j~4 service forestry vlclc!i rd. vaz 1m5
TRANSCRIPT
EnvironmentCanada
CanadianForestryService
JlJN b l\j~4Env.r6nnementCanada
NATURAL RESOUHCES CANADA
!I~ t~ & YUKON R. EG'ON
~l 8llPJ~SlDE RD.vlclc 'lj.~.uff8'l 1r~15 CAD.
Your Me Volre reference
Our file Notre reference
Forest Insect and Disease Survey,
Pacific Forest Research Centre506 West Burnside RoadVictoria, B.C. , vaz 1M5
November 30, 1982
SPECIAL REPORT
SURVEY FOR DWARF MISTLETOE INFECTION IN LODGEPOLE PINE
REGENERATION UNDER MOUNTAIN PINE BEETLE-ATTACKED STANDS
IN THE CHILCOTIN,
by
T.L. Shore, R.J. Andrews, and G.A. Van Sickle
PURPOSE
In the Cariboo Region large areas of mature lodgepole pine
have been killed by the mountain pine beetle (MPB). There is also
a high rate of dwarf mistletoe (DM) infection in these stands. An
estimate of the proportion of natural regeneration infected with DM
is needed as a basis for-prescribing silvicultural treatments
necessary to return this land to productive forest. This was a
pilot survey to evaluate methods, type of information obtained and
population variance.
METHODS
TI1e Tatla Lake-McClinchy Creek area in the west Chilcotin
was selected for study because it is predominantly covered in lodgepole
pine which has been heavily attacked by MPB. A series of eight cruise
lines, spaced systematically at 16 kilometre intervals along the roads
beginning at Chilanko Forks, were run on September 21-22, 1982. Along
each line five 30 m2
circular plots, spaced at 5D m intervals, were
sampled. All seedlings falling within the plot radius were tallied as
- 2 -
infected or uninfected. Height was recorded for all sampled
seedlings and age was recorded for the closest seedling to centre
in each stocked quadrant. Information on the overstory was ob
tained through a prism sweep at each plot centre. The status of
DM and }WB was recorded within the variable plot. A more detailed
description of the sampling method and rationale is given in
Appendix I.
RESuLTS
An average of 15.2 percent of the lodgepole pine regeneration
was infected with dwarf mistletoe (Table 1). The amount of infection
varied widely by location with very low infection levels occurring
between Chilanko Forks and Tatla Lake and much higher levels west
of Tatla Lake. Infection levels coincided with the age of regen
eration. The stands west of Tatla Lake generally had older regen
eration than the eastern stands (Table 1). It should be noted that
symptoms of DM are more visible in larger regeneration. This intro
duces a source of negative bias to the survey as infection may go
undetected in very small seedlings. The sampling frequency and
percentage infection of lodgepole pine regeneration by height class
are shown in Figure 1.
The overstory was in generally poor condition with an average
28.8 percent of the trees, representing 38.9 percent of the volume,
killed by MPB and 41.1 percent of the trees infested with DM (Table 2).
Approximately six percent of the MPB-killed trees were currently
attacked· which suggests that the beetle will continue to be active in
these stands for several years. Up to 43.5 percent of the overstory
was infected in the stands east of Tatla Lake. With time, these trees
probably will cause an increase in the presently low proportion of
infected seedlings in the area. There was a higher percentage of
infection (43.4) in the unattacked trees than in those killed by ~WB
(25.2). Consequently, as the MPB-killed trees decay and the stands
open up, an increasing proportion of the residual overstory will be
producing DM seed to further infect the regeneration.
TABL
E1
.R
esu
lts
of
asu
rvey
for
dw
arf
mis
tleto
e(D
M)
inlo
dg
ep
ole
pin
ere
gen
era
tio
nu
nd
erm
ou
nta
inp
ine
beetl
e-a
ttack
ed
stan
ds
inth
eC
hi.
leo
tin
,C
arib
oo
Reg
ion
,19
82
.
Num
ber
of
Perc
en
tN
umbe
ro
fA
ver
age
1A
ver
age
Av
erag
e2
Lo
cati
on
Seed
lin
gs
Infe
cte
dS
eed
lin
gs
Pe.r
cen
tH
eig
ht
(m)
Age
Ex
amin
edw
ith
DMp
er
ha
Sto
ck
ing
Py
per
Lk.
Rd.
521.
.93
,46
76
0<
0.5
8.0
Tatl
aL
k.N
.21
0.0
1,4
00
50
1.7
16
.4.
Tatl
aL
k.s.
370
.02
,46
7.55
<0
.51
0.6
Hor
nL
k.R
d.
80
.053
33
20
33
.21
5.3
Jet.
Hor
nL
k.R
d.-
Tat
lay
ok
oL
k.R
d.4
128
9.4
8,5
33
100
1.4
11
.6
18K
m.
w.o
fT
atl
aL
k.31
54
.82
,06
745
5.9
25
.0
462
35
.54
,13
36
0C
learw
ate
rL
k.1
.42
3.9
8K
m.
N.
of
~lcClinchy
Cr.
Bri
dg
e40
20
.02
,66
765
2.9
27
.8
Perc
en
tag
eo
fse
ed
lin
gs
infe
cte
dw
ith
D.M
.1
5.2
+1
3.6
(0<
=0
.10
)
lQu
ad
ran
tsco
nta
inin
go
ne
or
mor
ese
ed
lin
gs
wer
eco
nsi
dere
dst
ock
ed
;b
ased
onfi
ve
30m
2cir
cu
lar
plo
tsp
er
locati
on
.2
Bas
edon
on
etr
ee
per
sto
ck
ed
qu
ad
ran
t.
3rf
~lit
esp
ruce
reg
en
era
tio
nis
inclu
ded
this
beco
mes
2,8
67
seed
lin
gs
per
ha,
45p
erc
en
tst
ock
ing
.4 A
rea
log
ged
leav
ing
scatt
ere
dre
sid
uals
.
I~
I
-4-
Frequency of sampling and dwarf mistletoe infection byFIGU-RE 1.
------.----- ------,II
height class of lodgepole pine regeneration, Cariboo, 1982.
Infected
Uninfected
30.0%
16.7%
71.4% ;33.3% 100.07 a IOO . O% 0.0% f
._r._~~~__._~~~=:::r-~O~.O~%~.__. __J3 4 5 6 7 8 9 10 11 1221a
2209.6%
210
180 j~z 160
i~::JCY~
J~
140~
f..')ZHH
120~en
100
8017.8%
60
16~3%
40
20
HEIGHT CLASS (t--f)
TABL
E2
.S
tatu
so
fth
elo
dg
ep
ole
pin
eo
vers
tory
wit
hre
spect
tod
war
fm
istl
eto
ean
dm
ou
nta
inp
ine
beetl
ein
the
Ch
ilco
tin
,C
arib
oo
Reg
ion
,19
82.
Ste
ms
per
ha
Vol
ume
3P
erc
en
tag
eo
fT
ota
lL
ocati
on
per
haem
)S
tern
sp
erh
aV
olum
eh
a,
MPB
2p
erDM
J.T
ota
lDl
-1M
PB
To
tal
D~1
11PB
DM:t-'
1PB
Py
per
Lk.
Rd.
29
.22
19
.55
38
.59
.45
1.3
91
.65
.44
0.8
10
.35
6.0
Tatl
aL
k.N
.1
41
.57
13
.91
,09
7.1
8.5
.52
.28
6.8
12
.96
5.
19
.86
0.1
Tatl
aL
k.s.
28
2.1
16
6.8
64
7.8
11
.81
7.7
33
.14
3.5
25
.73
5.6
53
.5
Hor
nL
k.R
d.3
53
.03
00
.21
,06
0.6
25
.24
0.5
71
.43
3.3
28
.33
5.3
56
.7
Jet.
lIarn
Lk
.R
d.-
32
01
.60
.02
01
.61
7.2
0.0
17
.21
00
.00
.01
00
.00
.0T
atla
yo
ko
Lk.
Rd.
18K
m.
w.o
fT
atl
aL
k.6
01
.542
4.7
82
6.7
83
.44
5.2
99
.37
2.R
51
.48l~.
04
5.5
.-3
14
1.7
49
.12
59
.91
8.2
14
.23
6.2
Cle
arw
ate
rL
k.5
4.5
18
.95
0.3
39
.2
8K
m.
N.
of
McC
line
hyC
r.B
rid
ge
26
.30
.04
28
.74~6
0.0
39
.16
.10
.01
1.8
0.0
AVER
AGE
22
2.1
23
4.3
63
2.6
22
.32
7.6
59
.34
1.1
28
.84
2.1
38
.9
1 DMin
fecte
dw
ith
dw
arf
mis
tleto
e.
? -MPB
kil
led
by
mo
un
tain
pin
eb
eetl
e.
3lo
gg
edle
av
ing
scatt
ere
dre
sid
uals
.A
rea
I V1 I
- 6 -
Generally, stocking levels of the regeneration were fairly
good with art average of 3,450 seedlings per ha (including white
spruce at Horn Lake Rd.) and 60 percent stocking (0.8 milhectare
quadrants) (Table 1). The height distribution of this regeneration
is approxima ted by that of the sample (Figure 1).
~~AGEMENT CONSIDERATIONS
In the stands examined, :MPB attacks have killed up to 65
percent of the larger mature trees under which varying amounts of
advanced regeneration exist. From 0 to 55 percent of this regen
eration is already infected with DM and, as 43 percent of the
overstory trees surviving the bark beetle are DM infected, a
continuing source of infection remains... · The production of D1"1
seed from these trees will likely increase with increased light
as the stand opens, and decreased overstory stocking will allow
more of the seed to reach the regeneration. As the regeneration
grows it presents a larger target and the probability of being
infected increases.
A plan for identifying and priorizing treatment of such DM
infected stands should be considered and policy-based thresholds for
management action established. As shown in Fig. 2, depending on yet
to be determined levels of stocking and DM infection, stand management
options could include at least:
1. do nothing, stand should reach maturity with minimallosses;
2. remove infected overstory residuals;
3. remove infected overstory residuals and sanitize advancedregeneration;
4. remove overstory and regeneration and re-establishstand.
In order to utilize percent infection in management decision
making, the precision of the estimates will need to be increased. This
will involve running many more lines. On the basis of this pilot
survey, approximately 80 lines would be required to reduce the error
to within 25 percent of.the mean at the 90 percent probability level.
- 7 -
FIGURE 2. A possible format for relating stand management
options to percentage of regeneration infected
with dwarf mistletoe.
Ds----------------~ toc lng enslty--------------
Remove Overstory and Regen and Re-establish
Stand
IiI
Remove Overstory and Sanitize AdvancedbOlI :>... CI(1) H e,-11
Regenrl ctl +JI~+J CIo..c: cUI
f--=,-Q)--,:-fT(J) S P-4 I
I Remove Overstory1I
.-I
Do Nothing, stand should reach maturity with
minimal loss
a
III
o
Percentage
of
Regeneration
Infected
- 8 -
Literature Cited
Cochran, W.G. 1977. Sampling Techniques, 3rd Ed. John Wiley
and Sons. New York. 428 pp.
Freese, F. 1962. Elementary Forest Sampling. USDA Agriculture
Handbook No. 232. 91 pp.
Scheaffer, R.L., W. Mendenhall and L. Ott. 1979. Elementary
Survey Sampling, 2nd Edition. Duxbury Press, Massachusetts.
278 pp.
( i)
APPENDIX I
The sampling design used was Repeated Systematic Sampling
C.Scheaffer et ale 1979). The average proportion of seedlings
infected with dwarf mistletoe on each line was determined and the
average and variance of the infected proportions between lines
calculated. TIlis is basically a two stage sampling technique with
the lines as the first stage and plots as the second stage. As
the sample size was very small in comparison with the population,
the variance component is mainly between primary units (Cochran
1977). Also, because the plots on a line are not independent of
one another, a simple random sampling approach cannot be justified.
Although the plots are of equal size there is an unequal nt@ber of
seedlings in the plots. Thus the proportion of infected seedlings
for each line was calculated using a ratio approach (Freese 1962;
Cochran 1977).
Due to manpower and time constraints a sample size of eight
lines was selected. The origins of the lines were on the roads
intersecting the study area and were spaced systematically, with a
random start, at sixteen kilometre intervals. This interval was
based on total length of main roads intersecting the study area
divided by the sample .size. If the systematically selected line
origin point was "out of type" the first subsequent "in type" location
was selected. If both sides of the road were "in type", one was
selected randomly. Plots were spaced systematically with a random
start at 50 m intervals. The line was on a bearing perpendicular
to the road except where all five plots could not be contained "in
type" in which case a 900
turn was made at the last "in type" plot
on that bearing.
RECOMMENDED 110FIFICATIONS TO THE SURVEY METHOD
The plot size should be increased to include more seedlings.
A 50 m2
(4.0 m radius) plot size is recommended as this would also be
compatible with BCMF regeneration surveys.
(ii)
It is also recommended that- instead of running five plots
on a straight line perpendicular to the road, a 900
turn should be
made at the second plot and again at the third plot thus forming
an open rectangle. This would return the crew to the vicinity of
the road thereby reducing walking time and also reduce the risk
of running "out of type".