SIL VI CU LT UR AL SYSTEMS
whi ch a
dc lincd as an orderly rro ccd urc hy
odu ctio n
er naturally or artifi cially . Th e rcrr
t\ reprodu ction met hod may be
forest is replaced by new crop eith
manageme nt.
, clim ate, so il fact ors and object o f'
cies
spe
to
g
in
ord
acc
y
var
s
hod
met
l u#,Y
ps is carri ed o ut und er
/cro
new
of
ent
shm
bli
esta
The repl ace ment o r old forest and
iculture sys tem .
well def ined pro cess kno wn as a silv
p
as "the process by which the cro
A silviculture system is definedo.A
(>.J
ng in
1
l and replaced by new crop resulti
ova
rem
,
ded
ten
are
st
fore
g
utin
con stit
form.
production of woo d of a distriffi'ive
(ii )
ds (i) met hod s of reg ene rati on,
A silv icul ture sys tem com pre hen
tion of age classes.
Cha rac ter of cro ps and (iii) distribu
Cla ssif icat ion of silviculture system
onle for var iou s cou ntri es dep end ing
Dif fere nt clas sifi cati ons are availab
applied. For
duc ed and reg ene rati on tech niq ues
met hod s of fell ing typ es of crop pro
n made
' the foll ow ~g clas sifi cati on has bee
~
(I)
Hig h For est System:
rati
A. Systems of concentrated regene
on:
a. The clea r felling system.
b. She lter woo d systems.
1. Uni form system.
2. Gro up system.
3. Irre gul ar she lter woo d system.
B. Selection systems:
1. Selection system .
2. Gro up selection sys tem .
C. Accessory systems:
1. Tw o storied high forest sys tem .
2. High forest with reserve system.
3. Improvement fellings.
II.
Coppice Systems:
1. Simple coppice system.
2. Coppice with standards system.
I.A. (a). Clear Felling System:
a. Description:
Under this system successive areas are clear felled and regenerated often
artificially,
but
sometimes
naturally
as
well.
Theoretically
equal
areas
(compartments) are felled each year and regenerated immediately so that all age
classes from one year old to rotation age are present, but in practice this ideal form
is rarely attained.
b. Arrangement of fellings:
The size, form and arrangement of coupes is adjusted according to
requirements of the locality. Where danger of erosion, wind damage, frost etc. is
apprehended, the size and arrangement of coupes is modified to safeguard the
danger involved e.g., where the frost is likely to effect the progress of regeneration,
large successive clearings should be avoided and small scattered coupes are
preferred.
c. Regen·eration :
(1) Natural:
This may be obtained from the seed disseminated by fallen trees in the
coupe or from the adjoining un:ijlled area. The well known example of ~
pinaster from France can be cited as a case of clear felling with natural regeneration
from seed. No definite system of clear felling with natural regeneration from seed
has been established in India. In U .P ., clear felling with coppice regeneration
obtained by coppicing suppressed advance growth of sal has been applied in
Gorakhpur Division.
(2) Artificial regeneration :
In
on in Indian Forests.
Clear felling with artificial regeneration is quite comm
practice. Casuarina in
case of teak, clear felling with stump planting is a wide
ing. Replacement of poor
coastal areas is managed under clear felling with plant
by Taun gya method or
miscellaneous forests by economic species either
m. Sometimes instead of
department plantations is a common example of this syste
of valuable species as a
complete clear felling of the compartment a few trees
protection against frost or other local considerations are
left.
d. Advantages :
Some of the important advantages of clear felling are :
(I)
Easy to practice
(2)
Saves time in establishing young crop
(3)
Ther e is greater concentration of work and more out-turn
(4)
Timb er produced in even aged crops is claimed to be
per unit area.
superior than in un-
even aged crops.
e. Disadvantages :
(I) It exposes the area to climatic extremes, increases weed
growth and may result
in site deterioration.
(2) On slopes it may create a great erosion hazard.
(3) Intro duce s an artificially by production of even aged
crops.
f. Applicability :
cond
very favourable
The syste m is well suited to light demanders. It needs
unstable hill slopes or
itions of regeneration. The system is unsuitable on
wher e soil is likely to deteriorate _wjtq exposure. It
repla ceme nt of species by diff eren t~s.
Shelter wood system:
1. Uniform System
3
is commonly adopted f2.r
(i) a. Description
Under this system,. , the old forest is removed and regeneration obtained by
two or more successive fellings. The fellings are called regeneration fellings.
The rotation is divided into periods and compartments are allotted to
respective periodic blocks according to the age classes. The length of period
depends on regeneration conditions, climatic and soil conditions, hardiness of
~~
species and other local considerations.
The distribution of age classes in different p~riods is illustrated below.
Rotation 120 Years
P.B.III
P.B.IV
91-120 yrs. 61-90 yrs.
31-60 yrs.
0-30 yrs.
91-120 yrs.
61-90 yrs.
31-60yrs.
Beginning of period. P.B.I.
End of period.
1-30 yrs.
P.B.II
The practice of fixed periodic blocks present no difficulties when the crops
has no serious danger from any source. But in cases when the crop is likely to be
destroyed by calamities like fire, the whole arrangement is upset. Under such
conditions a system of floating P.B. is followed, when areas for regeneration are
selected afresh at each .hvision of working plan.
b. Regeneration fellings :
(1) Seedling Ceilings :
The object of these fellings is to open the canopy sufficieutly to create
r--{ eX9J M
.
favourable conditions for regeneration. The number of trees r-ftiftfetl (seed breaders)
depends on the sp~ies, incidence of weeds, soil factors and climatic conditions. On
the number of seed
hotter and exposed aspects, or on unstable slopes, shallow soi!_s,
.
.
bearer is increased. The seed she4 by seed bearers germinates and young crop is
established under proper tending operations.
(2) Secondary fellings :
They are made to uncover the young croP. with a view to provide more light,
rain and nourishment. The number of fellings depends on hardiness of species and
ghii when the seed
progress of regeneration. Sometimes e.g., in case of Pin us roxbur___,
final fellings.
bearers are few (6.g trees per acre), seedlings fellings are follower by
---
-
(3) Final Fellings :
When young crop is established and is safer from any danger, the
whole
ovenvood is removed.
c. Form of crop produced :
But
possible.
The object of uniform system is to produce as even-aged crops as
crops is
with great length of regeneration period, the tendency for uneven aged
uneven aged
quite marked. When pole stage advance growth is retained, the
character is well defined.
d. Advantages :
(1) The fellings follows the regeneration which is an important safe-g
uard.
(2) The regeneration operations extend over a long period and thus
the restocking
assured.
(3) The seed bearers provide large timber by enhanced increment.
(4) Selection of seed bearers provides opportunity to improve the crop
genetically.
(5) The even-aged forest develops under shelter of old wood.
e. Disadvantages :
1. Needs greater skill to practice.
s.
2. Young crop is likely to be damaged by secondary and final felling
3. Introduces erosion hazard on steep hill sides.
f. Applicability :
ration
The system 1s well suited in accessible areas where the regene
. On Steep
conditions are favourable to provide for its development under shelter
roxburghii is
slopes in Himalayas heavy openings may cause serious erosion. Pinus
is taken while
a classic example of this system. The advantage of advance growth
carrying out generation fellings. It has been applied successfully
to coniferous
supplement the natural regenration.
forests m Punjab. Sowings and plantings
em, but due to difficulty of natural
Shorea robusta has been worked under this syst
d upon .
generation, the advance growth is mainly relie
(2) Gro up Syst em
erou s groups scattered over
Under this system, the canopy is opened in num
th from the nuclH for making gaps in
the area. Usually , the patches of advance grow
rifugally in each gap, where usual
the canopy. The regeneration springs . up cent
out.
see<lJng, secondary and final fellings are carried
ately the whole compartment
The groups become larger and larger and ultim
tively uneven aged in the beginning
is regenerated. The crop produces is compara
an even-aged crop. The system _is _not /
but in pole stage it gives the appearance of
in Central Europe but m India 1t 1s
uncommon in combination with uniform system
not being practiced at present.
(3) Ind ian Irre gula r She lter Woo d System
:
where advance growth upto
This is a partial modification of uniform system,
l
in Punjab in case of coniferous deodar
16" dia. ln compact groups is retained
ularity in the crop. Other operations
forests in Punjab. This introduces some irreg
are same as under uniform system.
ent sacrifice of young crop.
The retention of advance growth is made to prev
~µ). - (B) Selection Syst em :
a. Gen eral description :
in the conduct of felling and
The system differs from all other systems
neration extend over the whole area
regeneration operations. The fellings and rege
and are not confined to some parts.
b. Fell ing and regeneration :
ps goes on annually over the
The foiling of trees singly or in very small grou
small areas; on extensive scale, the
whole area. But this is possible only in case of
ductive blocks, equal to the years of
whole area is divided into number of equal-pro
'
I
dyin~
felling cycle and one block is felled yearly. Under selection fellings dead,
ders,
diseased and trees of_exploitable size are removed. In case of light deman
small gaps are made to provid e favourable regenerati?_n conditions. ~
1s
( During the course of feilings ~- : · proper distribution of age classes
attempted.
The regene ration is supposed to come up naturally over the whole area. In
te
suitabl e places, it may be aided by sowings and plantings. Withou t adequa
regene ration the system will ultimately break down. The usual tending operati
ons
are carried out.
c. Form of crop produced :
Theoretically all aged classes should be represented on every acre. But in
practice all age classes are seldom evenly distributed over whole area.
d. Advan tages :
( 1) Protective features of forest are best assured.
(2) System is highly flexible.
(3) All seed years can be used.
(4) There is little disturbance of ecological and biological equilibrium.
(5) Fire danger is reduced.
(6) It is the best for aesthetic consideration.
e. Disadvantages :
( 1) It needs greater skill to manage the for4fs.
(2) The selection fellings often degenerate in revenue fellings.
(3) Cost of extraction of produce is higher.
(4) Biotic factors inimical to regeneration, retard the progress.
(5) Affords little opportunity to improve the crop.
f. Applicability :
a,
I
r
/
/
land slides,
pro tec tion against ero sion,
ere
wh
ted
sui
ll
we
is
tem
The sys
for smaller
sleep hills . ll is well su.itcd
in
ury
ess
nec
is
.
etc
ods
prevention of flo
de selection fe elings
of dif ferent size is nee ded . Cru
ce
du
pro
ere
wh
s
est
for
e
villag
s in Himalayas and
The remote coniferou s forest
as.
are
ble
ssi
cce
ina
in
on
are co mm
more in
er thi s sys tem , the -¢fing s are
und
d
rke
wo
are
ion
reg
e
tan
sale in sub mo un
nat ure of selection fiffings.
JS :
c . A<;ce sso Ry Sy.! reli
rest- System:
ctJ Tw o sto rie d High Fo
ches middle
d forest. When the forest rea
rie
-sto
two
a
to
lied
app
tem
It is a sys
d in
bearing species is introduce
de
sha
r
the
ano
and
up
ned
age., and it is heavily ope
storey and un der
s continue to grow. The upper
rey
sto
two
the
and
rey
sto
the un der
is removed
le system or the upper storey
tab
sui
er
und
er
eth
tog
led
fel
storey ma y be
allowed to grow.
completel y and lower ore is
n, to introduce a
d to provide soil protectio
Th e system can be adopte
a or to get early
od production from the are
wo
um
xim
ma
get
s,to
cie
sensitive spe
it is no t
le species for under storey,
tab
sui
g
din
fin
of
y
ult
fic
dif
returns. Bu t due to
bei ng pra cti ced in India.
2.
@
c!)
Hi gh Fo res t with standard
s:
nd
grow for entire 2
to
t
lef
are
es
tre
ed
ect
sel
few
It is not practiced in India, a
ally large sized timber.
rotation to provide exception
Co PP! C..E £: y.r TEJfJ
Simple Coppice System:
~f fellings , but the
ar felling in the conducy'
cle
to
r
ila
sim
is
tem
sys
The
I
thrown
regeneration is obtained by shoots
ls.
by cut stumps or even root su ck
nu mb er of
species to coppice. A large
of
lity
abi
on
s
end
dep
The system
that sal does no t
g degree e.g., it is reported
yin
var
to
ies
cop
s
cie
spe
board leaved
rakhpur Division.
coppice beyond 12" dia. in Go
6 high stu mp
the gro un d lea vin g 4" to
se
clo
led
fel
y
all
usu
Trees are
do rm ant sea son , jus t
e coupes are felled du rin g
Th
s.
ion
dit
con
al
loc
on
dep end ing
before bud s begin to swell.
I
T he sy st em
-✓ecwo od or sma II siz· ed maten·a
uct1·o11 o.·t· m
is " ia'p pl ie d for prod
i a,
1
40
t willows) to 30 or
d is
ps or
and ro ta tio n ad op te
the worn ,.out stum
t
en
m
le
pp
su
to
ne
d pl an tin gs are do
ning
years. So w in gs an
g operation of clea
in
nd
te
l
ua
us
e
Th
ies.
n of valuable spec
s of
in cr ea se pr op or tio
ith in case of specie
w
d
se
en
sp
di
es
im
met
ne. Thinings are so
taken /
an d th in in gs ar e do
is the only produce
d
oo
ew
fir
re
he
w
or from such forest
ve ry sh or t ro ta tio n
for 1 year (Baske
ve ry short varying
out.
lo w soil
or scrub forests with
po
e
th
a
di
In
In
.
ed
practic
It is th e ol de st system
is managed
globules in Nil- giris
us
pt
ly
ca
Eu
.
em
st
un de r this sy
fa ct or s ar e w or ke d
un de r th is system.
dards:
C op pi ce With Stan
ear cuttings,
cept the instead of cl
ex
e
ic
pp
co
e
pl
sim
r to
To e sy st em is simila
so m e trees are left
as standards.
e time of
ppice rotation. At th
co
of
le
tip
ul
m
a
is
dards
g
To e rotation for stan
are felled and youn
n
tio
ta
ro
r
ei
th
ed
ch
"a
dards which have re
s of
co pp ic e fellings stan
n of all age classe
io
ut
rib
st
di
er
op
pr
d. A t any time, a
standards are adde
e.
standards is desirabl
her locality factors.
ot
d
an
s
ie
ec
sp
on
dards depends
The number of stan
and of
ies of light crown
ec
sp
of
ly
ab
er
ef
pr
well grown trees
Standards should be
valuable nature.
sired, or the
d and timber are de
oo
ew
fir
th
bo
n
he
w
suited
The system is well
elter.
rant provision of a sh
ar
w
s
or
ct
fa
ic
at
im
cl
ontane
s forests in sub-m
ou
ne
lla
ce
is
m
r
fo
ely practiced
The system is wid
sts.
working village fore
r
fo
d
ite
su
l
el
w
be
The system can
tract in North India.
en