:_· .
s1;J. through a change in total site resources or productive c apacity such shifts in
·
.[ f.:· resource allocation will appear
1.
:,
.
as
an eariy inc:-ease in
tree
growth followed by a
return to annual growth patterns that do not differ from growth patterns of
untreated stands
It
[6]. The original increase is maintained after crown closure, but
46
£ ·iderrce jor fong-remr produc:iviry changes
b
a
c
T
I
,}
ro1a1ion
e-.l
'
,l.ge---'""
FIGuRE 3.1
m:ma
Possibie pn.uems of domin
mc:nc tre:1U11c:nt:
mt
;ree hr::!ghc
growth follo\ving
(J) initial i n c :-:::1sc in reso u rc (! .:iloc:rion wir.houc ::itc
.
ch an ge ; (b) i nc:-eas e in long-tenn fJroductivir.y; Jnd (c) :r:nsient i ncre:se
followed by long-tenn dc:cre:se in sire
? roduc t i vi ty
fUI1her growth improvements are no t evidenr. Hence
response does not indicate a change in long-term site
(ar'ier (61).
this pattern of grow
productivity (Figure 3.1 (a
The growth oa r te m after he rb ac e ous comcetition con tro l e:xemolifies but or
·'
.
w
of thre characteristic patterns of gro w th response to m:magement. Figures 3.1 C
wd (c) illustrate two olhertre atment-induced patterns in st:lnd produ c tivity Figu:.
3 .l(b) ill us trates a difference in site productivity that is maintained; Figure 3.1 (c
illustrates a trans i en t change in productivity. Tne di s tinc ti on between Figure 3 1 (
.
and Figure 3.1(b) is important. The growth pattern
­
of F!gure 3.1(b) indicJtes
chang e in site productivity that will most likely continue into fucure rotation
Although the growth pattern of Figure la does not necessmly rule out ¢e possi
bility that a positive change in lo ng- term site produc tivi ty may ye oc cu r, ic is mac
pro bable that the sail C:l!?acity is not fundamentally different Ulan the controL Th
growth pa.rtern in Figure 3.l(c) also re9resents
a change in sire produc tivity th;:.
wiU likely c on tinue into future rotations. In this case. the pattern i n di c:nes
decre:1se in t'raductivity.
Assumptions in long-term fie!d trial research
47
Until the pattem of growth change is evident, one has little basis for predicting
l11e consequences of management activities on long-term productivity. For slow­
growing stands, a reliable pattern may require 20 or m o re ye:u-s. For faster
growing stands or short-rotation plantations, 10 ye:u-s may be adequate co observe
these changes and to predict their long-term consequences.
ExperimentaL
Comrol: According co Mead
er
a/. (7], experimental designs
for long-term stu ies require the fol l owing (see chapter 9 for further discussion on
experimental design):
I. at least four replications in r :m dom ized or randomized complete block designs:
2. suitable pre-treaunent site and crop inform ation on individual experimental
plots;
3. minimum measurement plot ue:ts of 4GO mZ contD.ining at le:J.st 12 remaining
trees at the e:1d'or' the experiment:
4. buffer ucas of at le:J..St 10-m width surrounding each measurement plot th a t
receive experimental t.re:lUnents.
Few studies have been estD.blished which meet these ·experiment.'ll requirementS
and none have been cJ.ITied long enough to provide unequivocal results. Thus. our
current conclusions about long-tenn site productivity change are based on im­
perfect results and must be continually re-examined as ne'.v information becomes
available. Only when results from numerous imperfect s t udies, and our under­
standing of forest growth processes lead to the same conclusions, can we ensure
robust conclusions.
Research on possible declines in productivity resulting from removing species
/i: · · f om a stand or replacing mixed-species stands with plantations of one tree species
has been based largely upon results from plots matched with respect to manage..4 - :.;-;,:·-::.. .
f;S*;;· ment history and soil conditions or from randomly paired plots. In matched plots,
treatment effects and initial site differences are easily confounded by unrecog­
; :.. ..
·nized but
site factors or experimental bias. Such confounding is reduced
·
· ··
paired-plots where treatments are randomly assigned to experimental units.
. ·.�·;::Research on harvest u tiliza ti on is more amenable to controlled experimenta­
on: Comparisons among harvest u tiliza tion options within a rotation can be
: sil y designed as valid replicated experiments (see Ch ap t er 9). Unfortunately,
t l'
: ;tf:
,.
ll in
f.
·
.,....
·
.
important
£\•idence jar long-rerm producriviry changes
48
much of che
repiic:ued
av:1ilable
information on harvest utiliZJ.tion comes from non-
studies on large. operationally harves ted areas. This is cieariy
f
ir:
response co nutrient mineralization and water quality concerns raised by e:u-i;
.Brook watersheds (3].
rese:u-ch on the Hub bard
Resul ts from
such large-sc:J.Ic
studies are frequen liy confounded by differences in tree growth du e to regenera­
tition. Jnd site vari atio n. tion succ::ss. plnnt com
Studies of sice chan ge
after slash dispos<Il or lrne!ioracive rre:mnents usuaii:
have che strongest ex perimen tal
replicated and. in
designs. Muny of these experiments ue wer
_f
some. differences in s tocking , plant com peti tion , or i nsec
d am age have be:!n minimized
(9].
Reg dlc:ss of study purp-ose. minimum requirements for an acceptable desig:­
inc l ude : t) hav i ng lppra priate control plots ag:inst which tre:J.ted plots c:m be
evnlu:ued: Jnd 2) being
minimized or
me
n that JJl factors other than tre:unent huve
c:na i
:sured in order
co
bee:
Jccount for their con tribu t i o n co observe
d_ifferences in growth.
SPECIES CHANGE AND SINGLE SPECIES ROTATIONS
Plants and soils interu.ct. Extension of roots through soil, uptake and return c
various nutrients, concribution of or ganic
o n temperature and
matter, and t he influence. of vegetatic:
moisture dis uibution profoundly Jffect soils. Converse!:­
chemical and physicJ.l charilcteristics of the soil affect plant growth
and specie
distribution. Conc::m about the
specifically che
than
effects of species change on [ong-tenn site productivit:­
effect of conifer establishment, emerged from Europe mor
70 ye s ago. Between the late 1800's and e:u-iy 1900's, conifer plantation
were established on marginal crop and forest lands throughout Europe. Limite
. i
i
·.;
. !
experience in plantation establishment, coupled with the degraded condition
the lands, resulted in regeneration failures and poor
grow th . f3y
1953,
c
it wa_
generally assumed that site productivity was degraded by conversion·of pasture
fannlnnd, or hardwood forests to conifers (10}. Evidence far
site productivity was we:1.l.c,
such declines
however, because it was largely developed frar
'
*
Species change and single species rotation
49
observations of stands growing on different sites with different histories. These
e:l.r!y reports were fol l owed by reports of productivity decline in second-rotation
p lantings of Pinus
radiara in Australia
(11,
121 and New Zealand (13], and Pinus
parula in Swaziland [141.
None of these studies of species c onversio n meet
:til
of the previously dis­
cussed criteri a for infening long-tenn site productivity change. If only studies that
have adequate growth records and plots matched for similar management history
and site conditions are considered (Table 3.2), we c:Il1not conclude that c onver­
sion to conifer plantations leads to long-tetm productivity decline. Growth of
second- and third-generation conifer plantations 'is as likely to increase as to
d e c ::-e ase . relative to that of the first generation. For instance, Ev:ms (1 51 described
resuits t"rom secand-rot:Hion Pinus parula in S waziland where growth on 129 plots
ne
rotation age (l J-15 ye :l.rs ) was compared with growth of the first rot.ltion
on the same plots (Table 3.3). Overall, the second rota tio n averaged slightly less
volume production than the firs.c; a subst.Jntial productivity decline was largely
contined to one forest block. fn the other four biocks, productivity in the second
rot:ltian equalled productivity in the first rotation. This study is particularly nate­
worthy in that e:l.rlier evaluations of the sa.rne plocs by this author suggested a
general p r oduct ivity decline had oc curred
[t4J.
ft illustrates the benefics of
extended observations - and the problems of short-tenn data. Squire eta/. [16]
evaluated productiv ity of second-rotation radiat.a. pine in Australia using carefully
matched plots and stem analysis to compare growth in the current rotation with
that in previous rotations. These authors found that on both low- and high-quality
·
sites, growth through age 5 was greater during the second rotation. As in most such
7:·:.:.. !. studies . the reasons for the improved growth were speculative. but appeared to be
H:
J} \·
',.due to improved planting and establishment procedures.
,;]> gled from associated questions about harvest utilization, slash disposal, and soil
Issues of species change and second-rotation decline are not easily dis entan­
:1 :
tillage to be discussed later in this chapter. Tnis dilemma is illustrated by two
· ::.;:\.: ·
t1.r5- L> recent studies that combine results from designed field trials with retrospective
{tr, ' 1::
j; {:·:· .
r:.:-t::r..-·:.:
ompa.risons of previous r otation growth on the same site
Cellie
(1 7, 18].
·
et al. (17] assessed factors affecting heigh t growth of' second-rotation
P1nus radzata plantations in South Australia in the same area. as the afore-
-;..:.
-----· ..:._ .:...___:.;.;::.:...:.:...---·;· .;_-- -.
·
..... -·. --·.
.
. :..;;. =
:.::.::..'.
... -·-. :..:... .:-:....- .:::-·
:.:. : ::·.: ·... .
------·--- --- --···
··
----·-··
.
.
.
... . ...
..
- ... ··----· .. "'
•t(
v-.
0
TAIILE J.l
Summary of selectell invcstit;alious uf secoull-flll<lliuu •h:diue in cuuifo:r pl:wlilliuu
Locatlou
Australia
Specie
J'ilws
(Vicwrla) rculitllll
l!xpcrlmenl<ll
Date
Last
l hllhll:livil)•
lt.: uiiS (ill CUIIIJI;Ifi •lll
Oc isn
U.:suu•
EvaLn
Variables
liht ruti&tiuu)
Millchcllplots,
1975
j
IICCeHivc
Age (yr)
hl
l)l)lllillillll lfCI.: hcit:lll,
S.:Cllilll hll:&ll\111 lhUill lliUII
Sl<llld volume
hclt;hl: ·1 ld IU
jl<ldl Slit::..
fll!illiOU
li·l'1i.
Cuuuucn1S
!ioun:c
(IClJ
1111
·1 :!l1 Ill 1·-1-t% till
lllllll.l si1es; vuhw1c :;.I(){J'ii.
be!lt:f Ill SeCUIIli Hllillillll
Swa;dland Pimu
lv(atchcd plot
196-1
10-14
pawla
Australia
New
'Zcalallll
Pinus
Mean tree height ami
volulllC, SIOIIII.l volume
Volume oi ccomJ mt<uion
aver< sctl 7% lower. raugctl
fhllll - ::HI'A• I o
J(i
Successive
llasal OI!Cil
1-
1(1 'ii.
il
iiCCOSS
(fl!lfO:ij)CCii VC)
IJUollili<:S <111<1 Slilllll COIUI!tiliiiS
l'ilii/I
Matched plots
12-21
ll.:isht, basl!l Mea.
S t0111ll
VOIUIIIC
C:lllbC lli
Dccliu.:s in sct:OJHI-r.ll:llion
jlhldliCII \"II }' OCCUffCtl
Villlilht)'. hill l llll l CUIIIIIHIH
ou d.t,:e pll ilhln ; :;..:.:uml-
(II)
Mos1 u�:�:iiucs
cxhihilt:<.l t;rowth
11 cmh oi I ;II)UI e I a.
flllolliUII !;IIIWlh !;I!IIClOIIIy
l•.:ut:r than lir t-rutaliuu
t:ruwlh in luwo.:r slope pusiliOIIS.
If applic; hlc
114, lj)
winter dhluliht
:iliC
maaalou
1965
111
MMI:cd 1lcduu: in silc class
mdiaw
rmlitil(l
Scconl.l rotation
retluctiou aurilluh:tl
(I)J
51
Species change,and single species rotation
TA3LE3.3
Comparisons o( rotation-aged Pinus patu/a height and
in Swaziland (source:
\'Oiume for tim and second rmations
(151).
14- ye:IJ' rotation
Forest Block
First
Plots
13-yeu rotation
S<!Cond
no.
A
·--Height (m}
10
18.7
It
!7.4
c
!7.3
10
17.8
18.7
3
12 .
18.0
17.3
II
B
DaE
no.
··-
9
.;
301
316
306
297
3
301
l3
II
287
286
D&E
12
10
·-
16..:.
16.5 '
17.2
18.0"
l7A
l6A'"
193
275 :9.!
271" no
11
lor p
[11] and Bednall (12].
::.64
26S
=
rc. pccth·cfy.
mentioned stud i es by Keeves
----
16.4
-Volume (mJ ha'1)-
9
indiC:itc signitic:lnt differences between first and st:ccnd rotations
Second
Height ( m}
18.5
·
239·-
20
c
··
!6.8 .....
-Volume (mJ !la'1)-
A
First
Plms
,
31 1 0 and .01.
Th ese investig:Hors
estab l i sh e d P. radiara plan ta tions after harvesting matc h ed first- and sec ond r o t a ·
-
tion stands. They compared factOrial combinations of site-prep;u:J.tion treatments
and nutrient additions. Weed competition on all plots was minimized by herbi­
cides. At a ge
7. heigh t of th e current rotation exceeded heig ht of the previ o u s
rotation at the same age. Although the op timal treatments on bo th first- and
second-rotation sites resulted in similar grow th , the treatments that produced this
optimal growth differed between fi rs t- and second-rotation sites. Specifically,
heigh t gro w th was increased on second-rotation, but not on first-rotation sites, by
1.... ..
· , ·
\l' atments that induded nitrogen additions. These results suggest that removal of
· .
n i trogen in two rotations reduced site productivity on these sites .
)·.;
Allen
et ai.
[18]
reported results from a replicated study established after
t of part of a Pinus taed.a plantation. Growth of the previous plantation
�::r:•
} ts es tablished after either harvest of merch
.;.·., .- -
determined by stem analysis and compared with current rotation growth on
,
an tab le
pine stems (pine stem-only)
or. omplete above-ground harvest of pines and competing hardwoods followed
,
. by e;ther chop-bum or shear-pile and d isk-harrowi ng. Each of these four e a t :
.
J.l:l nts were split into two subplots where competition was either minimized
,
!hi.ough repeated herbicide a pplic ati ons or allowed to grow without herbicides.
Evidence for fong-rerm productivity changes
52
Like Cdlier c.r ai. (17], these investi gat ors found that height growth thro ug h
3 ye:lis of r.he current (second) roution was greacer than 8- ye:li height growth of
r.he first rotation for all tre:u.ments evaiuated. Although growth among the four
harvest and site pre;:nrration tre:mnents di ffer ed. competition control had the great­
st in fluence on short-term g rowth . Harvest utilization had no detectable effect on
8-ye:li he i g ht growth. In plots \V here competition was minim ized by repeated
h erbic ide lpp iic =.ti on , pine g ro wth was only slightly gre:uer in the more disturbed
5he:l!-pile ·:1nd hmowed site-prepared J.re:J.S than in ch op-b um areas. fn plots
\vhere nat ur :l l competition was not controlled, differences between site prepar:l­
ti on tre:uments were larger because site p re parati on provided some control of
veget:J.tion.
D espi te evidence to the contr::.ry, some au th o rs cl a im lS f:1ct that multiple
t"orest rotations with coni fers decre.::se site productivity. For instance, Shepparc
[19] writes: "A decline in productivity bet\veen suc:: :ss i ve crops of sprue\! ir.
Euro pe w:1s reported ar ound the tum of the ce n tury and similar reports have come:
'·
1:
for.vard since from a number of pinces for other species in other circumstances
Therefore, we must acknowledge that there is ... a danger in growing tree crops ir
m on ocu lture."
We c onci ude that current evidence does not indicate such declines occur or
if they do occur, are probably not related simply to estllbli shment of conife
species.
In contrast to these results, evidence fro m field trials c!e:l!l y shows th::
addition of nitrogen-fixing tree species to stands on N-deficient sites incre:l.Ses sit·
productivity. Hence, removing such beneficial species c o uld reduce long-teffi
productivity.
In western Washin g ton , USA, fo ur plots (0.08 ha each) in a 48-ye:u--olc
Pseud.otsuga. menziesii plantation were matched topographically beside four plol
in a strip of the same plantation interplanted with Alnus rubra (20]. In i ti a l tre:
density at planting averaged 1,700 Douglas-fir and 3,100 red alder per hectare. B:
ge 48, th e four plots in the pure stand averaged 970 Douglas-fir and th ose in th·
mixed stand averaged 660 Doug las- fir and 730 alder. The largest 100 Douglas-f
per hectare averaged 20% U1ller in the mixed stand and were larger in diamete
despite the greater stand density. Douglas-fir volume averaged 217 m3ha·1 in t.h
1
Species change and single species rotation
53
mixed stand versus 203 mJh;r1 in the pure. The additional alder volume in the
mixed stand averaged
175 m3ha·1•
The growth-enhancing benefits ofN2-fixing :llder at this site are not surprising
bec:J.U s e 30 years after interplanting,.soil in
nitrogen (1,000 kg ha·1
the mixed stand averaged 33% m ore
(21 ]). Moreover, 15-year response in a N-fenilizalion uial
in a nearby portion of the same Do ugl as fi r plantation averaged 88% (116 m3ha·1
:
-
aft er a s ngle application of 314 kg N ha 1 ; [22]). The l arge extended response to
i
,
N fertilizer at t11is location is unusual and attributed to imoroved nuuition and to
.
seco nd ary effects of increased growth on sund structure. On more naturally­
productive sites. however, growth-promoting benefits of J.lder in mixed stands are
less appa.re:H, perhaps ex p l a ined by greater lJTiounts of soil nitrogen at naturally
produ ctive sites and the earl y competitive ad\·;;.ntJge of this species [23].
Growth-enhancing effects of a tropic:i N ftix in g tree spec:es. Albiz.ia
fa/cataria (L) Fosb., in an equal-aged mixture '>Vith E:lcalyptus salig11a Sm were
quantified in Hawaii [24]. At 43 months, E:tc::lypws trees in the m i xe d pl an t i ng s
that contained 34% or mo re Albiz.ia were equal to or lil.rger than those in pure
sunds receiving four fertilizer a ppl i ca tions :::ch equivalent to 40 kg N, lS kg P,
.
and 33 kg K per hectare (24]. fn contras t to these results on the west coast of H awai i
Isl.and, Albiz.ia grew poorly and provided no growth enhancement in a companion
test in a much drier location of the isl and [88].
On N-deficient sites, both N2-fixing species and nitrogen fertilizers are
potential means to enhance tree growth, hence site productivity. Use of N2 fixing
-
: :: plants, however is.more complicated than use of fenilizers for several reasons:
,
��· 1) the N,-fixing plants mu st survive and thrive tn sufficient numbers and duration;
:
.f 2YSo·me N.,-fixing tree species may result in J.ssociated trees being overtopped or
a ged this problem can be avoided with early spacing control; and 3) as
......
-
.
_t :
t
.
:t.:--.::= ,... .. .
. .
· ?}. J?marized by Binkley
••:'XI
....;:• -
[23], larger quanti ties of nitra te and organic N are leached
]} 9,m' pure red alder stands or alder mixtures than from pure Douglas-fir. This
::.-:.:;;:. ..
.S mcrease teach i ng losses of nutrien t cations and lower soil pH. In summary,
1
1,.
_. •
•
;
•
•
... .
'
t
mC.cd {ui use
>·- ·+' •
t ·
.
.•
.
.
.
ofN.,-fixing
species to enhance stand and site productivity requires
.
-
,
efu l.planni- ng and ex cution.
r,'l::.
Sf:-=::5i.";.
·,· ;::.
\ .·
,5!_: ....
·
54
E: ·idence [or fong-lernt producriviry changes
HARVEST UTILIZATIO N AND NUTRIENT REw!OVAL
Nu tri tional Basis fo r Harvesting Impacts
Co ncerns abo ut species-induced reduc tio ns in site productivity ue no c succorte
by exi sting evidence. yet c o ncerns
term productivity s h ou ld
tass of essen ti al pbnt
about the influence of forest harvest on lam
not be summarily dismissed. Direct remov a.i and indire·.
nutrientS will oc cu r in forests ma.na.ged for wood and fib,
p rod uc tio n . Without nu trient rep lacement by n:uur:1i sources or by
praducti vity could
fertiliz:lli o :
d ec l i ne . Current q uest io ns bout impa.cts of harYest utiiizatic
on site productivity center on the rd:nive babnc:: between nutri<:!nt in p u ts ar
ex peru.
and the c:1 p :1ci ty of so i l co supply nutrientS to a growi ng forest.
Exc ellent
li terature revie.,vs o n nutrient disui b ut io n and cvdi n g i n m :J. i
j
-
..
forest biomes are J.vaiiable. General reviews of nuuien t cycl i n g in the borea.i ['2.:.
tempcr:lte [26j, and tro p ic:1! (271 forest biomes were pub lished in the proc ed iti
of the F!fth North Am t! ric :J. n
specific forest (!COSystcms
Forese Soils Con ference. Liter:ture
re vi ews
abc
J.re also available; (or example. about the dis:.ributi
and cyc l i n g of n utri en ts i n d ecid uo u s forests o f B elgium (28 1 .md i n trop ic:1i r:
•
forestS of Cen U<ll America (29 ) .
Disuib ution of nutrients in re p resentative · forest st=J.nds
temperate, and tropical forest b iom e s
are
? resen ted in
within the bore:
Ta b l e 3 .4. Within
t!:.
b io me, variability among stand
types is large and tends to mask d i fferences
totai n uuient co ntent among che
biomes. C!e:1riy, however. com paratively t ar
quantities of N, ?, K,
and in
·
Ca. and :vfg u e stored in th e vege t:J.tio n of tropical fore
the forest floor of bore:J.i fo res tS
.
D e pletio n of n u uien ts under various h arves ting regim es has been d ocu m e r.
or can be calcu la te d using dam fro m ecosyste!n studies in most commerci
important forest types. Most nuuient dep l etion is associated with direct biorr:
removal; loss of nuuients through accelerate.d erosion, leac hin g or g aseo us :
,
is relatively small. Comprehensive revie ws
p l antatio n s (37],
med i um- a ge forests
of re moval rates in short-rotat
[38], and [ong-rocation. systems
[3 91 ,...
completed for a sym posium on the impacts of intensive harve s tin g on fc
n uuient cyclin g. General su mm ari es [40, 4 1 ] and summaries far specific reg
or forest ecosystems (42. 43 , 44] are also available. The genera! consensus of c
'
'
·,
.
.
Cover Type
Picea mariana
Picea -Abies
Pinus bwtksiana
Pi11 us ba11k.ria11a
M ixed
Quercus
Fagus spp.
Pitws clliouiiP. palu.rtris
...
:
•
b
'
. .
TA U LE JA
Nutrient content and distcihUlion in major forest biomes.
- - - --- For e s t lhxlr
------- V eg e tation -------.
p
K
Ca
Mg
N
I'
1 67
42
1 2 1 ·1
52
15
277
413
27
387
17 1
346
84
1 59
85
146
36
19
52
1-165
213
1 00
43
·n OitEAL
328
3 2
1 02
1 052
253
(28) .
82
(34 ) '
2ti
2698
19
81
406
:n
1 3 "/
2::!()<)
3o7o
234
74 1
20· 1
510
1 ·1 8
<1·1
256
II
326
67
217
3·12
-
1 15
2(1
5 1 ·1
3·1
.j ()
TltOI'I( :AI .
-1 3 7
•kpth).
6460
249
1 ).1
51
Ovcrstory vegetation only, soil 1kpth to 35 em (appmx. mol in
26800 132900
254
365
II
13
3 18
(30] •
(30]
(31I <
(32) 4
920
-1 2
1 7 ·1
•1702
9!!708
1 127
2605
1113
53lB9
2!!9
766
6(:>- 1 0
33
I SO
1 1 ·1 0
22 1 5
4 · 1 80
43
702
<15911
16802
9383
1 65354
500
5
81
1 .5 2
1 03
24 1
468
H
868
187
ND
296
Mg
33
245
5 ·1 · 1
1 5-t
Ca
1 16
32
39
IH
29<1
·00
1'!..
1 14
o i OO
495
·1 592
13
))
S ource
K
559
3729
5 5 5·1
285
406
- - - - - -- Mineral :soil --------
-----·
Mu
K
Ca
N
I'
- - - - - ­- - - - - - - - - - - - - - - - - - - - - - - - - - - - - ­ k
g/ha - - ----- - - - - - - - - - - - - -- - - - - - - - - - - - - - --
5 2 ·1
3 I 'J
25·1
37
TEMPI.::t t ATE
15
1 ·1
I
II
20
51
29
Ccltis-triplochilun 1. 5 3 0
Cawlllillem-ceiba
;· ·
N
Pscudot.mga
IIICIIZ.icsii
.
. .JF}r\1 .
650
508
2576
1!!51.!2
(33 ) I
( 3 5 !"
3969
2!130
( 36 1 '
12 J l
uit cations •k•cnuiucd by l l t =/t iCIO. •l i ucstiuu.
Overs10ry vegetation only. soil depth 10 26 em (approx. rooting tkpth). soil cation:> dctcnuincd h}· I I F/ I I C:IO. digc.stion.
Soil depth to 1 00 em, soil cations determ ined by I IF/I ICIO. digestion.
Soil t l p th lo 1 00 em, soil P d tennincd by Dray No. I, :mil cations by N l l.(>Ac cxii Ktiuu.
<
'
'
h
Forcst lloor indud s leaf Iiller onl y , soil to
to 7 0 em,
40
em depth, total;; by unspcdli u digcstiun.
P, and cations extraeted. using i i 1 SO.II ICIO/I IN0 digcstilln.
1
Soil depth 10 base or D h horiwn (approx. 80 em), soil P and cations detwnincd by I I 1SO /I ICI eJtuaction.
Soil depth
1
Soil tlcplh 10 60 em, P by I I P/11 1SO. di gestion, cations by N I I.O Ac extractiun.
Forest ll oor includes "Iiller" and " trash", soil depth to 30 em. soil I' by Tnmg. cations hy cx trilction in N I I.O Ac. Soil depth 10 30 em, soil P and cations by 1 1 150/ I I CIO/I IN(
\ d i ge.stilln. \J\
&•idence for tong-£erm productivity changes 56
reviewers is that conventional stem-onLy harvests
littie impact an cree nutrition
probably S) occur
(and
in
in
future ro t:ltions. A
of mid- a ge stands will h
osph cri c inpu ts
of N
an
sufficient quantities to appro xi m a tely balance har
removals. and soi l reserves of K. C.a. md Mg arc generally c o ns idere d suffic:
the absence of atmospheric or weatherin g inp·
is based an esti m ated mineral reserves of shai:
for numerous rot:ltions. even in
A repon
so ils
as
the contr.li)' (321
to
determined by we:J.k extraction techn iqu es .
B y comparison. large nu tri e nt removals occur i n m o re intensive above-gro :
harvests o f short-ro tation forestry. fn a n c:l!'iy review, Kimmins (40] estimated :
.1
change from convemion<Il. me!·chamablc stem-only harvest to complete abc
gro und tree h:l.I'Vest o fva.rious northern con ifer ty
s (hemlock-cedar, pine, spn..
spmce - fi r, hemlod::-nr) and cottonwood. would incrc se removals of N
36-233%, P by 5..!-367%. K by 1 4-236% an d CJ. by 15- 1 79%. \Veils er a/.
es tim <Ited th::tt removals of P, K. CJ, Jnd �v{g would do u b l e for ! 6-ye:ll'- old ? :
raeda srands [n the somhe::tstem U.S
inste:ld of
a
.•
us i n g a c o m p l e te above -gro u nd har­
merchant.1ble·ste:n harvest. E·:en gre: uer removals would oc
un der intensive management sch em es such
proposed
a
thinnings i n
as
9ro p o sed by Koch (46 j . K
h arves ti n g scheme far P. ra.eda which
a
wo ul d i ncol1'0rate
muit:
35-ye:JI rot:uion. A t the end of the ro t.:J.tion, cro p trees would be :
vested with their taproot and crown intact. Utilizing Koch 's estimo.tes of projec
.
b iomass remova l s. and anilable d a t a on n u trient c o nc en trJ ti o n of P. taeda tis:
we calculated total nutrient removills under such a system (Table 3 .5). The 2:
1 4, 16. and 4 kgfha, respectively, of N, P, K. Ca. and Mg that would be remc
on an ann u al basis are abo u t 35% gre:lter than removals in two 1 6-year iO tati
·:
1
l .
with complete abo ve · ground ha.ryest (45j. Results from these earlier analyses h
be en confirmed in a more recen t review (4 1 ]. It se ems dear th at increased biorr.
locations will cre :J.te ln im b alan c
.
utilization and/or shorter rota tio n s at sam e
:[ : . '
nutrient inpu t-ex pan that co u Ld !e:J.d to groductivity.dec!ines.
hi
.; . .
·!
Di
ct Evidence of Productivity D ecline with Increased
Although nutrien t-balanc e
B iqmass Remava.
analyses p ro vide indirect e'lidence for projec:
deciines in [on g - \enn site productivity in managed forests, direct evidence of s
d ecli n es is rare. Most c ases where decre:l.Sed site p rod ucti vity has been associ ::.
Ha!>'esl utilizatioJI and nutrient removal
57
wilh i ncreased utilization of the pre vi ous stand occur on low-quality sites in coo l
-
climates (Table 3.6) w here the consequences o f N removals are greatest. Lun d kv i s t
(47] , after re view in g results of m atc hed plo t experiments of
whole-tree harvest­
ing in Pinus sylvestris and Picea abies, co nc l ud ed that, for most sites, growlh of
su b sequ en t stands was greatest w hen harvest slash was l eft in place rather th an
removed. In general, di fferences in height growth lffi o n g utilization regimes were
gre:J.test dwing the fi rst 10 years after p lan tin g : mean tree height in plots planted
aiter harvest wilh slash left in p lace ranged from 30% to 40% gre:Her than he i g h t
in plots w h e re slash was re mo ved . This early height-grow th advantage, however, .
d im i n i s hed there:J.fter. B y age l 6 o n the best qu a l i ty sites, a 3 % reduc ti o n i n height
g ro w th w a s associa ted with lo\ver biomass removals, re ve rs i n g the earl ier tre n d
o f i m pro ve d growth. Com pto n and Cole (4 8 1 repo rte d sim i l ar resu l ts fo r Do u g l a s
fi r grow th after co m p l e te above·ground .biomass remo vo.l that inc l uded forest floor
removal , com plete · u·ee harvest (stem , branc hes J.nd fo l i a g e) . or stem-o n ly
iemo vnl . On a low-quality and a medium-qua l i ty site, l O-year hei g h t g ro w th w as
lowest w he re biomas s removal was greatest. On both si tes. a p p l i c a ti o n of N
fert il i ze r removed or reduced growth di iferenc es .
It should be no ted that su bordinate vege tion was not controlled i n the
studies evaluated by either Lu ndkvist or Cole; tlms. differences i n ve ge ta tio n
among treatm e n ts cou ld contribute to the observed tree grow th patterns . Hence,
the effect of harvest treatments on soil properties and tree g row lh c o u l d n o t be
se p ar a te d fro m the effects of c o m pe ti n g vege tatio n .
Re m ai n i n g field trials provide weak evidence for productivity declines after
. .: .: : . increas ed harvest util ization. For the longest tenn s tudy of its kind in the USA,
.
.
} ;;:· :.:··. Williams et af. : [49] described res ul ts of h arves t utilization i n P. banksiana m
'7:: · Minnesota. Two h arvest-u til izatio n levels were in ves tig a ted : com p le te tree
·; :. %. :... .
·,(flbo ve-ground remo v al of stem, branch, and foliage) or tree length (removal of
. .: erchantable portions of the s tem ) . The treatmen ts were applied at two study si tes
·- ·· · · ·
;; ··.\.· - ith·. similar so il s but. were not replicated within a si te . At one site, 14 yeais
,
J I?.llowin g p lan ti n g , average tree height w as 1 1% less on the complete-tree
.
IW . arves ted plo t than on the tree-length harves ted p lot Con versel y, on the second
..-u: ··.
iJ :. .s.it . at the same age, height was 21% greater i n the complete- tree harvested pl o t
on the tree-length harvested pl o t. In the p re vio us ly descri bed s tu dy by A l le n
­
. : . ...
-·
• -;on -,••
•
,l0an
- iiiFt·:· ·:"
r..·.rs·:...
-
: ..
E. ·idence for long-rerrn producrivicy changes
58
et
aL ( 1 81, 1verage 3-ye:u- height gro w th of P. raeda following stem -only h arves
versus complete above-ground harvest of pi ne md h ardwoods did not differ. Thi
occurred despite large differences in bi o m ass md nu trient remova.is between the
two harvest tre:lUnems [50]. Furthennore, despi te differences in gro w th linen
site preparation and h erb ici de rre:tUnenrs with i n e:1ch h arves t intensity, there w a.
no evidence of interactio n between gro wth response to h::u...:est and th es.! c.re:u
.
ments. ft m u st
be n o te d tha t these l a t te r results are for young stands chat do nc
encire!y fui fi l o u r previo usly
stated requirements for 1c::e;Jtab lc ne!d evidenc.!. Thz
nse m ay yer. t"o l lo w the patte:-:1 of F:gure 3 . 1 (c) c:1n no t b ·
possibiiity th:u rcs
dism issed.
· SLAS H D £SPOSAL
Slush D isposal Im p acts
As is h arv es t uci i i z:1ti o n . s l as h d i s po sil l is also i m port.ilnt in c •::1l uating ;n nag ..;
ment im !J:lC:.S on long-term produc ivi ty.
Mechanized removli of slash i nca iic
o r windrows hJs che gre :ltest potentia! for ne;ptive s i ce i m p:1c:s bec:lUse i t
c:.
disp lace large quan ti ties of o rgnn i c m ntter, s o i l and associ:Hed nu u i e n ts e n m uc
,
of
the s ite [50, 54. 55, 5 6 ] . In
Pinus el/iorii
·
United S tates. Morris et a/. (56] repo rted that
P.
·
palusrris fo res tS
am o u n ts
i n the southe:·
of N. P. and K displac
i n to wi ndrows duri n g p i l i n g w i t h a b lad e exceeded remo vals from
s tem h arvestS
merchantab.
bv s i x fo l d The d i s o l a.c ed nutrients reoresenced
m o re than 0% '..
-
.
..
.
the total soil nu tri en t content to a 1 -m deeth. S imilar resul tS h ave been reoone
.
.
for New Zealand (54] and the P i e dm o n t o f the sou thern U.S. (50] , md, h enc e. c.:
.
probably be genemii zed to m any si tes p re p ared for plmting by these me:: h anic:
te:: hn iques (Tab le 3 .7).
B urning is ano th er common means for slash disposal . N i tro ge n toss fro .
these fi res can be
as
l arge as d is p l ac em e n t during w i n drow i n g In
.
bore:!l fares
w here debri s and fo res t door accumulations are large, more than 500 kg ;:ilha c:..
be lost during s l as h b u rn i n g
[6 1. 62]. Lo sses from o ther forest ty.pes.
o we ; e r
•
.
a.:
typically lower and m a y be s i mil ar to N removal d uri n g merchanc.acie ste.
h arves t
(631 . S las h burning is likely to c::lUse funher reductions of N s•ored
ve getati o n and soil com po ne n tS.
TA B L E 3.5 ·
Es1ima1ed nu lricm removals in a 35 -ycar ro1a1ion of inlcn ivdr m;ul;tgcd loblolly pine (Pi1111J
Ull:£1(1).
l l arvcslcd
Componcu1 o as s•
bi m
---
N
N u lricnl COIICCnlfa t i on• ---
p
K
- 'Ycj
- kg/ha -
Ca
1\lg
N utricnl removal
N
p
K
Ca
kg/ha
Ms
Corritlor thi1111i11g (age •I) 2·1,000
Whole lfcc
. 1 65
.0:20
. } ()()
. 1 20
.O'JO
llltcrmetliatc tll illllillg.r
Do1ewood, bark, and taproot
Tops, branches, ami foliage
D olcwood, bark, and taproot
Tops, branches, and fol iage
Source: Koch
as
5
26
29
.092
.0 1 2
.07 1
20
121
1 54
39
.05 1
.2·1·1
. :!-HI
.u:n
1 57
.-155
.0)·1
217
2-1
1 16
1 1 ·1
26
.
I IJ
27,300
. 176
. 0- 1 7
. Hit\
1 52,900
.092
.0 1 2
.07 1
32,900
..1 5 5
.05 1
.
2 · 1· 1
.OW
4 1i
39
16
.023
1 •1 1
I)
I ll
46
(.l')()
1 0<)
1 38
35
.2-10
.05-1
1 50
n
1!0
79
18
753
92
-191!
553
1 •1 1
.
·
(46). a weighted avcr;tgc usi11g lhc data o r \Vcll:i ami Juq;cn cn 1·1 5 ) ; t;tpmot ctuKcu tr;ttions were asstuued to b e equal t o bolewoou
conce nlrat ions. 7
47,700
Tot;ll rcu1ovcd
Comp u l cd
40
1 70,700
Fitwl ll an•cst
La1cral roots .(130
\Yl .�:h�:::::���t; .rl�d�:;;�.�;:.:. .. -··: . .
'!'��!:!!i 'W'¥8-'t'Y"11Mf51tll"'8"�
!!?.O:'!
·
·. :.: _·:: :·; ·. .:
: .--. ·:· :.·:=-=�-��.:i:::=:::: :. :; ;:-.::� ;. ; : :::
-- ·. .
. .
..
:
..
_
;·
-- · -
..
-.--.,:·-.·r--
·--
,.· -::•:u··--
· ···· ·· · -. , ,
........... --- . -
J
TA II I . E 3.6
0
lnll ucucc of harvc l utili:r.;uion (bioma:ili relllll\'ill) on pmducli dt)' of :.uh eiJIII.:nt :.tanu:i.
Location
Species
Experimental
l);uc
De it:n•
H ejlUII..
1 9 1!1
USA -
Pim1s
l l arvcs1 was
Nonh
lat:t/(1
main plot uf
Carolina
A c at la.sl
Pwducli \'it )'
eVii J . ( yf)
Variaht..::;
6
$plit - plut In
ltCll
(3
reps) ·
lte:iult"
I h:i lll, tliamctcr,
N1l diifcn:nces i n
vuhuw: imlcx;
:.uhsc•1u.:nt pine t:mwth
tulill accumuliut:d
a:.:iLI-..: i i•ll:d with h:u n::-1
hiuma:;:; (ahuve
u&ihliHiun
Cun uu e u&:;
Source
Fur plms with ;md without
( 1 8)
Difference:; in rcgenefiltion
( 9}
..:ump•.:titiuu cunuul
cmund)
USA -
Pirws
Non -replicated
1 969,
M i nnesota
ba11ksia11a
within s i te,
1 97 1
1 4, 1 7
2 :>iiCS
I IL:i!;ht. u i•uuet.:r.
Result:; were rcvef:'c•l llll
111111 :iiOIII.J h;l:\ill
two :;itcs; fullowiug
area
cumph:te-tree vs. stem-
- I I % llll
Pseudo-
1 979
CRO on 2
sites (no reps)
Washington uug11
confound 1\::iult:i
only hilf\'t::-1. piut: height:
1111
USA -
ucce:>s ami :iOil Jistucllauec
H
mcttziesii
liiiC
:.itc.
·1
I 'J'ii.•
:.e..:un.l :.ite
Tu&ill heigh&,
Must ..:um p lc& e h iu l l l il:\!i
hei hl g ro w th
renHl\'ill re:\ultcll in 1 '/ '"n•
lkt:l\:iL'iC llll Ill\\' ')Uillil)'
N · fenil iwtiun elimiluued
(52, 53 )
lleatmen& aliffeceuces
!'il.:s. 1)'il> increase 1111
hi�:h ' l ualit)' s ite
Sweden
Summary of
Picctl
IIUIIlerous HCD
t bit:s
PiiWS
var.
2 1 -25
l lcl&;lll gfllwth.
( icuwth l.::i:i in Mtulie:;
\'UIUUie
wlu:re hiumas:. reuul\'ill
cxpcrimcalls
gn::ue:it; ,liffet ence:; between
lh:iiUIICIII:i
syll•t:stris
:>llli1 lle 1
Oil
hijlh
'J IIitli&)' ;;ile:> illlll diminish
with wnd iljle
• CRO
.. completely mnuomi:tcd; RCD
.
, ,
'
!
, • •.
,
"' randomized ..:omplclc h l ocl:
, .. 7)
Slash disposaL
6 i.
Apart fro m th e i r effects on nutrient budgets, slash d i s posal and s i te prepara­
tion have numerou s direct and i nd irec t infl uences on soil ph ysical md chemical
pro penies. Use of heavy equ i p m e n t can le:1d to soil co m pa c ti o n and d isturbance
which h ave been associated with reduced growth in some stud ies (e. g . , (64, 65,
66, 67]). Com paction will be discussed as a separate to p i c i n a s u b se qu en t section.
G ro wth Fo l l o wi n g lvfech anical Slash D isposal
Vinu a l l y J.l l a v a i la b l e data from c:u-efu l l y desi gned fie l d experiments show that
s u rv i v al and e:u-ly growth of plan ted seed lings is greatest o n sites where biomass
removals '.•,: ere greatest and w here organic and mineral so i l h o ri zons were most
se•:ere ! y distu rbed d u ri n g mechanical slash di sposal (Ta b le 3 .7). f n th e short-term ,
m ec h a n i c ::1l s l ash d i spo s :1 l o ften en hances plan t.J. tion g ro w th because o f: l ) grea te r
ava i l ab i l i ty of n u trients, p art ic u l arl y
N; 2) greatly red uced p ! J n t com petition; and
on some si tes, 3) am e l i o ra t i o n o f soil compaction duri ng assoc i :J. te d t i l l ::� g e o pe r::�­
tio n s .
\'even.he!ess, tree res po nse to these treaunen ts i n o l de r controlled ex peri­
men ts i n d i c :lte s a s h i ft t9ward reduced g row th as the fore s t matures (pattern of
Fi gure 3 . 1 ( c)). S uc h res u l ts :u-e c o nsi stent w i th retros pec t i v e site preparation
rese:u-ch that s h o w s g rowth reductions assoc i ated w i th n u uien c re m o v a l and so i l
d ist urba nce d o n o t appear un ti l after crown-closure.
Fo r i nstance, after co m parin g
a seri es o f s tands d i ffering in yeais s i nce s i te preparati o n in the Piedmont of south­
eastern USA, B u rger and Klue nd er (68] conc l uded tha t growth o f s tands aged
5 ye:u-s o r less was i m proved by site preparation that included p i l i n g or severe soil
. disturbance; in older stands, however, decieased tree heig h t and· stand volume
�i�'·
:.: . were associated with these treatmen ts. Evaluation of the oldes t of the available
.
results presented in Tab l e 3.7 seems to confinn this relationsh i p. For i ns tanc e, in
·
· :.:: . th e Piedmont o f the southeast United S tates, early gro w th of Pinus taeda was
::grea r
f :bY.: .
·,
on
sites prepared
by shear-pile and disk harro wing than o n sites prepared
h "ppin g fo llo wed by a light burn, even w hen differences in vegetation
':'.-:-:: ...
.
%,-.c·o mpetition w ere m i n i m ized b y repeated herbicide
applications ( 1 8] . Examination
.
to f.. a.I! nu al he i g h t gro wth curves (Figure 3.2) for this study indicates th at most . of
"' ·t· '·
i : th hei.g h t growth advantage on shear-pile and h arro wed plots occurred before
:!' !:. : ·
t. ;}g. 6 and su gges ts that heigh t growth o n cho p and burn plots may be greater
·:.•
-
··
....
.. . .
ter age 6 . A re trospective study on a sim i l ar Piedmont s i te
-:'!':':. -
<
(69)
found that
I¥9DreFftWP»HI'A'W'Wili1W1i''¥!SRPGa;uJpxrllm»• n·'w,-.,;;· , rc,"ir
. .
.. : · . :..- : ·
_:._ . :.... ; -=; ·. : :. ·: .·
.
;&;;
'
•
. •
..
·-· · · -- ··-- · - ·· ·
-­
--•
··-·---..•••
-- ··-· - - - -. - ·
·· · ·
--- ----------·--·--------- ·--·---·--·· · · ..
--::- -
-
-
-····
----- ·'··- --··...-·-··
·---
· ·
-
-
---· ----------------- - ----
- --
·
-
·
- · · · · ··
- .-. - -
.
... ..._ • ••,.
.
. . ..
.
. ,.
•
.••
• • • · .. .. . • •• •
..
. ..
\ ·-.·: - · l
.
....
-
·.
.. ..
.
. · ­ - · ; - ­ --­
.
. . ... .
.
. .
.
.
. . ... . .
..
.-· .
___...
";.::
.. . ·-·---.-- ·-- . .
....
· ·-
.
._
..
--·-­
.
.
• . . ... - J . .. .. .
-·------
·'-
·
·
•
.
- - ·------ ··- - ·
L-:'('
TA B LE 3.7
l u llueuce of :>lash llispos;•l anll soil lli:>llu haw:e on
Operation:;
Sp•:cies
tlc
.s
P. wet/a
W i mlrowiut:
and burn i ng
Date
Ex pcrim.:n tal
Lo cat i o n
cvaluell
USA. North
Caro li n a
in i t .
i t:n
.subplot:;
1910
in muin plot
A uc "'
l 'futllll.:t i d l )'
1{..::-uh:.
Comuu:ut:i
Soun.:.;
J)omiuant 1n:e
l'inc limwth lifeillest
No IJetectahh:
hdt:ht aml tut;ll
in plut:. p1 .:pafcd hy
( I ll }
iiCCUIIIUbliUII llf
:.ll.:af- pilcJLiisl;iu
iullucucc of
hilllllil:.:i
h:;a:.t iu du•t•lhuw plms.
last eva I. V;u iahle:i
()'f)
!I
COIIl l lilfillt: 110\f\'e t
ut i lh.atiou
fuwlh uf :.uh:.<=• l ut:ut )tands_
(3 te llS)
hiuUiii.S
hilfVCSl
-
util il.alion
UCIIII:i (e \'er:>cd;
flfllliU.:th·ity
t:feia tef in
CUIH!Ill Wlatillll
W i nd cu wi n t:
.
Ji.
ttCn {-1 reps)
Australia,
llc d d iug
uulilaltl
Windmwing,
P.
New
humint:
rmlicaw
Zealand
V i ctoria
1 ')71
H. 5
lvkau tr..:.: hci !ih l
( ia uwth incn:asctl h)'
;u1d di;uu.:t.:r.
h<=•ldint:. Ll.:.:u:;a:>e.t Ia)'
:. ;u <l ,·ulum.:
CllD (3
reps)
I !J 7 K
:\.5
M.:au h <:c hdt:ht,
(5 7 )
wiudhlWIII
Nu :.it:nilkaut d i ff.:r.:uce
(5H}
diam.:t.:r iuHI :.t.:-1 11 iu ;u.:;L\ with hcavy wccd
\'tlluaue I
CUIIIJk:liliuu. W.:it;lll: -11%,
lliam..:tcr: - 7 '1.· uc inter
wiaHIIIlwc•l ;uc;a:a when only
iii"Cil:.
wi1h luw ..:wupclitillll
l"lli iiJlill <:il
Win•lmwiug
( m o t rake),
.
. I'- WC£111
li A.
outh
C;amlina
hc; h l in g , P-
ncn (2 rcps .
3
1% -
1 9 7:\
:.i t.:s)
5
h·l.:au u ..:.: hd t; l l l
Scalpint:b.
1'.
t i l l a •• • · lwnLill t\.
' :. !l\t:.>m·,..,·,;;.�\.¥ '1:v<vit. :&,
¥l'£t.".!•.;""'"""0.\'r'i. 0;,
s plil pltll
U S A.
Fl ori da
(kor,da
�.l.¢"-.����
,.,_""""'t*-''<'\_'�' · ">W>""l ,.,".,_'!",••J""z ·"-.
(1
,
a
"i''-
., •
f<=Jl:i.
5 sites)
- --' -"·· ·
. 1!.15!1
11
Mean u.:e hdt;ht
and dhh.
Ulel ..:h;ullilhk
,... .
·.
( 59)
h)' Will filtiut:
k• t ili-uuion
:.las h •lisposal, dliouii
I h : ight iuc(..:;,:.cd hy f.:nil i:u:r
;u u l hcdtlinu. d.:ca.:a.setl
U u.-u int: fulluwiut; hy tlbk
!ipaciut: ;uad .soil
harmwiuu iucc�:a:;.:d t:cowth; effects nbo
hu.-u inu full,lwc;l h)' :.calpiut: e v;a tuat..: d
• . . . ......."'
,.-t•. .."- ". --;.,1_..
.... • .,._._ .
(001
· ·-
·····--- -'- ·-·-·
!!t>· ·: ·
Op.:r ;tions ·
Species
Location
cvalucd
Experimental
design
Date inil. Hesuhs
Comments
Soun:c
No c.:hange in a\'crage
hlllg ·tCi lll (lrtllh!c.:ti \' it)'
D um in g
(7 1 )
tfC.:CS ;;
·1 . 1
as:.od;llcd w 1 1h slash
hanlwoo<.l species;
no vegetation contml;
oc planting
W i mlmwi n g followed by
GIOwtll cesJlOHSC (9 0 )
w;,s s i te depc nd ell l ,
Age a t Pmd uc.:t i d t )'
l as t eval. Variable:;
(yr)
D uming
lvl i x cd
conifers
W
i ml mwin g ,
V-blade, dbk
P. w cda
Matched plots
(non-n:plicateu)
at 44 locations
1 9·16)1
U S A,
CRD ( 1 2 n:ps)'
1 98 1
P. weda
bumiu :. 01111t
S muheastern
USA,
Split-plot
(4 reps)
:.l;lle:.
(uuulefllll:i
Imming
P.
mdima
N.:w
S I,
!>taud vuhum:.
C.:lll tlhh
h u mi ng
6
G eorg i a and
I>- len i l i ;-..a l i on
Win d mw i n g ,
·10
Smith Carolina
harrowing
Win d ro wi u c .
beddi n g ,
USA,
Washington
and On:gon
1 97!-i1 9S I
a
Mean tc.:.:
hd gh t
dbk h armw i n
staud \"Oiuanc autl
lx::.t tiCiiiJilelll
l tl t a l
the site:. tiHough age 3
b iu m a :.s
011
5()% Of
hut eaii)' 1:mwth advam;•gcs
diminished hy age 6
1\-J can u ce height.
V ari ab le res po ns e 111 s l ash
dbpo:.al, sustained response
:>laud \"Oillllle
a:. ocia1ed w i th 1 i l la1:e ;uut
l oc.:a t i u n s ) .
CIU) (3 re p s)
li was the
ami di;uuct.:r,
fc1 1 i l i t.atiuu
1971i
lU
Zealand
J\killl lfce hcighl.
Nu :>ignilicant difference i n
diameiCf illlll
areas w ilh heavy weed
\'il hUIII.:
11!111
favoccd
Dou g las-li c &
Cill!h Of 7
treaunents
ccsulletl in greatest
cwwth 011
ill
I site
least
S i te preparation
( I S)
a n d fenili:t;uiou
•l i t fcrctl a•uouu
i lc.\, H:.:. ul!.:. l:l llii(X:II
l.l y Cillegury
(58 )
c.:mupclitiou. W e i g ht : - H %,
diameter -
7% ur imerw he n only
hlw cump•.:litiou
w iudruwed ilfCil!\
••rea:>
w ilh
c.:umparcll
complclely raudomizeu. I n ten t io na l removal of surface Iiller ;u tl minc•< l soi I . ' 1 2 sites, no ceplieation w i t hi n s i t e . •
RCO. = randomized comple1e block, CRD
=
'-.>.>
Evidence for lon g -rerm productivity
standin g vo lume at age 3 1 of P. raeda planted o n
a
changes
site thnt had been w in d ro w e d
was 267 mJ/ha. compared co 345 m.lfha. o n an adjac:!nt si le that had been burned
p ri or co pla.ming. Ar. index age 25. height of dominant and co-dominant P. raedc
planted in imerwindrow li'e:J.s of tile windrowed sice was 3 .3 m less than height o r
trees near windrows or planted o n the djacent burned s i te (a 1 4% reducti o n ) . S terr
analyses of t"e lled trees i nd i c:J. led heights of trees plan ted in burned-only
anc
windrowed s i tes \Vere s i m ilar until about :1ge 7. After age 7. h e i g h t g ro w th wa:
less
in w i nd rowed Jie:J.s than in the burned-o n l y m!:J.s.
One re:1son for the :!:lily g ro w th advant=:ge o ften associ:ued w i th w i n d ro wi n
is im proved c o m 9'! ti t i o n contro l . [n the previous l y desc ribe d study b y Al len
e r a.
( 1 8 1 . only on chop-and-burn p l o ts w here competition di fferences w e re m i n im i ze:..
by herbicide applic:J.tion did hei g h t gro w th equal o r exc eed gro wth on wi n d ro we
plots after age 6. O n non-herbicided 9 lo ts . height gro wth rem ained gre:J.cer :
I
r
I·
•.vindrowed plot'i through :1ge 8. ?ualkl resul ts h ave b<:en re;:orted b y D yck
<It c:
(58], (Tabie 3 . S). Ac l o c a ti o n s when:! h<::lvy wed com petition existed. trees in no r
w i nd row e d or burned Jie:s grew ac similar races •h rou gh age 9 . A t [oc:tions whc
weed co m peti d on was low.
l
ul
1,4 .
l.l
-
t.O
<:l
a.a
a
a.s
!::
0
-
g row th w:J.s I owa i n wi ndro wed piots.
'
Chop/no
)'aetb,C:id•
•C•nd
a.•
Age
(years)
· FIGURE 3.2: Annual h e i gh t growth of dominant trees durin g the previom:
rotation and nrst 8 years o f c urre n t rotation following four site prepaiation-w·
contro l treacmenrs in the North Caro lina P iedm on t (after [1 8)).
65
Slash disposal
TAB LE J.S Gcowtll o( 8.5·ycar-old Pinus radiOJa in windrowed :tnd burned plotS \'Crsus in non-prepared plotS. · an wi tll di ffe ren t levels (open, partial, heavy) oi competing vc:gc!;ltion (source: (58]). Hcighl·
Diameter'"
Stc:m Volume•
(m )
(em)
(m lfU'ce)
3 .3 '
3.6'0
3.0
1 4 .6'
1 3 . 3"' .C66' .05i'
9.6'
l 5.i'
1 3.9°
1 2.5'
.032'
.OSP
JWJ'
Windrowed and burned:
Open
Partial
Hc.a,·y
Non·preparetl:
.
O pen
.
Pmial
9 .::.•
S.i"
Hc:J''Y
Dissim i l:!r u pcr.;cripts
\l·ieSl.
a= 0 l ).
We
o nc l u d e fiOm
c
p
-•.J
J,
·ithin a column indic:He signific::nt tliffcrcnccs among trC.1lmCntS
Jvai l J b l e Reid trials and
rctrospct:tive rcsc:uch th:lt !o n g <c!111
9roducti v i ty is freq uen t l y deleteriously affected b y
:1s .,,.indro w i n g but
.
m chnn
e
-
ic:ll s l ash
re m o v al such
not b y chopping or other opcr:Hions that !ea\'c the majori ty
or"
slash in p l ace.
Prod u c ti vi ty
C h a n ge Fol l o wi ng Sl ash B u rn i n g
Most s t u d ies
have
after harvest
versus
ences i n
n o t fo u n d consiste n t d i fferences i n
th ose that were noc
burned [/0,
growth on areas burned 7 1 J . Mo re o ver e:uly differ­
,
tre e growth be twee n b u rned and nonb urned plots are fre q ue n tl y n o t measurements (70).
subsLmtiared by l ater
A s with results from most mechanical slash removal studies, results from slash bu rn i n g studies are normally confounded : f. · ?Y differences in· vegetation regrowth and seedling escablishment. Slash burning . - · educe to cal "soil nutrients while incre:J.sing their availability. Slash burning
Jf iso i ncreases vegetation competition in some pl ac es yet decreases it in others. It
��1i·:.; is difficult to isolate these effec r.s wi tho u t a veget.3.tion-controi treatment. This i s
iJ!.: "" ':, . :;,
L tru e of older s tud ies s uch as the Morris plor.s
eval uated by Mille r and B i g!ey
: ji·,:
.
.
. & ,• •
I
t
•'
•
tl.;f,·- .
.
.
[72)
(j7 I]. These matched plots were established 1 946 through 1 95 1 to measure sl
:i. burn i g effects ti re hazard and natural regeneration. The plot-pairs we re
in
·
· ;;: ·- .
..
n
on
&i:. r.ep licated at any of
:. me plot
'-:-: ·
pairs
as h
no t
locations in western Washington and O regon, USA.
regenerated n atu rall y ; other pairs were planted. B urning had
.
the
44
66
Ew'dence for fong-rernt productivity chang es
several effectS o n s u b sequent stands. B y reducing numbers o f adv anc e regenern.­
don. nre shifted SP<!C!es composition away from shade-tolerant conifers. Slash
burning
nhanc::d regeneration o f P. mem;iesii, primarily be::::tuse more mi nera i
soi l was exposed for seeding. When si te index of - :nem:iesii or vol ume pro duc ­
tion of all spec ies were used
evidence to genl!ralize
a
lS
measures of site 9roductivity, there was no
productivity dedine. S iashbumi ng apparently decre::1sed
sund productivity J.t some loc:I.tions. buc incre:::sed it lt others. This rese:u-ch is of
;Jartic:..I! ar i n terest be::::tuse it re tJrescn ts the tong'!st :.nd most widely disuib u ted
data. b:J.se o f i ts kind. N
verthe!ess.
the resu its
.::e J.Inbiguous because o f the
severn.i confounding fn.ctors and des i g n problems .: scribed above.
SO I L P HYSI CAL C O N D rTI O N S
...l.. pm t"rom dfecr.s o n n utrien t budgl!ts. harvesti n g nd other fo res t m annge:n t! n t
a c ti vi t i es c:m h:J.ve direct a.nd indirect effects en s o i i factors lffecting si re p ro d uc ­
ti vi ty. In p a.rticu l :u-. use o f .heavy equi pm ent to iemove togs ca n te:.d co so i l
compaction 7 particularly o n the l 0-25% of the :;ite in skid trails. md co red uc ed
tree growth in some loc atio n s (6 . 65, 661 . but not :.i l
occurs, reco very c:tn occur quickly
lS
[73 ] . Where soil co m pac ti o n
reponed by
Thorud and Ftissd (74]
following harv estin g i n Mi n nesota. or can require more than 50 years as reported
by Perry (7 5 ] in North Carolina. and Grece:tn and S:.nds [76] in A us trali a . The risk
to lo n g- te rm sice p ro ductiv ity de9e n ds upon the s eed of recovery. R isks are l o w
w here c o m pac tio n is lim iced to the surface so i i md/or the J.Ineiiorating effects of
freezing and thawing, we tti n g and dryi n g, fauna. ac:ivicy, and root growth
are
large.
DeetJ compaction, pnrticul ari y when assoc i ated with degradation of so i l structure
(puddl ing) in warm clim ates with low shrink-sweil so ils, [XJSes a si gnific :mt
lon g-term risk.
A ·lELIORATIVE TREAT:V[ENTS
Reviews of res earc h o n !on g-\erm site productivity tend to focus on h arves t anc
associated management activities considered to h:ve go ten tially ne gati ve im pacts
Ameliorative rrearmerrts
h arve s t-
Several
67
and regeneration-associated practices. however, have the
po tential to improve productivity throughout the rotation and. perhaps. through
multiple rota tions.
P Fertilization a t Pla n ting
Phosphorus fertilization m ay be the best example of a management practice
long-tenn site productivity (Figure 3 . l (b)). On P -deficient
that [ mproves
ferti l i z a t i on at p l a n t in g has i m pro ved g rowth throu g h out
i nto a second rot ati o n . For inst:mce, G en tle
ec
a
si tes,
full rotation [77] and
a!. (781 re po rt P. radiara growth
res po nse to fert i l iza t i o n with two forms of . p hosp h o ru s at
age 1 6 in both the n rst
rotation and second rotation (Table 3.9). During the first rotation. hei g h t and
vo l ume accu m u lat i o n c u r,es
c h a ng e
in
site prod u c ti vity
su ggests this
trend
diverged throughout the rotation ind i c a t ive
( figure 3 . l (b)). Information presented in Tab le 3 . 9
has c on t in ued in the second rotation.
\Vh i l e P ferti l ization can
provide long-term growth responses, this i s not
always t h e c ase (e. g . , [79]). As B allard [89] points out. the g ene ral
res po n s e
to the l arge amounts o f applied P (50- l
is due
o r" a
removals i n forest harvest (5-70 kg/ha) and t he sustai ned
persi s tence of
kglha) i n comparison to
avai lab i l i ty provided b y
thi s amoun t of phosphorus.
TAU LE J.9 Re$ponsc of Pinus radiata to a single applic:1tion of phosphorus, in the rol:!tion fertilizer was applied .
and in Lhe second rowtion following fertilization (Source: (78]). Stem volwne•*
(mliha)
(m) ; t��·:-----i)il; Initial RotaJiort
; ;.;;...;:.:: ' No fertilization · -
,
Dominant tree height;.
. .
; ,;;. '=
· ;.:.)
...
.
l-\:y'".. -
· .· •
Rock phosphate
Super phosphate
·
.
0 ·
1:;>!; Se cond Rotation
:;
'"'f¥·:.:;·:.-:-•
:· · No fertilization
·
..
'
.. ·f9
- .,· ·
'·'"'
Rock ph osphate
13 .7'
:.::r;-- n:\-..
: . . Super phosoha!e
•
-------
1Jl:; ; ,;,Wilhin a rounion, dissimilar superscriptS indicate s i g nific:lJlt differences (a=.05).
To a 10 em (i.b.) diameter
1 1' :'-;
. - :;... .
-
. ...
·.
68
.
E'lidence jar long-(l!nn productivity changes
'i
.,
Liming
(C.1 additions)
fn co ntrast to w idespre:1d use of lime in agriculture. addition of CJ. and/or Mg t<
forestS is re!acive!y rare. Although so me forestS in G erm :m y were limed as eari
as
1 360. liming of forestS hns never been widespread. Wied emann ( [80]
- p. 27 c;.
ci tes several examples of growth incre:1ses of 20 to 25% during two or mar
decades after qu ick l ime (ClO) or limestone (CaCO) was add ed to es mb l i s h e :
stands of po le - si zed trees with he vy accu muJ ::u i o n o f fo rest Roar (raw humus
B aule and Fricker ( [8 1 1 - p
56) concluded: "In the fores t l i m i ng therefore in rna:
.
cas es is conducted less with the o bject o f providing the trees w i th
a.
su pp l y
c
c =:.Jc i u m but pre ·<!minently of improving the physic:::. ! . chem ic:::.! and b iol o g i c :
pro perties of the so i l . [t is actual l y possib le to m=:.ke ac id sci is or th o se wi ch a I a · .
c a lci u m content capab le of c:uTyi n g bra.::d -leaved trees by limi n g co a su fficie:
de p th . rn the l:lSt two decades. i n terest in l i m i ng h=:.s been stim u l at ed b y rec o g r.
"
tio n of the th rea t to long-term site pro du c v i ty posed by ac:d precipi ta ti o n .
Andersson and Lundkvist
[821 rec : n tl y
summarized results from ! i m i r
exoeriments ca m o le t.ed since 1 9 1 2 in S weden, Fin l and . and Germ anv. The
.
.
.
au thors concluded that long-tenn incre::1ses in site pro d uc tivity are generai
asso c i ated with l i m in g; however. response to l i m i n g often fo llows a pane:
similar to, but the reverse o f, he p attern il lustr:lted in Figure 3 . 1 (c). In mo st c ase
growth r: ue of l im ed trees fi rst decre:J.sed in com parison to the un l i med c o n e:
an d o n l y after abo u t 4 0 years. th en in c re:l.Sed i n c o m pariso n t o the u n l im
.
co n trol. The authors specu l ated that this growth pattern m ay occur because l ir
additions stimulated microbial activity th at immobilized N nonnally av ail a b le :·
tree uptake. They also suggested . that mi cronutrient deficiencies may have be
induced by. exc essive li"m ing and that positive growth responses o nly occurr
after natural acidific:1tion c ompens ated far lime-induced deficiencies. Regardlc
of the cause. chlorosis J.nd growth retard atio n can be a sho rt- term consequence
lime add itio n on m an y forest sites.
'
;
..
.
n:
f· ·
1:
(
;· ·
ij
I
I
Comparable long-tenn results are not generally availab le outside Eurac
Although lim i ng has often been included in programs desi g ned to evaluate for
fertiliz:J.tion. few programs have carried liming trials for extended periods of ti.
becaus e i ni tial results were not encouraging. For i n stanc e, CJ. add i tions w
included as part of the original ferti l izatio n trials i n slash pi n e i n the southeasc::
Conclusions
69
U.S. but were not included in subsequent rese:rrch becnuse Ca additions failed to
increase tree growth [83].
Tillage
Oilier ameliorative . practices !.hat may have long-tenn benefits are bedding, disk
harro wing, or rip p ing which can improve physic:1l conditions restricting root
growth. While th e short-tenn benefits of such trea.unents are cle:rr, long-tenn
benefits are not. Many responses to tre::lunent see:n to fall into responses illustrated
in Figure 3. l (a). Trees planted after these tre:1unents achieve an e:1riy growth
advantage which c an be maintained throughout the rot::Ition, bu t !.he advantage or
response does not increase; thus, this is not a tong-term change in site productiv­
ity. Such growth responses have been reported for P. el/iouii a n d P. caeda in the
C n i ted States following bedding (6], bedding and disk harrowing [84, 35. 861, and
following bedding and subsoiling for P. radiaw i n ew Ze:1land [37].
The p:1ttern of response to such tilla.ge tre:lunents may re!:lte to !.he re:1sons
for the observed initial response. Responses may be teJ7� porary where benefits of
tillage are largely due to: I ) decreased vegetative competi tion; 2) accelerated
occupation of rooting volume without an increase in absolute rooting volume; 3)
short-term i ncreases in N mineralization; and 4) beneficial changes in thermal .
.. regimes or water infiltration and distribution. Responses appear to be long-term
: . where amelioration of soi l physical conditions which restricted total rooting
. :,..
.�� :; volume were largely responsible for initially poor growth. Thus, bedding of sandy
}i· · sites does not ap pear to have long-tenn benefits because much of the in itial
::- ·· ;
, benefit is associ'ated with ephemeral increases in nitrogen mineralization and
. o petition con trol. Responses to bedding may be long-tenn, however, on fine­
soils where bed confi guratio n is maintained throughout the rotation and
drainage improved.
.:;
CONCLUSIONS
of factors affecting forest growth is incomplete; therefore,
from carefully controlled field trials. rather !.h an models, provide more
·.understanding
70
£ ·idence jar long- ;enn praducriviry changes
convincing evidence of raduc:.ivi ty changes c:ms e d by harvestin g practices. To
be acc pmble evidence of change in lo n g te rm site 9raductivity, three cond itio n s
-
must be met. Firsr. differences i n tree growth m u s t be a ttrib u tab l e to differences
in site conditions. rather than to differences in res o urce a1loc:J.tion among targe
and non-target species or to d i fferenc es in plan t species or genotype. Second.
growth results m ust be available for
a
sufficient time so that the [nfiuence o f
eohemeral d i fferenc es i n ini ti:ll s i te conditions has d i m i n i sh ed m d s a that c:mac '
.
ity of the site to su ppo rt tree g ro w th is stressed. Fi nal l y, adeq u ate experi mc:n tai
cancra ! must ex ist S h i fts i n reso urc e al loc:.tian will :1\:Jpe:lr as an earl y i nc rease ir.
.
tree growth. Th i s i nc :-e:1se i s maintained after cro w n c l o s ure but further gro w tl
.
i m pro vemen ts are nat e vide n t . Hence this pa t te rn of growth res po nse do e s n o
in d i c a te
l
change in lang-\eml si te productivi ty. F':!w studies m e t ad quate
ex pe rimental re q u i re m e nts and none have b ee n c:.rri cd long enough to providt
[eng-term res u l t s
iI
.
Regn.rdless of study purpose. m i n i m u m requ i rements fc
ac c ep tanc e are: l ) app ro p ria te conu·ol plots ag::.i n st v h ich treauncm di fference:
I
'
I
..
II·
·
.· ; .
c:m
b e evaluated: and 2) filcmrs oth e r than tre:J.unents
have b
n m i n i m i ze d
c
me:IS ured co account for their influence o n observed di fferences in growth.
Issues o f spec i e s chan ge an d second-rotation d ec l i n e l!"e not e a s i l y disen t.an
gled from . as so ci a ted q ues ti o n s on harvest util ization, slash disposo.l . and so:
tillage. D e s p i t e l ac k of evide n ce to sup o rt the concept that n p l ac i n g m ixc
vegetation with conifers decreases sile productivity, same au thors continue :
accept speci es - in d uc ed declines in productivity as f.:rc t. We con c l ud e chat curre:­
evidence does na t indic:ue such declines occur o r, if they do occur, are pro b ab i
not rel ated sim ply t o establishment of conifers and their conti nued managemer.
In contrast. evidence from field trials cle:lfly s hows th a t addition of nitroge:­
tixin g tree species to stands an N-deficient sites i n c :-e :l.S e s site productivity. Henc
removing such beneficial species co ul d reduce lang-term productivity.
Concerns about forest harvest o n [a n g tenn productivi ty s ho u l d no t be surr.
-
marily dismissed. Direct remav<Ii and indirec t loss
of es sen ti al plan t nutrients wi
occur i n forests managed for wood and fiber p roduc tio n Without replilc em en c c
.
natural saurc s or by fertilization, p roductivity co u l d decLine. Although n trie:­
balance analyses pro vi d e indirect evidence far projectin g declines in long-te::­
sice productivity in m anaged forests. direct evidence of tree growth rarely sho\
·
Urerarure cited
.
suc h d e cl i nes Most field trials pro vi d e we:J.k
71
vidence for prod uctivity dec l i ne s
that m ay be required to induce productivi ty decline. Apan
after i ncreased harvest uti l i zation because of poor study d esi g n and beca u se a
n u m b e r of rotations
from their effects on nutrient bud gets, slash disposal and site preparation h ave
n um e ro us direct and i n d irec t inn ue nces on soil ph ys i c a l and chemic al p rope rti e s
Virtu al l y
I av ai l :.1 b le
r
data from ca e fu l l y d esig n e d
.
field ex peri me n ts show that
survival and early growth of plamed seed l i n gs is gre:uest o n si tes w here biomas s
remo vals were greatest and where organic Jnd m i neral so i l hori zons were most
se ve re l y d isturbed during mechanic::ll slash d is pos a l . One reason fo r th e e:trl y
gro w th ad vantage o ften associated w i t h wi n d row i n g i s i m p rove d c o m peti t io n
contro l . \Ve
-
c oncLu de from
J va i l a b le
field trials Jnd retrospective rese:trc h th:u
lo n g te rm produ c t i vity i s frequen t l y d e let e rio u sl y affected by mechan ic:J.I s l as h
removal . fn contrJst. most stud ies ha,·e no t fo und consistent d i ffere n c es i n growth
on Jiea s b umed after h :trve.st
'
\ c rs us
those that were not b urned . As w i th re s u l t s
fro m m o s t mec h an ic a l s l as h removJ I , e ffe cts on so i l pro perties are norm :1i l y
confounded by d i ffere n ces i n \'cgetative regrowth and s edl i n g esta b l i s h m ent.
.
.
Native soil prod ucti v i ty can be i mpro ved O n P-delicient s i t es ferti l i zation a t
p l an ti n g can i m prove growth throug ho u t a fu l l ro ta tion a n d i n to a sec on d ro tatio n .
-
Other am e l i o ra t i ve practices th :lt ca n h ave lo ng te rm b e n e fi ts l!'e bedd i n g , d i sk
h arro w i n g , or ri p p i n g w h ich can im p ro ve phy sical conditions re stri c ti n
:. _- .
growth. While the shott-term bene fi ts of such trea tmen t s to tre e growth are c!e:1r,
v.
o n g- te rm benefi ts are less evide n t
£\ . .The cumulative
{¥£. rem ain
an t d .
.
effec ts of repe:Hed harvests and stand
;"".:.0"4
:;
root
g
u nq u
._Data.
i fi '
regeneration practices
a
E ffectively d e si gn ed arid implemented fie ld trials over a
r_¥1ge of soi l and climatic conditions are needed to pro vide re l i ab le qu ntific atio n :
'
·... ..
from such trials are ne ed ed to provid e independent v al i d at ion of c omputer
-;... :-'!'t ,' · '
and our understanding of factors affec tin g tree and stand perform ance
·
.
: :::.: · · ·.
·''
.,
r-.... .P astor
Si.
...
-
.
·· tilffl.
..
#
...
LITERATURE CITED
Post. W. 1.
.
, J. a nd
Devel? pment of a l inked fo es t productivi y- soil
, p rocess m odel. Oak Rrd e Nauonal Laboratol)', Enviro nmental S c ren ces
·: · · Divisio n Pu b l ic a tio n No.
p.
·
.;
- -:�:-..···
.
g
2455, 1 985, 1 62
•
£ ·idence for lang-terrn produc:ivicy changes
, .,
_ Kimmins. J.P. Co mmuni ty orgnniza.tion : methods of study and p redic ti o n
of the productivity and yie!d of forest ecosys tems . Canadian. Journal c
Botany. 1 983. 66, 2654-2672.
Reed. D.D Ho !m s. M.J Jones E.A Liechty, H.O and Mroz. G.D. ,:l
ecologic:ll growth mo dei for four northern hardwood species in upp<
Michigan. fn: Process Modeling oj Forese Growth Responses
£nt•ironmemal Stress. (Eds.) R.K. Dixon. R.S. Meidahl . G.A. Ruark, ar
W.G. Warre n. Timber Press . Ponlnnd. 1 990. pp. 288-293 .
.•
4. .•
.•
.•
Wdnstein. D .A. and B do in . R. E·,alu:uing e ffects of pollutants o n incegrnc,
ere:: process.::s :
l
m odel of c:ubon. water, a.nd nuuient baln.nces. fn: Proce
:\4o deling of Forest Ctowrll Responses ro E:tviromnenwl Stress. (Eds. ) R . .
D ixon. R.S. fc!dnhl. G.A. Ru:1rk. lnd W.G. Warre n. Ti mber Press. Ponlnr.
USA. ! 990. pp. 3 1 3-323 .
5.
.
6. ..'
7. \Visiol. K . J.nd Hl!ske!h, J.D. ( Eds.). P!am Cmwrft Modeling for F?esow
Jfamzgemem. CRC Press . B oc: R:ton. FL USA. l 987 .
Hughes. J.H., C.:rnpbe! l. R.C.. Duzln. H . W
. •
m d Dudley. C.S. S i ce int.
adjusunents for intensive forest managemen t treatments at Nonh C.1rol i
Weyerhn.euser Forest Rese:I.rch Tech ni c :l Report 042· l -+04n9124, l 979 .
Mead. D .J .. Whyte, A.G.D., Woo l lens. R.C.. and B ee ts , P.N. Desi gning l o :
tenn ex peri men ts t o study harves ting im pacts. In: Long·lerm Field TriaL
Assess Em·iromnental fmpacrs of Harvesting. Proceedings . IEA/13 E T6.
Workshop, Feb . 1 990, Fiorida, USA. (Eds.) W.J. Dyck and C.A. Mees. l'
Zealand Forest .Rese:I.rch Institute B ulletin 1 6 1 . 1 99 1 . pp. 1 07 · 1 24 .
8. Likens. G.E B ormnnn. F.H Johnson, N .M Fisher. D.W and Pierce, :=
Effects of forest cu tting and herbicide treaunent on n u trie n t budge in
Hubbard B rook watershed-ecosystem. EcologicaL Monographs, 1 970.
.•
.•
.•
.•
23-47.
9. Dye
WJ. and Mees, C.A. (Eds.). Long- Term Field Trials to Assess En vi
mental fmpac:s of Harvesri11g. P roceedings. IE.o.\JB E T6/A6 \Yorks
February 1 990, f1o rida. US A. New Ze:rland Forest Rese:rrc h fnst:
B ulletin 1 6 1 . 1 99 1 . ·
10. Ovin gton, J.D. Smdies of the development of woodla,n'd co nd i tio ns u
different trees. Journal of Ecology, 1953. 111. 12-34.
1 1 . Keeves. A. S ome evidence of loss of productivity with successive ro t:.
of Pinus radiata in the south·clSt of South Australia. Australian For,
1 966. 30, 5 1 -63.
:¥::'
· - ·­
Literature cited
73
B e:dn al l , 8 .H. The p robl e m of lower vo l umes associated w i th second rota­
tions i n Pinus radiara plan tations in Soulh Austral i a. Woods and Forest Dept,
S o u th Austral i a, B ul le tin 17. 1 968.
1 2. 1 3 . W hyte. A . G. D . Productivity o ( first J.nd second crops o f Pinus radiata on the
Mou tere s o i l s of Ne l so n . New Zealand Journal of Forestry. 1 97 3 , 1 8,
37- 1 03 .
14. E v an s . I. Two rotations of Pinus patula in th e Usutu fo rest. S w aziland.
Commo1twealrh Foresrry Review,
1 975,
54 . 64-8 1 .
15. Evans. J. A fu rth e r report on second ro tation prod uctivity i n the Usu t u Forest.
·
:
- res u l ts of the 1 977
Re view. 1973. 57, 253 - 26 1 .
S w azi i::J.nd
reJssessment. Commomvealth Foresrrv
'
1 6 . S q u i re . R. O . . Farre l l . P.W.. Fl inn. D . W.. and
.4.cbcrl i . B . C. Prod uctivity o f
R rs t Jnd second ro tation st.:lnds o f radiata p i ne o n san d y so i l s . A ustralian
Forestry. 1 9 8 5 .
S. 1 17 - 1 3 7 .
1 7 . C e ! l i er. K . i> L B o ard m a n . R . . Boomsma. D . B . . Jnd Zed. P.G . R es ponse o f
Pinus radiara D . D o n t o various s i l v icu ! t u r.:l l o n J dj J c e n t fi rst-and sec o n d ­
notation si tes near Tan tanoo !a. Soulh Austr:J. I i J . I . esta b l i s hment and gro w th
up to age
7 years. A usrraliart Forese Research. 1 9 85, 1 5 . 43 1 -447 .
1 8 . A l l e n . H.L.. Morri s . L.A . . and Wentworth. T.R. Producti v i ty
c o m pariso n s
between successive loblo l l y pi ne rotations i n the orth Caro l i n a P i edmonc.
In: Long- te'nn Field Trials to Assess Environme1llal Impacts of Harvesting.
P roceedings , IENB E
·�.-. · 1 9 .
-
-
·�:.
::
::Y..l-· · •· 1 0.
·
-'ff:-z:ii.. "".:'- ·
T6/A6
Workshop, Feb . 1 990, Flori d a, US A . (Eds.)
W.J. D yc k and C.A. Mees. New Zealand Forest Research Insti tu te B u l leti n
1 6 1 , 199 1 , p p . 1 25- 1 3 6.
S heppard,
·
K.R. Planratiolt Silviculture.
Martin us Nij h o ff, Dordrecht,
1986.
Miller, R.E. and Murray, M.D. The effects of red alder on grow th of Dou gl as -
.
fir. In : Utilization and management of alder. (Com p . ) D . G. B riggs, D . S .
USDA Fores t Servi c e G eneral Technical Reoort
..
P NW-70. Paci fic Nonhwest Forest and Range Experi me n t S tation, Portland,
·
?'1§.
1:
.
:
:
.
.
":'.. -.
... .. . .. .
. - n - O re go n , 1 97 8 , pp. 283-306.
.
•:.r.
DeBell, and
W.A . A tki nso n
.
1,:; �;:;�:JI:E�a;1��;��f'*11���:� f
- · ·(· .
r m·::-...
22 ,...,.·..·
fi·;·
!!;-:;··
· ··· · .
00 : - -· "2 ,
Mil ler, R.E. ·and Tamm t, R.F. Lo n g- terrn grow th respo nse of Dougl as-fir to
am monium- n i trate ferti l i zer. Forest Science, 1 9 8 3 , 9. 1 27- p7.
&·idence for fong rernt producriviry changes
74 8 inkiey, D. Mixtures of nitrogen ·nxing and non-nitrogen..,·fixing tree
species. fn: The Ecology oj Mixed-species stands of rrees. (Eds.) M.G.R. C.l!l ne!l er a/. Special P ub i ic :u ion No. 1 ·1 , British Ecological Society Oxford. B l ackwell Scientific Public:uions. Landon, 1 9 92 pp. 99- 1 23 .
?"'
_.,j ,
.
DeB dl, D.S Whitesell, C.D and Schubert. T.H. Using N ·fixing Albizia co
inc:e:LSe growth of Eucaiypws plantations in Hawaii. Forest Science, 1 98 9 . 24.
.•
35,
.• -75.
25.
K.r:1use. H.H Weeunan, G.F . and Arp. P.A. Nuuient cyc l i n g· in boreai
forest ecosystems of Nonh . meric:J. [n: Forese Soiis am/ Land Uu .
P:-oci! dings. Fi fth North . meric:m Forest Soils Conference. Fort C o l l i ns . CO. A ug. t 973. ( Ed.) C.T. Yo ungberg. Colomdo S tate Univ. Press. For: C a i l ins. 1 979. pp. 287-3 1 9 . 26.
R.:lston. C.W. \1 i neral c;·cl i n g in tem peru.te t'orest ecosystems. fn: Fo re: : So lis and L..1nd Use. Proc.:::! dings. Fifth North Americ:J.n Forest S o i h :
Conference. Fort Co l l i n s . Co iorJdo. A ugust 1 978. (Ed.) C.T. You n g berg CJiorado S tate Univ. Press, Fort C o l l i n s 1 979, pp. 3 20- Jo..i O .
.•
.
.
i .
27 . Co le. D.W. and Johnson. D . W. M ineral cyci ing in tropic:! t"orestS.
I
I
lI
.
!·
' . ..
fn: Fares
G
·
Soiis alld umd Use. Proceedi ngs. Fi fth ;-;ro rth Ame:ic:m Forest S o i l
Conference, Fan: C o l l i ns. Colo.. August 1 97 8 . (Ed.) C .T. Yo un g be rg
Colorado S tate Un iversity Press. Fan: Co l l i
n s 1 979, pp. 34 1 3 56 .
j
28 .
:
.
.
Duvi gneaud, P. and Oen:leyer OcS met S . B iologicJ! c yc l i n g of m i nerals i r
te:nperate deciduous forests. In : A n alys is of Temperare Forest Ecosystem:
(Ed.) D .E. Reichle. Springer- Verlng, New York. 1 970. pp. 1 99-225 .
29 .
Gal ley, F.B McGin nis. J.T C l e men ts , R.G Ch i l d G.L. and Ouever. L ·
MineraL Cycl in g in a TropicaL Moisr Faresr Ecosysiem. Un iversity o.
.
Geo rgi a Press, ALhens, 1 97 5, 243 p.
30.
Weeunan. G.F. and Webber, B. The influence of wood harvesting o n
nutrient status of two spruce stands; Ca11adian Journal of Foresr Research
1 972, 2. 35 1 -369 .
3L
32.
.•
.•
.•
,
th·
.
.
Foster, N.W. and Morrison. LK. D istribution and cycling of nutrients in natural Pinus bartbiana ecosystem. Ecology, 1 976, 5i, 1 1 0- 1 20.
Green. D.C. and G1igal, D .F. Nutrient accumulations in jack pine sr.ands o
deep and sh a l low soils over bed roc k Foresr Science. 1 9 80, 26, 25-33 3 . .
33.
O vi n g ton J.D . Qu<J.ntitative eco logy and the woodland ecosystem co nce::
Advances in EcologicaL Research. 1 9 62. 1, 1 03- 1 92.
.
75
Literarure cited
34. 8 urger, J.A. The effects o f harvest and site prepar:ltion o n the nutrient
budget of m i ntens i ve ly managed sou thern pine forest. P h . D . Dissertation,
University of Florida. Univ. Microfilms. Ann Arbor. Mich. (D iss. Abstr.
40: 4047B ), 1 979, 1 84 p.
35. C o l e , D . W.. Gessel, S .P., and D i c e, S.F. D istribution and cyc l i n g o f n i trogen,
phosphorus, potassium, and c:J.Jcium i n a second growth Douglas-fir eco­
s y stem . fn: Proceedings, Symposium 011 P r im ary Pro duc riv iry and Minerai
Cycling in NaturaL Ecosystems. (Ed.) H.E. Young. University of Main e
Press. Orono, 1 967, pp. 1 97-232.
36.
G reen land. D.J and Kowal. L\.f.L. Nutrienc c on t en t of the moist t..ro pi c :J. l
fo rests o f G hann. ?/am and Soil, t 9 60 . 1 2 . 1 5-+- 1 73 .
3 7.
1-tmsen . E. H . .1nd B o.ker, J . B . B io m o.ss and nutrient removal in shan: ro t:J.ti o n
i n te n s i v e l y c u l tured p l <in t t i o n s . [ n : Proceedings, Sym po s ium 011 fmpacr of
fll lensive Han!esring 011 Fo rest Nwrient C.rc/ing, S yr::1c u se. N Y. I J - 1 6
A u gust I 9 7 9 . Nonheastern Forese E.x peri m e n t S ta ti o n . B room al l . P N , 1 97 9 .
p p . 1 30- I 5 1 .
.•
3 3 . M o 1Ti so n . T. K . and Fost e r, N . \V. B i o m as s and c l e m e nt rem o v a l by com ple: ­
tree h arves ting o f m e d i u m rot:llion stJnds . f n : Proceedings. Symposium on
of flllensive Han,esring 011 Forest Nwrienr Cycling. S yrac u s e. N Y,
August 1 979. US D A NE Fo re s t Ex periment S tation. B roomal l . P N , 1 979,
pp. 98- 1 1 0.
fmpact
39.
·
:�,. : 40.
:li ;'
h ::
.”.
?-.·fa.rian , G .M. B i o m as s and nutrient removal i n lo ng rotation s tands . fn:
Proceedings, Symposium o n Impact of Intensive Ha rves tin g 011 Forest
Nutrient Cycling, S yrac u s e , NY, 1 3- 1 6 A u g u st 1 979. US D A No rtheastern
Forest Ex peri m en t S tation, B roomall, P N , 1 97 9 , pp. 98 1 1 0.
Kimmins, J.P. E v alu a t i on of the consequences for fucure tree productivity o f
the loss o f nutrients i n whole-tree harvesting. Forest Ecology and .lvfanagement, 1 977, 1 , 1 6 9- 1 83 .
;:>+ t-:: Man n , L.K. and o th ers (numerous). EffectS o f w ho le -!iee and s te m- on ly
e,. :'. : c learcutting on post harvest hydrologic losses, nutrient capi tal and regrowth .
"Y.r Forest Science , 1 988, 34, 4 1 2-428.
!
.
: f.:;). .
.
i{l42·.-.i ; Silkwonh, D.R. and Grigal ,
t i .'::.::.
D.F. D ete nn ini n g an d ev al u a ti n g nutrien t losses
harvesting of aspen. Soil Science Sociery of America
' Jo urnaL, 1 982, 46, 6 26-63 1 .
"t,;J-:: i:. . following w h o le - tree
It
!!
.....
;.
-;::. .
- .
·
£ ·r'dence jor long·£erm producriviry changes
i6 43 . Johnson. O .W. and Todd. O.E. Nutrient export by !e:1ching and whole-tree
harvesting i n a loblolly pin and m i xed oak forest. P!anc and Sail, l 987, 102,
.
99- 1 09 .
44 Miller. R.E Hazard. J. W.. B ig ley, R..5 and MJx. T.A. Some results and
design considerations from J. long-\erm study of slash burning effects. [n:
Research. Strategies for Long-ienn Sire Producriviry. Proceedings. lEA/B E
A3 Wo rks hop , S<!:mle. WA. August 1 988. ( Eds . ) W.J. O yck and C.A. Mee s .
l:E..vB E A3 Rt!port 8. New Zl!:lland Forest Rt!se:l!c fns titute S ui !etin 152,
.•
.•
1 989. pp. 63-78.
;!5. Wells. C.G. . Jo rge n se n. LR., lnd B urnette. C ..S. B iomass and minerll
elementS in J th i nned labially p i ne pi;mtJtion :lt ag'! 1 6. USDA Forest
.
.
a
ervtcl! .R ese:l!C:l
c-:1per S.c. · tt "" 6 l a.- 1 :;- , l 0 p.
•
46 .
Koch. P. A conc pt for sou them pine p ! am :uions o pera t i on i n the ye:u- 2020.
· [n: Forest P!aJttations · the Shape of the F!IWtl!. ?:-oc!:dings, Weyer hJeu ser
S c ie nc e S y m pos i u m No. l . T comJ. WA, 1 980. ?P· 69 -85.
-+7 . Lundkvist. H. Ecologicll effectS o f whole: tree h ar: es ti ng · some resul tS fro m
S wedish fi d d xperimencs. In: Predic:ing consequences oj fmensive FtJresr
Harvesting VII umg-ienn Produczivicy by site c!assiftcarion. (Eds.) T..M.
Williams and C.A. G resh:l!11 . IE.<VB E P:aject A .3 . Report 6. B aruch Forest
Science fnsti tute, Clemson Universi ty, G eo rge to w n . SC, USA, 1 988, pp.
1 3 1 - 1 40.
4 8 . Co m pton , J.E. and C o l e , D.W. Im pnct o f harvest intensity o f growth and
nutrition of successive ro Lltions o f D o u glas- fi r. I n : Lo11g·c·enn Field Trials to
Assess Environmental !m pacrs of Harvesrin g . Proceedin gs, IE.\/B E T6/A6
Workshop, Feb. 1 990. f1orid:1, USA. (Eds.) W.J. Oyck and C.A. Mees. New
Zealand Forest Rese:l!ch Institute 8 ul letin 1 6 1 , 1 99 1 . pp. 1 5 1- 1 6 1 .
49. WHii:l!11 s . T.M.. Aim. A.A., and Mace, A. C. I r. Fi fteen - ye :u- jack pine growth
on fu!l-:.ree h arves ti n g experiments in Northe:J.stern M innesota. In: Research.
Strategies for Lang-ienn Site Productiviry. Proceedings, IEAJB E . A3
Workshop, Seattle, WA. August 1 983. (Eds.) W.J. Oyck and C.A·. Mees
IEAJB E A3 Report 8. New Zealand Forest Rese:l!ch [nstitute Bulletin 1 52.
1989, pp. 1 1 1- 121.
50.
'•
Tew, D .T Morris. L.A. , Al le n , H.L., and Weils. C.G. Estimates of nutrient
removal . displacement and loss resulting from harvest and site preparation
of a Pinus raeda pl an tation in the P i ed mont of Nonh Caro lina. Forest
Ecology and Man.agemenr, 1 9 86, 15, 257-267.
.•
II
Lirerarure ciretl
52.
77
Cole, D . W. I m pac t of w hole-tree h arv esti ng and residue removal on
productivity and nuuient loss fro m seJec:ed soils of the Pacific Northwest.
Co l l e g e of Forest Resources, University of Wash i n g to n , Report AR- l O,
Seattle, WA, 1 98 8 , 1 2 p.
53.
B i gger, C.?vf. and Co le, 0 . \V. E ffec ts of harvest intensity on nuuient losses
and t"ucure productiv ity in high and low prod uctivity red alder and Doug l a s ­
nr stands. fn: Proceedings. Symposium 011 Foresr Sire and Continuous
Producriviry. USDA Forest Ser�ice General Technical Report PNW- t 6 3 .
1 983, pp. 1 67- 1 87.
54.
We b b er, 8 .
Potenti al increases i n nutrient requiremen ts of Pinus radiara
under i n tensi fied m a n agemen c. New
Zealand JoumaL of Forestry Science,
.
1 97 8 , 3 . 1 46 - ! 59 .
3 al l ard. R. r:: :·fect of s l ash and so i l removal on the productivity of second
ro tation r:1d i a tJ p i n e on a p u m i c e soi l . New Zealand JournaL of Foresrry
55 .
Science. 1 97 8 . S. 24 3 - 25 8 .
Mo rri s . L.A . . Pri tchetr. W. L., and S w inde!. B .F. D i s p l acement o r' n u u·ie n t s
i n to wi ndrows d u ti n g site preparation o f a pine flatwoods forest. So il Science
Sociery ofA merica Joumal. 1 98 3 , 1 7 , 59 1 -594 .
56.
57. · Turvey, N . D .
and C am e ro n, J.N. S i te preparation for a second rotation o f
radi:lt.a pine: so i l fo l iage c he m i stry and cifect on tree growth. A usrralia11
Foresr Research, 1 98 6 , 1 6, : 9- 1 9 .
:·
.
58 .
·fees, C.A., and Comerford, N . B . M edi u m - te rm effects o f
mechanical s i te p re p ara tion o n radia.t.a pine productivity i n New Zealand - a
retro s pective approac h . In: Research Strateg ies for Long- renn Sire
P roducriviry. Proceedings, lEA/B E AJ Worksho p, Se attl e , WA, A u g u s t
1 9 8 8 . (Eds.) W.J. Dyck and C.A. Mees. IE.� E AJ Report 3. New Zealand
Forest Rese:Jich Institute B u ll e ti n 1 5 2, 1 989, pp. 79-92.
D yck, W.J . .
. .
: : ·.Wilhite, L.P. and McKee, W.H. Jr. S i te preparation and phosphorus applica­
tion alter e;:u-l y gro w t h of lo b lo l ly pine. Southern Journal of Applied
Forestry, 1 98 5 , 9 , 1 03 - 1 0 9 .
ri::· Sari gumba, T.I. and A n d e rso n , G.A. Response of slash pine to differen t
.. sp ac i ngs and site-preparatio n tre:J.tmen ts . Southern Journal of Applied
!:
fo restry , 1 97 9 ,
3, 9 1 -94.
Kimm i ns, J.P. and Fell er, M.C. Effe c t of cle:Jicuttin g and bro adcast slash­
burning on nutrient budgets, streamwater chemistry and productivity in
.
c\•idetrce for fong-remr produc:ivicy changes
i8
Wes,em C.mada. fn: Proceedings. Div. L. XVI rUFRO WorLd Cungress.
1 976. pp. 1 86- 1 97 .
62.
ZJ.vitkavski. J. a n d N'ewton , M . E::ologic:ll imporunce o f snowbush
C onotltus vefurinus in the Oregon CJSc:des. Ecoiogy, 1 963, 49, I I J 4- l l 45. 63 .
We!Is. C.G. l!ld :(orris, L..-\. 1ai n ten:mce md im provement of soil
productivi ty. p. 306-3 1 3 . fn: Proceedings. Symposium Oil rite Lobioily Pine Ecosy-stem, De::e:nber 1 982. N.C. S c.ace Universi ty, Raleigh. NC. US. . 1 98 3 , pp. 306-3 1 8 . .
65.
HJ.tciie!I, G .E .. RJ.ls•on. G. W lnd FoiL R .R. Soil dismrb::mces in :eggin g.
JournaL of ForesrT)', i 970. 63. 772-775.
.•
J
-�
Hel m s . J.A . .1nci Hipki n . C. EffectS o f $C ii cam pac ion o n tree vo l:.:me in l
CJ.l i fcm i a ponderosJ. pine pl:mtation . We.m!m Journal oj.ipplied ,='.'J resn·y.
1986. 1. [ 2 1 - 1 24 .
66.
Froeh iich. H. -'-. .. Mi ies. D . W.R . . and Robbins. R . W. Growth of ;o t:n g Pinus
co n to rta on comp c:ed saiis in C:!:1tral W:.shington.
.
ponderosa and Pinus
Forest Ecology and Management.
·
67.
Clayton, J.L. . Kellogg. G . , an d Forrester. N . S o i i disturbance-:.ree growth
relations in central [dJ.ho c!earc:JtS. US DA Forest Service Rese:uc Nate
rNT- 3 i 2, 1 98 7 . 6 p.
63.
B urger. J.A. and Kluender, R.A. Site preparation - Piedmon c. In: Symposium on rlre Loblolly P ine Ecos:ysrem (Ease Regfon). (Eds. ) R.C. Kell ison and S.A. : 0
:f
1 986. 15. 235-294.
Gingricle. USD A Forest Service a n d Nonh Caro lina S c.a te Cniversi ty,
t
Raleigh. N.C., USA. 1 982, pp. 58-74. 69.
Fox, T.R., Morris. L.A., and Maimone, .A. Windrowing reduces growth in a lobloily pine plan tation in the Nonh C.l!'o lina P edmonc. In: Prcceedings
. Fifth B iennial S outhern S ilvicultural Rese:Jich Conferenc::, 1 -3 1\av. 1 988. Mem phis, TN . USA. (Camp.) J.H. Miiler. USDA Forest Service General Technical Report 50-74, 1989, pp. 1 33- i 3 9 . .
70.
Curran. M.P. and B allard. T.M. Some siashburning effectS on soil md
tree Productiviry oj Fo resr Soils, P':aceedings
of the 7th Nonh American Forest Soils Conference. (Eds.) S.P. Gessel er al. in B ri tish Columbia. In: Sustained
·
University of B ritish Columbia, Faculty of Forestry Public:nion, Vmcouver. B .C.. CJnada. 1 990, pp. 355-3 6 1 . 79
Literature cited
71.
fil ler, R.E. and B i g ley, R.E. Effects of burrting Douglas fir l oggin g s l ash o n
5tand develo men t and sice productivity. In: Sustained Productiviry oj Foresr
Soils, Proceed ings of the 7th North Americ:m Forest Soils Conference.
(Eds . ) S . P. Gessel er af. University of B ri tish Columb i a, Fac ulty of Forestry
P u b lication, Vancouver, B C, Canad a , 1 990, pp. 362·376.
·
\'fa rris, W G . fn ftuence of slash burning on regenerJ don. other plant c o ver
and !ire haz::trd in the Dougl:ls fir region . USDA Forest Service Rese:lich
P ::1 pe r 2 9 . P ci ii c Northwest Forest and Range Experimen t S tation, Portland,
OR, USA. 1 958.
-,.,
I -· .
.
73. \f i l ler, R.E. . S te i n , W.I.. Heni nger, R.L.. Scott, W . Little, S ., Jnd Goheen .
D . Mai n ta i n i n g Jnd im proving sice produc\ivity in the Douglas nr regio n . In:
:Yfainwining the LoHg Tt!mt Productivity of rhe Pacific No rrhwesr Forest
Ecos;:srems. (Eds.) 0 . .-\ . P rry er a/. Proceed i n g s , S y m posium. 1 987 . Timber
? res s . Portbn d . O regon USA. 1 987, pp. 98 t J 6 .
.
Frissel , S . S . Time chan ges i n so i i density fo l l o w i n g
c o m pa c t i o n under J n o:k forest. t-.·t inneso t a Forestry Rese:lic h Noce 15 7 ,
74. Th o rud, D . B . J n d
School o f Fo restry, Uni\'ersity o f Min neso ta . S L Paul. �v1 N , 1 97 6 .
7 5 . Perry. T. O . S c i i c om p ac t io n and loblolly p i n e tree growth. Tree P.1anrers '
Nares, ! 96 . 6 7 , 9.
76. G recean , E.L. and S ands. R. Co m pac tion o f forest soi ls: a revie•.v. A ustralian
Journal of Soil Rese a rch , 1 980, 18, 1 63 ! 83 .
77. P ri tc hett, W.L. and Comerford, N.B . Long tenn response to phosphorus
ferti l i zation on selec ted sou theastern Coastal P l ain soils. Soil Science So ciery
of America Journal, ! 982, 46, 64 0-644 .
Gentle, S .W. . H u m phreys, F.R., and Lambert.. M.J. An examinatio n o f a
Pinus radiara ferti l ize r trial fifteen years after treatment Forest Science,
1 9 8 6 , 32, 822 829.
. ]8.
'.;
.
$22.·:·. : Mead , D .J. and Gad gil, R.L. Fertil izer use in established radiata pine stands
-�;::
;jh:.:A. ·· .
..•
.
·
.
;:. ·
in New Zeai and. New Zealand Journal of Forestry Science, 1 978, 8,
; ·-;;. t o5 1 3 4
in : ·. :·
::-:: Wiede m an n
·
,
E. Eruagskundliche und waldbauliche Grundl agen der
Forstwirtschaft. S auerl ande r ' s Verl ag. Frankfurt: am Main . Jrd edi tion, 1 950,
.
·:· : 34 6 p .
·
· j·_ '
·
.
l{t':·:
"
!s""'
.
It
,
Evidence for long- (erm producriviry changes
80 8 1 . B a.ule, H. and Fricker, C. The Ferrilizer Treatment of Forest Trees. B LV
Verlag S y eselkchaft, Munich, 1 970.
82. A ndersson, F.O. and Lundkvist, H. Long-tenn S wedish field experimen ts i n
fo rest managemen t p rac tic es and site productivity. In: Research Strategies
fo r Long- (erm Sire Producriviry. Proceedings, IEA.IB E A3 Wor ks ho p,
Seattle, WA, Aug. 1 983. (E ds.) W.J. D y ck :md C.A. Mees. IE..VSE A 3
Report 8 . New Zc:1 l and Forest Research Institute B u l letin 152, 1 98 9 ,
p p . 1 2.5 - 1 37 .
8 3 . Pri tchett. W.L. ::m d S m i th. W. H . Forese Fenil i zation in the U. S . S o u theast.
[ n : Fores t So ils
and Forest Land Managemelll. Proc edings. Fourth Nortb
American Fo res t So i l s Conference , Laval Un iversi ty. August 1 97 3 . Laval
U n i vers i ty Press. Quebec, 1 97 5 , p p . 467-476.
84. H aywood . J . D . P l a n t e d pi n es do not
re spo nd to bedd ing on an Ac ad i a 8 e:1urega.rd- Ko l en si I t l o o..m si te. U S D A S o u th ern Fores t Ex peri men t S ta.tio n
Researc h Note 50-25 9 . 1 9 80.
85. Ti arks, A.E. Effect of site preparatio n and fertili zation on s l ash pine
gro w i n g on a good si te. In: Proceedings. Second B iennial Southern
S i lvicul ture Res earc h C o n ference, Nove m ber 1 982, Atlan ta. U S A . USDA
Fores t S ervice General Tech nical Report S E-24, 1 983, pp. 34- 3 9 .
8 6 . Mc Kee, W. H . J r., and W i l h i te, L . P. Lob lo l l y pine res ponse t o bedding a n d
fertil ization varies b y drain age c l as s o n lower A t l an tic CoastJI P l a i n s i tes.
South ern Journczl of Applied Forestr)', 1 986, 10, 1 6- 2 1 .
87 .
Maso n, E. G . , C u l l e n , A .W.J ., and Rijkse. W.C. G rowth of two Pinus radiara
stock types on ri p ped and ripped/bedded plots at Karioi forest. New Zealand
Journal
of ForeSt!)' Science,
1 988, 1 8 . 287-296.
,.,