LOSS EVALUATIONS IN FOREST RECREATION AREA&/
Richard S. Smith, Jr.-2 /
Abstract: We defined a s e t of management goals f o r
r e c r e a t i o n f o r e s t stands which say t h a t we w i l l attempt
t o maintain a healthy and vigorous, all-aged, mixed s p e c i e s ,
properly stocked stand with numerous old-growth t r e e s . An
i n f e s t a t i o n of dwarf m i s t l e t o e may well prevent us from
reaching most of these goals. The dwarf m i s t l e t o e s a f f e c t
t h e t r e e s both d i r e c t l y and i n d i r e c t l y through o t h e r p e s t s .
A l l dwarf m i s t l e t o e evaluations and control e f f o r t s should
include consideration o f associated p e s t s . Recreation
f o r e s t stands r e q u i r e proper s i l v i c u l t u r a l management f o r
adequate d i s e a s e prevention.
INTRODUCTION
Before we can consider some o f t h e ways
i n which dwarf m i s t l e t o e i n f e s t a t i o n s a f f e c t
r e c r e a t i o n f o r e s t s we should recognize t h a t
there are several administratively different
types of r e c r e a t i o n f o r e s t s . There a r e multiple-use f o r e s t s , where r e c r e a t i o n i s a secondary use, and o t h e r s where i t i s t h e primary
use. There a r e r e s t r i c t e d - u s e r e c r e a t i o n a r e a s ,
such a s some wilderness a r e a s , where f o r e s t
management a c t i v i t i e s a r e not allowed, and
o t h e r a r e a s where various l e v e l s o f management
a r e required. Among t h e s e managed r e c r e a t i o n
areas a r e two general types: t h e dispersed
r e c r e a t i o n a r e a , with o r without secondary
uses; and t h e developed r e c r e a t i o n a r e a , such
a s t h e campground, p i c n i c a r e a , v i s i t o r c e n t e r ,
o r o t h e r . I t i s mainly t h e l a t t e r a r e a s -t h e developed, i n t e n s i v e l y used, single-purpose
r e c r e a t i o n s i t e s - - which we a r e u s u a l l y concerned with when we t a l k about dwarf m i s t l e t o e
e f f e c t on f o r e s t r e c r e a t i o n a r e a s , and it i s
mainly t h e s e a r e a s I w i l l discuss i n t h i s paper.
In t h i s d i s c u s s i o n , I w i l l cover t h e goals
of f o r e s t management i n r e c r e a t i o n s i t e s , how
dwarf m i s t l e t o e has kept us and can keep us from
r e a l i z i n g t h e s e goals o r make t h e s e goals more
c o s t l y t o achieve, some a c t u a l examples of
dwarf m i s t l e t o e and associated p e s t s e f f e c t s
i n developed r e c r e a t i o n s i t e s a n d , l a s t l y , f o r e s t
r e c r e a t i o n management philosophy and t h e prevention of i n s e c t and d i s e a s e l o s s e s i n f o r e s t
r e c r e a t i o n areas.
MANAGEMENT GOALS IN FOREST RECREATION AREAS
Before we can a s s e s s t h e adverse e f f e c t s
of a p e s t a c t i v i t y , we must f i r s t determine
what our management goals a r e f o r t h e s t a n d ,
a r e a , o r f o r e s t . The four southern-most
National Forests i n C a l i f o r n i a , because of
tremendous r e c r e a t i o n use and p r e s s u r e s , have
been designated as "recreation f o r e s t s " ; t h a t
i s , they a r e f o r e s t s where r e c r e a t i o n w i l l be
t h e primary use and a l l o t h e r uses w i l l be
secondary, o r not allowed. Because of t h i s
new r e s p o n s i b i l i t y i n recreation, f o r e s t managers have pushed ahead i n attempting t o
describe o b j e c t i v e l y and a c c u r a t e l y t h e management objectives of a r e c r e a t i o n f o r e s t . I
personally am e n t h u s i a s t i c about t h e i r views
and s e l e c t i o n of management o b j e c t i v e s i n recr e a t i o n f o r e s t s and would l i k e t o use t h e goals
they developed i n our discussion o f l o s s evaluat i o n s . These a r e :
1. Maintain a t t r a c t i v e f o r e s t s f o r
r e c r e a t i o n a l use and enjoyment.
2 . Provide p r o t e c t i o n from excessive
i n s e c t and disease l o s s e s .
à ‘ ~ r e s e n t e a t t h e Symposium on Dwarf Mistletoe
Control Through Forest Management, Berkeley,
C a l i f . , April 11-13, 1978.
Â¥^supervisor Plant P a t h o l o g i s t , Forest I n s e c t
and Disease Management S t a f f , C a l i f o r n i a Region,
USDA Forest Service, San Francisco, C a l i f .
3. Provide favorable conditions f o r maintenance of water flow and y i e l d .
4 . Reduce t h e p o t e n t i a l f o r l o s s by uncontrolled f i r e .
5.
Maintain and enhance w i l d l i f e and
fisheries habitats.
6. U t i l i z e t r e e s removed from t h e
f o r e s t i n achieving t h e preceding goals.
7. Provide educational and i n t e r p r e t i v e
services.
I would expect t h a t t h e s e goals would be
g e n e r a l l y a p p l i c a b l e t o most f o r e s t r e c r e a t i o n
a r e a s i n t h e West. Managers a t these southern
f o r e s t s a l s o l i s t second o r d e r o b j e c t i v e s
p e r t a i n i n g t o stand management :
1. Maintain an all-aged o r i r r e g u l a r
sized stand structure.
2 . Retain o l d growth t r e e s a s long a s
possible.
3.
Control stocking t o d e s i r a b l e l e v e l s .
4.
Maintain mixed species composition.
5.
Maintain healthy, vigorous t r e e s .
6.
Maintain a n a t u r a l appearing stand.
The second order o b j e c t i v e s a r e more
s p e c i f i c and t h e r e f o r e a r e e a s i e r t o r e l a t e
l o s s e s a g a i n s t than a r e t h e more generalized
primary o b j e c t i v e s . You may view t h e stand
management goals f o r your f o r e s t r e c r e a t i o n
a r e a s somewhat d i f f e r e n t l y , but f o r purposes
o f t h i s d i s c u s s i o n , I w i l l use t h e above a s
o b j e c t i v e s i n describing t h e e f f e c t s of dwarf
m i s t l e t o e i n f e s t a t i o n s on f o r e s t r e c r e a t i o n
goals.
ment, when we f i n d ourselves with an i n f e c t e d ,
overmature, thinning, even-aged overstory and
few o r no younger age c l a s s e s which can be used
t o replace t h e decadent overstory. The f o r e s t
r e c r e a t i o n area i s gradually denuded and l o s e s
much o f i t s a e s t h e t i c value. A t t h i s point we
may be l e f t with t h e a l t e r n a t i v e s of e i t h e r
c l o s i n g t h e r e c r e a t i o n s i t e o r attempting t o
regenerate it slowly through a s e r i e s of small
s e l e c t i v e overstory c l e a r c u t s and p l a n t i n g s .
The attempt t o regenerate t h e stand during t h e
continued use of t h e s i t e gives us t h e addit i o n a l problems of coordinating our regenerat i o n a c t i o n s with r e c r e a t i o n use and p r o t e c t ing our p l a n t i n g s from r e c r e a t i o n - u s e damage.
E i t h e r of t h e options -- t o close t h e s i t e and
regenerate o r t o regenerate during continued
use -- i s c o s t l y .
Retain Old-Growth Trees
As t r e e s age and move i n t o t h e overmature
age c l a s s , t h e i r v i g o r s t a r t s t o diminish.
Dwarf m i s t l e t o e i n f e c t i o n adds a d d i t i o n a l
s t r e s s t o t h e s e t r e e s causing them t o decline
i n v i g o r a t a more r a p i d r a t e . These declini n g t r e e s a r e more s u s c e p t i b l e t o a t t a c k by
bark b e e t l e s and other p e s t s . Thus, t h e p i c t u r esque old-growth t r e e s we wish t o r e t a i n tend
t o d i e o f f more quickly i f i n f e c t e d by dwarf
m i s t l e t o e . In some cases, we can a l l e v i a t e t h e
s t r e s s by pruning t h e l a r g e , broomed branches -caused by dwarf m i s t l e t o e i n f e c t i o n -- from
these t r e e s . This is a c o s t l y operation and
broom pruning often i s considered undesirable
by t h e landscape a r c h i t e c t s .
Control Stocking t o Desired Levels
EFFECTS OF DWARF MISTLETOE ON FOREST RECREATION
GOALS
Having developed a s e t o f primary and
secondary goals, and using t h e more s p e c i f i c
secondary g o a l s , we can now look a t how dwarf
m i s t l e t o e i n f e s t a t i o n s may prevent us from
reaching t h e s e goals, o r permit u s t o reach
them a t a higher c o s t . These goals and proj e c t e d i n f e s t a t i o n e f f e c t s a r e as follows:
Maintain an A1 1-Aged Stand.
I n f e c t i o n o f t h e overstory by dwarf
m i s t l e t o e w i l l r e s u l t i n t h e i n f e c t i o n and
eventual d e s t r u c t i o n of a l l , o r most a l l , of
t h e understory t r e e s of t h e same and o t h e r
s u s c e p t i b l e species within t h e immediate v i c i n i t y o f t h e i n f e s t e d overstory t r e e s .
The
t r e n d w i l l be away from t h e desired all-aged
stand toward an even-aged i n f e s t e d overstory.
The r e a l e f f e c t of t h i s t r e n d w i l l u s u a l l y not
be f e l t u n t i l t h e l a s t s t a g e s of stand develop-
The r e c r e a t i o n objectives of stocking
c o n t r o l i n an a l l - a g e d stand should be t o
maintain adequate cover (overstory) f o r shading, p r o t e c t i o n , and a e s t h e t i c s , and s u f f i c i e n t understory and l e s s e r vegetation f o r
purposes of overstory replacement, screening,
and a e s t h e t i c s . The stand management stocking
o b j e c t i v e s should be t o develop a stand which
i s not s t r e s s e d by overstocking and which meets
secondary o b j e c t i v e s 1 and 2 . Dwarf m i s t l e t o e
i n f e c t i o n o f a stand may r e s u l t i n an understocking of t h e i n f e s t e d stand which i s l e s s
than d e s i r a b l e o r acceptable t o t h e r e c r e a t i o n
stocking goals. The e f f e c t s of dwarf m i s t l e t o e
on t h e overstory is t o put s t r e s s on t h e i n f e c t e d
t r e e s , increase t h e i r s u s c e p t i b i l i t y t o o t h e r
p e s t s -- p a r t i c u l a r l y bark b e e t l e s -- and t o
cause t h e overstory t o gradually t h i n .
The e f f e c t on t h e understory w i l l be more
dramatic. The r a i n of dwarf m i s t l e t o e seeds
from t h e i n f e c t e d overstory w i l l r e s u l t i n heavy
i n f e c t i o n o f t h e understory and t h e d i r e c t
k i l l i n g o f t h e s u s c e p t i b l e t r e e s by t h e dwarf
m i s t l e t o e . The thinning o f t h e overstory and
t h e lack o f replacement t r e e s i n t h e unders t o r y w i l l r e s u l t i n t h e gradual decrease i n
stocking over time o f t h e f o r e s t r e c r e a t i o n
area. A r t i f i c i a l regeneration with nonsuscept i b l e s p e c i e s , o r patch c u t t i n g of i n f e c t e d
overstory and regeneration with s u s c e p t i b l e
s p e c i e s , a r e t h e a l t e r n a t i v e c o n t r o l procedures
t h e stocking of overstory and understory were
s e r i o u s l y a f f e c t e d . I f t h i s i s t h e case, dwarf
m i s t l e t o e would a f f e c t t h e o t h e r goals long
before i t s e f f e c t s would be f e l t here. Basic a l l y , I view t h e maintenance of a n a t u r a l
appearing stand a s a key goal. I b e l i e v e t h e
purpose of t h e f i r s t f i v e goals, i n p a r t , i s t o
prevent our f a i l i n g i n t h i s goal. And, i f we
do f a i l i n achieving t h e o t h e r goals, it i s
only a matter of time u n t i l we f a i l t o achieve
t h i s one.
Maintain Mixed Species Composition
COMBINED PEST EFFECTS
I n f e c t i o n of a t r e e species by dwarf
m i s t l e t o e i n a mixed c o n i f e r stand w i l l tend t o
e l i m i n a t e t h i s species gradually from current
and f u t u r e stands. Infected overstory t r e e s
w i l l be a t a competitive disadvantage with
overstory t r e e s o f o t h e r species. Susceptible
understory s p e c i e s w i l l become i n f e c t e d and
d i e , and t h e i r removal w i l l r e s u l t i n l e s s
s p e c i e s mix i n t h e replacement stand. The
e l i m i n a t i o n of a s p e c i e s from a mixed c o n i f e r
stand w i l l increase t h e s t a n d ' s v u l n e r a b i l i t y
t o d e s t r u c t i o n by o t h e r p e s t s and decrease i t s
a e s t h e t i c value.
Maintain a Healthy, Vigorous Stand
The presence of dwarf m i s t l e t o e i n a
stand means t h a t a p o r t i o n o f t h e stand i s not
h e a l t h y . The added s t r e s s brought on by t h i s
p e s t w i l l r e s u l t i n decreased v i g o r o f t h e i n f e c t e d t r e e s and increased s u s c e p t i b i l i t y of t h e
stand a s a whole t o o t h e r p e s t s , such a s bark
b e e t l e s . These o t h e r p e s t s may b u i l d up on t h e
dwarf m i s t l e t o e i n f e c t e d t r e e s and from them
spread out and i n f e c t o r i n f e s t and k i l l t r e e s
n o t i n f e c t e d by dwarf m i s t l e t o e . Thus t h e dwarf
m i s t l e t o e i n f e c t e d t r e e s may pose more of a
t h r e a t t o t h e h e a l t h and vigor of t h e stand
than j u s t t h e number of i n f e c t e d t r e e s i n d i c a t e s .
Secondly, dwarf m i s t l e t o e i n f e c t i o n s may prov i d e f o r t h e entrance of o t h e r p e s t s i n t o t h e
i n f e c t e d t r e e s . Decay fungi frequently e n t e r
t h e o l d e r dwarf mistletoe bole swellings of
t r u e f i r causing a h e a r t r o t , making t h e t r e e s
s u s c e p t i b l e t o stem f a i l u r e , and thereby increasi n g t h e hazard t o r e c r e a t i o n i s t s i n t h e s e stands.
Cytospora canker i n f e c t s red f i r a t s i t e s of
dwarf m i s t l e t o e i n f e c t i o n s causing branch
m o r t a l i t y . In many instances excessive branch
m o r t a l i t y has f u r t h e r decreased t h e vigor o f
t h e i n f e s t e d stand.
Maintain a Natural Appearing Stand
Most r e c r e a t i o n i s t s would probably not
n o t i c e an unnatural appearance u n t i l a stand
has experienced a good deal o f m o r t a l i t y and
The e f f e c t s of dwarf m i s t l e t o e on a stand
do n o t occur alone. In r e a l l i f e these e f f e c t s
occur i n combination with t h e e f f e c t s from
o t h e r p e s t s . These o t h e r p e s t s may o r may not
influence o r be influenced by t h e dwarf mistlet o e problem. Our evaluations of t h e dwarf
m i s t l e t o e e f f e c t s should include, t h e r e f o r e ,
an evaluation of t h e o t h e r p e s t problems,
present or imminent. The dwarf m i s t l e t o e cont r o l s we i n s t i t u t e must consider t h e e f f e c t s
of these o t h e r p e s t s on t h e stand and t h e
e f f e c t s of our control procedures on t h e s e p e s t s ,
and t h e l o s s e s they cause. In t h e Forest S e r v i c e ' s
C a l i f o r n i a Region, we f e e l s o strongly about t h i s
need t o consider t h e t o t a l p e s t complex i n a
stand t h a t we now a r e using a team approach i n
our p e s t evaluations. A b a s i c team would i n clude both an entomologist and a p a t h o l o g i s t
who would look a t a l l major i n s e c t s and diseases
a f f e c t i n g t h e stand. To i l l u s t r a t e t h i s need
f o r teamwork I would l i k e t o describe b r i e f l y
t h e p e s t evaluations we conducted t h i s year
on two very d i f f e r e n t r e c r e a t i o n areas. In each
case, dwarf m i s t l e t o e was a major problem and
t h e p e s t evaluation was conducted by a patholo g i s t , entomologist, and l o c a l f o r e s t manager.
Recreation Area A i s a l a r g e a r e a
surrounding a lake and containing s e v e r a l
campgrounds, p i c n i c a r e a s , summer homes, t r a c t s ,
and considerable acreage f o r dispersed recreat i o n . The stand i s b a s i c a l l y a young sawtimber
overstory with a sapling understory, varying
from absent t o very t h i c k . I t is a mixed stand
of ponderosa pine, incense cedar, white f i r ,
sugar pine, and black oak. The overstory i s
heavy t o ponderosa pine. Incense cedar predominates i n t h e understory. Islands of o l d
growth ponderosa pine a r e s c a t t e r e d throughout
t h e stands. Last year t h e a r e a experienced
considerable m o r t a l i t y of ponderosa pine. A
survey of t h e a r e a revealed t h a t 90 percent of
t h e m o r t a l i t y was caused by a complex of i n s e c t s
and diseases. The major p e s t s i n t h i s complex
were dwarf m i s t l e t o e , pine engraver b e e t l e ,
western pine b e e t l e and Annosus r o o t disease.
Seventy-two percent of t h e dead t r e e s had a
Hawksworth dwarf m i s t l e t o e r a t i n g of 4 , 5, o r 6.
Thirty-eight percent o f t h e t r e e s had signs o f
p i n e engraver b e e t l e a t t a c k and over 50 percent
of t h e dead t r e e s has been attacked by t h e
western pine b e e t l e .
Overstocking was cons i d e r e d t o be a contributing f a c t o r . The mort a l i t y was diagnosed as r e s u l t i n g from t h e
combined e f f e c t s o f dwarf m i s t l e t o e , t h e two
bark b e e t l e s , and overstocking. The prognosis
was f o r a d d i t i o n a l m o r t a l i t y t o occur i n t h e
n e a r f u t u r e r e s u l t i n g from t h e combined continued
e f f e c t s o f t h e s e p e s t s and Fomes annosus.
In planning f o r removal of t h e dead and
p a r t i a l l y dead t r e e s , we had t o consider t h e
production o f s l a s h and i t s p o t e n t i a l f o r
c r e a t i n g another b u i l d up of t h e pine engraver
b e e t l e . In a d d i t i o n , over 60 percent of t h e
dead t r e e s s t i l l had green b u t t s and r o o t crowns
which, when c u t , would c r e a t e stumps s u s c e p t i b l e
t o i n f e c t i o n by Fomes annosus. Annosus root
d i s e a s e c e n t e r s created during previous s a n i t a tion-salvage c u t t i n g s were found i n developed
r e c r e a t i o n s i t e s . Stump treatment with borax
was, t h e r e f o r e , a consideration i n t h e control
plan. With t h e prognosis f o r dwarf m i s t l e t o e
and overstocking t o s t r e s s t r e e s and contribute
t o o r cause f u t u r e bark b e e t l e problems, plans
f o r a combined dwarf mistletoe-thinning program
were a l s o considered. The evaluation of a r e a A
i d e n t i f i e d f o u r major p e s t s , concluded t h a t
i n t e r a c t i o n s between t h e s e p e s t s did occur, and
suggested c o n t r o l options i n which a l l f o u r
p e s t s and t h e l o s s e s they caused were considered.
The stand i s s t i l l young, with adequate stocking
and a good species and age c l a s s mix. Much of
t h e p e s t c o n t r o l could, t h e r e f o r e , be accomp l i s h e d a t l i t t l e cost and d i s r u p t i o n .
Stand B i s an over-mature, mixed c o n i f e r
stand with sparse understory and a thinning
overstory. The stand i s mainly ponderosa pine,
J e f f r e y pine, and white f i r with occasional
incense cedar and sugar pine. A survey ident i f i e d dwarf m i s t l e t o e on ponderosa and J e f f r e y
p i n e s , t r u e m i s t l e t o e s on white f i r and incense
cedar, a i r p o l l u t i o n , f l a t h e a d s , J e f f r e y pine
b e e t l e , f i r engraver, and western pine b e e t l e
a c t i n g together i n various combinations t o cause
most of t h e m o r t a l i t y . The stand has a long
h i s t o r y of dwarf m i s t l e t o e and o t h e r p e s t
problems. The prognosis was f o r continued
m o r t a l i t y i n t h e overstory and l o s s of t h e
understory pines r e s u l t i n g i n t h e l o s s of most
c o n i f e r s . Because t h e stand was s o o l d , stocki n g s o t h i n , regeneration d i f f i c u l t t o e s t a b l i s h
and dying from dwarf m i s t l e t o e when e s t a b l i s h e d ,
stand management and p e s t management options
were l i m i t e d and c o s t l y .
Broom pruning o f i n f e c t e d overstory t r e e s
was suggested a s a means of reducing s t r e s s
and lowering m o r t a l i t y i n t h e near f u t u r e .
Other c o n t r o l options such a s overstory removal,
thinning, and p l a n t i n g would have t o be t a i l o r made f o r small groups of t r e e s and should cons i d e r species composition, a l l major p e s t s
p r e s e n t , t r e e v i g o r , and stand s t r u c t u r e . The
f l e x i b i l i t y f o r c o n t r o l and stand management
we had i n Stand A i s not a v a i l a b l e here i n
Stand B. But, t h e now younger Stand A could,
without stand management and p e s t c o n t r o l ,
develop over time i n t o a stand-pest condition
s i m i l a r t o t h a t of Stand B .
STAND MANAGEMENT IN FOREST RECREATION AREAS
Forest r e c r e a t i o n stands a r e dynamic,
i n t e r a c t i n g , growing, changing ecological
systems. They a r e not s t a t i c and w i l l not
remain unchanged r e g a r d l e s s o f our a c t i o n s o r
i n a c t i o n s . These a r e statements I b e l i e v e we
can a l l accept on a b i o l o g i c a l b a s i s . But we
appear t o have a problem accepting t h e s e i d e a s
on a management and administrative b a s i s . How
many f o r e s t managers p r a c t i c e t h e same l e v e l
o f s i l v i c u l t u r e i n r e c r e a t i o n f o r e s t stands a s
i n timber stands? Are r e c r e a t i o n f o r e s t s t a n d s
worth more o r l e s s than timber s t a n d s , and i s
t h e investment i n maintaining these s t a n d s
commensurate with t h e values placed upon them?
In t h e a r e a of r e c r e a t i o n stand management,
we a r e s t i l l s u f f e r i n g from t h e e f f e c t s o f an
o l d e r out-dated philosophy which advocated t h a t
man influence o r a f f e c t t h e r e c r e a t i o n s i t e a s
l i t t l e as possible s o a s t o keep it "natural."
This, of course, meant t h a t we should do no
stand management. We can no longer accept t h i s
older philosophy i f we a r e t o achieve t h e newer
management goals described e a r l i e r i n t h i s paper.
Proper stand management and s i l v i c u l t u r a l
management a r e t h e b a s i s of an e f f e c t i v e i n s e c t
and d i s e a s e prevention program i n our r e c r e a t i o n
f o r e s t stands. The longer sound stand management i s excluded from r e c r e a t i o n stands, t h e
more severe t h e i n s e c t and disease l o s s e s w i l l
become i n t h e s e stands and, as we saw i n
comparing Stands A and B, t h e fewer and more
c o s t l y w i l l be our c o n t r o l options. This is
p a r t i c u l a r l y t r u e of dwarf m i s t l e t o e problems
where s i l v i c u l t u r a l controls a r e t h e most
e f f e c t i v e c o n t r o l s a v a i l a b l e t o us.