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REPORT NO. 80 - 10 



PREDICTION OF WESTERN SPRUCE BUDWORM 
DEFOLIATION ON DOUGLAS-FIR 



c/.- 


Methods Application Group 

Forest Insect and Disease Management 

Forest Service, USDA 

2810 Chiles Road 

Davis, California 95616 




TABLE OF CONTENTS 


INTRODUCTION 1 

METHODS 2 

Field Procedures 2 

Laboratory Procedures 3 

Analysis 3 

Evaluation of Prediction Accuracy 7 

RESULTS 8 

Evaluation of Equations Based on Year of 
Data Collection 8 

Evaluation of Single Westwide Equation 15 

Evaluation of Equations Based on Age 
of Infestation 16 

CONCLUSIONS 21 

RECOMMENDATIONS 22 

LITERATURE CITED 22 


APPENDICES 


24 


Report 80-10 


3400 
August 1980 




PREDICTION OF WESTERN SPRUCE BUDWORM 
DEFOLIATION ON DOUGLAS-FIR 




ABSTRACT 

A series of equations have been developed to predict defoliation on 
Douglas-fir caused by the western spruce budworm* These are based on egg mass 
density and result from data collected westwide from 1976 to 1979, Analyses 
presented are based on year of data collectiony the combination of all data to 
produce a single equation^ and the grouping of data by age of infestation. 

Use of the appropriate model will allow prediction into the correct 
defoliation category 8 out of 10 times. 


INTRODUCTION 

Western spruce budworm, |Chor1 stoneura occidental is] Freeman defoliator 
of Douglas-fir and true firs in western North America. [Egg massKlensi^has 
been used to monitor population trends, evaluate long-term efforts of control 
projects and forecast defoliation by this insect. 


Egg mass survey methods were developed by Carol in and Coulter (1972) for 
Oregon and by McKnight, et al . (1970) for Colorado. These were reasonably 
successful when used in the areas for which they were developed but westwide 
application has been unreliable. 


The need for consistent prediction methods westwide, led to the formation 
of a Western Spruce Budv/orm Egg Mass-Defoliation Working Group in 1976 
(Grimble and Young 1977). This Group consisted of forest entomologists from 
USDA-Forest Service Regions 1, 2, 3, 4, 6, the Intermountain Forest and Range 
Experiment Station, and the FIDM Methods Application Group. The Group's 
objective was to coordinate collection of egg mass data and conduct analysis 
to: 

1. Develop reliable defoliation prediction models for Douglas-fir based 
on western spruce budworm egg mass densities 

2. Make procedures comparable v/estwide for egg mass sampling, 
descriptions of defoliation, and reporting of results of egg mass 
surveys 


1 Authors are, respectively. Survey Entomologist and Biometrician, USDA 
Forest Service, Forest Insect and Disease Management, Methods Application 
Group, Davis, CA. 


METHODS 


Data collection was based on repeated sampling from the same trees and 
sampling units for a three-year period. Standardized methods for egg mass 
collection, defoliation estimation, and reporting were developed and used 
beginning with the 1976 field season and continued through the 1979 field 
season. This has resulted in the largest known data base of this kind ever 
compi 1 ed . 


Field Procedures 

Entomological Unit . The Entomological Unit was the smallest area for 
which a defoliation prediction was made. These had the following attributes: 


1. A distinct geographical area 

2. A distinct management unit 

3. An area of contiguous susceptible host type 

4. Contained an active western spruce budv/orm infestation 


Entomological units varied from 1000 to 100,000 acres in size. Each 
Region determined unit boundaries and the number of units to be sampled. 


Clusters . Estimates of egg mass density and defoliation prediction were 
made from clusters of 3 sample trees each. Easily accessible clusters were 
randomly located throughout each entomological unit in areas of visible 
defoliation. A minimum of 20 clusters was recommended for each unit. 


Sampl ing . In each cluster, three Douglas-fir 30-60 feet in height, open 
grov/n, with light to moderate defoliation were selected as sample trees. 
Heavily defoliated trees were not sampled because they did not contain 
sufficient foliage for oviposition. Field sampling was conducted during late 
July or August after most adult activity had ceased. 

One 70 cm branch was removed from each quadrant of the mid-crown of each 
sample tree with a pole pruner. These were used to classify defoliation 
intensity. Two branches were returned to the laboratory for egg mass counts. 


Description of defoliation - Defoliation was estimated from the first 25 
current shoots on each branch, starting from the tip. Shoots were taken from 
alternate sides of branches, i.e., 25 from the left side of the first branch, 
then 25 shoots from the right side of the next branch. 

Each shoot v/as evaluated individually and rated 1, 2, 3, or 4 to indicate 
degree of defoliation according to the following system: 


Percent Defoliation 


Rating 


0 - 25 
25 - 50 
50 - 75 
75 - 100 


1 

2 

3 

4 


2 


Hand tally counters were used to maintain a cumulative tally as each was 
examined. For example, if the first shoot was about 40 percent defoliated, 
the tally counter was punched twice; if the next was about 60 percent 
defoliated, the counter was punched three more times, and so on until all 25 
shoots had been examined and classified. The cumulative total of ratings for 
each branch represented the estimated percent defoliation for the branch. A 
data form was designed which accommodated all defoliation estimates from a 
cl uster . 


Laboratory Procedures 

Two branches per tree were used for egg mass counts. These were 
transferred to the laboratory and placed directly in cold storage until 
examined for the presence of eggs. 

All needles, both attached and loose, were thoroughly examined. Needles 
containing egg masses, regardless of size or condition, were removed and 
placed in a container with a branch identification label. They were then 
examined microscopically by an experienced technician to determine if they 
were old, new, parasitized or non viable. This was recorded on a data form 
along with length of egg masses, and number of rows per egg mass. No criteria 
were established for separating old and new egg masses; this decision was 
based on the judgment of the technician. 

Two methods of estimating foliage area were used: grid and length x width. 
In the grid method, each branch was clipped into 10-15 cm segments, arranged 
over a grid calibrated in centimeters, and the number of square centimeters 
covered was recorded. For the length x width method, direct measurements were 
taken in the field and recorded on the identification tag that accompanied 
each branch. 


Analysi s 

Cluster level summaries . Data recorded on the forms were manually edited, 
coded, and keypunched by Regional personnel. Data files were created at the 
Fort Collins Computer Center (FCCC), and FIDM/MAG initiated computer edit 
runs, made corrections, and processed annual summaries. Summaries for egg 
mass density and defoliation were prepared for each entomological unit. Unit 
means and standard errors v/ere computed from individual cluster means. 

Egg Mass densities used in this report are expressed as the number of egg 
mass per square meter of foliage based on the length x width method. These 
data are also available for the "Grid" method, however since not all Regions 
used that method, a much larger data base was available by using the length x 
width method. 

Defoliation estimates based on the four-class system were reduced by 12.5 
percent to adjust the estimates to the midpoint of each class. 


3 


Other statistics generated by the summary programs included the following 


1. Egg mass densities per square meter based on the grid method of 
determining branch area where these data were available 

2. Egg masses per branch 

3. Viable egg masses per branch 

4. Old egg masses per branch 

5. Number of rows per mass 

6. Egg mass length 

7. Unadjusted defoliation estimates 

8. Defoliation index 

The following equations were used to compute cluster level means: 



Egg Mass Density-,- 




where 


cl uster 


j = tree 
k = branch 

t = number of trees per cluster 
b = number of branches per tree 
L = length of branch in centimeters 
W = width of branch in centimeters 
EM = new egg masses 
DEE = defoliation 


4 


Entomological Unit Means . Cluster means were used to compute 
entomological unit means as follows: 


Egg Mass 


m 


S EM. 
i = l 


m 


Defol i at ion 


DEE. 

1 

m 


where m = number of clusters in an Entomological Unit 


Relating egg mass densities to defoliation . Only data from Regions 1, 2, 
3, and 4 were included in the analysis. R-6 data were not analyzed because 
they consisted primarily of "0" egg mass densities and the lowest levels of 
defol i at ion. 

Generally, only those entomological units with data from 10 or more 
clusters were used in the analysis. We felt that in most cases, fewer than 10 
data pairs (clusters with matching egg mass and defoliation) in a given year 
would not provide enough information upon which to make a prediction. 

Three approaches were used to analyze the data: (1) comparing data 
collected in each Region by year of collection without regard to age of 
infestation; (2) combining all entomological unit summaries westwide; and (3) 
grouping all Regional data by age of the infestation. Linear, quadratic and 
cubic regression equations were computed for each approach using egg mass 
density and defoliation as the independent and dependent variables, 
respectively. 


1. Analysis by year of data collection . Two separate data listings were 
made for each Region. The first data set included all clusters as follows: 

1976 egg masses--1977 defoliation 

1977 egg masses — 1978 defoliation 

1978 egg masses--1979 defoliation 

The second data set included only those clusters containing matched data 
for all three years (table 1). The "All Data" columns show the total observed 
paired data and the "Matched" columns show just those clusters with data from 
all three years. 


5 


Table 1. Number of data pairs used for analysis - Regions 1-4, 1976-79. 


Year 

Region 1 

Reg 

ion 2 

Region 3 

Region 4 

All 

data 

Matched 

All 

data 

Matched 

All 

data 

Matched 

All 

data 

Matched 

76-77 

66 

45 

19 

10 

62 

42 

112 

91 

77-78 

49 

45 

56 

10 

104 

42 

127 

91 

78-79 

119 

45 

102 

10 

88 

42 

145 

91 

Total 

234 

135 

177 

30 

254 

126 

384 

273 


Simple linear regression models (Y = A + BX) were computed for each 
Region ' s data set. 

2. Analysis of entomological unit summary data . The entomological unit 
summaries were used to develop a linear regression model on a vjestwide basis. 
Of 56 unit summaries available for use in development of this model, 45 were 
used. The remaining 11, randomly selected from the original 56, were used to 
verify the model by computing a predicted defoliation from egg mass densities. 

3. Analysis relative to age of infestations . The entomological units 
investigated during this project were in different stages of infestation. 

Some had been continuously defoliated for many years, while others were just 
beginning to show visible defoliation. We felt that infestation age might 
have a significant bearing on predictability, therefore data were sorted 
according to infestation age. Regional FIDM personnel provided this 
information for each entomological unit based on the year defoliation was 
first recorded for the unit on an aerial sketchmap. Infestation age was 
determined using the following formula: 

lA = (X-Y) + 1 


where lA = infestation age 

X = year of current survey 

Y = year defoliation first recorded on sketchmaps of the unit 

Entomological units v/ere sorted into five categories (table 2). Analyses 
were conducted for each Region and westwide by age and a series of predictive 
equations v/as developed. 


6 


Table 2. Reorganization of paired Entomological Unit data by infestation age. 


Entomological 


Age of Infestation (in 

years) 


Region Unit 

1 

2 

3 

4 

>5 

1 3-1 





78-79 

11-1 



76-77 

77-78 

78-79 

11-2 



76-77 

77-78 

78-79 

11-3 



76-77 

77-78 

78-79 

12-1 





78-79 

12-2 





78-79 

12-4 





78-79 

2 10-1 



76-77 

77-78 

78-79 

10-2 





78-79 

10-3 





78-79 

12-1 





77- 78 

78- 79 

12-2 




77-78 

78-79 

12-4 





78-79 

12-7 





78-79 

3 2-13 


77-78 

78-79 



2-16 


76-77 

77-78 

78-79 


3-8 


76-77 

77-78 



3-15 


76-77 

77-78 

78-79 


6-4 

76-77 

77-78 

78-79 



7-7 


76-77 

77-78 

78-79 


10-5 

76-77 





4 3-3 



76-77 

77-78 

78-79 

12-50 





77- 78 

78- 79 

13-4 

76-77 

77-78 

78-79 



13-80 



78-79 



15-1 


76-77 

77-78 

78-79 


15-2 


76-77 

77-78 

78-79 


Evaluation of Prediction 

Accuracy 





Since equations were 

based on 

both cluster level summaries and 


entomological unit summaries, two 

eval uation 

procedures 

were used. 



7 


For those equations based on cluster summaries, all individual cluster 
egg mass densities representing an entomological unit were entered into the 
equation being evaluated and used to calculate adjusted defoliation estimates. 
Each of these estimates was converted to the proper defoliation category 
(table 3) and an average predicted defoliation category determined for the 
entire unit. In the same manner, the actual adjusted defoliation recorded for 
each cluster egg mass density was converted to the proper category and the 
actual average defoliation category determined for the unit. These values 
were then compared to determine accuracy of prediction. 


Table 3. Adjusted defoliation and defoliation categories. 


Adjusted 

Defol i at ion 
(percent) 

Defol i at ion 
Category 

<12.5 

1 

12.5 - 37.5 

2 

37.5 - 62.5 

3 

>62.5 

4 


For the equation based on entomological unit summaries, the unit egg mass 
density was entered into the equation and a unit defoliation estimate 
computed. This estimated adjusted defoliation and the actual adjusted 
defoliation were converted to defoliation categories as above and compared to 
determine accuracy of prediction. 


RESULTS 


Evaluation of Equations Based on Year of Data Collection 


Egg mass and defoliation statistics used to compute Regional linear 
predictive equations are presented in tables 4a-4d^. Regression models 
developed from these statistics are shown in tables 5a-5d. 


The original intent of this project was to collect matching egg mass 
densities and defoliation estimates over a period of time to establish 
predictive equations. With this in mind, the accunmul ated experience over 
time, represented by the three-year combined regressions from each region, was 
evaluated using procedures described (tables 6a-6d). 


2 Quadratic and cubic models were developed but are not presented. They 
did not improve predictions over the linear models and only added 
compl exity. 


8 


Table 4a. Egg mass and defoliation statistics used in linear model (Table 5a) 
(R-1). 


Egg Mass Defol i at ion 


Year 

n 

Mean 

S.E. 

Smal 1 est 

Largest 

Mean 

S.E. 

Smal 1 est 

Largest 

All Data 










76-77 

66 

35.3 

3.5 

.0 

111.7 

51.5 

2.9 

12.5 

87.5 

77-78 

49 

25.4 

2.8 

0.8 

85.9 

51.0 

2.6 

21.5 

86.2 

78-79 

119 

35.4 

2.2 

1.7 

98.5 

34.1 

1.2 

14.0 

75.8 

Combined 

234 

33.3 

1.6 

.0 

111.7 

42.5 

1.3 

12.5 

87.5 

Matched 

Data 









76-77 

45 

37.7 

4.4 

.0 

111.7 

54.2 

3.2 

12.5 

87.5 

77-78 

45 

26.4 

3.0 

0.8 

85.9 

51.6 

2.6 

21.5 

83.1 

78-79 

45 

34.6 

3.4 

5.6 

89.6 

34.5 

2.1 

15.0 

75.8 

Combined 

135 

32.9 

2.1 

.0 

111.7 

46.8 

1.3 

12.5 

87.5 


Table 5a. Linear regression model coefficients (R-1). 


Year 

n 

Y = 
A 

A + BX 

B 

r2 

Syx 

All Data 

76-77 

66 

33.24 

.518 

.378 

18.85 

77-78 

49 

39.70 

.447 

.222 

16.47 

78-79 

119 

29.16 

.138 

.061 

12.85 

Combi ned 

234 

33.06 

.285 

.124 

18.53 

Matched Data 

76-77 

45 

35.93 

.484 

.427 

16.56 

77-78 

45 

40.93 

.406 

.208 

15.93 

78-79 

45 

27.33 

.207 

.106 

13.75 

Combi ned 

135 

34.87 

.362 

.196 

18.03 


9 


Table 4b. Egg mass and defoliation statistics used in linear model (Table 5b) 
(R-2). 


Egg Mass Defol iation 


Year 

n 

Mean 

S.E. 

Smal 1 est 

Largest 

Mean 

S.E. 

Smal 1 est 

Largest 

All Data 










76-77 

19 

15.2 

4.4 

.0 

58.1 

48.2 

5.4 

12.5 

87.5 

77-78 

56 

9.8 

1.0 

.0 

40.2 

51.1 

3.0 

14.7 

87.5 

78-79 

102 

14.0 

1.3 

.0 

62.5 

49.2 

2.1 

12.5 

87.2 

Combi ned 

177 

12.8 

1.0 

.0 

62.5 

49.7 

1.6 

12.5 

87.5 

Matched 

Data 









76-77 

10 

6.7 

2.2 

.0 

20.9 

42.6 

4.8 

21.7 

69.7 

77-78 

10 

7.5 

2.5 

.0 

21.3 

41.4 

6.8 

17.5 

72.5 

78-79 

10 

8.3 

3.0 

1.1 

26.7 

29.9 

4.3 

12.5 

51.6 

Combi ned 

30 

7.5 

2.5 

.0 

26.7 

38.0 

5.5 

12.5 

72.5 


Table 5b. Linear regression model coefficients (R-2). 


Year 

n 

Y = 
A 

A + BX 

P 

r2 

Syx 

All Data 

76-77 

19 

41.37 

.448 

.136 

22.39 

77-78 

56 

44.83 

.646 

.049 

21.84 

78-79 

102 

39.04 

.723 

.219 

18.39 

Combi ned 

177 

41.78 

.618 

.137 

19.92 

Matched Data 

76-77 

10 

33.93 

1.285 

.341 

13.18 

77-78 

10 

43.27 

-.251 

.009 

22.64 

78-79 

10 

21.81 

.975 

.454 

10.67 

Combi ned 

30 

33.42 

.605 

.074 

17.15 


10 


Table 4c. Egg mass and defoliation statistics used in linear model (Table 5c) 
(R-3). 


Egg Mass Defol i at ion 


Year 

n 

Mean 

S.E. 

Smal 1 est 

Largest 

Mean 

S.E. 

Smal 1 est 

Largest 

All Data 

76-77 

62 

19.2 

2.2 

0.5 

69.4 

63.8 

2.8 

12.5 

87.5 

77-78 

104 

15.9 

1.8 

.0 

103.2 

41.2 

2.5 

12.8 

87.2 

78-79 

88 

20.3 

2.5 

.0 

116.3 

47.4 

3.0 

12.7 

87.5 

Combined 

254 

18.2 

1.3 

.0 

116.3 

48.9 

1.7 

12.5 

87.5 

Matched 

76-77 

Data 

42 

22.1 

2.8 

0.5 

69.4 

63.5 

3.7 

12.5 

87.5 

77-78 

42 

16.5 

2.9 

.0 

85.4 

35.2 

3.7 

12.8 

86.3 

78-79 

42 

18.4 

3.6 

.0 

71.4 

37.7 

4.2 

12.6 

87.3 

Combi ned 

126 

19.0 

1.8 

.0 

85.4 

45.5 

2.5 

12.5 

87.5 


Table 5c. Linear regression model coefficients (R-3). 


Year 

n 

II 

>- 

< 

A + BX 

B 

r2 

Syx 

All Data 

76-77 

62 

47.50 

.849 

.432 

16.65 

77-78 

104 

28.17 

.820 

.363 

20.18 

78-79 

88 

30.89 

.812 

.445 

21.20 

Combi ned 

254 

34.32 

.797 

.365 

21.54 

Matched Data 

76-77 

42 

43.70 

.895 

.479 

17.38 

77-78 

42 

20.70 

.881 

.478 

17.34 

78-79 

42 

19.64 

.984 

.720 

14.61 

Combi ned 

126 

26.71 

.988 

.517 

19.47 


U 


Table 4d. Egg mass and defoliation statistics used in linear model (Table 5d) 
(R-4). 


Year 

n 


Egg Mass 



Defol i at ion 


Mean 

S.E. 

Smal 1 est 

Largest 

Mean 

S.E. 

Smal 1 est 

Largest 

All Data 










76-77 

112 

17.5 

2.2 

.0 

90.3 

29.8 

1.8 

12.6 

87.5 

77-78 

127 

10.7 

1.3 

.0 

70.8 

29.5 

3.7 

12.5 

84.2 

78-79 

145 

19.7 

1.9 

.0 

102.8 

35.5 

1.8 

13.1 

87.5 

Combi ned 

384 

16.1 

1.1 

.0 

102.8 

31.9 

1.0 

12.5 

87.5 

Matched 1 

Data 









76-77 

91 

17.5 

2.4 

.0 

90.3 

27.3 

1.6 

12.6 

72.4 

77-78 

91 

12.2 

1.8 

.0 

70.8 

32.1 

2.1 

12.5 

84.2 

78-79 

91 

20.9 

2.6 

.0 

102.8 

36.3 

2.3 

13.1 

87.5 

Combi ned 

273 

16.9 

1.3 

.0 

102.8 

31.9 

1.2 

12.5 

87.5 


Table 5d. Linear 

regression 

model coefficients 

(R-4). 


Year 

n 

Y = 
A 

A + BX 

B 

r2 

Syx 

All Data 

76-77 

112 

24.18 

.323 

.161 

17.13 

77-78 

127 

19.06 

.981 

.614 

12.05 

78-79 

145 

27.71 

.396 

.181 

19.33 

Combi ned 

384 

24.19 

.478 

.254 

17.33 

Matched Data 

76-77 

91 

20.56 

.387 

.343 

12.52 

77-78 

91 

20.37 

.960 

.645 

12.26 

78-79 

91 

28.94 

.353 

.164 

20.02 

Combi ned 

273 

23.74 

.484 

.300 

16.49 


12 


Table 6a. Predicted defoliation vs. actual defoliation (R-1). 


Entomological Unit 

Number 

Cl usters 

Predicted 

Defol i at ion 
Category 

Actual 

Defol i at ion 
Category 

3-1 (78-79) 

9 

2 

2 

11-1 (76-77) 

12 

3 

0 

o 

(77-78) 

9 

2 

3 

(78-79) 

15 

2 

2 

11-2 (76-77) 

18 

2 

3 

(77-78) 

15 

2 

3 

(78-79) 

18 

2 

2 

11-3 (76-77) 

9 

2 

3 

(77-78) 

7 

2 

2 

(78-79) 

17 

3 

2 

12-1 (78-79) 

20 

2 

2 

12-2 (78-79) 

16 

2 

2 

12-4 (78-79) 

9 

2 

2 


Table 6b. Predicted 

defoliation vs. actual defoliation 

(R-2). 

Entomological Unit 

Number 

Cl usters 

Predi cted 

Defoliation 

Category 

Actual 
Defol i ation 
Category 

10-1 (76-77) 

7 

3 

2 

(77-78) 

21 

3 

3 

(78-79) 

18 

3 

3 

10-2 (78-79) 

20 

3 

3 

10-3 (78-79) 

10 

3 

2 

12-1 (77-78) 

13 

3 

2 

(78-79) 

7 

3 

2 

12-2 (77-78) 

21 

3 

3 

(78-79) 

12 

3 

3 

12-4 (78-79) 

10 

3 

2 

12-7 (78-79) 

13 

3 

2 


13 


Table 6c. Predicted defoliation vs. actual defoliation (R-3). 


Entomological Unit 

Number 

Cl usters 

Predi cted 

Defol i ati on 
Category 

Actual 

Defol i at ion 
Category 

2-13 (77-78) 

20 

2 

2 

(78-79) 

19 

2 

3 

2-16 (76-77) 

10 

3 

4 

(77-78) 

20 

3 

3 

(78-79) 

20 

3 

3 

3-8 (76-77) 

12 

2 

3 

(77-78) 

16 

2 

2 

3-15 (76-77) 

10 

2 

3 

(77-78) 

20 

2 

2 

(78-79) 

16 

2 

2 

6-4 (76-77) 

10 

2 

3 

(77-78) 

10 

2 

2 

(78-79) 

10 

2 

2 

7-7 (76-77) 

10 

2 

3 

(77-78) 

19 

3 

3 

(78-79) 

19 

3 

3 

10-5 (76-77) 

10 

3 

3 


Table 6d. Predicted defoliation vs. actual 

defoliation (R-4). 

Entomological Unit 

Number 

Cl usters 

Predicted 

Defol i ation 
Category 

Actual 
Defol i ation 
Category 

3-3 (76-77) 

28 

2 

2 

(77-78) 

34 

2 

2 

(78-79) 

29 

2 

2 

12-50 (77-78) 

20 

2 

2 

(78-79) 

17 

2 

2 

13-4 (76-77) 

19 

2 

2 

(77-78) 

19 

2 

2 

(78-79) 

18 

2 

2 

13-80 (78-79) 

20 

2 

2 

15-1 (76-77) 

27 

2 

2 

(77-78) 

27 

2 

2 

(78-79) 

25 

2 

3 

15-2 (76-77) 

25 

2 

2 

(77-78) 

24 

2 

2 

(78-79) 

22 

2 

2 


14 


After the regional equations were developed, the data were rearranged by 
year of collection to show individual years equations (tables 5a-5d). 
Examination of the individual regressions by analysis of covariance 
demonstrated some differences in both slope and Y intercept (table 7). This 
indicated that year is a significant sampling variable and that idea led to 
the grouping of data by age of infestation. 


Table 7. Results of analysis of covariance. 


Stati stical 

Region 


Region 

Region 

Region 

Test 

1 


2 

3 

4 

Number of data sets 

3 


3 

3 

3 

Observations per set 

45 


10 

42 

91 

F test for common slope 

NS 


NS 

NS 

** 

F test for single regression 

** 


NS 

** 

** 

Analysis of covariance 






testing defol i at ion 

** 


NS 

** 

** 

NS = not significant ** 

= significant 

(.01) 



Evaluation of Single Westwide Equation 





The form of the model that 

provided 

the 

best fit 

for this 

equation was Y = 

A + B (In X). The resultant 

equation 

was: 



Y = 15.8 

+ 10.14 

(natural log 

of X) 



The coefficient of determination (r^) was .319 and Syx was 13.85 

As stated, this model was based on 45 of 56 available data sets. The 
remaining 11 data sets were used for model verification on the basis of 
predicted adjusted defoliation category versus actual adjusted defoliation 
category (table 8) . 


.15 


Table 8. Verification of single westwide equation. 


Egg Mass 
Density 
(per m£) 

Actual 

Defol i at ion 

Actual 

Defol i ation 
Rating 

Predicted 
Defol i ation 

Predi cted 
Defol i ation 
Rating 

23.2 

36.5 

2 

47.7 

3 

31.6 

29.4 

2 

50.8 

3 

1.7 

24.9 

2 

21.2 

2 

24.6 

31.1 

2 

48.3 

3 

15.1 

61.9 

3 

43.3 

3 

17.0 

74.1 

4 

44.5 

3 

2.1 

15.7 

2 

23.3 

2 

11.1 

58.2 

3 

40.2 

3 

2.1 

15.6 

2 

23.3 

2 

3.5 

14.4 

2 

28.5 

2 

8.8 

38.6 

3 

37.9 

3 

The verification indicated that this model will 

allow correct prediction into 

one of four 

defoliation categories 7 out of 11 

times. 


Evaluation of Equations Based 

on Age of Infestation 


Linear model coefficients 

, all in the form 

Y = A + BX were developed for 

each Region 

by age of infestation (table 9). Missing equations 

indicate that 

no entomological units for a 

given infestation 

age class occured 

in that 


Region . 

Linear model coefficients for a combined westwide equation based on 
similarly aged infestations are shown in table 10. 


Table 9. Linear model coefficients by age of infestation. 


Age of Infestation 
(in years) 

Number 

Cl usters 

A 

B 

r2 

Syx 

Region 1 






3 

39 

36.22 

.516 

.538 

14.85 

4 

31 

46.58 

.349 

.149 

17.74 

^5 

ion 

28.75 

.154 

.070 

13.28 

Region 2 






3 

7 

28.93 

1.009 

.667 

12.94 

4 

41 

46.56 

1.274 

.163 

18.15 

5 

103 

36.42 

.833 

.255 

18.60 

Region 3 






1 

20 

53.36 

.899 

.273 

13.09 

2 

72 

34.99 

1.037 

.380 

21.78 

3 

104 

28.92 

.919 

.415 

20.55 

4 

54 

26.64 

.873 

.598 

17.13 

Region 4 






1 

19 

15.18 

4.640 

.729 

5.44 

2 

71 

18.26 

.416 

.521 

8.94 

3 

116 

24.34 

.410 

.242 

15.08 

4 

81 

25.64 

.829 

.522 

15.85 

5 

65 

21.79 

.316 

.151 

18.38 


Table 10. Linear model 

coefficients by 

age of infestations (all 

Regions) . 

Age of Infestation 
(years) 

n 

A 

B 

r2 

Syx 

1 

39 

26.13 

2.347 

.631 

16.03 

2 

143 

27.54 

.719 

.295 

21.93 

3 

266 

27.57 

.622 

.387 

19.08 

4 

207 

34.87 

.692 

.339 

19.51 

5 

268 

34.27 

.156 

.032 

19.76 


Each equation was evaluated by computing defoliation based on individual 
cluster egg mass densities using the proper equation by age of the infestation 
in the entomological unit (tables lla-lld). 


17 


Table 11a. Predicted average defoliation category based on age of infestation 
vs. actual average defoliation category (R-1). 


E.U. 

Age of 
Infestation 
Date (in years) 

n 

Regional 

Predicted 

Defol . Category 

Westwide 
Predicted 
Defol. Category 

Average Actual 
Defol. Category 

3-1 

78-79 

5 

10 

2 

2 

2 

11-1 

76-77 

3 

12 

3 

3 

3 


77-78 

4 

9 

3 

3 

3 


78-79 

5 

15 

2 

2 

2 

11-2 

76-77 

3 

18 

3 

3 

3 


77-78 

4 

15 

3 

3 

3 


78-79 

5 

18 

2 

2 

2 

11-3 

76-77 

3 

9 

3 

2 

3 


77-78 

4 

7 

3 

3 

2 


78-79 

5 

14 

2 

2 

2 

12-1 

78-79 

5 

20 

2 

2 

2 

12-2 

78-79 

5 

14 

2 

2 

2 

12-4 

78-79 

5 

9 

2 

2 

2 


Table 

11b. Predicted average defoliation category based on age of 
vs. actual average defoliation category (R-2). 

infestation 

E.U. 

Date 

Age of 
Infestation 
(in years) 

n 

Regional 

Predicted 

Defol . Category 

Westwide 
Predicted 
Defol . Category 

Average Actual 
Defol . Category 

10-1 

76-77 

3 

7 

2 

2 

2 


77-78 

4 

20 

3 

2 

3 


78-79 

5 

18 

3 

2 

3 

10-2 

78-79 

5 

20 

3 

2 

3 

10-3 

78-79 

5 

10 

2 

2 

2 

12-1 

77-78 

5 

13 

2 

2 

2 


78-79 

5 

7 

2 

2 

2 

12-2 

77-78 

4 

21 

3 

2 

3 


78-79 

5 

12 

3 

0 

L. 

3 

12-4 

78-79 

5 

10 

2 

2 

2 

12-7 

78-79 

5 

13 

3 

2 

2 


18 


Table 11c. Predicted average defoliation category based on age of infestation 
vs. actual average defoliation category {R-3). 


E.U. 

Date 

Age of 
Infestation 
(in years) 

n 

Regional 

Predicted 

Defol . Category 

Westv;ide 
Predicted 
Defol. Category 

Average Actual 
Defol. Category 

2-13 

77-78 

2 

20 

2 

2 

3 


78-79 

3 

19 

2 

2 

3 

2-16 

76-77 

2 

10 

3 

3 

4 


77-78 

3 

20 

2 

2 

3 


78-79 

4 

20 

3 

3 

3 

3-8 

76-77 

2 

12 

3 

2 

3 


77-78 

3 

16 

2 

2 

2 

3-15 

76-77 

2 

10 

3 

2 

3 


77-78 

3 

20 

2 

2 

2 


78-79 

4 

16 

2 

2 

2 

6-4 

76-77 

1 

10 

3 

2 

3 


77-78 

2 

10 

3 

2 

2 


78-79 

3 

10 

2 

2 

2 

7-7 

76-77 

2 

10 

3 

2 

3 


77-78 

3 

19 

3 

2 

3 


78-79 

4 

18 

2 

3 

3 

10-5 

76-77 

1 

10 

3 

3 

3 


Table 

lid. Predicted 
vs. actual 

average defoliation category based on age of 
average defoliation category (R-4). 

infestation 

E.U. 

Date 

Age of 
Infestat 
(in year 

ion 

s) n 

Regional 

Predicted 

Defol . Category 

Westwide 
Predicted 
Defol . Category 

Average Actual 
Defol . Category 

3-3 

76-77 

3 

28 

2 

3 

2 


77-78 

4 

34 

2 

3 

2 


78-79 

5 

28 

2 

2 

2 

12-50 

77-78 

5 

20 

2 

2 

2 


78-79 

5 

17 

2 

2 

2 

13-4 

76-77 

1 

19 

2 

2 

2 


77-78 

2 

19 

2 

2 

2 


78-79 

3 

18 

2 

2 

2 

13-80 

78-79 

3 

19 

2 

2 

2 

15-1 

76-77 

2 

27 

2 

2 

2 


77-78 

3 

27 

2 

2 

2 


78-79 

4 

25 

2 

3 

3 

15-2 

76-77 

2 

25 

2 

2 

2 


77-78 

3 

24 

2 

2 

2 


78-79 

4 

22 

2 

2 

2 


19 


Using the results of the evaluations presented in tables 6a-6d, lla-lld, 
and those found by evaluating all entomological units using the single 
westwide equation, a probability of correct prediction matrix was developed 
(table 12). 


Table 12. Probability of correctly predicting defoliation using various 
prediction equations. 


Equation 

Number of 

Entomological Units 

No. Predicted 
Correctly 

Percent Correct 

Regional Simple Linear 

56 

38 

67.9 

Single Westwide 

56 

33 

58.9 

Regional , Aged 

56 

47 

83.9 

Westwide, Aged 

56 

38 

67.9 


These results indicate consistently low levels of predictability using all 
equations except those developed on a Regional basis that consider infestation 
age. 


The Single Westwide Equation developed from the entire data base, 
represents the most general of the equations, and thus would be expected to be 
the poorest predictor. The various Regional linear equations and the westwide 
aged equation are also general, but since they represent four and five 
equations respectively to predict the same values predicted by the single 
equation, it would be expected that there would be an increase in the 
probability of a correct prediction. The same argument can be used in 
discussing the Regional Aged Equations. These 15 equations v/ere developed 
from data sub-units that produced the v/estwide aged equation and would be 
expected to be better predictors than the single equation. 

The relative success of making a correct prediction by region and age of 
infestation is shown in table 13. 


20 . 


Table 13. Probability of correctly predicting defoliation on 

Entomological Units using Regional equations based on 
infestation age. 


Age of 
Infestation 
(in years) 

1 

Region^ 

2 3 

4 

Total All 
Regions 

1 

_ 


2/2 

1/1 

3/3 

2 

- 

- 

3/6 

3/3 

6/9 

3 

3/3 

1/1 

4/6 

5/5 

13/15 

4 

2/3 

2/2 

2/3 

2/3 

8/11 

2.5 

7/7 

7/8 

- 

3/3 

17/18 

Total by Region 

12/13 

10/11 

11/17 

14/15 

47/56 

1 No. Correctly Predicted/Total No. Predicted 



CONCLUSIONS 


Based on the results of this evaluation, the following conclusions can be 
drawn : 

1. Substantial variability exists in the relationship between egg mass 
density and subsequent defoliation caused by western spruce budworm 
in Douglas-fir both within and between Forest Service Regions in the 
West . 

2. Using equations developed from the existing data base, defoliation on 
entomological units within Regions can be predicted into the cor- 
rect defoliation category 8 out of 10 times when the age of the 
infestation being evaluated is known. 

3. Examination of the intercepts of all equations developed shows that 
it is impossible to predict into defoliation category 1. This is due 
to the definition of the defoliation categories. Categories 2, 3, 
and 4 represent ranges of defoliation ratings within which all 
possible numbers represented by those categories can occur. Category 
1, however, can only be represented by a single number, the highest 
value within the category, and therefore does not represent a range. 

4. There is a substantial amount of variability in predicting 
defoliation that remains unexplained. Physical characteristics of 
cluster locations have been shown to be quite useful in hazard rating 
stands in regard to the Douglas-fir tussock moth (Stoszek 1977, and 
Heller and Miller 1977) and should be examined to attempt to explain 
some of this variability. 


21 


RECOMMENDATIONS 


We recommend that: 

1. Regions determine the relative age of infestations and utilize the 
appropriate equations presented in table 9 as predictors of 
defoliation. Where specific equations have not yet been developed 
for a Region, it is recommended that the appropriate equation 
presented in table 10 be used until a Region-specific equation can be 
devel oped. 

2. Use data collection and analysis procedures that conform to this 
publication in future egg mass surveys. 

3. Examine physical site characteristics of the clusters to determine 
their effect on defoliation prediction. 

4. If Regions continue to collect data to refine these predictive 
equations, it is recommended that the following change in evaluating 
defoliation be made: 


Percent Defoliation Rating 


none visible 0 
Trace-25 1 
25-50 2 
50-75 3 
75-100 4 


The addition of a "0" category will allow category 1 to represent a range 
of defoliation. This should result in revising the Y-intercepts downward, 
thus allowing prediction into category 1 and producing a model that more 
accurately reflects the true situation on the entomological unit. 


LITERATURE CITED 

Carolin, V.M. and W.K. Coulter. 1972. Sampling populations of western spruce 
budworm and predicting defoliation on Douglas-fir in eastern Oregon. USDA 
Forest Service, Res. Pap. PNW-149. Pacific Northv/est Forest and Range 
Experiment Station, Portland, Oregon. 38 pp. 

Grimble, D.G. and R.W. Young. 1977. Western spruce budworm egg 

mass-defoliation surveys. A working group progress report. USDA Forest 
Service MAG Rpt. No. 77-3. Forest Insect and Disease Management, Methods 
Application Group, Davis, California. 21 pp. 

Heller, R.C. and W.A. Miller. 1977. Color infrared photos define site 
conditions favorable for Douglas-fir tussock moth outbreaks. J_n 
Proceedings, Sixth Biennial Workshop on Aerial Color Photography in the 
Plant Sciences and Related Fields, August 9-11, 1977, Colorado State 
University, Ft. Collins, Colorado, pp. 43-52. 


22 


McKnight, M.E., J.F. Chansler, D.B. Cahill, and H.W, Flake. 1970. Sequential 
plan for western spruce budworm egg mass surveys in the central and 
southern Rocky Mountains. USDA Forest Service, Res. Note RM-174. Rocky 
Mountain Forest and Range Experiment Station, Ft. Collins, Colorado. 8 

pp. 

Stoszek, K.J. 1977. Factors influencing tree and stand susceptibility to 
Douglas-fir tussock moth attack. Bull. Entomol . Soc. Amer. 23(3): 171-72. 


23 



24 


APPENDIX 1 


WESTERN SPRUCE BUDWORM 
EGG MASS-DEFOLIATION SURVEY 
Egg Mass Data Form 


Survey 

Code 

(1-3) 

222 

Form 

(4) 

2 

Year 

(5-6) 

Region 

(7-8) 

Host 

(9-10) 

Forest 

(11-12) 

Unit 

(13-14) 

Cl uster 
(15-17) 


T 

R 

E 

E 

B 

R 

A 

N 

C 

H 

Length 

cm 

Width 

cm 

Grid 

Area 

cm^ 

Mew Egg Masses 

Egg 

Viabil ity 

Old 

Egg 

Masses 

Number 

Rows 

Length 

mm 

"Good" "Bad" 
>50% . >50% 

18 

1 

1 

19-21 

22-24 

25-29 

30-32 

33-35 

36-38 

39-41 

42-44 

45-47 


2 

49-51 

52-54 

55-59 

60-62 

63-65 

66-68 

69-71 

72-74 

75-77 

18 

2 

1 

19-21 

22-24 

25-29 

30-32 

33-35 

36-38 

39-41 

42-44 

45-47 


2 

49-51 

52-54 

55-59 

60-62 

63-65 

66-68 

69-71 

72-74 

75-77 

18 

3 

1 

19-21 

22-24 

25-29 

80-32 

33-35 

36-38 

39-41 

42-44 

45-47 


2 

49-51 

52-54 

55-59 

60-62 

63-65 

66-68 

69-71 

72-74 

75-77 


COMMENTS 


Date Prepared by 


25 


APPENDIX 2 


WESTERN SPRUCE BUDWORM 
EGG MASS-DEFOLIATION SURVEY 
Defoliation Survey Data Form 


Survey 

Code 

Form 

Year 

Region 

Host 

Forest 

Unit 

Cluster 

(1-3) 

?22 

(4) 

3 

(3^ 

(7-8) 

(9-10) 

(11-12) 

(13-14) 

(15-17) 


Free 

Branch 

Defol i at ion 

Comments 


1 

(21-25) 


1 

2 

(26-30) 



3 

(31-35) 



4 

(36-40) 



1 

(41-45) 


2 

2 

(46-50) 



3 

(51-55) 



4 

(56-60) 



1 

(61-65) 


3 

2 

(66-70) 



3 

(71-75) 



4 

(76-80) 



COMMENTS 


Date 


Prepared by 


26 


APPENDIX 3 


Raw cluster level data. 

Northern Region (R-1) Douglas-fir 


Egg Mass Defol i at ion 


Forest 

Unit 

Cl uster 

■76 

■77 

■78 

■79 

■77 

■78 

■79 

2 

1 

1 

7.4 









3 

43.5 

119.6 



66.4 



2 

2 

2 

33.5 

15.7 



29.9 





4 

20.6 

2.0 



16.2 





5 

1.9 

.0 



14.5 





7 

1.7 

4.7 



13.6 





8 

0.8 

1.0 



15.6 



2 

3 

7 

10.4 







2 

4 

1 

24.0 









3 

2.1 

9.5 



23.2 



2 

5 

3 

80.6 

47.4 



53.2 





4 

5.6 

5.4 



25.3 



3 

1 

1 


5.1 



62.4 





2 

66.7 

22.1 

59.8 


31.2 

38.7 

33.2 



3 

41.4 




18.8 





4 



18.6 



39.8 

29.9 



5 

68.1 

29.3 

32.1 


54.7 

53.4 

36.7 



6 










7 










8 

14.1 

26.6 

16.7 


56.3 

46.7 

23.0 



9 

.0 

9.4 

7.0 


22.7 

35.3 

24.7 



10 

13.0 

15.1 

13.6 


55.7 

42.3 

39.4 



11 

10.6 

7.1 

17.0 


22.7 

55.1 

31.7 



12 



24.3 



69.7 

72.3 



13 



26.5 



29.6 

19.6 



14 



16.8 



69.7 

54.3 


27 


Northern Region cont'd 


Egg Mass Defol i at ion 

Forest Unit Cluster “’TC Hi '78 79 “77 78 79 


2 



13.8 


47.2 

33.4 

3 



14.5 


48.4 

29.0 

5 

33.3 






7 

27.5 


22.6 


59.3 

33.2 

8 

14.2 


27.2 


48.0 

31.6 

10 



17.8 


59.7 

20.7 

11 



45.7 


71.4 

38.7 

12 



20.9 


34.8 

31.3 

13 



12.3 


54.7 

30.2 

14 



31.6 


52.1 

23.8 

1 

68.5 

28.7 

26.7 

70.2 

86.2 


2 

23.4 

85.9 

89.6 

22.4 

80.2 

66.7 

3 

50.2 

56.6 

33.0 

80.2 

43.2 

17.2 

4 

60.4 

40.6 


77.7 



5 

31.0 

13.3 

30.7 

49.2 

27.7 


6 







7 

0.8 

1.1 

31.6 

23.3 

47.3 

38.9 

8 

89.2 

16.9 

31.1 

77.1 


29.3 

9 

96.8 

74.7 


85.5 



10 

111.7 

30.8 

15.1 

87.5 

82.7 

34.7 

11 

56.4 

13.7 

9.7 

78.6 

68.2 

47.4 

12 

78.1 

26.2 

26.7 

73.4 

68.8 

22.1 

13 

59.9 

40.5 

58.0 

80.3 

82.0 

31.4 

18 



57.6 


85.0 

21.0 

20 



35.0 


42.4 

14.0 

21 



39.5 


53.2 

16.2 

22 



44.3 


82.7 

40.4 

23 



21.1 


49.3 

18.4 

24 



53.0 


39.5 

17.7 

25 



36.9 


70.6 

21.5 


28 


Northern Region cont'd 


Egg Mass Defol iation 

Forest Unit Cluster ~T6 77 78 79 “77 78 79 


1 

11.3 

20.4 

5.8 

60.2 

61.8 

18.7 

2 

24.0 

2.2 

6.9 

30.3 

36.0 

24.8 

3 

75.6 

48.7 

30.9 

67.2 

44.4 

23.8 

4 

51.8 

31.3 

49.3 

40.7 

44.8 

29.3 

5 

43.0 

24.2 

29.5 

58.2 

60.2 

44.2 

6 

41.4 

36.2 

61.6 

49.7 

63.5 

63.4 

7 

21.7 

16.3 

8.1 

66.2 

83.1 

75.8 

8 

65.2 

100.00 


48.4 


50.2 

9 

56.5 

66.6 

78.1 

45.4 

58.7 

21.8 

10 

64.8 

14.5 

14.5 

85.9 

78.7 

21.9 

11 

105.0 

36.0 

24.0 

83.2 

75.7 

27.9 

12 

89.3 

52.2 

67.3 

72.9 

64.5 

38.4 

13 

26.4 

33.6 

40.2 

55.3 

60.9 

28.1 

14 

27.0 

28.0 

30.6 

67.2 

62.7 

23.9 

15 

12.6 

9.3 

5.6 

42.7 

32.6 

15.0 

16 

27.9 

25.5 


54.5 


49.0 

17 

9.4 






18 

1.6 

5.0 

19.2 

12.5 

55.0 

51.8 

19 

54.8 

24.7 

46.9 

79.1 

59.0 

41.7 

21 



68.2 


63.8 

33.8 

22 



31.1 


45.4 

33.8 

1 

55.7 

44.5 


87.5 



2 

95.4 

29.4 


87.5 


35.9 

3 

42.8 

50.1 

48.5 

87.1 

68.9 

54.6 

4 







5 

42.6 

55.5 

50.6 

69.9 

61.8 

55.5 

6 

87.9 

37.1 

51.8 

79.0 

35.7 

24.7 

7 

15.2 

15.8 

38.1 

63.4 

26.9 

26.8 

8 

11.2 

0.8 

80.0 

36.7 

29.7 

47.8 

9 

6.7 

0.9 

55.5 

34.1 

41.5 

54.8 

10 

18.9 

15.0 

55.6 

24.3 

23.6 

28.4 


29 


Northern Region cont'd 


Forest 

Unit 

Cl uster 


Egg 

Mass 



Defol i at ion 

■76 

■77 

■78 

■79 

■77 

■78 

■79 

11 

3 

11 

59.8 


101.7 



36.1 

50.7 



12 



108.0 



50.8 

25.5 



13 



47.3 



40.3 

16.9 



14 



19.7 



76.0 

46.2 



15 



280.8 



41.1 

33.6 



16 










17 



56.4 



52.2 

40.1 



18 



23.9 



25.2 

38.1 



19 



67.7 



52.7 

29.8 



20 



3.4 



36.8 

37.2 



21 



98.5 



53.8 

47.9 



22 







54.7 



23 



113.0 



53.2 


12 

1 

1 

7.3 

1.9 

6.7 


24.1 

23.6 

15.5 



2 










3 

18.9 

5.8 

15.8 


58.6 

37.3 

26.6 



4 










5 










6 










7 










8 

24.7 

50.1 

26.0 


61.9 

38.4 

43.8 



9 










10 










11 



34.3 



41.8 

45.7 



12 

37.7 

27.9 

44.4 


46.6 

48.3 

43.4 



13 










14 



37.3 



65.5 

61.5 



15 



22.1 



36.5 

30.2 



16 



25.8 



44.4 

25.2 



17 



49.8 



36.0 

23.9 



18 



49.3 



72.5 

47.6 


30 


Northern Region cont'd 


Egg Mass Defol iation 

Forest Unit Cluster '76 'll '78 '79 "’IT 78 79 


19 



41.4 


42.6 

39.3 

20 



77.5 


55.3 

43.8 

21 



72.5 


52.7 

46.5 

22 



35.2 


27.7 

43.5 

23 



9.4 


36.2 

22.1 

24 



68.6 


70.2 

41.8 

25 



61.8 


52.2 

59.2 

26 



13.8 


34.0 

27.7 

27 



48.5 


30.4 

30.4 

28 



2.8 


28.1 

16.2 

1 

5.1 

4.7 

18.0 

42.4 

40.8 

31.8 

2 







3 

43.2 

27.5 

59.4 

42.0 

22.0 

29.2 

7 



95.1 


38.8 

36.1 

9 



12.6 


26.3 

16.2 

10 



77.5 


46.2 

51.9 

11 



18.6 


18.5 

20.6 

12 



26.1 


27.2 

37.9 

13 



2.1 


35.7 

40.2 

14 



17.1 


43.2 

24.0 

15 



3.6 


25.2 

23.6 

16 



116.3 


57.2 

58.1 

17 



24.2 


28.1 

48.0 

18 



125.2 


55.2 

34.1 

19 



90.0 


20.7 

25.9 

20 



20.4 


26.7 

49.5 

22 



39.5 


52.1 

40.3 

2 







3 

2.0 

5.6 

7.8 

35.2 

37.3 


4 

5 

46.7 

25.5 

27.5 

53.0 

52.2 

57.9 

48.3 

20.7 


31 


Northern Region cont'd 


Egg Mass Defol i ation 

Forest Unit Cluster '76 'll ‘78 '79 'll ‘78 '79 

6 


10 







11 

.0 

1.3 

6.2 

26.0 

21.5 

16.7 

12 







13 



81.5 


49.2 

39.2 

14 



12.1 


34.4 


15 



18.5 


28.5 

20.6 

16 



7.7 


41.7 


17 



63.2 


81.3 

38.7 

2 



24.1 


63.7 


5 

10.9 

9.6 

39.1 

14.9 

26.2 

37.0 

6 



20.2 


42.2 

29.9 

10 

27.1 

52.8 

18.0 

83.2 

69.4 

34.4 

11 



44.8 


63.3 

17.9 

12 



62.9 


37.5 

43.9 

13 



53.6 


45.4 

19.1 

14 



4.3 


32.7 

15.8 

15 



27.2 


20.7 

40.8 

16 



14.7 


77.7 

25.6 


32 


Rocky Mountain Region (R-2) Douglas-fir 


Egg Mass Defol iation 

Forest Unit Cluster '76 'll '78 '79 'll '78 '79 


1 

3.4 

.0 

.0 


35.1 

67.3 


2 

.0 

1.7 

1.1 

5.4 

36.7 

69.2 

31.5 

3 

4.5 

.0 



18.0 



4 

3.3 

.0 

1.1 

1.1 

21.7 

17.5 

24.9 

5 

2.4 

2.8 

5.6 

13.0 

28.0 

28.8 

12.5 

6 

43.1 

23.4 

69.7 


76.7 

87.5 


7 

4.6 

6.6 

8.2 

7.0 

53.7 

68.8 

38.6 

8 

1.3 

.0 



12.5 



9 


9.6 

23.4 

25.0 


70.9 

43.8 

10 


17.2 

8.3 

1.8 


79.2 

42.1 

11 


16.6 

25.2 

16.8 


87.5 

87.5 

12 


3.3 

7.2 

13.4 


19.2 

32.7 

13 


40.2 

27.9 

10.8 


25.4 

19.6 

14 


3.9 

7.0 

8.2 


44.0 

41.2 

15 


9.7 

13.3 

18.7 


25.2 

49.4 

16 


15.6 

5.8 

34.7 


49.7 

44.2 

17 


17.7 

15.4 



53.2 


18 


13.3 

4.6 



43.9 


19 


16.1 

18.7 



64.1 


20 


15.9 

26.2 

31.1 


87.5 

80.2 

21 


16.0 

7.3 

18.2 


40.9 

54.5 

22 


13.7 

40.6 

32.1 


75.9 

74.2 

23 


18.5 

29.8 

41.1 


84.6 

83.8 

24 



16.0 





25 



12.3 





26 



51.9 

61.2 



86.7 

27 



4.0 

.0 



43.2 

28 



21.7 






33 


Rocky Mountain Region cont'd 


Egg Mass Defol i ation 

Forest Unit Cluster 'll '78 HT' ~ni m 


1 

18.9 

42.0 

57.3 

71.9 

2 

20.9 

92.0 

67.7 

64.3 

3 

32.9 

19.8 

57.1 

87.3 

4 

18.0 

34.7 

80.2 

82.6 

5 

32.3 

51.5 

69.2 

53.0 

6 

28.5 

43.0 

50.0 

72.2 

7 

1.5 

32.7 

87.5 

85.3 

8 

21.4 

97.9 

86.2 

52.7 

9 

17.4 

33.4 

76.6 

75.7 

10 

10.2 

23.5 

82.2 

57.5 

11 

5.7 

67.0 

86.1 

76.8 

12 

9.2 

11.2 

87.5 

87.2 

13 

9.1 

23.1 

87.5 

81.3 

14 

17.2 

19.0 

87.5 

69.7 

15 

30.4 

20.8 

87.5 

77.8 

16 

5.8 

2.4 

87.5 

87.2 

17 

13.7 

3.9 

87.5 

70.3 

18 

20.6 

60.8 

85.0 

57.8 

19 

11.3 

77.3 

62.2 

65.4 

20 

37.3 

67.3 

51.5 

61.5 

1 

3.0 

7.8 

21.2 

30.4 

2 

4.9 

6.4 

26.0 

34.4 

3 

4.3 

3.7 

28.4 

43.1 

4 

1.2 

22.4 

33.8 

31.3 

5 

12.1 

18.0 

28.1 

20.9 

6 

6.3 

2.9 

35.0 

38.8 

7 

5.1 

4.9 

41.6 

68.8 

8 

11.9 

6.0 

31.7 

32.2 

9 

5.6 

13.3 

50.0 

60.0 

10 

4.4 

• 

LO 

24.2 

31.3 


34 


Rocky Mountain Region cont'd 


Egg Mass Defoliation 

Forest Unit Cluster ~"76 Hi "78 HT ~ni TS 79 


3 




24.2 



82.7 

4 




25.2 



76.0 

5 




22.9 



57.1 

6 




24.0 



86.0 

7 




19.7 



58.1 

1 

42.6 

5.7 



87.5 



2 

11.0 

1.0 

1.8 


84.9 

27.7 


3 


2.8 

.0 

49.3 

38.2 

33.6 

17.2 

4 

15.4 

20.5 

2.2 

.0 

57.1 

19.7 

19.2 

5 


6.8 

2.0 

21.2 


17.2 

38.2 

6 


.0 

.0 

7.0 


14.7 

16.0 

7 


3.5 

4.8 





8 


10.5 




41.1 


9 


10.0 

1.4 



49.8 


10 

2.3 

4.5 



84.1 

42.4 


11 


3.4 

4.1 

2.5 


23.7 

46.6 

12 

20.9 

21.3 

2.3 

6.0 

54.4 

37.9 

23.6 

13 

8.8 

2.3 

1.1 

4.5 

69.7 

21.2 

13.4 

14 

16.8 

6.0 




25.4 


15 


4.4 

.0 



17.1 


77 






36.5 


1 


12.7 

45.5 



60.5 


2 


2.1 

47.8 



70.8 


3 


7.0 




64.7 


4 


6.5 

1.6 

16.6 


36.8 

25.9 

5 


5.6 

15.0 

41.7 


66.3 

63.9 

6 


12.5 




49.9 


7 


00 

• 

26.0 



64.8 


8 


9.2 

53.3 

4.0 


85.6 

82.4 

9 


13.5 

64.0 



61.1 



35 


Rocky Mountain cont'd 


Egg Mass Defoliation 

Forest Unit Cluster '76 'll '78 '79 'll '78 '79 


10 

2.3 

10.4 

11.5 

13.8 

39.7 

36.4 

51.6 

11 

58.1 

7.1 


22.1 

39.2 

63.7 

46.0 

12 

9.7 

.0 

26.7 

11.2 

33.2 

42.0 

48.2 

13 

.0 

9.1 

22.8 

19.4 

31.7 

72.5 

35.2 

14 


10.9 



40.7 

31.6 


15 


1.0 

27.5 

22.4 


63.4 

58.7 

16 


10.3 

23.2 

8.2 


82.2 

65.6 

17 


23.5 

45.6 


41.9 

81.3 

61.5 

18 

54.5 

12.4 

16.9 


51.4 

56.7 


19 


12.2 

7.1 

37.4 


62.1 

69.0 

20 


8.6 

33.9 

22.5 


40.9 

43.6 

21 


4.0 

31.5 

35.1 


71.6 

79.7 

1 



1.2 

5.7 


39.2 

30.5 

2 



8.0 

10.1 


44.6 

38.0 

1 



3.6 

2.5 


53.3 

69.0 

2 



3.8 

2.7 


32.7 

54.4 

3 



6.9 

3.4 


31.4 

52.6 

4 



7.5 

6.2 


30.8 

40.2 

5 



1.7 

.0 


29.2 

30.4 

6 



5.5 

.0 


32.2 

30.2 

7 



0.9 

8.1 


21.4 

19.8 

8 



1.3 

1.4 


35.3 

31.8 

9 



.0 

.0 



25.0 

10 



6.0 

.0 


32.4 

30.1 

11 



3.8 



44.8 


12 



3.9 



32.7 


13 



0.9 





1 



0.8 

1.0 



64.6 

2 



8.5 

1.4 



28.5 


36 


Rocky Mountain Region cont'd 


Egg Mass Defoliation 

Forest Unit Cluster Hi ^8 HW “T7 78 79 


3 

1.1 

.0 

40.8 

36.2 

4 

1.8 

1.0 

30.2 

42.2 

5 

1.1 

0.8 

30.2 

28.7 

1 

12.6 

6.7 

33.3 

30.2 

2 

15.1 

25.3 

46.3 

61.3 

3 

40.8 

25.6 

55.8 

65.1 

4 

34.8 

22.4 

31.7 

29.1 

5 

17.4 

16.0 

38.2 

32.7 

6 


36.3 


33.0 

7 


27.9 


55.2 

8 


13.9 


25.7 

9 


58.9 


57.2 

10 


55.9 


52.2 

11 


26.1 


44.7 

12 


33.1 


54.8 

13 


58.1 


35.3 

14 


6.5 


30.2 

15 


15.6 


37.2 

1 

3.8 

9.3 

16.7 

54.7 

2 

11.1 

0.9 

32.2 

39.5 

3 

15.5 

5.2 

18.8 

23.6 

4 

6.0 

CO 

• 

55.5 

68.0 

5 

1.7 

1.4 

20.8 

29.6 

6 

27.7 

17.8 

53.1 

57.9 

7 

62.5 

30.3 

44.5 

61.2 

8 

11.7 

24.3 

23.3 

36.4 

9 

26.2 

13.2 

52.0 

31.3 

10 

9.4 

11.3 

42.0 

34.5 

11 

21.6 

15.6 

42.2 

43.9 

12 

6.6 

2.0 

59.7 

43.2 


37 


Rocky Mountain Region cont'd 


Forest 

Unit 

Cl uster 


Egg Mass 


Defol i at ion 

■76 

00 

'79 

00 

UO 



13 


17.2 

7.6 

37.0 41.2 



14 



.0 

29.0 



15 



6.1 

35.4 



16 



15.5 

27.4 



17 



16.6 

62.7 



18 



15.0 

33.7 



19 



1.8 

17.6 



20 



12.2 

24.0 



21 



7.3 

28.1 



22 



9.2 

32.0 



23 



18.1 

31.7 



24 



1.7 

41.5 



25 



3.1 

30.3 

12 

8 

1 



2.7 

68.7 



2 



2.5 

63.2 



3 



1.3 

37.9 



4 



1.8 

36.9 



5 



1.4 

54.6 



17 



9.2 



38 


Southwestern Region (R-3) Douglas-fir 


Egg Mass Defol i at ion 

Forest Unit Cluster ' 76 ‘ 77 T8 ' 79 ' 77 T8 "79 


1 


18.8 

25.4 

33.8 


84.5 

75.0 

2 


31.9 

12.4 

39.2 


25.5 

53.1 

3 


10.7 

42.2 

68.0 


66.1 

67.8 

4 


10.7 

24.3 

36.0 


69.1 

63.4 

5 


0.7 

.0 

3.2 


21.2 

16.7 

6 


3.8 

3.2 

63.2 


20.6 

81.8 

7 


.0 

0.9 

15.9 


15.7 

25.3 

8 


3.3 

5.7 

87.8 


17.2 

65.2 

9 


10.4 

8.5 

115.8 


14.8 

84.8 

10 


2.1 

7.9 

11.0 


16.6 

26.6 

11 


.0 

.0 

.0 


38.3 

24.0 

12 


18.2 

21.1 

91.6 


18.2 

77.5 

13 


6.6 

13.2 

52.8 


35.7 

87.5 

14 


9.7 

33.4 

21.9 


65.2 


15 


14.6 

41.3 

40.9 


75.7 

83.6 

16 


7.3 

14.1 

25.2 


82.7 

85.2 

17 


24.9 

42.0 

38.5 


81.3 

86.3 

18 


12.1 

22.0 

52.2 


61.5 

80.6 

19 


8.9 

13.3 

32.1 


76.7 

86.2 

20 


2.8 

27.9 

33.8 


50.3 

87.4 

1 

53.4 

30.8 

39.5 

78.2 

87.5 

33.3 

80.2 

2 

50.9 

73.4 

65.9 

36.7 

82.8 

73.4 

65.7 

3 

20.7 

30.1 

23.9 

36.9 

62.8 

58.3 

46.2 

4 

56.7 

46.1 

71.4 

10.2 

87.2 

64.7 

70.9 

5 

17.4 

21.8 

71.3 

89.1 

73.7 

59.4 

76.7 

6 

36.9 

26.6 

44.8 

52.2 

83.6 

65.9 

64.9 

7 

49.3 

19.1 

46.6 

157.2 

83.6 

36.2 

76.1 

8 

44.9 

19.3 

6.6 

21.2 

87.2 

25.7 

34.9 

9 

37.9 

32.5 

25.6 

30.5 

86.6 

78.8 

57.7 


39 


Southwestern Region cont'd 


Egg Mass Defol iation 

Forest Unit Cluster “^'6 Hi ^ ^ 


10 

12.6 

3.9 

14.2 

21.8 

80.1 

53.9 

50.1 

11 


16.5 

39.4 

16.8 


73.1 

86.3 

12 


33.6 

46.9 

27.2 


67.7 

70.2 

13 


6.9 

6.7 

16.7 


65.4 

80.4 

14 


8.9 

26.7 

32.7 


65.7 

70.5 

15 


8.1 

12.4 

26.0 


34.2 

71.3 

16 


20.8 

83.1 

15.2 


50.5 

79.6 

17 


24.2 

35.6 

104.3 


68.2 

46.6 

18 


14.3 

44.7 

53.3 


33.6 

85.2 

19 


6.5 

1.0 

2.0 


31.1 

42.1 

20 


2.0 

18.9 

27.5 


52.6 

55.8 

1 

18.5 

21.0 

5.1 

20.5 

80.2 

20.7 

25.0 

2 

0.9 

2.4 


1.5 

20.8 


14.7 

3 

8.3 

7.4 


8.6 

45.1 


17.3 

4 

19.7 

15.0 



65.8 



5 

2.0 

22.1 

2.4 

15.0 

53.3 

43.6 


6 

7.9 

17.9 

4.0 

7.0 

41.7 

24.4 

16.2 

7 

2.9 

11.7 

23.8 

28.2 

64.2 

39.0 


8 

6.0 

4.4 

2.4 

22.7 

58.2 

27.7 


9 

6.8 

26.1 

9.9 

54.8 

64.7 

51.9 


10 

38.4 

34.0 

41.4 

114.9 

87.0 

57.6 


11 

32.5 

17.1 

16.5 

74.1 

84.2 

42.5 

60.4 

12 

69.4 

18.7 

40.6 

60.6 

86.1 

24.2 

62.9 

13 


8.3 

13.1 



22.2 


14 


17.8 

.0 



39.0 


15 


9.0 

35.4 



22.5 


16 


5.0 






17 


6.6 

.0 



38.9 


18 


3.7 

.0 



23.6 


19 


27.6 

29.2 



42.2 


20 


26.5 

49.8 



55.9 



40 


Southwestern Region cont'd 


Forest 

3 


Egg Mass Defoliation 


Cl uster 

■76 

■77 

■78 

■79 

■77 

■78 

■79 

1 

5.5 

7.7 

4.6 

42.9 

15.3 

24.4 

13.7 

2 

0.5 

1.1 

1.1 

1.1 

21.7 

13.2 

12.7 

3 

32.6 

6.1 

4.9 

14.0 

70.6 

20.5 

28.2 

4 

37.6 

3.7 

2.8 

3.8 

86.7 

13.7 

12.9 

5 

4.6 

.0 

1.2 

.0 

32.3 

14.0 

12.8 

6 

18.7 

3.1 

.0 

7.0 

87.2 

16.5 

12.9 

7 

18.3 

4.4 

1.8 

3.9 

85.4 

13.5 

15.4 

8 

10.2 

4.7 

2.7 

1.1 

87.5 

19.7 

13.4 

9 

21.0 

.0 

5.0 

3.8 

87.0 

14.5 

25.3 

10 

1.8 

7.1 

11.3 

28.4 

45.2 

37.8 


11 


4.4 

3.3 



26.7 


12 


3.1 

0.8 

.0 


17.1 

13.1 

13 


.0 

0.9 

.0 


13.2 

19.2 

14 


3.7 

1.0 



13.2 


15 


15.6 

3.3 

3.6 


14.9 

14.7 

16 


11.9 

0.9 

3.1 


17.1 

14.8 

17 


3.0 

1.9 



15.7 


18 


3.6 

.0 

.0 


16.2 

12.7 

19 


4.4 

3.5 

.0 


15.3 

17.3 

20 


.0 

.0 

19.9 


13.7 

12.7 

1 

14.4 

1.9 

.0 

1.0 

73.2 

12.8 

16.7 

2 

9.4 

28.4 

3.5 


72.2 

21.5 

14.2 

3 

12.4 

8.1 

9.8 

31.1 

59.0 

28.9 

14.3 

4 

6.9 

4.3 

8.5 

13.7 

57.2 

30.9 

12.6 

5 

11.1 

6.4 

3.8 

19.0 

45.7 

24.6 

13.9 

6 

1.4 

7.0 

2.1 

7.3 

42.1 

18.2 

12.7 

7 

13.5 

22.5 

2.1 

4.9 

74.6 

15.5 

14.1 

8 

12.3 

14.7 

1.1 

8.2 

46.2 

20.6 

17.0 

9 

7.9 

6.3 

1.1 

20.9 

41.7 

13.2 

13.7 

10 

6.9 

5.2 

3.1 

33.2 

54.2 

20.1 

15.1 


41 


Southwestern Region cont'd 


Egg Mass Defoliation 

Forest Unit Cluster '76 '77 '78 'IT ~ni 78 79 


1 

3.7 

1.9 


.0 

40.9 


13.6 

2 

1.8 

.0 

.0 

.0 

12.5 

14.1 

14.0 

3 

49.8 

85.4 

52.2 

58.1 

78.1 

86.3 

75.0 

4 

55.0 

43.4 

58.5 

17.8 

78.7 

81.1 

86.7 

5 

14.4 

21.4 

38.7 

30.0 

41.2 

63.4 

68.5 

6 

6.4 

3.5 

1.7 

62.9 

44.4 

24.1 

80.4 

7 

19.2 

16.0 

70.9 

43.2 

68.1 

85.4 

87.3 

8 

1.1 

1.1 

1.4 

.0 

13.1 

21.2 

22.1 

9 

12.6 

2.8 

12.3 

20.8 

56.1 

67.8 

57.7 

10 

12.3 

5.8 

1.1 

.0 

26.0 

18.9 

13.3 

11 


1.3 

4.8 

.0 


13.3 

12.8 

12 


39.7 

35.8 

28.9 


82.4 

55.1 

13 


9.0 

22.3 

13.5 


77.1 

59.6 

14 


15.8 

23.2 

21.8 


83.7 

56.0 

15 


74.6 

20.4 

52.6 


86.7 

60.9 

16 


18.4 

19.6 

22.9 


55.5 

54.8 

17 


41.2 

54.0 

53.9 


87.0 

57.4 

18 


15.1 

25.3 

28.9 


47.2 

37.0 

19 


68.1 

116.3 

13.4 


86.6 

81.5 

20 


103.2 

44.5 

52.4 


87.2 

60.3 

1 

11.4 




51.7 



2 

13.2 




77.5 



3 

32.0 




67.7 



4 

13.6 




73.9 



5 

7.6 




79.9 



6 

20.1 




87.2 



7 

4.3 




59,9 



8 

14.9 




85.7 



9 

38.6 




84.3 



10 

14.7 




73.0 




42 


Intermountain Region (R-4) Douglas-fir 


Eqq Mass Defol i at ion 

Forest Unit Cluster '76 'll '78 '79 *77 '78 ‘79 

Ogden Zone 


1 

26.0 

1.7 

9.8 

8.3 

47.2 

37.0 

16.4 

2 

24.7 

4.4 

33.4 

16.0 

16.7 

27.6 

65.8 

3 

29.8 

23.9 

69.8 

8.5 

16.2 

49.7 

13.9 

4 

33.1 

19.3 

27.6 

6.0 

30.6 

49.8 

22.1 

5 

60.8 

27.7 

55.1 

2.8 

53.2 

54.7 

14.0 

6 

28.6 

17.2 

16.8 

22.9 

31.5 

48.2 

40.1 

7 

58.7 

11.3 

2.1 

7.8 

23.7 

26.7 


8 

39.7 

37.5 

2.6 

2.0 

72.4 

84.0 

30.6 

9 

18.8 

25.7 

102.8 

8.8 

32.3 

55.5 

18.1 

10 

9.1 

26.4 

52.5 

63.2 

25.2 

27.7 

66.7 

11 

45.2 

2.1 

65.8 

38.5 

39.1 

69.3 

26.1 

12 

8.7 

20.9 

37.1 

20.5 

36.6 

62.3 

46.2 

13 

9.1 

1.3 

26.2 

4.0 

17.3 

23.0 

14.5 

14 

41.5 

62.5 

75.3 

51.9 

37.9 

78.5 

65.0 

15 

55.5 

52.6 

47.4 

51.2 

35.7 

38.9 

37.5 

16 

34.5 

19.3 

29.9 

11.2 

36.5 

57.7 

18.6 

17 

44.7 

11.0 

54.9 


21.1 

20.2 


18 

75.6 

58.7 

38.9 

19.0 

60.7 

84.2 

22.7 

19 

21.6 

29.5 

31.7 

25.9 

19.8 

56.3 

40.9 

20 

22.9 

31.6 

74.0 

14.9 

49.2 

38.2 

14.2 

21 

26.3 

1.1 

18.1 

5.8 

63.7 

57.3 


22 

75.9 

51.9 


22.8 

37.3 


26.7 

23 

41.0 

16.4 

68.7 

27.0 

20.0 

31.4 

86.0 

24 

40.6 

6.0 

65.7 

26.4 

14.9 

31.7 

75.6 

25 

34.1 

10.1 

55.2 

31.7 

20.3 

20.9 

25.6 

26 

76.6 

70.8 

67.7 

33.1 

37.9 

55.2 

13.9 

27 


18.2 

40.8 

13.2 

29.8 

33.6 

19.7 

28 

6.8 

6.6 


0.8 

23.0 

13.5 

23.9 

29 


20.7 


2.4 

67.4 


20.8 


43 


Intermountain Region cont'd 


Egg Mass Defoliation 

Forest Unit Cluster '76 '77 '78 '79 '77 '78 '79 


30 


.0 

2.5 

.0 

13.7 


14.2 

31 


59.5 


3.7 

17.7 


16.5 

32 

14.7 

7.0 


7.7 

21.7 

22.0 

17.7 

33 


17.4 

19.3 

22.1 

18.2 

24.1 

14.0 

34 

0.8 

5.8 


4.1 

13.7 

19.2 

23.6 

35 


17.5 

38.8 

18.0 

41.3 

31.4 

16.2 

36 


38.0 

63.3 

20.0 

40.8 

58.7 

14.2 

37 


5.4 

39.5 

41.9 

45.8 

31.7 

85.1 

38 


37.0 

55.7 

33.2 

24.3 

62.0 

78.4 

39 


17.7 



38.0 



40 


1.0 



22.2 



1 

.0 

1.0 

0.7 

1.8 

15.3 

17.9 

26.2 

2 

.0 

.0 

.0 

1.6 

15.4 

15.7 

26.6 

3 

.0 

.0 

.0 


19.2 

14.0 


4 

4.6 

10.4 

29.5 

34.6 

33.1 

41.1 

44.3 

5 

.0 

2.7 

6.5 

6.1 

19.7 

25.3 

41.4 

6 

0.9 

3.2 

9.9 


28.1 

21.2 

17.2 

7 

0.9 

0.8 

6.0 

7.2 

21.8 

20.6 

31.7 

8 

6.9 

17.5 

24.5 

19.6 

57.0 

51.2 

42.8 

9 

1.8 

0.8 

8.2 

5.9 

18.8 

22.7 

39.8 

10 

.0 

.0 

.0 

0.7 

17.0 

14.7 

20.2 

11 

2.9 

.0 

1.8 

4.0 

19.9 

16.3 

28.6 

12 

.0 

.0 

2.3 

0.9 

13.1 

16.7 

15.3 

13 

2.0 

8.7 

27.2 

97.0 

12.8 

20.2 

54.0 

14 

.0 

2.5 

6.8 

7.9 

15.5 

14.9 

39.5 

15 

0.7 

.0 

1.8 

18.2 

14.8 

13.2 

35.6 

16 

.0 

2.0 

3.0 

9.4 

14.7 

17.2 

22.2 

17 

0.9 

0.8 

6.1 

11.8 

16.9 

15.7 

57.7 

18 

.0 

4.3 

1.9 

12.8 

18.2 

22.1 

37.1 

19 

.0 

1.2 

24.9 

4.5 

17.4 

19.6 

18.9 


44 


Intermountain Region cont'd 


Egg Mass Defoliation 

Forest Unit Cluster ""TB -.yg rjg- -rjj 


1 

8.7 

23.7 

16.0 

22.5 

46.0 

60.7 

57.9 

2 

59.6 

66.9 

79.0 

40.7 

58.4 

75.7 

87.5 

3 

0.7 

.0 

.0 

.0 

13.3 

13.7 

16.4 

4 

10.7 

2.2 

16.5 

5.9 

19.4 

24.2 

53.0 

5 

.0 

.0 

.0 

1.3 

14.7 

13.9 

13.7 

6 

56.0 

51.9 

58.2 

88.0 

57.5 

66.9 

62.1 

7 

35.2 

14.5 

22.1 

29.5 

37.2 

51.3 

58.4 

8 

.0 

1.7 

1.0 

.0 

19.6 

14.7 

14.8 

9 

.0 

3.4 

7.9 

17.7 

19.8 

36.2 

42.3 

10 

2.1 

0.9 

5.3 

12.1 

22.7 

16.5 

61.3 

11 

3.5 

.0 

4.6 

12.7 

20.7 

16.4 

32.7 

12 

2.2 

.0 

6.4 

3.6 

20.2 

22.9 

34.7 

13 

47.2 

28.0 

25.3 

12.5 

40.7 

39.0 

70.2 

14 

81.6 

41.3 

58.4 

32.2 

36.4 

46.0 

55.0 

15 

17.8 

26.3 

56.1 

75.8 

34.2 

40.2 

82.6 

16 

90.3 

43.7 

63.5 

41.9 

54.0 

72.1 

87.5 

17 

15.6 

5.4 

11.8 

21.0 

31.6 

41.7 

55.9 

18 

.0 

.0 

.0 

1.2 

14.4 

18.0 

13.3 

19 

3.2 

29.1 

23.9 

63.6 

32.7 

55.3 

68.6 

20 

44.1 

10.0 

15.4 

12.6 

29.5 

32.6 

51.7 

21 

2.8 

1.5 

4.6 

19.4 

22.0 

24.2 

62.2 

22 

.0 

.0 

1.0 

.0 

13.9 

14.8 

14.2 

23 

48.7 

18.3 

24.8 

7.5 

45.2 

55.2 

67.9 

24 

2.8 

2.7 

9.1 


27.4 

48.2 


25 

40.6 

25.7 

16.9 

29.1 

67.2 

83.8 

73.7 

26 

1.7 

.0 

1.8 


13.4 

15.2 


27 

88.0 

29.0 

65.6 

61.1 

28.6 

68.5 

75.2 

1 

.0 

.0 

.0 

1.3 

16.7 

13.9 

13.3 

2 

.0 

1.2 

2.3 

.0 

17.4 

15.1 

15.8 

3 

0.8 

1.1 

8.5 


12.8 

15.7 


4 

.0 

1.7 

7.2 

22.3 

12.6 

18.1 

62.8 


45 


Intermountain Region cont'd 


Forest Unit 

15 2 


Boise Zone 
12 20 


Eqq Mass Defoliation 

Cluster '77 '78 ^ ~^77 ^78 7^ 


5 

1.6 

0.7 

3.5 

.0 

16.4 

18.2 

14.5 

6 

22.2 

10.4 

21.7 

28.0 

25.4 

24.7 

25.8 

7 

1.6 

.0 

3.7 

1.3 

12.8 

15.8 

15.2 

8 

1.7 

2.3 

.0 

.0 

14.5 

13.6 

14.7 

9 

7.7 

1.1 

6.2 

2.1 

12.8 

13.7 

16.7 

10 

2.6 

.0 

1.9 

1.9 

16.1 

13.3 

21.3 

11 

25.8 

9.9 

18.5 

30.0 

15.1 

18.5 

48.0 

12 

6.4 

5.3 

5.8 


22.6 

14.9 


13 

.0 

.0 

4.3 

0.9 

13.6 

12.5 

14.6 

14 

1.9 

1.2 

0.9 

4.0 

15.2 

14.4 

19.1 

15 

.0 

.0 

0.9 

.0 

19.4 

13.7 

13.5 

16 

64.5 

17.1 


17.8 

42.6 


30.3 

17 

.0 

2.5 

1.0 

3.9 

17.0 

15.8 

27.2 

18 

5.6 

2.4 

2.8 

4.4 

13.7 

15.3 

15.3 

19 

1.2 

3.9 

1.8 

1.3 

16.7 

13.5 

13.1 

20 

4.8 

1.7 

2.7 

0.7 

12.7 

17.5 

20.7 

21 

7.0 

1.3 

19.0 

5.4 

21.1 

20.2 

35.8 

22 

2.0 

.0 

1.1 

0.8 

13.2 

15.2 

13.6 

23 

3.6 

2.8 

.0 

.0 

13.0 

14.7 

16.4 

24 

.0 

.0 

.0 

4.5 

13.1 

12.5 

14.9 

25 

0.8 

1.7 

2.0 

1.6 

15.8 

13.4 

13.6 

1 

15.2 




87.5 



3 

18.8 




87.5 



5 


.0 





23.2 

8 

2.6 




64.1 



10 

2.6 




19.5 



11 

17.8 

3.3 

6.2 


48.1 

30.9 

21.3 

13 

9.1 




81.1 



19 

4.3 







21 

8.1 




71.7 




46 


Intermountain Region cont'd 


Egg Mass Defol i at Ion 


Forest 

Unit 

Cl uster 

•76 

'll 

'18 

'79 

'll 

'18 

'79 

12 

30 

5 

3.0 

.0 

6.4 

3.6 


15.3 

16.3 

12 

40 

1 



2.6 

.0 


13.2 

20.7 



3 

2.1 

.0 

1.9 

5.5 


13.1 

15.2 



5 

0.7 

.0 

1.4 

3.2 


13.6 

27.8 



7 




9.7 



33.7 



9 

15.0 




83.2 





10 


.0 








15 

5.9 




81.1 





26 


.0 






12 

50 

1 


1.4 

.0 

.0 



14.5 



2 


.0 

0.8 

.0 


13.4 

16.7 



3 


.0 

2.7 

0.7 


13.4 

18.0 



4 


.0 

3.4 

0.8 


12.7 

21.0 



5 


.0 

.0 

0.6 


14.4 

26.5 



6 










7 


3.7 

.0 



13.7 

17.1 



8 


3.4 

.0 

2.7 


12.5 

25.7 



9 

6.9 

3.8 

8.0 

2.7 

65.6 

29.7 

34.6 



10 


5.9 

3.1 

2.1 


14.1 

18.3 



11 

8.2 

6.8 

1.7 

1.3 

43.3 

18.4 

40.2 



12 










13 










14 


11.1 

4.6 

1.1 


13.3 

23.2 



15 


4.0 

5.1 



15.7 




16 


6.3 

3.7 



18.2 




17 










18 

5.1 

5.4 

5.8 


71.7 

12.8 




19 


5.1 

1.5 

.0 


14.4 

18.8 



20 


0.6 

8.0 

1.9 


47.7 

65.4 



21 

.0 

3.8 

1.1 

.0 

37.1 

14.9 

20.9 


47 


Intermountain Region cont'd 


Forest 

Unit 

Cl uster 

* ,^99 

Mass 


Defol i at ion 

77 

00 

■79 

CO 

7^ 



22 

8.0 

20.5 

3.7 

16.2 

29.6 



23 

10.1 3.8 

1.7 

.0 

55.2 29.3 

55.8 



24 

11.1 

4.2 


35.7 




25 

3.6 

1.2 

0.7 

21.9 

17.8 

13 

80 

1 


21.9 

14.5 


42.0 



2 


20.2 

19.6 


26.8 



3 


6.8 

7.2 


40.5 



4 


4.2 

3.4 


20.1 



5 


9.5 

3.9 


53.7 



6 


6.3 

3.3 


35.2 



7 


20.5 

6.9 


37.7 



8 


14.0 

10.0 


30.7 



9 


34.0 

17.4 


50.2 



10 


65.6 

47.1 


55.7 



11 


43.0 

38.8 


28.2 



12 


6.2 

5.2 


19.5 



13 


27.0 

11.6 


26.3 



14 


183.6 

71.0 


41.2 



15 


39.3 

8.8 


56.3 



16 


22.0 

26.7 


57.1 



17 


61.8 

37.3 


32.0 



18 


81.9 

23.0 


21.2 



19 


15.8 

19.8 


40.9 



20 


12.7 

21.0 


53.7 


48 


APPENDIX 4 


Egg mass and defoliation means and standard errors (S.E.) by 
Forest, unit, and year. 


Northern Region (R-1) Douglas-fir 


Forest 

Unit 

Year 

Egg Mass Densities 


Defol i at ion 

n 

Mean 

S.E. 

n 

Mean 

S.E. 

2 

** 

76-77 

12 

19.3 

6.9 

9 

28.7 

6.3 



77-78 

9 

22.8 

13.0 

— 

— 

-- 



78-79 

-- 

-- 

-- 

-- 

-- 

— 



79-80 

-- 

-- 

-- 

-- 

— 

-- 

3 

** 

76-77 

10 

28.9 

7.5 

8 

40.6 

6.5 



77-78 

7 

16.4 

3.7 

19 

50.3 

2.8 



78-79 

19 

23.1 

2.9 

19 

33.5 

2.8 



79-80 

-- 

-- 

-- 

-- 

-- 

-- 

11 

1 

76-77 

12 

60.5 

9.2 

12 

67.1 

6.6 



77-78 

12 

35.8 

7.4 

16 

63.1 

4.9 



78-79 

17 

37.6 

4.6 

15 

29.1 

3.8 



79-80 

-- 

— 

-- 

— 

-- 

— 


2 

76-77 

19 

42.6 

6.6 

18 

56.7 

4.4 



77-78 

18 

31.9 

5.6 

18 

58.4 

3.2 



78-79 

18 

34.3 

5.5 

20 

35.9 

3.6 



79-80 

-- 

-- 

-- 

-- 

-- 

-- 


3 

76-77 

10 

43.6 

9.9 

9 

63.3 

8.4 



77-78 

9 

27.7 

6.9 

18 

44.8 

3.5 



78-79 

18 

72.2 

14.2 

19 

39.4 

2.8 



79-80 

-- 

— 

-- 

-- 

-- 

— 


** 

76-77 

41 

48.1 

4.7 

39 

61.4 

3.5 



77-78 

39 

32.1 

3.8 

52 

55.1 

2.2 



78-79 

53 

48.2 

5.4 

54 

35.2 

2.0 



79-80 

-- 

-- 

— 

-- 

— 

-- 

12 

** 

76-77 

11 

20.3 

5.1 

11 

44.3 

5.9 



77-78 

11 

19.3 

5.7 

55 

42.1 

2.1 



78-79 

55 

37.7 

4.0 

50 

34.0 

1.7 



79-80 

— 

— 

— 

-- 

-- 

-- 


.49 


Rocky Mountain Region (R-2) Douglas-fir 


Forest 

Unit 

Year 

Egg Mass Densities 


Defol i at ion 

n 

Mean 

• 

LU 

• 

n 

Mean 

S.E. 

10 

★* 

76-77 

8 

7.8 

5.1 

8 

35.3 

7.5 



77-78 

23 

11.4 

2.0 

51 

59.5 

3.4 



78-79 

46 

17.7 

2.1 

53 

58.1 

3.0 



79-80 

53 

25.8 

3.2 

— 

-- 

— 

12 


76-77 

12 

20.2 

5.9 

14 

53.8 

5.3 



77-78 

36 

8.1 

1.0 

69 

42.6 

2.1 



78-79 

66 

14.1 

2.0 

82 

41.7 

1.8 



79-80 

82 

13.3 

1.6 

-- 

-- 

— 


50 


Southwestern Region (R-3) Douglas-fir 


Forest 

Unit 

Year 

Egg Mass Densities 


Defol iation 

n 

Mean 

S.E. 

n 

Mean 

S.E. 

2 

13 

76-77 

-- 

-- 

-- 

-- 

-- 

-- 



77-78 

20 

9.9 

1.9 

20 

46.9 

6.0 



78-79 

20 

17.9 

3.1 

19 

66.2 

5.7 



79-80 

20 

43.1 

6.7 

-- 

-- 

-- 


16 

76-77 

10 

38.1 

5.1 

10 

81.5 

2.5 



77-78 

20 

22.3 

3.7 

20 

54.6 

3.7 



78-79 

20 

36.3 

5.3 

20 

65.6 

3.4 



79-80 

20 

42.8 

8.5 

-- 

-- 

-- 

3 

8 

76-77 

12 

17.8 

5.8 

12 

62.6 

5.9 



77-78 

20 

15.1 

2.1 

16 

36.0 

3.1 



78-79 

16 

17.1 

4.3 

6 

32.8 

9.3 



79-80 

11 

37.1 

10.6 

-- 

— 

-- 


15 

76-77 

10 

15.1 

4.1 

10 

61.9 

9.5 



77-78 

20 

4.4 

0.9 

20 

17.5 

1.4 



78-79 

20 

2.6 

0.6 

16 

15.7 

1.2 



79-80 

17 

7.8 

2.9 

-- 

-- 

— 

6 

4 

76-77 

10 

9.6 

1.2 

10 

56.6 

4.1 



77-78 

10 

10.5 

2.7 

10 

20.6 

1.9 



78-79 

10 

3.5 

1.0 

10 

14.4 

0.5 



79-80 

9 

15.5 

3.8 

-- 

-- 

-- 

7 

7 

76-77 

10 

17.6 

6.1 

10 

45.9 

7.7 



77-78 

20 

28.4 

7.0 

19 

61.5 

6.6 



78-79 

19 

31.7 

6.8 

20 

52.7 

5.7 



79-80 

20 

26.1 

4.8 

-- 

-- 

-- 

10 

5 

76-77 

10 

17.0 

3.4 

10 

74.1 

3.7 



77-78 

-- 

-- 

— 

-- 

-- 

-- 



78-79 

-- 

-- 

-- 

-- 

-- 

-- 



79-80 

-- 

-- 

-- 

-- 

-- 

-- 


51 


Intermountain Region (R-4) Douglas-fir 


Egg Mass Densities Defo1 iation 


Forest 

Unit 

Year 

n 

Mean 

S.E. 

n 

Mean 

S.E. 

Ogden 

Zone 








3 

3 

76-77 

29 

34.7 

3.9 

40 

32.9 

2.4 



77-78 

40 

22.3 

3.0 

34 

43.6 

3.3 



78-79 

32 

43.4 

4.3 

35 

33.7 

3.9 



79-80 

37 

18.8 

2.6 

-- 

-- 

-- 

13 

4 

76-77 

19 

1.1 

0.4 

19 

20.5 

2.3 



77-78 

19 

2.9 

1.0 

19 

21.1 

2.2 



78-79 

19 

8.5 

2.3 

18 

33.3 

2.9 



79-80 

17 

14.3 

5.6 

-- 

-- 

-- 

15 

1 

76-77 

27 

24.6 

5.7 

27 

31.1 

3.0 



77-78 

27 

15.8 

3.6 

27 

39.6 

4.2 



78-79 

27 

22.0 

4.6 

25 

52.5 

4.7 



79-80 

25 

24.5 

5.0 

-- 

— 

-- 

15 

2 

76-77 

25 

6.5 

2.7 

25 

16.9 

1.3 



77-78 

25 

2.7 

0.8 

24 

15.6 

0.6 



78-79 

24 

4.8 

1.3 

23 

21.6 

2.6 



79-80 

23 

5.7 

1.9 

-- 

-- 

-- 

Boi se 

Zone 








12 

** 

76-77 

18 

7.5 

1.4 

14 

64.1 

5.6 



77-78 

28 

3.3 

0.6 

25 

18.7 

1.8 



78-79 

26 

3.7 

0.8 

24 

25.9 

2.6 



79-80 

21 

1.9 

0.5 

-- 

-- 

— 

13 

80 

76-77 

-- 

-- 

-- 

-- 

-- 

-- 



77-78 

— 

-- 

-- 

-- 

-- 

-- 



78-79 

20 

34.8 

9.2 

20 

38 . 5 

2.9 



79-80 

20 

19.8 

3.9 






52