Survival and Development of the Flat-Headed Fir Borer in Forest

AN ABSTRACT OF THE THESIS OF

DONALD W. SCOTT for the degree of DOCTOR OF PHILOSOPHY in Entomology, Forest presented on August 11, 1978 Title: SURVIVAL AND DEVELOPMENT OF THE FLATHEADED FIR BORER IN FOREST RESIDUES AS AFFECTED BY

HOST AND MICROC TIC CONDI ONS Abstract approved: Redacted for Privacy

The purpose of this study was to examine various host and microclimatic influences affecting the survival and development of the flatheaded fir borer, Melanophila drummondi (Kirby) in Douglas - fir, Pseudotsuga menziesii (Mirbel) Franco residues. It also expands current knowledge of the biology, bionomics, life history, ecology, and biotic potential for decomposition of forest residues by this insect. The primary study objective was to determine the optimum host and microclimatic conditions for development of the flatheaded fir borer by measuring the rate of beetle development with an index employed in other studies on forest insects. The monthly rates of development of larvae from clearcut and partial cut (shelterwood system) logs and from 15.6°, 21.1o, and 26.7oC controlled-temperature rearings were determined over the development season. Inner phloem moisture content and pH were monitored monthly from four quadrants (south-top, south-bottom, north-bottom, and north-top) on logs from each treatment throughout the season. Measurements of ambient air temperature and precipitation for the two field sites were used to correlate the microclimate of the host to these physical factors of weather. In addition, various other studies examined the relationship between inner phloem temperature and ambient air temperature on cloudy and clear days and also between logs of different bark thicknesses, and at the top and bottom of a log. Forest residues are attacked immediately after they become available from timber cutting or tree mortality in the spring and summer. Tops down to 7.62 cm in diameter are utilized by this beetle, although thinner bark of small diameter residues afford less protection from temperature extremes, parasites and avian predators than thick-barked residues. Eggs are typically deposited on the tops or upper sides of logs and residues by woodborers, and they also prefer clearcuts over partial cuts. Furthermore, larval densities are higher on the tops and sides of residues and on clearcuts, compared to other locations. The top portion and upper sides of residues are characterized by warmer inner phloem temperatures, lower moisture contents, and less acidity than the bottom half of logs and residues on the ground. In addition, clearcut logs are generally characterized by these qualities. Temperature and moisture differences around the logs are believed to affect the distribution of the flatheaded woodborers within logs. Although the flatheaded fir borer invades residues on both clearcuts and partial cuts, the clearcuts are preferred because of warmer temperatures. The rate of development is also greatest on clearcuts, and maturity to adult is reached sooner due to faster accumulation of heat units on these sites. The clearcut represents optimal conditions for development and survival of this insect. Larvae reared at three different constant temperatures in the laboratory failed to develop past the 3rd instar (pre-pupa), presumably because of the lack of a cold period which is required to break diapause in this resting stage. Parasitism accounts for the greatest proportion of woodborer mortality. Other mortality factors include resinoisis, predation, and unknown causes. Various parasites were reared and identified as mortality factors, but Atanycolus longifemoralis Shenefelt was most frequently observed. Other parasites and predators are discussed in their role as natural enemies of the flatheaded fir borer. An accurate and precise linear regression method is described which enables the estimation of inner phloem surface area of larval galleries from measurements of the gallery length. Its use in estimating woodborer-caused deterioration in forest residue surveys is emphasized. Survival and Development of the Flatheaded Fir Borer in Forest Residues as Affected by Host and Microclimatic Conditions

by Donald Wayne Scott

A THESIS submitted to Oregon State University

in partial fulfillment of the requirements for the degree of Doctor of Philosophy Completed August 1978 Commencement June 1979 APPROVED:

Redacted for Privacy Professor of Entomology in charge of major

Redacted for Privacy Chairman of Department of Ento gy

Redacted for Privacy Dean of Graduate School

Date thesis is presented August 11, 1978 Typed by Ilene Anderton for Donald Wayne Scott ACKNOWLEDGEMENTS

I am gratefully indebted to the many individuals who contributed valuable advice and assistance during the course of this study. Appreciation is extended to Dr. William P. Nagel for accepting me into a graduate study program under his guidance at Oregon State University. I am especially grateful to Dr. Ralph E. Berry for taking over the major responsibility of guiding my graduate program following the resignation of Dr. Nagel from the university, and also for the many helpful comments and suggestions he offered on the research and in writing the thesis. Special thanks are due to Boyd E. Wickman of the U.S. Forest Service's Pacific Northwest Forest and Range Experiment Station for serving in the capacity of research director. I am grateful for his encouragement and the valuable technical advice and consultation he provided in the conduct of my research. I would also like to thank the other members of graduate committee: Drs. Robert I. Cara, Clarence G. Thompson, Richard G. Clarke, and Lyle R. Brown who offered many useful comments and advice during the course of the study. I wish to thank Dr. Kuo C. Lu, John D. Lattin, Julius A. Rudinsky, William P. Stephen, Dennis M. Burgett, and Robert L. Goulding for the use of laboratory facilities and equipment. Finally, I wish to express my sincere appreciation to my parents who have inspired and encouraged me to seek knowledge, and to my loving wife, Kathy, without whose sustain- ing encouragement, enduring patience, and personal sacrifice this would not have been possible. Support for this research was provided by the United States Department of Agriculture, Forest Service, Cooperative Research Agreement 16 USC 581; 581a-581i, Supplement Numbers 131 and 193. TABLE OF CONTENTS

Chapter Page

I. INTRODUCTION 1

II. OBJECTIVES OF THE STUDY 5

III. DEFINITION OF TERMS 9

IV. SPECIES STUDIED 12 General Description and Terminology of Flatheaded Borers 12 Distribution 15 Host Record 15 Life History and Biology 16 Flight 21 Attack Behavior 25 Basking Behavior 28 Host Selection and Orientation 30

V. MATERLALS AND METHODS 33 Field Study Sites 33 Entomology Farm 33 McDonald Forest Site 34 Experimental Design and Field Plot Layout 36 Design for Development and Survival Studies 36 Log Sampling Method 39 Bark pH Determination 40 Bark Moisture Content Determination 42 Log Sampling Schedule 42 Design for Physicochemical Studies 44 Instrument Calibrations 45 pH Meter 45 Hyg rothe rmographs 46 Yellow Springs Instrument Tele-Thermometer 47 Beetles 48 Identification 48 Ins tar Determination 50 Development Index 54 Flight Occurrence 56 Calculation of Monthly Thermal Units 57 Measurement of Larval Galleries 59 Chapter Page.

Weather Measurements 60 Statistical Analysis and Computer Graphics 61

VI. RESULTS AND DISCUSSION 63 Biological Investigations Woodborer Species Attacking Logs 63 Distribution of Woodborers Within Logs 64 Frequency of Woodborer Occurrence by Quadrant 64 Woodborer Densities by Quadrant 74 Relationship Between Log Diameter, Bark Thickness, and Beetle Attack 79 Beetle Development 82 Comparison of Developmental Rates 84 Effect of Temperature 97 Development Related to Log Exposure 103 Beetle Mortality 105 Larval Mortality Distribution Within Logs 105 Larval Mortality Factors and Their Relative Efficacies 108 Parasitism 110 Unknown Causes 111 Resinosis 113 Predation 113 Seasonal Mortality Trends and Population Point Estimates 115 Regression Estimation of Gallery Surface Area 120 The Role of Microclimate on Host Bark and the Flatheaded Fir Borer 124 Host-Microclimate Interactions 124 Moisture Content 124 pH 136 Factorial Analysis (Moisture Content and pH) 143 Temperature Studies 143 Beetle -Microclimate Interactions 162 Effect on Woodborer Distribution 162 Effect on Food Quality 165 Effect on Rate of Development 167 Effect on Mortality 168 Estimation of Insect-Caused Deterioration 171 Chapter Page

VII. SUMMARY AND CONCLUSIONS 174

BIBLIOGRAPHY 184

APPENDICES 198 LIST OF FIGURES

Figure Page

1. The flatheaded fir borer, Melanophila drummondi (Kirby); a, larvae; b, pupa; c, adult. 13

2. Generalized life cycle of Melanophila drummondi. 17 3. Development of Melanophila drummondi in Douglas-fir logs cut May 3, 1975 at McDonald Forest, Benton County, Oregon. 22

4. Correlation of Melanophila drummondi flight occurrence with ambient air temperature in McDonald Forest, Benton County, Oregon (May- October, 1976). 24

5. Map of McDonald Forest, Benton County, Oregon showing the location of study site. 35

6. Frequency distribution of the clypeus widths of Melanophila drummondi Kirby larvae feeding in inner phloem of Douglas-fir logs from McDonald Forest, Benton County, Oregon, 1975-1977. 53 7. Frequency distribution comparison of all stages (larvae, pupae, and adults) of Melanophila drummondi (M.D.) and Chrysobothris species (C. spp.) in Douglas -fir logs, 1975-1977. 65

8. Comparison of the distribution of Melanophila drummondi larval densities over the four quadrants of partial cut and clearcut Douglas-fir logs from McDonald Forest, Benton County, Oregon, 1975- 1976. 75

9. Comparison of the distribution of Chrysobothris species larval densities over the four quadrants of partial cut and clearcut Douglas -fir logs from McDonald Forest, Benton County, Oregon, 1975- 1976. 76 Figure Page

10. Comparison of the overall mean larval densities of Melanophila drummondi and Chrysobothris spp. between partial cut and clearcut Douglas -fir logs from McDonald Forest, Benton County, Oregon, 1975-1976. 80

11. Comparison of the development index values of Melanophila drummondi reared in Douglas -fir logs on a partial cut and clearcut at McDonald Forest, Benton County, Oregon, 1975-1976. 85

12. Comparison of the changes in monthly distribution of all developmental stages of Melanophila drummondi reared in Douglas-fir logs on a partial cut and clearcut at McDonald Forest, Benton County, Oregon, from October 1975-April 1976. 91

13. Comparison of the partial cut and clearcut monthly thermal unit exposure above 10°C, the assumed development threshold temperature for Melanophila drummondi, at McDonald Forest, Benton County, Oregon, 1975-1976. 99

14. Comparison of the partial cut and clearcut accumulative monthly thermal unit exposure above 10°C, the assumed development threshold temperature for Melanophila drummondi, at McDonald Forest, Benton County, Oregon, 1975-1976. 101

15. Comparison of mean seasonal efficacies of flatheaded woodborer mortality factors in Douglas -fir logs, 1975-1976. 109

16. Linear plot of the cumulative surface area over cumulative length of Melanophila drummondi Kirby larval galleries in Douglas-fir logs. 121

17. Logarithmic plot and linear regression equation of the cumulative surface area over cumulative length of Melanophila drummondi Kirby larval galleries in Douglas-fir logs. 123 Figure Page,

18. Correlation between inner phloem moisture content (percent of dry weight) of infested Douglas-fir logs and total monthly precipitation from a partial cut and clearcut in McDonald Forest, Benton County, Oregon, 1975-1976, and from a second clearcut study on same site, 1976-1977. 126

19. Seasonal inner phloem moisture content trends in Douglas-fir logs infested with woodborers on a partial cut and clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. 127

20. Patterns of inner phloem moisture content in Douglas-fir logs infested with woodborers on a partial cut in McDonald Forest, Benton County, Oregon, 1975-1976. 133

21. Patterns of inner phloem moisture content in Douglas-fir logs infested with woodborers on a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. 134

22. Seasonal inner phloem pH trends in Douglas -fir logs infested with woodborers on a partial cut and clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. 138

23. Correlation between inner phloem pH and moisture content (percent of dry weight) of infested Douglas - fir logs from a partial cut and a clearcut in McDonald Forest, Benton County, Oregon, 1975- 1976, and from a second clearcut study on same site, 1976-1977. 140

24. Patterns of inner phloem pH in Douglas-fir logs infested with woodborers on a partial cut in McDonald Forest, Benton County, Oregon, 1975- 1976. 142 Figure Page

25. Patterns of inner phloem pH in Douglas-fir logs infested with woodborers on a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. 144 26. Diurnal temperature comparison of the inner phloem of two woodborer infested Douglas-fir logs and ambient air during a cloudy day (A) and a sunny day (B) in November, 1976 at Corvallis, Benton County, Oregon. 149 27. Relationship of the inner phloem temperature of Douglas-fir logs to ambient air temperature in Corvallis, Benton County, Oregon (plot represents daily maximum temperatures from November 14, 1976 to April 12, 1977). 152 28. Diurnal temperature comparison of the inner phloem at the top and bottom of a woodborer infested Douglas-fir log and ambient air on November 19, 1977 at Corvallis, Benton County, Oregon. 160 LIST OF TABLES

Table Page

1. Factor levels for a factorial experimental design used to test the influence and interactions of four factors on bark moisture content and pH. 45

2. Distribution of clypeus widths of Melanophila drummondi larvae feeding in inner phloem of Douglas-fir logs at McDonald Forest, Benton County, Oregon. Data from 1975-1977. 54

3. Comparison of the mean number of buprestid woodborers distributed within Douglas-fir logs, 1975-1977. 67

4. Correlation and regression statistics for the relationship between the location of woodborers in Douglas -fir logs and the inner phloem moisture content and pH at these sites, 71

5. Densities of Melanophila drummondi larvae reared in Douglas-fir logs at three constant temperatures, 1975-1976. 77

6. Densities of Chrysobothris spp. larvae reared in Douglas-fir logs at three constant temperatures, 1975-1976. 77

7. Correlation statistics for the relationship between attack of flatheaded woodborers and the diameter and bark thicknesses of Douglas -fir logs. 82

8. Comparison of the development index values of Melanophila drummondi from Douglas-fir logs under different constant temperature regimes, 1975-1976. 84

9. Comparison of the mean development rate of Melanophila drummondi in Douglas-fir logs subjected to five environmental conditions, October 1975 - April 1976. 88 Table Page

10. Percent distribution of Melanophila drummondi in each developmental stage in Douglas -fir logs from a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. 93

11. Percent distribution of Melanophila drummondi in each developmental stage in Douglas -fir logs from a clearcut in McDonald Fore'st, Benton County, Oregon, 1976-1977. 95

12. Comparison of seasonal development of M. drummondi from Douglas-fir logs cut at two different seasons and placed on a clearcut in McDonald Forest, Benton County, Oregon. 96

13. Comparison of the seasonal development of Melanophila drummondi in the top-half and bottom - half of logs located on a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. 104

14. Comparison of mean mortality of Melanophila drummondi within four quadrants of Douglas -fir logs exposed to five environmental conditions, 1975-1976. 106

15. Results of analysis of variance used to test statistical differences in the mortality of Melanophila drummondi in Douglas-fir logs at five environmental conditions. 107

16. Seasonal trends and point estimates of mortality for a Malanc...221111a drummondi population infesting Douglas-fir logs on a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. 116

17. Seasonal trends and point estimates of mortality for a Melanophila drummondi population infesting Douglas-fir logs on a partial cut in McDonald Forest, Benton County, Oregon, 1975-1976. 117 Table Page

18. Distribution of Melanophila drummondi mortality factors within Douglas-fir logs located ona clearcut in McDonald Forest, Benton County, Oregon, 1975- 1976. 119

19. Distribution of Melanophila drummondi mortality factors within Douglas -fir logs located on a partial cut in McDonald Forest, Benton County, Oregon 1975-1976. 120

20. Seasonal inner phloem moisture content trends in Douglas-fir logs infested with woodborers and held at three different constant temperatures, 1975- 1976. 130

21. Seasonal inner phloem moisture content trends in Douglas-fir logs infested with woodborers on a clearcut in McDonald Forest, Benton County, Oregon, 1976-1977. 132

22. Seasonal inner phloem pH trends in Douglas-fir logs infested with woodborers and held at three different constant temperatures, 1975-1976. 141 LIST OF APPENDICES

Appendix Page

A-1 Changes in inner phloem temperature at the top and bottom of a Douglas-fir log in a simulated clearcut during the first 24 hours following cutting on September 2, 1977. 198

A -2 Changes in inner phloem temperature at the top and bottom of a Douglas -fir log in a simulated clearcut during the first month following cutting on September 2, 1977. 199

A -3 Changes in inner phloem moisture content at the top and bottom of a Douglas -fir log in a similated clearcut during the first 24 hours following cutting on September 2, 1977. 200

A-4 Changes in inner phloem moisture content at the top and bottom of a Douglas -fir log in a simulated clearcut during the first month following cutting on September 2, 1977 201

A -5 Changes in inner phloem pH at the top and bottom of a Douglas-fir log in a simulated clearcut during the first 24 hours following cutting on September 2, 1977. 202

A -6 Changes in inner phloem pH at the top and bottom of a Douglas-fir log in a simulated clearcut during the first month following cutting on September 2, 1977. 203

B Summary of Tele-ThermometerLaboratory Recorder operation and voltage divider network construction (Robert D. Bronson, School of Engineering, Oregon State University, Corvallis, Oregon, December 13, 1976.) 204

C Buprestids captured in flight at McDonald Forest, Benton County, Oregon, during the summer, 1976. 206 Appendix Page

D-1 Example of FORTRAN plotting program used to produce Figure 8. 207 D-2 Example of FORTRAN plotting program used to produce Figure 13. 210 E Temperature and precipitation records for McDonald Forest study sites, Benton County, Oregon, from June 1975 through May 1977. 215 F Comparison of mean mortality of Chrysobothris spp. within four quadrants of Douglas-fir logs exposed to five environmental conditions, 1975- 1976. 216 G-1 Factorial analysis of variance table and intermeans of main factor effect levels and first- order interactions of factors on phloem moisture content for 15. 6°, 21. 1°, and 26. 7 °C constant temperature studies. 217 G-2 Factorial analysis of variance table and intermeans of main factor effect levels and first- order interactions of factors on phloem pH for 15. 6°, 21. 1°, and 26. 7 °C constant temperature studies. 221 H-1 Factorial analysis of variance table and intermeans of main factor effect levels and first- order interactions of factors on phloem moisture content for the partial cut and clearcut field studies. 226 H-2 Factorial analysis of variance table and intermeans of main factor effect levels and first- order interactions of factors on phloem pH for the partial cut and clearcut field studies. 230 SURVIVAL AND DEVELOPMENT OF THE FLATHEADED FIR BORER IN FOREST RESIDUES AS AFFECTED BY HOST AND MICROCLIMATIC CONDITIONS

I. INTRODUCTION

The flatheaded fir borer, Melanophila drummondi (Kirby)1, is an important pioneering invader of dying and recently dead conifer trees in the northern coniferous forest biome of North America. These Melanophila beetles are among the most rapid and prominent invaders of fresh host material of the insect fauna indigenous to this biome-type. Consequently, they play an important role in the initia- tion of the biotic decomposition of accumulated residues resulting from natural and catastropic tree mortality as well as from timber harvesting practices. The significance of the flatheaded fir borer in the overall decomposition of wood residues in nutrient cycling is minor in terms of the actual amount of organic transformation for which they are directly responsible. However, they do play a major indirect role in the physical breakdown by creating, upon emergence, portals of entry through which important wood-decay fungi may infect the residue and enhance its breakdown (Hopkins, 1902a). The galleries, which the larvae excavate while feeding in the

1 Insecta:Coleoptera:Buprestidae 2 phloem, produce a considerable inner phloem surface area which provides a suitable substrate for fungal spore germination. These galleries likely maintain an atmosphere of favorable temperature, moisture, oxygen, and acidic requisites that enable the establish- ment of wood-destroying fungi. In addition, these tunnels provide habitats for numerous smaller secondary insects which may further break down the residue by their feeding, foraging, and provisioning activities. Thus, these secondary invaders may consume the residue directly, or they may mediate decomposition by introducing into the tunnels fungal spores that are carried in mycangium 2 or on the setae of their bodies. The flatheaded fir borer usually invades dead or dying trees (Burke, 1910; Essig, 1958; Keen, 1952), but can be very destructive to living trees as well (Chamberlin, 1924a; Doane et al. , 1936; Essig, 1958; Hopkins, 1904). This beetle occasionally causes heavy timber losses when it attacks live trees, often killing the largest and best in the stand (Essig, 1958). In California, for example, heavy outbreaks of this beetle were reported in Douglas-fir, Pseudotsuga menziesii (Mirbel) Franco, in Yosemite National Park during

2Any fungus storage structure in a beetle (Farris and Funk, 1965). 3

1932-1935. 3 More recently, this insect killed groups of weakened Douglas-fir near Medford, Jackson County, Oregon, and was investigated by the Oregon State Department of Forestry during the mid- 4 1970's. According to Chamberlin (1924a), live trees that are heavily attacked are killed in one or more seasons. On the other hand, if beetle attack is lighter and the trees are more vigorous growing, the larvae are often killed and the wounds caused by the larval mines are healed over. In the past, little attention has been given to this insect by forest entomologists, probably because it does not exemplify the more salient characteristics observed during the depredations of certain "economic pests" (e.g. the defoliation of trees by foliage- feeding larvae or the dramatic population buildup of some bark beetles to levels such that adjacent, healthy, vigorous - growing trees are attacked and killed). Consequently, previous studies have concentrated on the taxonomy (cf. Horn, 1882; Leconte, 1859; Sloop, 1937), or have been summaries of observations or notes concerning the distribution, hosts, and habits recorded during field collections

3Donald De Leon, "The fir flatheaded barkborer outbreak in Douglas-fir in Yosemite National Park" (unpublished report, Pacific Southwest Forest and Range Experiment Station, Berkeley, Calif- ornia, 1937), p. 2. (Hereinafter referred to as "the fir flatheaded barkborer outbreak. ") 4 Personal communication from LeRoy N. Kline, Oregon State Department of Forestry, 2600 State Street, Salem, OR 97310. 4 or faunal surveys (cf. Burke, 1910, 19193; Chamberlin, 1924b; Hardy, 1942, 1948; Nelson and Westcott, 1976; Ross, 1968), or have been observations recorded while investigating some other insect or insect-related problem (cf. Kimmey and Furniss, 1943; Zethner-M611er and Rudinsky, 1967). The life history is generally known (Anderson, 1966; Burke, 1917; Scott, 1974a, 1974b), but until now the details of its biology were uncertain or at best poorly understood. De Leon5 conducted studies on the life history of the flatheaded fir borer during an outbreak in California, and summarized his notes in a report filed at the Pacific Southwest Forest and Range Experiment Station in Berkeley, California. Unfortunately, he never published this information. Since much of his findings concerning the biology of this beetle are relevant to the present study, I will refer to his results whenever they apply. Scott (1974a) reported other findings on the biology of the flatheaded fir borer in a brief note. His relevant findings are incorporated in a later section on the life history and biology of this insect.

5De Leon, "The fir flatheaded barkborer outbreak," pp. 7-17. 5

II. OBJECTIVES OF THE STUDY

A considerable amount of interest has been given recently to the need for environmentally acceptable management of natural and manmade forest residues in Pacific Northwest forests. In view of this concern the U.S. Forest Service undertook a major integrated program in 19756 to develop research projects and to develop management strategies for this material. The impact of forest residues and the impact of the treatment of these residues on the components of the forest environment are considerable. Forest residues and their treatment affect the soil, water, air, fire, scenery, plant and forest growth, animal habitat, insects, and disease (Cramer, 1974). Hence, before environmentally sound residue management strategies can be developed and effectively employed, it is necessary to have a thorough understanding of the various interactions of the biotic and abiotic components of the forest ecosystem with residues and their treatment. Most of the past studies on the role of woodboring insects in the deterioration of recently killed timber were concentrated on identifying the species responsible for damage, recording rates of deterioration, and describing the injury caused by woodborers

6Forest Residue Reduction Program, Pacific Northwest Forest and Range Experiment Station, Portland, OR 97208. 6 (cf. Gardiner, 1957; Kimmey and Furniss, 1943; Parmelee, 1941; Richmond and Lejeune, 1945; Wickman, 1965; Wright and Harvey, 1967; Wright and Wright, 1954). Except for the early work by Graham (1920; 1922; 1924; 1925), the microclimatic aspects of woodborer development and survival have been little investigated. Review of these earlier studies points out a need for additional information concerning the influence of host and microclimatic conditions on the development of woodborers, and the need for more accurate and precise quantitative methods for estimating various parameters of residue utilization by woodborers. Information of this kind will provide a basis for further research on the potential of manipulating residues to promote residue deterioration. Accordingly, the present study is intended to expand on the current knowledge of the biotic potential for decomposition of forest residues resulting from natural or catastrophic tree mortality as well as from timber harvesting operations. This overall goal will be accomplished by studying the flatheaded fir borer, an important biotic component that has been sorely neglected in previous biological and ecological studies on forest residues, and in forest entomology in general. In addition, the study is designed to provide further details of the biology, bionomics, life history, and ecology of the flatheaded fir borer developing in Douglas-fir residues. 7

The specific objectives of this study were to:

1. Study the host and microclimatic conditions necessary for the optimum development and survival of the flatheaded fir borer in Douglas-fir residues. This objective was accomplished by investigating the trends and influences of the following on the beetles' development and survival: inner phloem temperature, moisture content, and pH of infested Douglas-fir logs during the first season following

cutting;

2. Develop a linear regression method for estimating the utilization of residues by the flatheaded fir borer in terms of the amount of inner bark surface area exposed by the feeding activities of the larvae in the inner phloem;

3. Identify, and analyze the natural correlations between the physical processes of weather and the microclimatic and host variables indicated above. These include correlations of inner phloem moisture content with monthly precipitation; inner phloem pH with inner phloem moisture content; and the regression of inner phloem temperature with ambient air temperature. It should be noted that the information obtained and reported here represents the processes occurring only during the first year 8 following cutting or natural tree mortality. Therefore, extrapolation of host and microclimatic data beyond this initial period should be avoided. 9

III. DEFINITION OF TERMS

In the foregoing I have made liberal use of the term forest residue. Before proceeding further, I will clarify my usage of this term by defining it, as well as a few others which will appear throughout the remainder of this dissertation. According to Cramer (1974), the term forest residue was initially used when referring to logging slash, but has now come to include "...both living and dead, mostly unwanted, woody materials that accumulate naturally on the forest floor or are left after timber harvesting." Schwarz et al. (1976) define slash as "the residue left on the ground after timber cutting and/or accumulating there as a result of storm, fire or other damage. It includes u_nutilized logs, uprooted stumps, broken or uprooted stems, branches, twigs, leaves, bark and chips. " (They cite Ford-Robertson (1971) as the source of this definition.) For the purpose of discussion in this dissertation, however, I have chosen to restrict the definition of forest residue to apply only to the recent dead, 7.62 cm or larger in diameter, woody material that can serve as a suitable host for M. drummondi, and that accumulates naturally on the forest floor as a result of fire, wind, snow and ice storms, floods, or other catastrophes, or that 10 is left as unutilized debris after a timber harvesting operation. Other terms used throughout this study are defined as follows: Clearcut - the removal of virtually all the trees, large or small, in a stand in one cutting operation (Schwarz et al.,

1976). Shelterwood cutting system - an even-aged system in which a new stand is established under the protection of a partial canopy of trees. The old stand is removed in a series of two or more harvest cuts, the last of which removes the shelterwood when the new even-aged stand is well established (USDA Forest Service, 1973). The term partial cut will be used as a synonym for shelterwood. Site Class - a quantitative measure of the productive capacity of an area which is essentially uniform with respect to those factors controlling productivity for the crop or stand under study. The quantitative measure is based on the volume, height or maximum mean annual increment that is attained or attainable on that area at a given crop age (Schwarz, et al., 1976). Site Class III represents the median forest productivity class within a site classification scheme for Douglas-fir in the Pacific Northwest composed of five broad classes. Site Class I in this scheme is the most productive and Site Class V is the 11

least productive for Douglas-fir (McArdle et al. , 1961). DBH (Diameter Breast High) - the diameter of a standing tree measured at 1.37 m above the level ground (Ford- Robertson, 1971). -1) Thermal Conductivity (cal cm-1 sec-1 deg - a measure of the rate of heat flow through materials subjected to a temperature gradient (U. S. Forest Products Laboratory,

1974). -1 -1) Specific Heat (cal g deg - the ratio of the heat capacity of the material to the heat capacity of water; the heat capacity of a material is the thermal energy required to produce one unit change of temperature in one unit mass (U. S. Forest Products Laboratory, 1974). Thermal Diffusivity (cm 2 sec-1) - a measure of how quickly a material can absorb heat from its surroundings; it is the ratio of thermal conductivity to the product of density and specific heat (U.S. Forest Products Laboratory, 1974). 12

IV. SPECIES STUDIED

This section provides a review of the most pertinent published and unpublished information concerning the bionomics, life history, biology, and ecology of the flatheaded fir borer. In writing this section, I included my personal observations on the flatheaded fir borer when I believed that these observations provided new information or augmented information already published on this beetle. Most of my observations were made while conducting the research for this dissertation. Due to the nature of these observations, it seemed most appropriate to include them here, rather than in the Results and Discussion section,

General Description and Terminology of Flatheaded Borers

The flatheaded fir borer (Figure 1) belongs to the family of woodboring beetles, Buprestidae, commonly known as metallic woodborers or jewel beetles because of the metallic or irridescent appearance of the adult. Among forest entomologists the adults are generally known as short-horned woodborers, because of their relatively short antennae. The larvae are known as flatheaded woodborers, because of their dorso-ventrally flattened and laterally expanded prothorax which could be mistaken as the head. These names describe gross characteristics that, in part, distinguish these 13

(b)

0 5 lOmm

(C) Figure 1. The flatheaded fir borer, Melanophila drummondi (Kirby); a, larva; b, pupa; c, adult (redrawn from Graham, 1963). 14 beetles from the long-horned (adult) and roundheaded (larvae) woodborers of the family Cerambycidae. The frass that is packed in the galleries by the larvae while feeding is also distinctive for each of these families, as are the cross sectional shapes of the galleries themselves. The flatheaded fir borer was chosen for this study for the following reasons:

1. It is one of the most abundant of woodboring beetles (Chamberlin, 1924a; Hardy, 1942, 1948).

2. It invades its host shortly after the host becomes available (Scott, 1974a).

3. It is an univoltine insect which usually completes its development within a year (Anderson, 1966; Kimmey and Furniss, 1943; Scott, 1974a). 4. It is readily accessible for study since its entire immature life is spent in the phloem or outer sapwood region (Burke, 1919a; Scott, 1974b).

5. It is easily identified since it is the only Melanophila species that is commonly reared from Douglas-fir (Deyrup, 1976). The flatheaded fir borer was studied only in Douglas-fir because this tree represents the major commercial timber species in the Pacific Northwest. 15

Distribution

Melanophila drummondi is a widely distributed species, probably occurring wherever its hosts grow in North America. This beetle is known to occur from Alaska and the Hudson Bay Region to Mexico, and eastward to Michigan. According to Chamberlin (1926), it has also been reported from Europe, and Essig (1958) lists its distribution as Palearctic. Specimens are recorded from Canada, Alaska, Washington, Oregon, California, Wyoming, Montana, Idaho, Colo- rado, New Mexico, Arizona, Utah, Minnesota, and Michigan according to Chamberlin (1926).

Host Record

The known hosts for the flatheaded fir borer have been summarized by Barr (1971). He cites the following hosts for this beetle: Douglas-fir, Pseudotsuga menziesii (Mirbel) Franco; western larch, Larix occidentalis Nutt.; nobel fir, Abies procera Rehder; grand fir, Abies grandis (Dougl.) Lindl.; white fir, Abies concolor (Gord. and Glend.) Lindl. ex Hildebe.; California red fir, Abies magnifica A. Murr.; subalpine fir, Abies lasiocarpa (Hook.) Nutt, ; Pacific silver fir, Abies amabilis (Dougl. ) Forbes; Engelmann spruce, Picea engelmannii Parry ex Engelm.; white spruce, Picea glauca (Moench) Voss; sitka spruce, Picea sitchensis (Bong.) Carr.; western hemlock 16

Tsuga heterophylla (Raf.) Sarg.; and mountain hemlock, Tsuga mertensiana (Bong.) Carr. Scott (1974a) recently reared M. drummondi from ponderosa pine, Pinus ponderosa Laws, and reported that no other reference to pine as a host for this beetle could be found. However, further search of the literature revealed that Hardy (1948) reported collecting adult M. drummondi on newly cut lodgepole pine, Pinus contorta Dougl. ex Loud. Although he did not indicate whether he observed oviposition on this tree, it is reasonable to assume that lodgepole pine is a valid host since the beetle has been reared from at least one other Pinus species. However, lodgepole pine and ponderosa pine are probably uncommon hosts for this beetle. Nelson and Westcott (1976) recently reported a new host record for M. drummondi. They indicate that E. Reeves and G. Foster reared this beetle from deodar cedar, Cedrus deodara (Roxb.) Loud. on November 21, 1974 at Banning, Riverside County, California. Deodar cedar is a commercially important tree in the western Himalaya (Harlow and Harrar,1969), and is widely planted as an ornamental species in the western United States.

Life History and Biology

Figure 2 shows a generalized life cycle for the flatheaded fir borer. Adults which emerge in the spring and early summer fly to host trees where they feed on foliage and twig phloem. Adults 17

Mating a Ovipositing Larval Feeding (Spring- Summer ) (Summer- Winter) Melanophila drummondi Kirby

GENERALIZED

Overwinter in Bark Cell LIFE CYCLE as Prepupa Feeding on Host Foliage (Spring - Summer)

Pupation (Late Winter - Spring)

Emergence a Flight (Spring - Summer) Figure a. Generalized life cycle of Melanophila drummondi. 18 apparently prefer feeding on the same host species fromwhich they were reared, but will eat other host foliage as well (Scott, 1974a). It is believed that adults require feeding on host foliage prior to mating, in order to mature sexually (Scott, 1974b). Foliage feeding prior to mating has been previously shown for some Melanophila species (West, 1941, 1947) as well as for other species of buprestids

(Beal, 1932). Scott (1974a) observed adult feeding by M. drummondi in the laboratory on Douglas-fir, western hemlock, and ponderosa pine, but no mating was observed. Another related species, M. acuminata De Geer, also eat pollen, young tender bark, and dead insects (Craighead, 1950; Evans, 1962). After feeding for a time on foliage, the adults fly to a susceptible host where mating occurs. The eggs are deposited in the crevices of the bark and beneath bark scales (Burke, 1919a; Scott,

1974b). The egg stage was not observed in the present study, but De Leon7provided a description of the eggs during his study. He states that the eggs "...were roughly circular in shape, silvery white in color and an estimated 2 mm in diameter." My observations of the larval galleries suggest that the eggs are laid singly or in groups of 2 or 3. This evidence is similar to the findings of West (1947) concerning egg deposition of a related species, M. californica Van Dyke. He states that "although eggs may be laid singly they

7De Leon, "The fir flatheaded barkborer outbreak, " p. 15. 19 more often occur in groups of two to eight; the largest group observed contained 13 eggs." The very small larvae bore into the bark to the phloem- cambium region soon after hatching from the eggs. For most M. drummondi larvae, the remainder of the immature stage is spent in this area of the host, but some larvae do mine in the outer sapwood (Burke, 1919a; Scott, 1974b). In the present study, I observed the smallest larvae feeding exclusively in the inner phloem, whereas some of the older larvae feed about equally in the phloem and the xylem, etching the latter to approximately 1 mm in depth. In one instance, a last-instar larva was found mining approximately 6 mm 8 into the outer sapwood. Similarly, De Leon found two larvae just beneath the wood of dying Douglas -fir. The feeding habits of M. drummondi resemble the feeding by M. californica which also injures both phloem and xylem in pines (West, 1941). There are three larval instars, the last being a prepupa . When live healthy trees are attacked by M. drummondi, serious "gum-spot" defects form in the wood when the wounds caused by the larval mines heal over (Burke, 1910; Chamberlin, 1924a; Doane et al 1936; Essig, 1958; Hopkins, 1902b, 1904; Keen, 1952). Chamberlin (1924a) points out that these gum-spots are the results of unsuccessful attacks in which sap

8 Ibid. 20 pockets form, seriously reducing the value and usefulness of the lumber from these trees. After feeding in the phloem throughout summer and early winter, the third-stage larvae (prepupae) overwinter in a "U-shaped" position in pupal cells cut in the outer bark usually near the surface. Deyrup (1976) suggests that by constructing the pupal cells in the outer bark, the larvae are afforded protection from exposure should the loosened bark fall from the tree. However, he further points out that the larvae located within these cells are particularly vulner- able to parasitic wasps in late summer and early spring. Apparently, in order for the development to proceed further, the mature larvae must be exposed to a winter resting period (diapause) in the bark cells. Typically this period is associated with colder weather. However, immature larvae hatching from eggs laid during the late summer overwinter in the inner phloem, but do not mature to the adult stage until they have passed a second winter as prepupae in the outer bark. I found that the larvae from logs exposed to constant temperatures in the laboratory entered the prepupal stage but failed to pupate because they lacked an exposure to a cold period that is presumably required to break diapause. Delayed development is most likely to occur in residues resulting from logging operations during the late summer. It also may result when live trees are attacked and the larvae are forced to grow 21 more slowly. Development of the larvae in growing trees is further complicated by the fact that maturity is not reached until all radial growth of the tree has ceased (Anderson, 1966). West (1941) showed that a related species, M. californica has slow growth in living host material and requires 2-5 years to complete development. Pupation occurs in either the bark or the outer sapwood between February and June of the following year (Essig, 1958). In my studies, I found that larvae developing in Douglas -fir logs that had been attacked after cutting in May, 1975, pupated as early as the following January (Figure 3). The pupae had transformed to adults by February and remained in the bark cells until warmer temperatures triggered emergence and flight the following month. The duration of the life cycle is normally one year (Kimmey and Furniss, 1943; Scott, 1974a). However, larvae that attack apparently healthy trees grow more slowly, and may take longer to reach maturity (Anderson, 1966). Prolonged life cycles are also common for other Melanophila beetles developing in living trees (Burke, 1919a; West, 1947), and occasionally in dead hosts as well (Beer,

1949).

Flight

The normal flight season for M. drummondi occurs from May through September (Burke, 1919a; Essig, 1958), although flight can 22 - ct

- w LL

- W

"") z - "")

>- .CC Figure 3. Development of Melanophila drummondi in Douglas -fir logs cut May 3, 1975 at McDonald Forest, Benton County, Oregon. 23 occur earlier depending on rate of larval development and spring ambient air temperatures. M. drummondi developing in Douglas-fir logs on a warm south- facing slope in McDonald forest (see p.34) have flown as early as March. In a study during 1976-77 at McDonald forest, I found that 24 infested Douglas-fir logs examined on February 21, 1977 showed no evidence of adult emergence. However, the same logs on March 25, 1977 contained 12 emergence holes distributed over 6 of the 24 logs.

The "threshold" temperature for beetle flight is unknown. In a study on the seasonal flight of the flatheaded fir borer, I found that beetle flight occurred over the range of daily maximum temperatures of 12. 2oC to 39. 4oC. However, only one beetle was taken at the lowest daily maximum temperature, and the temperature never fell below this low daily maximum of 12. 2°C during the duration of the study (May-October, 1976). Flight occurrence of M. drummondi is significantly correlated with ambient air temperature (Figure 4). Although the percent of flight occurrence increases somewhat with increasing ambient air temperature, the upper and lower thermal thresholds for flight could not be determined from these data according to the methods described by Taylor (1963). Scott (1974b) found that the greatest numbers of beetles were taken on days when the temperature exceeded 23. 9oC. 24 100 ae w 80 cc 60

0 40

(D 20

0 10 20 30 40 TEMPERATURE ( °C)

Figure 4. Correlation of Melanophila drummondi flight occurrence with ambient air temperature in McDonald Forest, Benton County, Oregon (May-October, 1976). ( Correlation coefficient is significant at P < 0.05.) 25 Attack Behavior

The flatheaded fir borer attacks residues shortly after cutting (Scott, 1974a). In a study conducted at McDonald forest in which a Douglas-fir tree was cut in May, 1975, M. drummondi were observed attacking this host within 10 days after it was cut. If the beetles have emerged and are flying, it is reasonable to assume that attack of host material could occur even sooner than 10 days after cutting since attractive host volatiles (e. g. monoterpenes) are immediately released from the severed parenchyma or thin-walled epithelial cells surrounding the resin ducts or canals. These volatile compounds make up a portion of the turpentine fraction of oleoresin contained within these cells (Mirov, 1961). The changes that occur in the temperature, moisture content, and pH of the inner phloem at the top and bottom of a Douglas-fir log in a clearcut during the first month following cutting are given in Appendix A for information, but will not be discussed here. The flatheaded fir borer attacks the entire length of the bole of a susceptible host, but most attacks occur above the basal 9. 144 to 12. 192 m and are decisively heaviest towards the top of Douglas -fir trees killed by fire (Kimmey and Furniss, 1943). De Leon9 reports

9De Leon, "The fir flatheaded barkborer outbreak. " p. 6. 26 that beetles attacking live trees seem to prefer the lower half of the bole initially, although many other trees are attacked above the mid- section first. Regardless of where the attacks were initiated, the attacks extended uniformly over the full length of the bole in living trees. This latter point is consistent with my observations on Melanophila attacks on forest residues as well. One explanation why the beetles prefer the lower portion of the bole rather than the upper portion might be that the thicker bark on the lower bole allows more space for larval feeding and especially pupation. Moreover the thicker bark provides greater protection from parasites because the larvae may be out of reach of the wasps' ovipositors. This is, however, only speculation, and data are not available to substantiate this hypothesis. Furthermore, this apparently does not hold in the case of fire-killed Douglas-fir, where the tops were preferred although in this case there might be some overriding factor involved with fire-killed trees, such as the bark may have been scorched to the cambium during an intense ground fire making the lower trunk less suitable for oviposition. Kimmey and Furniss (1943) recorded an interesting note regarding time of attack of fire-killed trees. They observed that when the inner bark dried out more slowly than usual in some trees killed by fire, Melanophila attacked these trees during the second year following a fire. Attack normally occurs the first year. 27 In one study conducted at McDonald forest, I found that beetles preferred longer logs rather than short sections of logs. A 30.48 cm DBH Douglas-fir tree was felled into a clearcut on

May 3, 1975. The basal 4.88 m of the tree was left intact, and the remaining portion was cut into roughly 1 m long sections, and each section separated from the others by approximately 1 m. On May 13, 1975 the site was revisited and an estimated 25 to 30 M. drummondi were observed walking over the bark, mating, and probing the bark crevices with the ovipostor. Beetles were conspicu- ously absent from all of the short log sections. During my observation I noted that a beetle would occasionally take flight briefly, but then settle back down on another portion of the intact log. During the time I observed this activity (about a half-hour) the beetles did not leave the intact log. The reason for confinement of the beetles to this one log section is uncertain, but probably resulted from a greater concentration of attractive host odors emanating from this longer section of log through volatilization of unidentified compounds caused by solar radiation. The topic of olfaction by M. drummondi will be covered in another section. Another observation on the location of the attack on the tree made by Zethner-Mg6ller and Rudinsky (1967) showed that the flatheaded fir borer also breeds in the dead roots of Douglas-fir, close to the soil surface. Melanophila acuminata, a related species 28 breeding in freshly fire-killed conifers, similarly prefers the lower trunk or exposed roots (Evans, 1973). In a study designed to determine the smallest diameter of the residues left after logging that is usable by the flatheaded fir borer, the top 3.05 m of the two Douglas-fir trees were placed in an open clearing in the sunlight at McDonald Forest in July, 1977. This site was revisited on March 10, 1978 and the bark was removed from the top along the entire length. In both logs M. drummondi larvae were found mining the inner phloem on the upper side, and Scolytus unispinosus Le Conte galleries were found on the underside of the logs In one log 4 M. drummondi were found at a diameter of 8.89 cm but 3 larvae had been parasitized by braconid wasps of the genus Atanycolus Foerster. In the second log I found 2 M. drummondi prepupae that had overwintered in bark cells in the outer phloem at a diameter of 7. 62 cm. The remainder of both logs contained galleries of S. unispinosis and several unidentified cerambycid larvae working in the wood. Thus, it appears that residues down to at least 7.62 cm are utilized by the flatheaded fir borer.

Basking Behavior

Buprestid beetles are frequently most active in hot sunny weather, and are attracted to those portions of the tree boles that are exposed to the sun (Anderson, 1966). Stark, et al. (1973) attribute 29 the common occurrence of these beetles in logging areas and mill yards to their heliophilic behavior. The beetles of this family are frequently found basking in the sun on the bark of a tree or a log. This habit is typical of the genus Melanophila as well as that of mating and ovipositing on warm, sunny days (cf. West, 1941). Con- sequently, M. drummondi are most frequently seen in forest clearcuts, road right-of-ways, and in other clearings where logs and slash piles remain after logging. All of these areas have in common the fact that they are usually dry, well illuminated and warmed by the sun. The beetles' activity under these conditions usually consists of flying about, periodically alighting on the bark of a tree or log, and basking for several minutes in the warmth of the sun before taking flight again. Frequently, while on the bark, they can be observed walking across the bark to a new location where they pause briefly in the sunlight before moving again or flying. M. drummondi is one of the most active buprestid beetles that I have observed in the field, and its activity is obviously stimulated greatly by sunlight. However, it can also spend considerable time resting motionless on the bark under the same conditions as when it assumes the basking habit. Scott (1974b) demonstrated the preference of the flatheaded fir borer to sunlight over shade. He found that 61. 3% of the Melanophila beetles were taken on traps receiving full sunlight compared to 3. 25% caught in full shade. The remaining proportion were 30 captured in partial sunlight. He further suggested that the beetles seek out the sunny areas in order to "balance" their energy budgets so that their heat gains equal their heat losses.

Host Selection and Orientation

One area of insect research which has received considerable attention over the past decade has been on the host selection by phytophagous insects. The scientific literature is replete with studies on the primary and secondary attraction and host selection of insects, especially within the Orders Lepidoptera and Coleoptera. Yet even with such a preponderance of research represented by the literature, very little research has been directed at the cerambycid and buprestid woodborers. Thus, it is difficult to discuss this aspect of the bionomics and ecology of the flatheaded fir borer effectively. Phytophagous insects have long been known to be attracted to odors emanating from the host plant (alluded to by Hopkins, 1902a). Wickman (1969) found that several Melanophila spp. were attracted to turpentine. In a study designed to determine if the flatheaded fir borer responds to various volatile substances associated with conifers or produced by other bark-inhabiting insects, Scott (1974b) placed vials containing various monoterpenes, synthetic bark beetle pheromones, and other volatile compounds on hardware cloth screens 31 coated with Stikem Special sand,and collected the beetles that were attracted. He found that, of the compounds tested, trans-verbenol, acetone, and camphene attracted the greatest number of beetles. All of these compounds are known to occur naturally in conifer trees. He further suggested that the flatheaded fir borer selects a suitable host by detecting a certain concentration and quality of host volatiles emanating from a susceptible host. In another study, Scott (1974b) and Scott and Gara (1975) described a unique slit organ on the distal lobes of antennal annuli 3-11 of M. drummondi which contained numerous olfactory sensilla. They suggested that these organs function to concentrate odor molecules within the lumen of the slit and may be used to help guide the beetle during flight in orienting to a susceptible host. Considering this information, Scott (1974b) proposed a method of employment of the antennal sensory structures of M. drummondi for host selection, orientation, and oviposition. The details of this system are too involved to repeat here, and it will suffice to say that the proposed method involves the concentration of host odors in the lumen of the special antennal slit organs in such a manner that the beetle flies along an increasing odor concentration gradient until it reaches the host. Until quantitative data are produced that either verifies or 32 refutes the system proposed by Scott (1974b), there is no reason to doubt that the flatheaded fir borer selects and orients to a susceptible and suitable host in the manner suggested. 33

V. MATERIALS AND METHODS

Field Study Sites

Studies were conducted at two different field locations: one located at the Oregon Agricultural Experiment Stations Entomology Farm on the Oregon State University campus at Corvallis; the other located 8 km northwest of Corvallis at Oregon State University's McDonald Forest.

Entomology Farm

All research at this site was conducted on the south side of the laboratory building. The building was bordered along the south side by an access road. A large open field approximately 1 ha in size bordered the other side of the access road, and provided conditions that simulated a clearcut. Part of the field is used as a vegetable garden during the summer and is left plowed during the winter. Vegetation over the remainder of the field consisted of various relatively short (< 1 m high) naturally occurring weeds and grasses. The field is bordered along the south and west by a creek 34 and dense vegetation consisting of various trees and shrubs partly overgrown by a blackberry thicket.

McDonald Forest Site

This study site was located in the Oak Creek drainage (5 1/2, SE 1/4, Sec 7, T 11 S, R 5 W, W.P.M.) of McDonald Forest (Figure 5). The site was situated at about 305 m in elevation in a 2.02 ha clearcut on a fairly steep (48%) south-facing slope, and was bordered on the west by a 4.86 ha partial cut, on the north with mature saw timber, and on the south and east by a road. The timber type was principally Douglas - fir /grand fir, occasionally interspersed with western hemlock and big leaf maple Acer macrophyllum Pursh. The timber varied in age ranging between 110-120 years and up to 150 years old. The land was classified site class III and the soil type was Olympic clay. A second site was located in the partial cut bordering on the west side of the clearcut. This site was located at approximately the same elevation, and at about 46 m to the west of the clearcut site. Except for the partial timber overstory and microclimate of the partial cut, both sites were similar in all other respects. McDonald Forest receives a mean precipitation of 107.4 cm annually. The clearcut and partial cut units were logged early in 1974 and the timber left until the following year. Consequently, the logs 35

OREGON STATE UNIVERSITY SCHOOL SF FORESTRY coRvALLis. OREGON PAUL DUNN 3 McDONALD FORESTS

SCALE 1" = 5000' :OPAP.LED ;QOM SERIAL ,0T05 GATED 3 -66 zantsr LEGENO .00404, 3,.f4Cf0 40.03 1001 iounota .MC aumsto Fzon 1/1.1. 40701 0(13

;:.3re. lows G..

aOwffl JOUNOwv

Figure 5. Map of McDonald Forest, Benton County, Oregon showing the location of study site (lower left circled). 36 became heavily infested with flatheaded woodborers. This available woodborer population, the steep south-facing clearcut slope and the adjacent partial cut presented ideal conditions to study the flatheaded fir borer development and survival in forest residues under two different cutting regimes, and therefore two different microclimates.

Experimental Design and Field Plot Layout

In view of the previously mentioned research objectives it was necessary to conduct two separate studies; one study to examine the development and survival of the insect, and another to examine the microclimatic and physicochemical conditions of the host. The two different experimental designs are described separately below.

Design for Development and Survival Studies

The basic design used to study the development and survival of the flatheaded fir borer involved whole-log sampling of randomly selected logs which had been randomly placed on the clearcut and partial cut sites. On May 3, 1975, four 25.4 cm DBH Douglas-fir trees were felled and cut into approximately 1 m long sections and the sections consecutively numbered. Random numbers were drawn from a table of ten-thousand random digits (Rohlf and Sokal, 1969), and used to assign a location to each log in a two-dimensional 37 randomized array. This was done for both the clearcut and partial cut treatments. The arrays consisted of placing 36 logs into a rectangle having 3 rows and 12 columns, with each log separated from the others by approximately 1 m. A 12-log replicated sample utilized 24 of the infested logs from each of the clearcut and partial cut treatments. The remaining 12 logs from each treatment were covered with Chickopee woven plastic screening which was secured with staples around the log to prevent these logs from becoming infested with woodborers. These covered (uninfested) logs were used as controls to compare with the infested logs in the study of the physicochemical properties of the residues described later. On May 10, 1975, six additional Douglas-fir trees ranging in diameters from 10. 16 cm DBH to 17.78 cm DBH, were felled and cut into 108 logs of approximately 1 m in length. The logs were randomized as described above, and placed in the clearcut in a rectangular array with 9 rows and 12 columns. The controls consisted of covering 36 of the logs with woven plastic screening as previously described to prevent infestation by woodborers. These 108 logs were used in a controlled-temperature laboratory study in which 12 replicated infested logs and 12 uninfested control logs were placed into each of 3 controlled-temperature rooms. The rooms were maintained at 15. 6°C with an average relative humidity of 43.7% (range, 38% to 51%); at 21. 1°C with an average relative 38 humidity of 30. 4% (range, 28% to 34%); and at 26. 7°C with an average relative humidity of 38. 4% (range, 33% to 427). All logs were allowed to remain in their respective locations on either the clearcut or partial cut in order to be attacked by the woodborer population emerging from the timber left after cutting the previous year. Each log was identified with an aluminum tag stapled to one

end. The log sections were placed into the arrays with their axis in an east-west direction so that the sides of the logs would be exposed to varying amounts of solar radiation. Positioning the logs in this manner allowed me to determine the effects of solar radiation on larval distribution around the log as well as on the physicochemical properties described later. The west end of every log was marked with an arrow pointing upward, so that the top section could be identified when the logs were brought into the laboratory for sampling. A preliminary sample was taken from the clearcut logs in June, July, and August, 1975, to determine if the logs were infested. One randomly selected log was sampled each month. From the August preliminary sample, I determined that the logs were sufficiently infested by the flatheaded fir borer so that the logs for the controlled- temperature study could be transferred to the laboratory and placed in the 15. 6 °C, 21. 1°C, and 26. 7 °C controlled-temperature 39 rooms located in Cord ley Hall at Oregon State University. Log sampling for the field and laboratory studies was also initiated at this time. Log Sampling Method. The method chosen for sampling the logs in this study consisted of removal of the outer bark by dissection with a wood chisel to expose the larval galleries and extract the larvae for measurement. Southwood (1971) gives other useful methods of sampling animals in plant tissues, including X-rays (cf. Berryman, 1964; Berryman and Stark, 1962; Bletchly and Baldwin, 1962; De Mars, 1963; Fisher and Tasker, 1940; Wickman, 1964, 1966) and circular punch sampling (Furniss, 1962). Although these other methods are nearly as efficient and probably much quicker and less costly than whole log dissection, dissection of the larvae from the bark was necessary to properly identify and measure them. I dissected the larvae from the bark by carefully shaving away thin layers of the bark with a wood chisel until I encountered a larva, pupa, or adult. After removing the insect from the bark, I continued to remove thin layers of the bark just covering the gallery to expose the gallery for measurement. This dissection method required extreme care while shaving the bark away to avoid destroying parts of the gallery or damaging the woodborers. In the laboratory, I divided the log into four equal quadrants which identified the cardinal direction each quadrant faced (i. e. north 40 or south) and the vertical position with respect to the log axis (i. e. top or bottom). To simplify reference to a sample, I assigned roman numerals to each of the four quadrants in a clockwise manner beginning with the south-top quadrant on the west end of each log; hence the south-top was labelled quadrant I, the south-bottom quadrant II, the north-bottom quadrant III, and the north-top quadrant

IV. I made several measurements on each log at this time, including the diameter at the middle of each log which I assumed to represent the mean diameter (taper factor on short log sections is negligible), the length of each log, the wet weight, and the average thickness of the inner and outer phloem determined by averaging four measurements--one from the middle of each quadrant taken at the end of of the log. Bark pH Determination. To obtain a pH measurement from the bark, I removed a 25. 8 cm2 section from each quadrant on the logs, prior to dissection of the bark to collect the larvae. I separated the bark sample from each quadrant into inner and outer phloem components and broke the components into particles small enough to pass through a 1. 27 cm hardware cloth screen. I weighed the bark chips wet and placed them in a beaker to which I added distilled water at the mass to volume ratio of 1:10 (after Bollen and Lu, 1970). The bark suspensions were left at room temperature for 24 hours to allow time for the acids to leach from the bark. After 24 hours, I 41 stirred the leachate -bark chip suspension and measured its pH using

a Corning®triple purpose pH electrode on a Corning®model 12 research pH meter. I also recorded the pH of the distilled water that was used in each sample at each sampling period to detect possible errors in bark pH readings. Erroneous readings might result from distilled water contaminated with metal ions from holding tanks and pipes that can complex with hydroxyl (OH) groups to form bases and would alter the pH by allowing a build-up of free hydrions (H+) resulting in an increased acidity. Also, an erroneous pH reading might result, for example, if the distilled water was contaminated with a chemical having a dissociation constant (Ka) greater than any of the acids that leach from the bark. pH is generally defined as -log H+, or it may be defined in terms of the dissociation constant of an acid (pKa) as -log Ka (Gueffroy, 1975). The greater the dissociation constant, the stronger the acid and lower the pH. The pH of the distilled water remained fairly stable throughout the study, averaging 5.55 + 0.05. Occasionally a bark pH reading differed enough from other readings taken from a similar location and bark type to suggest an error. However, these differences probably represented variation resulting from leaching of more concentrated bark acids or from microbiological activity in these locations in the bark rather than from the pH of the distilled water used, or, possibly 42 from poor technique in taking the reading. By averaging all four quadrants to obtain the mean pH for the log, the occasional differences noted in individual readings were moderated. In the final analysis, these differences were of little consequence to the beetles' development, and were therefore ignored. Bark Moisture Content Determination. I determined the moisture content of the bark by oven-dry weight calculations using the following formula given by the U. S. Forest Products Laboratory

(1974):

Percent moisture content =

weight when cut oven-dry weight X 100 (1) oven-dry weight

Bark samples were dried in a desiccating oven at 85°C for 24 hours in order to determine moisture contents accurately to within + 1%, as suggested by Litvay (1973). The moisture content deter- minations were made on the same samples used to determine the pH. Log Sampling Schedule. Initially, the sampling schedule required sampling one replicated infested treatment and an uninfested control log from each of the two field treatments (i. e. clearcut and partial cut) and from each of the three laboratory treatments (i. e. 15. 6 °C, 21. 1 °C and 26. 7°C) each month from August, 1975 until after beetles had flown in March or April, 1976. However, 43 the dissection of the bark necessary to obtain undamaged specimens

for identifcation and measurement, and to expose the galleries for

measurement, required a much greater expenditure of time than

anticipated and I had to modify the sampling intensity.

I was able to sample one infested treatment log from nearly

every treatment each month, and one uninfested control approxi-

mately every other month from each of the treatments. Because of the great expenditure of time required to sample the logs, I also found it necessary to drop the replicated log of each treatment from the original sample design.

I repeated the study on the clearcut the following year (1976-

1977). The 1976-1977 season proved to be an unseasonally dry year, with slightly warmer than average monthly temperatures and less than normal rainfall. This allowed me to make an interesting comparison with the clearcut results from the more typical, previous 44

season. I set up the second year's study on the clearcut and sampled the logs in the same manner as previously described.

Design for Physicochemical Studies

Additional experiments designed to test the influences and interactions of multiple factors on the physicochemical host components (moisture content and pH) were conducted on the logs from the randomized field design described previously. The design for this. study was an unreplicated four-factor factorial experiment involving phloem type, sample position with respect to the relative incidence of solar radiation, type of field or laboratory treatment the sample was subjected to, and the time of year (month) in which the sample was taken. For this study, I examined the influence and interactions of 2 types of phloem, 4 sample positions, 5 sample treatments, and 4 sample months (Table 1). Phloem type, sample position, and sample treatment were fixed treatment effects, and sample month was considered a random treatment effect in this study. I was able to obtain samples only during the months of October, December, January, and March (Table 1) for all five of the treatments. All other months had a missing 45 sample from one or more of the five treatments and could not be used in this analysis.

Table 1. Factor levels for a factorial experimental design used to test the influence and interactions of four factors on bark moisture content and pH.

Factor No. of Levels Factor Levels

Phloem type 2 Inner phloem Outer phloem

Sample position 4 South-top quadrant South-bottom quadrant North-bottom quadrant North-top quadrant

Sample treatment 5 Clearcut Partial cut 15. 6 °C 21.1°C 26, 7 °C

Sample month 4 October December January March

Instrument Calibrations pH Meter

The pH meter was calibrated before each use at room 46 temperature using Beckman phthalate pH buffer solution (pH 4.01). To check the accuracy of the pH electrode, I plotted on graph paper the readings obtained by measuring two known pH buffer solutions with the pH electrode, against the actual pH of the buffer

solutions. For comparison, the reference calibration line was

obtained by plotting the actual pH values of the buffer solutions on the graph as well. From the graphs, I found that the pH electrode read within 2.5 percent of the actual pH value of buffer solutions. I considered this accuracy to be within acceptable limits for these studies.

Hygrothermographs

Belfort C) seven-day continuous drum hygrothermographs were used to measure temperature and relative humidity at the field locations. I calibrated the hygrothermographs in the laboratory using a Weksler Instruments sling psychrometer. I calibrated the hygrothermographs at approximately 3-month intervals at the field sites. The hygrothermographs were housed in weather instrument shelters located on the sites. 47

Yellow Springs Instrument Tele-Thermometer

All measurements of inner phloem temperatures were obtained using a Yellow Springs Instrument (YSI) No. 418 tubular-pointed metal probe. I inserted the probe 7.0 cm into the bark at the ploem-cambium region on the west end of the logs. To protect the probe from shorting out by moisture or precipitation, I shielded the exposed portion of the probe with a section of Tygon® flexible plastic tubing. I then molded a piece of No. 2 Roma Plastilina® (a clay-like product) over the Tygon® tubing and up against the exposed end of the log to insulate the probe from direct solar radiation that might cause the metal of the probe to heat-up and result in an erroneous reading. I measured the temperature continuously on a YSI model 47 Scanning Tele- Thermometer and recorded it on a YSI model 80 Laboratory Recorder. I also recorded ambient air temperatures concurrently using a YSI No. 405 air temperature probe inside a weather instrument shelter located about 1 m from the logs. All inner phloem temperature readings were taken on logs under simulated clearcut conditions at the Entomology Farm site. 48

I calibrated the Scanning Tele- Thermometer in an ice bath before use. In addition, a characteristic curve of the Tele- Thermometer output voltage versus temperature was obtained experimentally, by concurrently recording the millivolt response of the recorder with every 1°C change in temperature over the range of temperatures 20 °C to +50 °C. In order to measure temperatures below 0 °C, a voltage divider was construced using precision resistors that allowed me to adjust the recorder input voltage to nearly full scale deflection over the recorder range of 160 mV to 0 mV, which corresponded to a temperature range of

- 20oC to +50oC. Appendix B summarizes the details of the Tele-Thermometer-Laboratory Recorder operation and voltage divider network.

Beetles

Identification

Identification of buprestid beetles collected in the larval stage from Douglas-fir posed a special problem in this type of field study. Taxonomic keys to buprestid larvae below the generic level are not presently available. Consequently, specific identification of buprestids from wood or bark is only possible by rearing the larvae 49 to the adult stage. This is also a problem since artificial diets for buprestids have not been formulated, as they have for cerambycids (cf. Galford, 1969; Gardiner, 1970; Harley and Willson, 1968; Wollerman et al. , 1969), and other bark or wood-inhabiting insects (cf. Bedard, 1966; Galford, 1967; Schmidt, 1966; Solomon, 1966). Larvae were not reared on diet in this study, but it is possible that these artificial diets could be used to artificially rear buprestid larvae. The larvae were not reared through for identification purposes because it would have required too much time, and I would not have been able to separate the Chrysobothris beetles by species in the larval stages without undertaking a major taxonomic investigation that was well beyond the scope of this study. Benoit (1964; 1966a; 1966b) provided larval descriptions of numerous species of Chrysobothris, as well as two Melanophila species, but only C. dolata Horn and C. trinerva (Kirby) are reported to occur on Douglas- fir (Deyrup, 1976), and neither of these species were taken during flight studies at McDonald forest during my studies (see Appendix C). The four species of Chrysobothris that I captured in flight (Appendix C) are probably a good indication of the species which I encountered in Douglas-fir logs as larvae since two of the species were reared from Douglas -fir logs. However, four other Chrysobothris species invade Douglas-fir as well (Deyrup, 1976). Since these species could not be separated in the larval stages, I will refer to this group 50 as the "Chrysobothris complex" for purposes of reporting results of my research. Conversely, M. drummondi is the only Melanophila species that is commonly reared from Douglas-fir (M, californica is the other species of this genus that invades Douglas-fir). Therefore, M. drummondi is the only woodboring larvae that I could identify to species in the larval stage. I was able to identify this species easily by comparing larvae to drawings of the dorsal, dextral, and ventral views of an M. drummondi larva illustrated by Burke (1917). Larval specimens were also compared with those of the Hopkins' collection at the Forestry Sciences Laboratory, Corvallis, Oregon for con- firmation. Other M. drummondi larvae found overwintering in intact sections of bark removed from logs, were reared in the bark sections to adult in order to confirm tentative identification of the larvae. Adult beetles were identified with little difficulty by using the taxonomic keys of Barr (1971).

Instar Determination

As with most species of the family Buprestidae, nothing is known about the number of larval instars of the flatheaded fir borer. Dyar (1890) found that age of lepidopterous larvae is related to the width of the head capsule. Thus, a distribution of head capsule widths frequently allow the separation of instars when the 51 measurements are distributed with greatest frequency around two or more mean widths, over the entire range of head capsule widths measured. This method of measuring the head capsule widths and plotting the distribution of these widths has been employed with reasonable success on several bark beetles of the family Scolytidae (cf. Goldman and Franklin, 1977; Hall and Dyer, 1974; McGhehey and Nagel, 1969; Prebble, 1933; Reid, 1962; Walters and McMullen, 1956), but is not possible with buprestids because the head is small, retracted deeply into the prothorax, and not accessible for measurement without destroying the specimen. The clypeus (that part of the head below the front, to which the labrum is attached anteriorly), on the other hand, is both accessible for measurement and also highly sclerotized so that its size or shape would remain constant within an instar, but would increase in size with each molt of the larva. Measurement of the width of the clypeus was suitable for separation of larval instars, much like the results obtained from measuring head capsule widths of lepidopterous and other insect larvae. 10 Benoit suggested that this structure might be better than the head capsule measurement for instar determination in this insect.

10 Personal communication from Dr. Paul Benoit, Forest Insect and Disease Survey, Laurentian Forest Research Centre, P. 0. Box 3800, Ste. Foy, Quebec GIV 4C7, letter dated April 22, 1976. 52

I measured the widths of the clypeus of all buprestid larvae with an AO0Instrument No. 424 10X Filar Micro- meter Eyepiece on an AO®stereo dissecting microscope, and plotted the clypeal widths in a frequency distribution (Figure 6).

Clypeus widths fell into three general frequency peaks. The first occurred at a mean width of 0.51 mm, the second at 0.70 mm, and the third at 0.97 mm. Although the latter showed a bimodal peak, the range of frequencies on either side indicated that these were all from the same frequency class, and additional observations would probably bear this out. Statistics for the clypeal widths of M. drummondi (Table 2) show an average growth factor of the larval stages of 1.38. I selected the frequency class limits where I judged the natural breaks in clypeal widths to occur, and also on the basis of morphological differences (noted for pre-pupae) or when larvae were collected while in the process of molting. The three frequency classes indicated correspond to the three stadia of M. drummondi. Because the Chrysobothris spp. larvae could not be identified, I could not separate larval stages from a frequency plot of clypeus widths. Numerous peaks occurred at irregular intervals, which I assumed resulted from the confounding effect of measuring more than one species of Chrysobothris larvae. Thus, many of the results 53

s- IMP

11 0 1 0.40 0.5 0 0 50 0.70 0.180 0.90 1 00 1.10 1.20 Clypeus width, mm Figure 6. Frequency distribution of the clypeus widths of Melanophila drummondi Kirby larvae feeding in inner phloem of Douglas -fir logs from McDonald Forest, Benton County, Oregon, 1975-1977. 54 of this research cannot be related to any single species of the Chrysobothris complex, as I have been able to do for M. drummondi.

Table 2. Distribution of clypeus widths of Melanophila drummondi larvae feeding in inner phloem of Douglas-fir logs at McDonald Forest, Benton County, Oregon. Data from 1975-1977.

Mean and Range S.E. Std. Dev. Instar Sample Size (mm) (mm) (mm)

I 22 0.37-0.62 0.51+0.013 0.06

II 29 0.63-0.77 0.70+0.006 0.03

III 210 0.78-1.20 0.97+0.003 0.04

Development Index

It is often desirable in entomological studies to compare the effects of several experimental treatments or diets on the development of groups of an insect under consideration. When comparing groups of insects in which individuals within a group are distributed over several developmental stages, it is convenient to convert each group of individuals to a single index number that characterizes an average stage of development for each group. Dyer et al. (1968) proposed an index of development for bark beetles which converted the percentage of each stage of brood development into seven index values that were numbered from 100 to 700 to 55 correspond to the seven stages of beetle development. The index value of 100 represents 100% eggs, while the index of 700 represents 100% adults; with the indices for 100% of each of four larval instars and a pupal stage falling into 100 unit intervals between 100 and 700. Dyer and Hall (1977) used this method in a study on the factors affecting diapause in Dendroctonus rufipennis (kirby) larvae. McCambridge (1974) similarly employed a development index to express changes in development rates of mountain pine beetle, Dendroctonus ponderosae Hopkins. According to his method, the sums of ratings of 1.00 for each egg, 2.00, 3.00, 4.00, and 5.00 for four larval instars, 6. 00 for each pupa, and 7.00 for each adult, are divided by the total number of individuals to obtain the development index (DI). In my studies on the flatheaded fir borer, I adopted the method by McCambridge (1974) for determining development index values, but with the following modification: each 1st, 2nd, and 3rd instar larva were assigned index values of 1. 00, 2.00, and 3.00 respectively; pupae were assigned an index value of 4. 00; and adults an index value of 5.00. I did not assign the egg stage an index value since none were found. Also, with this convention, it is easy to convert from larval development stage to index value and vice versa because each instar number corresponds exactly with its index value. Results of my studies on the development of the flatheaded fir 56 borer reported here are based on the calculation of development index by the following formula:

(S) (n) (2) DI - N where DI = development index

S = stage of insect development (e. g. 1. 00, 2. 00, 3. 00, etc.)

n = number of individuals in stage of development

N = total number of individuals in all stages of development

Flight Occurrence

The method used to calculate occurrence of flight by the flatheaded fir borer in response to temperature (Figure 4) was described by Taylor (1963). Each trapping occasion is classified by either a 1, if one or more insects are captured, or 0 if no insects are caught. Such a classification of flight activity assumes that a response of 0 indicates no flight when temperatures are outside the beetles' range of upper and lower temperature thresholds for flight occurrence. Conversely, a response of 1 indicates that flight occurred while temperatures were within the upper and lower thres-

holds. If the temperature of each trapping occasion is recorded (in 57 this case, daily maximum temperature) and the l's and 0's summed for each temperature, then the percent flight occurrence at any temperature is the sum of the l's and 0's at that temperature divided by the number of occasions that temperature occurred, times

100. An important assumption in the determination of the temperature threshold for flight by the method described by Taylor (1963), is that the trap must be sensitive enough to catch an insect whenever the population is active. If it is not, as taylor points out, the chance element in the sample will be great and the threshold distributions will be blurred by the lack of resolving power of the trap. Similarly, a lack of sensitivity occurs when the trapping period is long relative to the rate of temperature change. Undoubtedly, both of these factors contributed to my inability to define the threshold temperatures for M. drummondi flight. In addition, a low adult population might also have contributed to this lack of success.

Calculation of Monthly Thermal Units

Knowledge of the temperature below which an insect ceases to develop (development threshold) is necessary for accumulating degree-days or thermal units in certain studies concerning the influence of temperature on insect development. I have not attempted to determine the exact development 58 threshold temperature for the flatheaded fir borer in this study, although I have good reason to believe that it must be somewhere o near 10 C. Evidence to support this belief is derived partly from my observations on M. drummondi brood reared at constant temper- 11 ature and partly from the findings of West on a related species, M. californica, During my studies, I found that certain M. drummondi larvae (6 out of 33) failed to develop past the 1st or 2nd instar when reared at 15. 6°C. These individuals are probably variants within the population and have slightly higher development temperature thresholds than the rest of the population. Because only a few larvae failed to develop further at 15. 6°C, it is reasonable to assume that the remainder of the population has a lower development threshold temperature which is probably closer to

10°C. 12 In temperature studies with M. californica, West found that little if any development occurred when pre-pupae were subjected o to a prevailing temperature of 10 C. He considered this to be

11West, A. S., "The California flatheaded borer, Melanophila californica Van Dyke, and the pine flatheaded borer, Melanophila gentilis Lec.: A review of progress conducted at the Hackamore Field Laboratory during the seasons of 1936-1939" (unpublished report, Pacific Southwest Forest and Range Experiment Station, Berkeley, California, 1939), 93 pp. (Hereinafter referred to as "The California and pine flatheaded borers. ")

12West, "The California and pine flatheaded borers. " 93 pp. 59 the approximate development threshold temperature of M. californica. Based upon this evidence, I will assume that this temperature oC, of 10 is also the development threshold for M. drummondi for the purpose of calculating thermal units. Although this is only approximate and has not been derived experimentally, it is probably close enough to the actual development threshold temperature for M. drummondi to use for illustrative purposes in this dissertation. Assuming a thermal development temperature of 10°C for the flatheaded fir borer, I calculated the thermal units by the following equation:

Thermal Unit = maximum temperature + minimum temperature 10_°C C 2 (3)

The thermal units calculated in this manner were summed to determine monthly degree-day accumulations.

Measurement of Larval Galleries

Perimetric measurements of the overall gallery shape were used to determine the surface area of flatheaded fir borer galleries. The method consisted of making a "transfer" of the exposed gallery onto a sheet of paper and then measuring the perimeter of the transfer with a polar compensating planimeter to determine the area of the gallery. Because this value 60 represents only one surface of the gallery (i. e. one -half of the actual gallery surface area) the values obtained have to be doubled for estimation of both surfaces of the gallery. This method slightly underestimates the true gallery surface area in that it assumes planar surfaces. The gallery is actually slightly concave, since, like most buprestid galleries the flatheaded fir borer gallery is ellipsoidal when viewed in cross section. This method does, however, provide a "best approximation" of gallery surface areas by the simplest and most expedient method once the gallery has been exposed. The "transfer" was made by rubbing an artist's charcoal stick on the edges of the gallery, blowing off the excess charcoal, then rubbing the gallery depression with the fingers or palm as a sheet of white typing paper is held in place over the gallery depression. This transferred the charcoal from the edge of the gallery to the typing paper, thereby giving the "mirror image" of the gallery. During the study I measured eighteen flatheaded fir borer galleries by this technique. Each gallery perimeter was measured five times with the polar compensating planimeter; the area for each gallery represents the average of five measurements.

Weather Measurements

All measurements of temperature and relative humidity were 61 measured on the field sites as previously indicated. I obtained measurements of precipitation from the U.S. Weather Bureau located on the Oregon State University campus at Corvallis.

Statistical Analysis and Computer Graphics

I conducted most of the statistical analyses on the Oregon State University's CDC 3300 computer using the Department of Statistics' Statistical Interactive Programming System (SIPS) (Rowe and Barnes, 1976). All statistical tests employed are according to the methods described by Sokal and Rohlf (1969). I consulted with statisticians from both the Department of Statistics, Oregon State University and the U. S. Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, for the appropriate statistical procedures to use for testing of some of the data, and _for designing the experiments. I drafted all graphs except Figure 6 on the Oregon State University Computer Center's Gerber 1022 flatbed plotter. The plotter was accessed by creating a plot tape which was written in FORTRAN, utilizing a set of pre-programmed subroutines available on the Computer Center's CDC CYBER 70 Computer as a user- accessed library program. Documentation for the program is available in the CYBER COMPLOT user's manual (Fuhrur, 1977). 62

Examples of FORTRAN programs used to draw two of the figures in this dissertation are given in Appendix D. 63

VI. RESULTS AND DISCUSSION

Biological Investigations

Woodborer Species Attacking Logs

The wood and bark of dead and dying Douglas -fir is a diverse microcosm of microbial and invertebrate animal life. In this study, I focused upon a small segment of that diversity by considering only the assemblage of wood- and barkboring buprestids that invade this host during the first year following cutting. In terms of this invertebrate biomass the buprestids and cerambycids represent the most important segment. Flatheaded fir borers were the only woodboring species I could identify with certainty in the larval stages. The other buprestid larvae encountered were species of Chrysobothris, Buprestis and Dicerca. These larvae were not reared so their specific identity is unknown. It is, however, instructive to speculate on their identity. For example, in the flight study at McDonald Forest during the summer of 1976 (Appendix C), I suggested that the four species of Chrysobothris adults captured in flight (i. e. C. pseudotsugae Van Dyke, C. laricis Van Dyke, C. caurina Horn, and C. sylvania Fall) were probably the same species found as larvae in Douglas-fir. According to Deyrup 64 (1976), other Chrysobothris species invade Douglas-fir as well, including C. carinipennis Leconte, C. dolata, C. breviloba Fall, and C. trinerva, but I captured none of these during my studies. Eight species of Buprestis also occur on Douglas-fir. Deyrup (1976) cites: B. aurulenta Linneaus; B. langi Mannerheim; B. ad'ecta Leconte; B. connexa Horn; B. nuttalli Kirby; B. laeviventris Leconte; B. subornata Leconte; and B. lecontei Saund. Of these, B. aurulenta; B. lecontei; and B. langi were captured in flight at McDonald Forest. Several unidentified individuals of this genus were collected from the bark in the larval stage during the course of the study. The final genus, Dicerca, several larvae of which I collected from Douglas-fir, contains three species that invade Douglas-fir, but are difficult to distinguish (Deyrup, 1976). They are: D. tene- brosa Kirby; D. sexualis Crotch; and D. crassicollis Leconte. In addition to the species of the four genera listed here, species of Chrysophana Leconte; Chalcophora Solier; and Anthaxia Eschscholtz also breed in Douglas-fir (Deyrup, 1976), but I did not encounter larvae of these genera in my studies.

Distribution of Woodborers Within Logs

Frequency of Woodborer Occurrence by Quadrant. Figure 7 shows a comparison by quadrant, of the frequency distributions of the 65

300 _ 1. SOUTHTOP 2 SOUTHBOTTOM 3 NORTH BOTTOM 250. 4 NORTH TOP

>--200 z a w E100 _

111111I .111MIN 50 . MISMNIMP

0 1 2 3 4 1 2 3 4 M.D. C.SPP.

Figure 7. Frequency distribution comparison of all stages (larvae, pupae, and adults) of Melanophila drummondi (M.D.) and Chrysobothris species (C. spp. ) in Douglas-fir logs, 1975-1977. 66 total combined development stages of buprestid woodborers collected from all Douglas-fir logs during the study period 1975-1977. The distributions for the flatheaded fir borer and the Chrysobothris complex are plotted separately. Figure 7 shows similarities in the frequency distribution patterns of the flatheaded fir borer and the Chrysobothris complex. Statistically significant differences in the mean number of insects per log quadrant of both groups of buprestids occurred in the top portion of the logs (south- and north-top) compared with the bottom portions (south- and north-bottom) when tested at the P < 0.05 level with a paired t-test (Table 3). Of the total buprestids found in all quadrants of Douglas-fir logs, the top-half of the log contained 76.8% of M. drummondi and 80. 7% of Chrysobothris flatheaded woodborers. These findings, that the flatheaded woodborers prefer the, tops of logs to other locations, agree with the results reported by Wickman (1965). Graham (1922), after studying the effects of physical factors of the environment on the ecology of some woodboring insects, concluded that woodboring insects may be grouped according to their ecological requirements. He characterized Chrysobothris species as having high temperature requirements for development, and placed them into a group characterized by this environmental condition. He summarized this group and others as follows: 67

Table 3. Comparison of the mean number of buprestid woodborers distributed within Douglas -fir logs, 1975-1977. Mean + S. E. No. Insects/ No. logs Log Quadranta Log quadrant Sampled M. drummondi Chrysobothris spp.

South-top 31 9. 1 + 1. 6a. 6.5 + 1. 3a 2.0 + 0. 6b South-bottom 31 2.2 +.... 0. _ North- bottom 31 2.2 + 0.5b 1.2 + 0.4b

North-top 31 5.4 + 0.8c 5.4 + 1.2a

aAll paired combinations of log quadrants tested with paired t-test. Means followed by the same letter in each column are not significantly different (P > 0.05). 68

Group I. Insects requiring high temperature for development- - represented by Chrysobothris.

Group II. Insects unable to endure extremes of temperature or moisture --represented by bark beetles such as Ips pini (Say), and by Monochamus (sp.).

Group III. Insects requiring cool moist conditions--represented by Hylurgops (sp.) and some Cerambycidae. Graham (1922) added that insects like Chrysobothris spp. are found on the top portions of logs exposed to full sun, one-third shade, and to a lesser extent, one-half shade. These beetles are most abundant in log sections exposed to full sunlight, and occur rarely on the sides of logs and almost never in heavy shade. I would place the flatheaded fir borer in Group I as well because of its distribution within Douglas- fir logs, and observed preference for warmer sites. The flatheaded fir borer occurred nearly twice as often in the south-top quadrant as in the north-top (Figure 7), whereas I found the Chrysobothris complex occurring with only a slightly greater frequency in the south-top quadrant as in the north-top. The differences noted in the mean number of M. drummondi per log quadrant for the south- and north-top quadrants are significant at P <0.05 (Table 3). Cerezke (1977) in studying the damage to white spruce by a cerambycid woodborer, the white-spotted sawyer, Monochamus 69 scutellatus (Say), found that the mean number of larval entrance holes was significantly greater on the south aspect than on the north aspect, but only on the butt log samples. Cerezke's research showed that densities of larval entrance holes for this cerambycid borer were distributed around the surface of the logs, but occurred most frequently at the top and upper sides of white spruce logs taken from the middle and top positions of trees. Cerezke's (1977) results with M. scutellatus are similar to my results with the Melanophila sp. and Chrysobothris spp. beetles in that they are able to endure the temperature extremes that occur in the top portions of the logs. M. scutellatus differs from the buprestids I studied, however, in its relative temperature requirements for development. For this reason, Graham (1922) included this cerambycid in his Group II category and the buprestids in his Group I category. My results with M. drummondi and Chrysobothris spp. also support Graham's inclusion of these buprestid borers in his Group I category. Differences in frequency of buprestid occurrence between the top and bottom of logs (Figure 7) correspond to temperature and moisture differences between the upper and lower portions of the logs. I will discuss these differences in more detail later. Clearly, the top portion of a log, being exposed more directly to solar radiation, is warmer and drier than the bottom. Although c:a.ar.. ative 70 measurements were not obtained, observations on the oviposition habits of adult females suggest that females typically oviposit on the warmer top and upper sides of logs. The warmer and drier portions of the logs are probably favored as oviposition sites by females, which explains why these woodborers occur most frequently in the tops of logs. The location of beetles within the bark on the logs is correlated with the moisture content of the inner phloem at these sites in Table

4. The negative correlation coefficients shown in Table 4 indicate that these beetles occur with increasing frequency as the average moisture content of the inner phloem of these locations decreases, at least on the clearcut. A study of the coefficients of determination, however, reveals that moisture content alone accounts for little more than a quarter of the variation observed in the locations of beetles in the inner phloem of Douglas-fir logs on a clearcut. A large portion of the remaining variation in beetle location in the bark (about 70%) is probably attributable to differences in bark temperature. However, direct statistical correlations between beetle location in the bark and the bark temperature at these locations can not be computed from my data, since I collected measurements of inner phloem temperature only from the top-half of the logs during the development period. Temperatures from the bottom- half are also needed to accurately correlate beetle location within Table 4. Correlation and regression statistics for the relationship between the location of woodborers in Douglas-fir logs and the inner phloem moisture content and pH at these sites. Correlation Coefficient of F-value for regression Coefficient (r) Determination (r2) ANOVA Beetle location Beetle location Beetle location versus versus versus No. of Moisture Moisture Moisture Content Treatment Samples Content pH Content pH pH n. s. s. s. . S. Partial Cut 28 -0.202 0.16211. 0.041 0.026 1.107n. 0.70311 (1975-1976) S. s. Clearcut 28 -0.531 0.28411. 0.282 0.081 10.193n 2.288n (1975-1976) s s s. Clearcut 20 -0.541 -0.163n 0.292 0.027 7.431n O. 492n (1976-1977) n. s. Not significantly different from zero at P = 0.05. Correlation significantly different from zero at P < 0.05. , Correlation highly significantly different from zero at P< 0.01. 72 the log with the mean monthly inner phloem temperatures for these locations. The F-test for the regression analysis of variance (Table 4) further indicates that the amount of beetle occurrence explained by the variations in moisture content or pH is not significant, even though the correlations between these variables may be. Therefore, correlations such as these should be viewed cautiously, because both temperature and moisture content of bark are transient phenomena. Both parameters are subject to considerable variation not only between months, but between days, and even within days as well (e. g. Appendix A). Thus, these correlations are only valid within a range of measurements of moisture content or temperature that are possible for any given quadrant, and largely depend on: 1) when the sample was taken and 2) the local environmental conditions the log was subjected to prior to and at the time of measure - ment. These conditions might be such factors as precipitation, solar radiation, wind, soil moisture, bark thickness, density or specific gravity of bark, and others. Therefore, the correlation coefficients given above are only crude indicators of the relationship between the location of woodborers in logs with the inner phloem moisture content at these sites. More accurate correlations probably could have been shown, had 73 measurements been taken at least daily, and these measurements averaged over each month to get a mean monthly estimate with which to compute the correlations. Furthermore, just because larvae, pupae, or adult woodborers are found within a particular quadrant does not necessarily mean that they feed and develop only in that location. I frequently observed larval galleries meandering back and forth between two or three quadrants. In addition, it is often difficult to determine the quadrant of a gallery's origin because the gallery may become hopelessly mixed in a network of galleries as it is being traced through the quadrant, particularly when larvae are present at high population densities. Although I have no supportive figures, general observations on the galleries in logs (and particularly on logs of larger diameters) suggest that most galleries begin and end within the same quadrant. They typically meander within a quadrant, but largely follow a longitudinal course with the log axis. The distributions of the Dicerca spp. and Buprestis spp. in logs were also noted. The Dicerca larvae were nearly evenly distributed over the logs as follows: south-top, 2; south-bottom, 2; north-bottom, 2; north-top, 3. The Buprestis larvae were also nearly evenly distributed as follows: south-top, 1; south-bottom,

0; north-bottom, 1; and north-top, 1. I do not know whether distribution patterns similar to those of M. drummondi and 74

Chrysobothris spp. might have emerged, had more individuals been found. However, Dicerca spp. and Buprestis spp. are both less abundant and they normally succeed the Melanophila and Chryso- bothris beetles when invading a host. The Buprestis species are especially common during later successional stages of forest residue decomposition by xylophagous insects. For example, in 1972 I collected B. aurulanta on old weathered logs on a clearcut in the Bull Run Watershed, Multnomah County, Oregon, in which the bark had long fallen off, and the exposed wood was deeply weather-checked and white with age. Woodborer Densities by Quadrant. Examination of woodborer distribution density over the log also reveals buprestids preference for certain locations on the log for larval development. Flatheaded woodborer densities for the four quadrants of each log were based on area calculations made from measurements of the length and width of each log quadrant. The larval density plots for M. drummondi (Figure 8) and the Chrysobothris complex (Figure 9), in partial cut and clearcut logs, show that densities are highest on the top and upper sides of these logs for both groups of beetles. These density patterns are similar to the distribution patterns for these beetles (Figure 7). These observations generally hold true for Melanophila and Chrysobothris in the logs from the 21.1°C and 26.7°C temperature treatments as well (Tables 5 and 6), although 75

100 _ 1 SOUTH -TOP 2 SOUTH-00TT014 3 NORT1+110TTON 80 ... 4 MONTH -TOP

40 S 20

1-7 1 2 3 4 1 2 3 4 PARTIALCUT CLEARCUT

Figure 8. Comparison of the distribution of Melanophila drummondi larval densities over the four quadrants of partial cut and clearcut Douglas-fir logs from McDonald Forest, Benton County, Oregon, 1975-1976. 76

100 _ 3. SOUTHTOP. .101111111, 2 SOUTHBOTTOM 3 NORTHBOTTOM BO . 4 NORTH TOP

60 ...

40.

20=- 11111111,

0. n n 1 2 3 4 1 2 3 4 PAIRTIALCUT CLEAR UT

Figure 9. Comparison of the distribution of Chrysobothris species larval densities over the four quadrants of partial cut and clearcut Douglas-fir logs from McDonald Forest, Benton County, Oregon, 1975-1976. 77

Table 5. Densities of Melanophila drummondi larvae reared in Douglas -fir logs at three constant temperatures, 1975- 1976. 2 Constant Mean + S. E. No. Insects/m by Quadrant Tempe rature Treatment I II III IV

15. 6 °C 13.7+ 9.3 15.3 +9.9 13.7+8.0 7.5+ 4.1

21. 1 °C 42.2+11.8 5.8+4.1 5.5+4.4 22.9+10.1 26.7°C 21.5+10.8 8.1+ 2.7 11.9+5.2 13.8+ 7.6

Table 6. Densities of Chrysobothris spp. larvae reared in Douglas - fir logs at three constant temperatures, 1975-1976. 2 Constant Mean + S. E. No. Insects /m by Quadrant Temperature Treatment I II III IV

15. 6 °C 7.5+ 4.1 4.6+3.9 9.3+4.8 14.1+11.6 21. 1 °C 15.6+ 9.5 4.7+2.7_ 11.6+5.2_ 11.9+ 5.5

26. 7 °C 34.3+17.6 22.7+7.1 9.0+4.4.... 21. 8+ 7. 8 78 it is not entirely clear why the Melanophila and Chrysobothris densities in the logs from the 15. 6°C treatment vary from this observed pattern. These results, however, indicate that lower larval densities tend to be more evenly distributed over the log surface. Some of these differences may be accounted for by the fact that the logs for the three temperature treatments were brought in from the field in August, 1975, while the clearcut and partial cut logs were allowed to remain in the field through the remainder of the season, thereby becoming more densely populated with woodborers than the temperature treatment logs. Analysis of variance for both the flatheaded fir borer and the Chrysobothris complex showed the quadrant differences in larval densities within logs to be statistically signficant at P < 0.05. In addition, the larval densities between treatments were significantly different at P <0.05 for the Chrysobothris spp. but not for M. drummondi at this probability level. A multiple comparison among the mean densities was not conducted because visual inspection of the results (Figures 8 and 9, and Tables 5 and 6) satisfactorily reveal the outstanding differences of primary interest (i. e. the differences of the woodborer densities at the top versus the bottom of the logs). Of great interest are the overall larval density differences between logs from the clearcut and the logs from the partial cut. 79 To illustrate these differences, I calculated the mean larval densities from the averages over all four quadrants on each log, and plotted these densities in Figure 10 for both buprestid groups taken from partial cut and clearcut logs. Although the density differences between partial cut and clearcut logs appeared substantial, they were not statistically significant for either woodborer group at the P = 0.05 level when tested with either an analysis of variance or an unpaired t-test, but significance was found at P< 0. 10 for both buprestid groups. These results and those of the last section indicate that Melanophila and Chrysobothris beetles prefer the top and upper sides of logs lying in sunlight and partial shade for oviposition.

Relationship Between Log Diameter, Bark Thickness, and Beetle Attack

I computed correlations to test how strongly attack by the flatheaded fir borer and the C1.r.ysobothris species is related to log diameter or bark thickness. Observations on the number of M. drummondi and Chrysobothris spp. found in each of 30 logs, and the diameter and bark thickness measurements of each log were used for these analyses. The log diameters ranged from 10.7 - 34. 3 cm and averaged 20.1 + 1.2 cm, and the bark thickness varied from 4.0 - 20.0 mm with an average of 8,2 + 0,7 mm for the

30 logs. 80

MELANOPICLA ORUMMONDI 2 CHRYSOOOTHRIS SPP. =r

>- H 10 111, zLa a 5. z 0 1 2 1 2 PARTIALCUT CLEARCUT

Figure 10. Comparison of the overall mean larval densities of Melanophila drummondi and Chrysobothris spp. between partial cut and clearcut Douglas-fir logs from McDonald Forest, Benton County, Oregon, 1975-1976. 81 Results of these analyses (Table 7) indicate that the relationship between beetle attack and log diameter or bark thickness are not close, nor do they differ_ significantly from zero at P = 0.05 level of probability. Attack by M. drummondi more closely relates to bark thickness than to log diameter. On the other hand, attack by Chrysobothris spp. more closely relates to log diameter than to bark thickness. The reason for this is that M. drummondi develops nearly exclusively in the phloem. Thus, bark thickness is more crucial for this beetle's development (because of its requirements for nutrition, growing space, and protection against natural enemies and extremes in the elements) than is log diameter. Unlike M. drummondi, the Chrysobothris species are more closely tied to the log diameter than to the bark thickness for their development, because the later stages of development of this group are spent in the sapwood rather than in the phloem. Richmond and Lejeune (1945) investigated the possible existence of a correlation of diameter and heights of fire killed spruce with woodborer infestation but they also could not find any marked relationship. In an effort to explain the variation in attack, I fitted a step- wise multiple linear regression model to M. drummondi attack data, with log diameter, log length, and bark thickness entering the model as the independent variables. However, even with these variables in the model I was only able to explain 19. 2% of the variation in 82 M. drummondi attack, and this is not significant when subjected to an F test in an analysis of variance. It is likely that other factors such as inner phloem moisture content and temperature, as well as irradiance or radiant flux density 13 of the bark, illuminance, and others would greatly improve this model.

Table 7. Correlation statistics for the relationship between attack of flatheaded woodborers and the diameter and bark thicknesses of Douglas-fir logs. Correlation Coefficients (r) Beetle attack versus No. of Species Samples Log diameter Bark thickness s. M. drummondi 30 0.188n. 0.321n.s.

Chrysobothris spp. 30 0.203n. s 0.1575n. s n. s. Not significantly different from zero at P = 0.05.

Beetle Development

The results in the preceding sections applied specifically and separately to both the flatheaded fir borer and to the Chrysobothris species complex. This section, however, is restricted to the development of the flatheaded fir borer exclusively. The difficulty in identifying all flatheaded woodborers in the

13The rate of flow of energy through a unit area of a specified surface. 83 larval stages except for M. drummondi precludes the possibility of studying aspects of buprestid ontogeny in any detail. The most obvious and important prerequisite for any developmental study of an insect is the ability to identify and measure all forms or stages occurring throughout the developmental process; this I was able to do for only the flatheaded fir borer. This section on the development and a later section .on beetle mortality constitute the ,major portion of this dissertation. As a result I have placed most of the emphasis here. It is important to remember that these studies were conducted under near ideal conditions for development of this insect. Flat- headed woodborers invading forest residues on southern aspects encounter warmer temperatures and drier host conditions than under any other circumstance; this is especially true for clearcuts. Solar radiational effects on the microclimate of forested and cut-over areas will be treated extensively later in the role of microclimate on the development and survival of M. drummondi. Rates of development vary according to the subcortical temperatures experienced by the immature insect, and these temperatures are influenced by many factors, including the aspect of the cutover slope upon which the infested residues are found. Therefore, the following results do not necessarily apply to all situations, but they do suggest that developmental differences are the result of 84 microclimatic variations between sites. By optimizing the microclimatic conditions through manipulation of residues one can speed up biodeterioration within the forest ecosystem. Comparison of Developmental Rates. To follow the progress of the insects' development at each of the five treatments through time I computed the development index (DI) for the flatheaded fir borer for every month a treatment was sampled. Figure 11 compares the rate of flatheaded fir borer development under partial cut and clearcut conditions, and Table 8 compares the development under the three constant temperature treatments.

Table 8. Comparison of the development index values of Melanophila drummondi from Douglas-fir logs under different constant temperature regimes, 1975-1976.

No. in Sample and Development Index Valuesa Month n 15.6°C n 21.1 °C n 26. 7°C

Sep 11 2. 1 Oct 6 2. 0 6 2. 2 5 2. 4 Nov 3 2.5 45 2.7 Dec 2 2.4 13 2.8 5 2.7 Jan 4 3. 0 1 3. 0 9 3. 0 Feb 8 2.8 22 3.0 Mar 17 2.6 1 3.0 3 3.0 2 3. 0 Apr 1 3. 0

a: No. in sample and development index values are based on whole- log samples. 85

5.00 w 4.00

1-1 3.00

02.00I w 1.00

0.00 OCT NOV DEC JAN FEB MAR APR 1975-76

PARTIAL CUT CLEARCUT

Figure 11. Comparison of the development index values of Melanophila drummondi reared in Douglas-fir logs on a partial cut and clearcut at McDonald Forest, Benton County, Oregon, 1975-1976. 86

Initial inspection of these results indicates that by the time 14 sampling was initiated in October for most of the treatments the beetles were already well advanced in development. The flatheaded fir borer remains active all summer and logs sampled near the end of the summer are most likely to have high population densities. High density populations are desirable in view of the amount of effort that is required to remove the bark from the logs to obtain specimens. Unlike the numerous eggs laid by each ovipositing bark beetle female of the family Scolytidae, flatheaded fir borer females lay only two or three eggs at a time. Also, the larvae that hatch from these eggs grow to be several times larger than the bark beetle larvae, and therefore require more inner bark surface area per larva for growing space. Thus, they are limited in numbers by their size relative to the surface area size of their host. By the time I commenced sampling the various treatment logs in September or

14 The 26.7 oC treatment was first sampled in September (see Table 8). Although not indicated in Figure 11, the clearcut was first sampled in June if one considers the preliminary clearcut samples taken in June, July, and August as mentioned earlier. The results for the preliminary clearcut samples were not included in Figure 11 because comparable samples from the partial cut for these months were not available. However, these preliminary results from the clearcut will be included in other tables later. 87 October, the larvae were already in various stages of development because of continuous attack by this beetle over the summer months. Therefore, the rate of beetle development for the various treatments (Figure 11 and Table 8) is not shown for any months earlier than September or October. Results from the clearcut treatment for June, July, August, and September are presented in a later table. Figure 11 also shows that no partial cut sample was made during the month of February. For statistical analysis of these results, the DI plotted for the clearcut sample in February was deleted as well, so that the paired t-test could be used to test the partial cut and clearcut flatheaded fir borer development rates. The DI for the February clearcut sample was included on the graph so that I could illustrate the flatheaded fir borer development trend with continuity through time. The rate of M. drummondi development under clearcut conditions was not significantly greater than under partial cut conditions at the P = 0.05 level (Table 9) , but it was significant at the P< 0. 10 level. For all practical purposes, the clearcut and partial cut differences are significant. The mean development rate for the flatheaded fir borer from the clearcut logs is significantly greater than the 26. 7°C constant temperature development rate at the P < 0. 10 level as well. 88

Table 9. Comparison of the mean development rate of Melanophila drummondi in Douglas-fir logs subjected to five environmental conditions, October 1975 - April 1976. a Environmental No. Logs Condition Sampled Mean + S. E. Rate of Developmentb

Clearcut 6 3,407 + 0. 234a

Partial cut 6 3.027 + 0.095 ab

26. 7 °C 6 2.850 + 0.102 abc

21. 1 °C 6 2.750 + 0.120 bcd

15. 6 °C 6 2.583 + 0.156 cd

aClearcut and partial cut differences tested with paired t-test; all other combinations tested with unpaired t-test. bMeans followed by the same letter in each column are not significantly different (P > 0.05). 89 Examination of the mean development rates for the five treatments during the 1975-1976 season (Table 9) reveals that the relative rate of development of the flatheaded fir borer varied from treatment to treatment according to the following order:

clearcut > partial cut > 26. 7°C > 21. 1°C > 15. 6

The conditions represented by the clearcut are optimal for development on the basis of these observed differences in the mean seasonal rate of M. drummondi development. Although I cannot determine from these results what the optimum constant temperature for rate of development is without rearing larvae over a wider range of constant temperatures than those used in my research, it is apparent that the clearcut conditions represent the optimal conditions for field rearing of this insect. As Davidson (1944) reminds us, The "optimum" temperature for development is now often defined as that temperature at which the largest number of individuals are able to complete their development and become healthy insects. It may include a range of several degrees: it is not necessarily the temperature at which development proceeds at the fastest rate. I used the term "optimum" in regard to the rate of development in the discussion above, but as I will show in a later section, the term also satisfies Davidson's definition, in that the largest percentage of individuals completes their development on the clearcut site as well. 90 My findings, that developmental rate of the flatheaded fir borer increases with increasing temperatures, are consistent with the findings of numerous other workers on forest insects (cf. Dyer and Hall, 1977; Dyer et al., 1968; Gaumer and Gara, 1967; Mc Cambridge, 1974; McMullen, 1976; Vite" and Rudinsky, 1957) as well as with the findings reported by Davidson (1944) and Taylor and Harcourt (1978) for non-forest insects. The flatheaded fir borer reached the pre -pupal stage (DI = 3.00) in January at all three constant temperature treatments (Table 8). Although the mean seasonal rate of development for this insect varied between the three constant temperatures (Table 9), none of the rates were significantly different from the others (P >0.05). Flatheaded fir borers reared at any of the three constant temperature treatments failed to develop past the pre -pupal stage. This finding supports the existence of a diapause for the 3rd-instar larvae of this species, which probably requires exposure to a cold period to terminate. Figure 12 shows that flatheaded fir borers developed at a faster rate on the clearcut than on the partial cut. Development to the pupal and adult stages was reached sooner on the clearcut and increasingly smaller proportions of earlier instars occurred on this site over time as well. A comparison of the proportions of developmental stages of 9 1

OCT NOV DEC JAN FEB MAR APR 1975-78

En.:1 1ST INSTAR ZNO INSTAR 1:3 3RD INSTAR 1111 PUPA ADULT

Figure 12. Comparison of the changes in monthly distribution of all developmental stages of Melanophila drummondi reared in Douglas-fir logs on a partial cut and clearcut at McDonald Forest, Benton County, Oregon, from October 1975-April 1976. 92 M. drummondi on the clearcut for the months of March and April (Figure 12) may appear confusing at first glance. It appears as though the proportion of 3rd instars increased, while the proportions of pupae and adults decreased from March to April. This apparently anomalous result was probably due to differences in the total number of individuals in the samples for each month. Table 10 indicates, for example, that only 6 individuals were found in the log sampled for March, whereas four times as many individuals (24 M. drummondi) were taken from the log sampled in April. On the basis of differences in numbers of individuals between these two monthly samples, the experimental probability (see Boot and Cox, 1970) of finding 3 M. drummondi in the adult stage in March is 50% (3 out of a total of 6) as indicated in Table 10. On the other hand, the probability of finding exactly the same number (3) of M. drummondi adults in the April sample is considerably lower (i. e. 3 out of a total of 24, or 12. 5%). Thus the results seen in Figure 12 for the comparison of the proportional stages of M. drummondi from a clearcut log in March with the proportional stages from a clearcut log in April, are really a result of the unequal number of observations upon which the proportions are based for the samples from these two months. Table 10. Percent distribution of Melanophila drummondi in each developmental stage in Douglas-fir logs from a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. Percent in each stage Adult Month n 1st 2nd 3rd Pupae

Jun 2 100

Jul 6 83.3+15.3 16.7+15.3

Aug 12 66.7+13.6 33.3+13.6 10.2+ 4.8 Sep 39 38.5+ 7.8 51.3+...... 0.6

Oct 2 100

Nov 12 8.3+ 8.0 91.7+ 8.0

Dec 29 3.4+ 3.4 96.5+ 3.4

Jan 23 60.9+10.2 39.1+10.2 8.7+ 5. 9 Feb 23 56.5+10.3 34.8+ 9.9 50. 0+20.4 Mar 6 16.7+15.2 33.3+19.2 29.2+ 9. 3 Apr 24 45.8+10.2 25.0+ 8.8 94

The weather during 1976-1977 was unseasonally warm and dry in Oregon (see Appendix E). The proportional distribution of the developmental stages of M. drummondi on the clearcut during the unusual 1976-1977 season (Table 11) may be compared with the clearcut results from the more typical season of 1975-1976 in Table

10. Although it first appears that the development of the flatheaded fir borer is more advanced early in the 1976-1977 season (compare September months in Tables 10 and 11), this advanced development is not generally maintained during the remainder of this season when compared to the previous one. Some of the differences indicated in the proportional distribution of the flatheaded fir borer developmental stages between these two seasons (Tables 10 and 11), probably resulted from differences in the total number of individuals from the sample months for both seasons upon which the proportions were based. However real or artificial these differences may be, a comparison of the monthly development indicies for these two seasons (Table 12) reveals that, on the average, these two different seasons did not differentially affect the rate of M drummondi development as suspected. The difference between the development rates of the two seasons from September through April (excluding January) were not statistically significant at the P = 0.05 level when tested with a paired t-test. Consideration of these results leads to three Table 11. Percent distribution of Melanophila drummondi in each developmental stage in Douglas- fir logs from a clearcut in McDonald Forest, Benton County, Oregon, 1976-1977. Percent in each stage Month n 1st 2nd 3rd Pupae Adult

Sep 6 16.7+15.2 50.0+20.4 33.3+19.2

Oct 12 16.7+10.8 83.3+10.8

Nov 7 14.3+13.2 85.7+13.2

Dec 2 100.0

Jan 0 Feb 16 50.0+12.5_ 37.5+12.1_ 12. _ 8.3 Mar 6 50.0+20.4 33.3+19.2 16.7+ 2.3

Apr 6 50.0+20.4 16.7+ 2.3 33.3+19.2 96 possible explanations for the lack of statistical differences in the rate of development of M. drummondi during the two seasons:

1) The seasonal differences were not great enough. to significantly influence beetle development; 2) the unequal number of individuals between the two seasons each month obscured the actual differences because the proportions were based upon different total numbers; or 3) there is no real difference between the two seasons' effect on beetle development, regardless of any temperature differences.

Table 12. Comparison of seasonal development of M. drummondi from Douglas-fir logs cut at two different seasons and placed on a clearcut in McDonald Forest, Benton County, Oregon.

Development Index Month n 1975-76 Season n 1976-77 Season

Jun 2 1.00 Jul 6 1.17 Aug 12 1.33 Sep 39 1.72 6 2.17 Oct 2 3.00 12 2.83 Nov 12 2.92 7 2.86 Dec 29 2.96 2 3.00 Jan 23 3.39 0 Feb 23 3.52 16 3.62 Mar 6 4.33 6 3.67 Apr 24 3.83 6 3.83 97

Probably a combination of the first two explanations is correct. The third explanation is probably not valid based on the results of the constant temperature rearings (Tables 8 and 9). Effect of Temperature. Temperature ranks high in its ability to regulate the rate of developmental processes in both plants and animals. Recognizing the significance of temperature in relation to biological processes, and particularly of plants, Cleary and Waring (1968) discussed the collection, processing, and interpretation of temperature data in analyzing the growth and distribution of Douglas-fir in the field. The practice of summing thermal units has been generally established as a basis for temperature-rate related studies (cf. Allen 1976; Arnold, 1959, 1960; Baskerville and Emin, 1969). Employing this method of summing thermal units or degree days, Wickman (1976) recently related the egg hatch and dispersal of Douglas -fir tussock moth, Orgyia pseudotsugata (McDunnough) to the phenological development of its host, white fir, in California. Working with another forest defoliator, Ives (1973) related heat units to outbreaks of the forest tent caterpillar, Malacosoma disstria Hubner. Consideration of site differences in the accumulation of thermal units effectively demonstrates the differences in the development of an insect species on two distinct forest sites. On the adjacent 98 partial cut and clearcut sites in McDonald Forest, for example, I measured ambient air temperatures and plotted the daily accumulated thermal unit exposure separately for each month for the flatheaded fir borer on each site (Figure 13). I assumed a basal threshold development temperature of 10°C for reasons previously mentioned. The lower bounds on the partial cut and clearcut curves represent the daily exposure of thermal units (i. e. degree-days) up to 10°C, accumulated separately for each month shown. The upper bounds for each curve represent the daily exposure of thermal units over oC, 10 accumulated separately for each month. Hence the area between the upper and lower bounds for each curve represents the total thermal exposure above the development threshold for the flatheaded fir borer, as measured by the ambient air temperature on each of the two field sites each month. The patterns of monthly thermal units for the partial cut and the clearcut are similar (Figure 13). The greatest degree-day accumulation on both areas occurred between May15 and October, and little thermal exposure occurred between November and April. This latter period corresponds well with the overwintering pre-pupal stage (3rd instar) of M. drummondi (compare Figures 3 and 13).

15Not shown on graph because temperature measurements were not available for this month, but can roughly be illustrated by extrapolation of the curves from the months of April to June. 99 300

200

1.00 I

0 ES

3000

> 2500 co cn 2000

1500 --

\ , X \ wcc 1000 \\\

> 500

0 JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR 1975-76 r PARTIAL CUT CLEARCJT Figure 13. Comparison of the partial cut and clearcut monthly thermal unit exposure above 10°C, the assumed development threshold temperature for Melanophila drummondi, at McDonald Forest, Benton County, Oregon, 1975- 1976. 100 The period of little thermal exposure results from substantial decreases in solar radiation during this period. Since I did not measure solar radiation, I plotted monthly precipitation along with the monthly thermal units for comparison. Precipitation is closely tied to solar radiation in the Pacific Northwest by an inverse relationship. Although perhaps not entirely clear from the results shown in Figure 13, the area under the clearcut thermal-development curve is greater than the area under the partial cut curve. This is more clearly seen in the comparisons of the monthly accumulated thermal exposures plotted for the partial cut and clearcut in Figure 14. The accumulation of degree-days above the development threshold of 10°C for M. drummondi is consistently greater for the clearcut than for the partial cut throughout the development season. These temperature-related differences in the microclimate of the two sites explain the differences noted earlier in the rates of development of beetles reared in Douglas-fir logs on these sites, since the effect of temperature on the rate of development of poikilothermic animals is accumulative. Allen (1976) briefly discussed the mathematical assumptions underlying the temperature-related development of organisms. For more details on this subject, the reader is referred to the previously mentioned papers as well as those by Abrami (1972); Lindsey and Newman (1956); Stinn.er et al. (1974); and Wang (1960). 101

LI 3000 - 0 co c 2500 - c")

1-4 z 2000 -I- D _J 1500 - a CLEARCUT

A PARTIAL CUT I 1000 - 0 w cc 500

0 o JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR 1975-78

Figure 14. Comparison of the partial cut and clearcut accumulative monthly thermal unit exposure above 10°C, the assumed development threshold temperature for Melanophila drummondi, at McDonald Forest, Benton County, Oregon, 1975-1976. 102 It should further be noted from these curves (Figure 14), that the greatest accumulative exposure of thermal units on both partial cut and clearcut sites occurs during the months of May through October, whereas little accumulative exposure occurs after October, as we saw in Figure 13 above. I have made no attempt to assign development stages to, or to correlate time of emergence and flight with the monthly accumulative thermal exposure curve (Figure 14) or to cumulative degree - days for the following reasons: 1) The development and emergence of the flatheaded fir borer in forest residues in asynchronous, since residues are continuously attacked over a period of time during the season. To correlate each development stage with a precisely measured accumulated thermal exposure would be impossible from my observations without individually rearing numerous insects through development from the egg to the adult stage; and 2) the basal threshold temperature for M. drummondi development has not been precisely determined. I based all of the calculations of thermal units in Figures 13 and 14 on the assumed threshold temperature of

10 °C. It is informative to examine these curves because they are different and represent the theoretical temperature-dependent time scales for development of the flatheaded fir borer under two different microclimatic conditions. Moreover, the development threshold of 10°C assumed for 103

M. drummondi relates closely to the development thresholds reported for other subcortical insects. For example, 6. 1 -9. 4oC has been reported as the development threshold for Dendroctonus pseudotsugae (Dyer et al., 1968); Vita and Rudinsky (1957) report that temperatures below 8. 0°C prevent further development of this beetle. Beal (1931) reported that development of the western pine beetle, Dendroctonus brevicomis Leconte does not occur below 10°C. Development Related to Log Exposure. A comparison was made of the development rates of beetles occurring at different positions in the logs on the ground. Observations were pooled for the top two quadrants and for the bottom two quadrants of logs from the clearcut only, since the observations from these logs were most complete over the development season, 1975-1976. One log was dissected each month and the living, non-parasitized larvae from each quadrant were measured and the mean development index computed for the pooled quadrants each month (Table 13). I found larvae occurring on the bottom-half of the clearcut logs only in the September, December, January, and February samples. Since the logs sampled at each of these months were chosen at random, I used a paired t-test to compare the differences between the mean development at the top and bottom of these clearcut logs over the four months. The results presented in Table 13 show differences in rate of 104 development between flatheaded fir borers from the top-half and bottom-half of the logs. Although the beetles in the top-half of the logs developed at a faster rate than those from the bottom-half on clearcuts, the difference between the development rates of these two positions is not significant at the P = 0.05 level.

Table 13. Comparison of the seasonal development of Melanophila drummondi in the top-half and bottom-half of logs located on a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976.

Top -half Bottom -half Number in Mean development Number in Mean development Month sample index sample index

Jun 2 1.00 0

Jul 6 1.17 0

Aug 12 1.33 0

Sep 30 1.77 9 1.55

_ _ Oct 2 3.00 0

Nov 12 2.92 0

Dec 27 2.96 2 3.00

Jan 15 3.53 8 3.00

Feb 16 3.69 7 3.14

Mar 6 4.33 0 --

Apr 24 3.83 0 105

Beetle Mortality

Of primary importance to either the local or overall abundance of an insect species are the numerous considerations of the population and the factors of the environment that interact with it (Clark et al., 1970). In the foregoing sections I have presented the observations and results of my studies on various characteristics of woodborer 'populations' (particularly of the flatheaded fir borer). In this section, I will consider some of the biotic components of the 'environment' and their interactions with the population, with special regard to their influence on the abundance of woodborer species in forest residues. A later section will cover some of the physical components of the environment and their influence on the abundance and distribution of woodborers. Some overlap of these topics is inevitable, but a more complete and comprehensive discussion will follow. Larval Mortality Distribution Within Logs. Mortality of both the flatheaded fir borer and the Chrysobothris complex occurred in the larval stages during the course of my studies. I found no pupal or adult mortality for either buprestid group, although mortality during these stages does occur. More samples of the treatment logs are probably required to detect pupal mortality, since prevalence 106 rates for pupal mortality are much lower than that for larval mortality among these buprestids. The mean mortalities of M. drummondi in Douglas -fir logs exposed to five environmental conditions (Table 14) are given along with their 95% confidence limits. To test for differences between treatments, the data were transformed by the angular or arcsine transformation (arcsine 43, where p is a proportion) in order to normalize them to meet the assumptions of the analysis of variance. The arcsine transformation was applied because most the the per- centages were < 30 or > 70%. The back-transformed confidence limits are given in lieu of the standard errors since stating standard errors would be misleading after using a none-linear transformation for testing the results, according to Sokal and Rohlf (1969).

Table 14. Comparison of mean mortality of Melanophila drummondi within four quadrants of Douglas-fir logs exposed to five environmental conditions, 1975-1976.

a Mean + C. L. Percent Mortality by Quadrant Environmental North-Top Condition South-Top South-Bottom North-Bottom 23. 5+18. 6 Clearcut 27.7+ 1.8 17.9 +18. 1 14.0+ 9. 7

Partial cut 34. 5+10. 4 31. 1-F24. 1 50. 0+99. 9 31. 7+30. 3 25.0+48. 4 26. 7°C 30. 0+44. 1 16. 7 +11.6 14. 6+10. 2

0 19.3 +18. 3 21. 1 C 19. 8+14. 5 31. 8+26. 8 6.7+ 8.9 oC 100.0+ 0.0 15. 6 83. 3+24. 1 50. 0+ 0.0 28. 3+23. 4

a95% confidence limits for means computed in arcsine transformed scale ( arcsine4) and back- transformed to original scale for reporting here. 107 The analysis of variance (Table 15) determined that the differences in M. drummondi mortality between the five treatments are highly significant (P < 0. 01). In addition, a priori comparisons of means and group means in the analysis of variance tested the following two hypotheses:

1) H0: p. constant temperature mortality = p.2 field treatment mortality; the alternate hypothesis being, H1: µ f p,

2) H [J, partial cut mortality = p.2 clearcut mortality; with 0 1 and alternate hypothesis of, H1: p.i p.2. Neither of these a priori comparisons proved to be significantly different at the P = 0.05 level of probability.

Table 15. Results of analysis of variance used to test statistical differences in the mortality of Melanophila drummondi in Douglas-fir logs at five environmental conditions. a

ANOVA TABLE

Source of variation df SS MS

Among groups (among treatments) 4 3,036.58 759.15** Constant temperature vs. field treatments 1 117.10 117. lOn s Partial cut vs. clearcut 1 214.04 214.04n s Within groups (error; mortality within treatments) 15 2,326.24 155.08 aAnalysis of variance conducted on arcsine transformed data (arcsine 4)). 4":4 Significant at P = 0.01. n. s. Not significantly different at P = 0.05. 108 The significant differences between treatment mortalities found in the initial analysis of variance probably result from the rather high mortality prevalance rates of the 15. 6°C constant temperature treatment (Table 14). The mortality calculated for the 15. 6°C treatment led to a much higher percentage than the other treatments since they were based on fewer total observations than the others but with roughly the same number dying as in most of the other treatments. Mortality comparisons for the Chrysobothris complex are included in the table in Appendix F for the readers' information, but will not be discussed here. Larval Mortality Factors and Their Relative Efficacies. As with most natural insect populations, numerous factors account for larval mortality in populations of the Melanop_hila and Chrysobothris flatheaded borers. I observed several of these factors during the course of my investigations, and found that parasitism appeared to be the most important, followed in descending order of importance by unknown causes, resinosis, and predation (Figure 15). These factors account for an overall mortality of 29. 2% (143 dead out of 489 total) for M. drummondi, and 29.7% (141 dead out of 475 total) for the Chrysobothris complex. Because I had no prior knowledge of the causes of mortality of the flatheaded fir borer or the Chrysobothris complex, I was 109

100 _ MELANOPICILA DRUMMOND" 2 CHRYSOGOTHRIS SPP.

80_

1111011011101,

60._ 11111111BNINO/

40...

20_

0-1 r-1 n 1 2 1 2 1 2 1 2 PREDATION PARASITISM MEMOS= UNKNOWN

Figure 15. Comparison of mean seasonal efficacies of flatheaded woodborer mortality factors in Douglas-fir logs, 1975-1976. 110 unable to design experiments that would accommodate appropriate statistical comparisons of the differences in these mortalities. Parasitism: The relatively large proportion of the total mortality caused by parasitism (Figure 15) is accounted for by the actions of four hymenopterous parasites; Atanycolus longifermoralis Shenefelt (Braconidae), Coeloides brunneri Viereck (Braconidae), Pristaulacus (= Aulacostethus) minor (Cresson) (Aulacidae), and Doryctes fartus (Prov. ) (Braconidae). All four of these species were reared from M. drummondi or Chrysobothris spp. larvae. In addition, I reared two individuals of Neoxorides pilulus Townes and Townes (Ichneumonidae) from unidentified cerambycid larvae. A. longifemoralis were most frequently taken of the woodborer parasites. This species is a primary ectoparasite on M,. drummondi, but parasitizes Chrysobothris spp. and other woodborers as well (Shenefelt, 1943). It is of interest that numerous C. brunneri were reared from M. drummondi, since this parasite occurs regularly on the Douglas- fir beetle, Dendroctonus pseudotsugae Hopkins which inhabits the underside and shady side of down logs (Ryan and Rudinsky, 1962). Apparently, C. brunneri will overlap hosts when M. drummondi venture into bark which is shaded, since these authors observed that C. brunneri normally only oviposits in fairly deep shade. Deyrup (1975) suggests that M. drummondi is an abnormal host for C. 111 brunneri because of its normally shaded habitat and also because the ovipositing females of this parasite have host size preferences that limit their range of normal hosts. Other parasites of M. drummondi listed by Deyrup (1976), although not encountered in my studies, include Atanycolus anocomidis Cushman (Braconidae) (cf. Shenefelt, 1943), Xorides insularis (Cresson) (Ichneumonidae) (cf. Townes and Townes, 1960), Neoxorides borealis (Cresson) (Ichneumonidae) (cf. Muesebeck et al., 1951), Pristaulacus rufitarsus (Cresson) (Aulacidae) (cf. Townes, 1950), Dolichomitus foxleei Townes and Townes (Ichneumonidae) (cf. Townes and Townes, 1960), and Neocatolaccus sp. (Pteromalidae). In studies on the flatheaded fir borer outbreak in California,

De Leon16 reported the frequent occurrence of Odontaulacus (= Aulacostethus) editus (Cresson) (Aulacidae) and Atanycolus montivagus (Cresson) (Braconidae) on larvae of M. drummondi. Moreover, he reported that 0. editus was much more common than A. montivagus. Burke (1910) also reports that M. drummondi is the host for A. montivagus Unknown Causes: Woodborer mortalities for which I could not identify causes were included in the category of "unknown" factors.

16De Leon, "The fir flatheaded barkborer outbreak, " p. 17. 112 These mortalities possibly result from such factors as high and low-lethal temperatures, desiccation, disease, and others. Sidor (1970, 1971) reported the occurrence of cytoplasmic polyhedrosis in Melanophila picta Pall. in Yugoslavia. He found the virus disease in the larvae of M. picta during high population densities in Poplar, Populus spp. It is not known whether this disease or others occur in populations of M. drummondi in North America, however. Diseases of Chrysobothris spp. have not yet been reported in the literature (cf. Martignoni and Iwai, 1975, 1977). On December 15, 1975, I collected three dead M. drummondi larvae that had small patches of mold growing on them. I cultured the molds on Sabouraud Maltose Agar, and had the cultures identified by Dr. William C. Denison, Associate Professor of Botany, Oregon State University. One culture was identified as Aspergillus niger Van Tiegh. , one as Penicillium 12: , and the third was unidentified. I do not know for certain whether these fungi were responsible for beetle mortality or if they invaded the larvae secondarily. I suspect that they were actually saprozoic, since Moore (1970) reported them as saprobes frequently covering adult southern pine beetles, Dendroctonus frontalis Zimmermann, that had been killed by other entomogenous fungi and bacteria. Aspergillus spp. and Penicillium spp. are commonly found among the microflora of 113 Douglas-fir forest soils (Wright and Bo llen, 1961) and of other forest soils as well (Bo llen and Wright, 1961). Resinosis: Numerous dead larvae were found in which resin flowed into the gallery from surrounding tissues and drowned the larvae (resinosis). This is thought to result from the rupturing of intact longitudinal resin canals in the outer portion of the growth ring as the larva feeds near or partially into the sapwood. Appar- ently these resin canals tend to concentrate in the late wood, often toward the grouping of 5 to 30 or more in tangential rows in Douglas-fir (Panshin and de Zeeuw, 1970). Resinosis is undoubtedly an important factor in the natural resistance of living hosts to attack by woodborers, and also in the healing over of wounds resulting from unsuccessful attacks. Predation: Several entomophagous insects prey on bark- and woodboring insects in Douglas-fir and other hosts inhabited by these insects. Chamberlin (1939) provided a fair review of the predators of scolytid beetles in which he included predacious species from the orders Coleoptera, Hymenoptera (ants of the family Formicidae), Diptera, Hemiptera, and Neuroptera. In addition to insect predators, he also reviewed the other important bark beetle predators including certain centipedes, mites, birds, mammals, amphibians, reptiles, and even fish that destroy beetles during various stages of their life cycles. 114

Much less, however, is known of the predators of Buprestidae. Undoubtedly, some of the predaceous families of Coleoptera of bark beetles discussed by Chamberlin (1939) (e.g. Staphylinidae, Histeridae, Cucujidae, Nitidulidae, Elateridae, Rhizophagidae, Corynetidae, and others), prey on buprestid species as well, when the larval mines of these latter woodborers extend into portions of the logs which are inhabited by bark beetles. The most important Coleoptera predator of the flatheaded fir borer encountered during my studies was the blackbellied clerid Enoclerus lecontei (family Cleridae) (Wolcott). This beetle reportedly is often found associated with M. drummondi larvae (Cowan and Nagel, 1965). Another predacious beetle (family Ostomidae), occasionally found in empty Chrysobothris spp. galleries in the sapwood, is Temnochila virescens var. chlorodia (Mannerheim). This beetle is an aggressive predator which is reported to feed on other predators and parasites of bark beetles and woodborers as well as on the phytophagous borers (Cowan and Nagel, 1965). In addition to the two predators mentioned above, a colydiid beetle, Deretaphrus oregonensis Horn (family Colydiidae) is reported to destroy several species of buprestids in the West (Burke,

1919b). According to Hatch (1961), this species occurs in south- eastern British Columbia, Washington, Idaho, and only in the eastern 115 part of Oregon. It is, therefore, probably not an important predator of buprestid borers in Douglas-fir in western Oregon. None were found in the present study. Beetles of the families Melyridae and Corynetidae (in hardwoods only) have also been reported as predators of buprestids (cf. Chamberlin, 1939). Avian predators such as woodpeckers are also known to feed on buprestids, although I did not observe this predation on woodboring larvae in the logs in my study. Predation by woodpeckers, however, is probably not an important factor in reducing woodborer population levels except in thin-barked logs. On the other hand, they do contribute directly to the decomposition of woodborer- 17 infested residues as a result of their feeding habits. De Leon noted in his report, for example, that while woodpecker work was very heavy at times and almost always confined to the upper-half of standing trees where the bark was thinner, the heaviest flatheaded fir borer broods were located in the lower-half of the boles where the bark was thickest. Seasonal Mortality Trends and Population Point Estimates. The seasonal mortality trends for a sample of a flatheaded fir borer population infesting Douglas-fir logs on a clearcut (Table 16) and on a partial cut (Table 17) are shown by the causes of mortality on these two sites. The results shown by these trends can be used

17 De Leon, "The fir flatheaded bark borer outbreak, " p. 6. 116

Table 16. Seasonal trends and point estimates of mortality for a Melanophila drummondi population infesting Douglas-fir logs on a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. b a No. Dying From Total in No. No. Unknown Causes Month All Stages Living Dead Parasitism Predation Resinosis

Jun 2 2 0

Jul 6 6 0

Aug 12 12 0

3 Sep 42 39 3 0 0 0

3 Oct 40 28 12 9 0 0

0 2 Nov 15 13 2 0 0

0 0 Dec 40 29 11 11 0

10 Jan 40 26 14 4 0 0

0 Feb 28 24 4 0 0 4

0 3 Mar 9 6 3 0 0

0 0 Apr 27 24 3 3 0

Total 261 209 52 27 0 4 21

Point Est. (") for 569.4 456.0 113.4 58.9 0 8. 7 45. 8 Population

aIncludes instars 1-3, pupae, and adults.

Represents larval mortality only (i. e. instars 1-3); no pupal nor adult mortality were observed. 117

Table 17. Seasonal trends and point estimates of mortality for a Melanophila drummondi population infesting Douglas-fir logs on a partial cut in McDonald Forest, Benton County, Oregon, 1975-1976.

b a No. Dying From Total in No. No. Month All Stages Living Dead Parasitism Predation Resinosis Unknown Causes

Oct 16 14 2 2 0 0 0

Nov 9 9 0

Dec 26 18 8 8 0 0 0

Jan 19 17 2 2 0 0 0

Feb No sample

Mar 16 6 10 7 0 0 3

Apr 12 5 7 4 3 0 0

Total 98 69 29 23 3 0 3

Point Est. (Y) for Popula- tion 392.0 276.0 116.0 92.0 12.0 0 12.0

a Includes instars 1-3, pupae, and adults.

bRepresents larval mortality only (i. e. instars 1-3); no pupal nor adult mortality were observed. 118 to estimate the total population mortality if the total number of units, N, comprising the population (in this case, the logs are considered sample units) are known. Cochran (1963) gives the method used to calculate the population total for a simple random sample as the product of the sample mean (7) and the total number of units in the sample (N) Since the mean is a parameter estimate, the product of these two quantities provides the unbiased estimate of the population Total (4). The reader is referred to Cochran (1963) for the proof of this corollary. The results from point estimates of total M. drummondi population mortality indicate that an estimated 19. 9% (113.4 dead out of 569.4 total) mortality occurred on the clearcut, whereas an estimated 29.6% (116.0 dead out of 392.0 total) mortality occurred on the partial cut (see Tables 16 and 17). The largest proportion of individuals of the flatheaded fir borer survived to adulthood on the clearcut, as suggested earlier. Tables 18 and 19 show the distribution of the various causes of M. drummondi mortality within Douglas-fir located on the clearcut and partial cut, respectively. Although the general tendency exists for increased mortality with increased host abundance, the proportional mortality is actually constant (or nearly so) on the clearcut, but varies considerably on the partial cut due to small and varying numbers of observations available from each quadrant of the 119 sample logs. The mortality results, at least for the clearcut samples, show a classical example of density independence with host density, but are based on these limited observations. All of the mortality factors were combined in this comparison, and this prohibits the separate classification of mortality factors into the density dependent or independent categories. These results simply present the distribution of mortality factors within the infested logs, without regard to their density relationships to the host. The scope and design of this research prohibits a detailed study of the population dynamics of woodborers.

Table 18. Distribution of Melanophila drummondi mortality factors within Douglas-fir logs located on a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. Total c a No. Dying From Log Total in No. No. Unknown Percent Quadrant All Stages Living Dead Parasitism Predation Resinosis Causes Mortality

5 I 136 110 26 18 0 3 19.1

II 22 19 3 1 0 0 2 13.6

III 25 20 5 3 0 0 2 20.0

IV 78 60 18 5 0 1 12 23.1

Total 261 209 52 27 0 4 21 19.9

aIncludes instars 1-3, pupae, and adults. bRepresents larval mortality only (i. e. instars 1-3); no pupal nor adult morality were observed.

c From all causes. 120

Table 19. Distribution of Melanophila drummondi mortality factors within Douglas-fir logs located on a partial cut in McDonald Forest, Benton County, Oregon, 1975-1976.

b No. Dying From Totalc a Log Total in No. No. Unknown Percent Quadrant All Stages Living Dead Parasitism Predation Resinosis Causes Mortality

I 48 29 19 16 0 0 3 39.6

II 9 5 4 1 3 0 0 44.4

III 3 1 2 2 0 0 0 66.6

N 38 34 4 4 0 0 0 10.5

Total 98 69 29 23 3 0 3 29.6

a Includes instars 1-3, pupae, and adults.

bRepresents larval mortality only (i. e. instars 1-3); no pupal nor adult mortality were observed.

c From all causes.

Regression Estimation of Gallery Surface Area

The measurements of gallery surface area and length described earlier, permitted me to develop an accurate, predictive linear regression model of the amount of inner phloem surface area exposed by the feeding activities of flatheaded fir borer larvae. I first plotted a linearly-scaled scattergram of the cumulative gallery surface area obtained with each associated measurement of cumulative length, and observed the linearity of the results before "fitting" them to a predictive model by a linear least-square regression method (Figure 16). Although the correlation coefficient is high and significant (r = 0. 985), the curve is not linear and therefore 121 z 25 r =oae5 U Q 20 w . .4b cr : . 5 w Pii .1 *- I I.I'. ...1 ..***Ow CO I- 1 i i 0 0 10 20 30 40 50 GALLERY LENGTH (CM)

Figure 16. Linear plot of the cumulative surface area over cumulative length of Melanophila drummondi Kirby larval galleries in Douglas-fir logs. 122 violates the assumption of linear regression that the expected value for the variable Y for any given value X is described by the linear

function, = a + bX, (4)

where a is the Y-intercept and b is the slope of the regression line. The true relationship of the length and surface area variables can be described by the formula,

Y = aXb , (5)

and a curve of this general shape becomes straight when both variables are transformed to the logarithmic scale (Sokal and Rohlf,

1969). The regression equation (4) is then rewritten as,

loge C" = logea + b log X. (6) e

Figure 17 shows this double logarithmic transformation carried out on the results of Figure 16, along with the predictive regression equation and coefficient of determination. Clearly, the variations observed in gallery surface area (i. e. 99,1%) are accounted for by the measured values of the independent variable, length. Because the model predicts the cumulative gallery surface area from cumulative measurements of the gallery lengths, the necessary assumption for the model is that the cumulative (or total) gallery 123

1 22.00 LOGY=-2.593+1.503LOGX r2 =0.991 10.00 Li CC

C.) 1.00

cr)

LI/ .10 .06 1.00 10.00 100.00 GALLERY LENGTH (CM)

Figure 17. Logarithmic plot and linear regression equation of the cumulative surface area over cumulative length of Melanophila drummondi Kirby larval galleries in Douglas-fir logs. 124 length is always measured from the beginning of the gallery. There- fore, to use this regression method to determine the surface area of a flatheaded fir borer gallery of any length up to 44.0 cm, the gallery length must be measured from its beginning. Furthermore, the resultant surface area predicted by the model, based on the length measured from the beginning of the gallery, represents only the inner surface (i.e. one-half) of the woodborer gallery, and must be doubled to obtain the total gallery surface area.

The Role of Microclimate on Host Bark and the Flatheaded Fir Borer

Host-Microclimate Interactions

Among the physical and chemical properties of Douglas -fir bark, moisture content, pH, and temperature serve as fairly good indicators of the suitability of forest residues to attack and utilization by the flatheaded fir borer. The following paragraphs discuss the interactions of host and microclimate during the development season; a later section examines the effects of the microclimate on the flatheaded fir borer, although some overlap between sections is necessary. Moisture Content. Moisture content of Douglas-fir logs varies over the season following cutting depending on several factors, the most important of which is precipitation (Brackebusch, 1975). In a 125 study of the relationship of the inner phloem moisture content of clearcut and partial cut logs with their monthly exposure to precipitation (Figure 18), I found that a high and significant correlation exists between these variables. This relationship may have biological significance to the flatheaded fir borer in terms of food quality, since moisture content serves as a medium and solvent in the leaching of various carbohydrates, acids, and other products (cf. Graham and Kurth, 1949; Hergert and Kurth, 1952) that may function in woodborer nutrition or metabolism. The seasonal moisture content trends for the partial cut and clearcut logs (Figure 19) show that the moisture content of logs from a partial cut is greater throughout the season than logs from a clearcut. My findings, that logs in open areas have lower moisture contents than logs that are shaded, agree with the results reported by Brackebusch (1975). It is also apparent from examining the moisture content trends over time for both sites, that the moisture content of the logs increases through the rainy season, generally October through March in western Oregon (compare Figures 13 and

19). The phloem moisture content differences between partial cut and clearcut Douglas-fir logs reflect the microclimatic differences between these two sites. Clearcuts, for example, are typically warmer than partial cuts, but result in cooler night time 126

120 r =0.880 ae

- 100 si z w eo v GO w cr 40 *

(s) 0 20 I - 0 0 45 SO 135 180 MONTHLY PRECIPITATION (MM)

Figure 18. Correlation between inner phloem moisture content (percent of dry weight) of infested Douglas-fir logs and total monthly precipitation from a partial cut and clearcut in McDonald Forest, Benton County, Oregon, 1975-1976, and from a second clearcut study on same site, 1976-1977. (Correlation coefficient highly significantly different from zero at P < 0.01.) 127

200

I 150 .w

0 100

0 O I 0 OCT NOV DEC JAN FEB MAR APR 1975-76

PARTIAL CUT CLEARCUT

Figure 19. Seasonal inner phloem moisture content trends in Douglas-fir logs infested with woodborers on a partial cut and clearcut in McDonald Forest, Benton County, Oregon, 1975-1976 (plotted values represent the average percent of dry weight of four quadrants measured from each log). 128 temperatures (Edgerton and McConnell, 1976). The cooler day time temperatures and warmer night time temperatures of the partial cut in comparison to the clearcut result from the forest canopy's ability to absorb, reflect, radiate, and transmit incoming solar radiation. Reifsnyder and Lull (1965) indicate, for example, that a forest absorbs between 60 and 90 percent of the total solar energy received, depending on the density of the stand and the development of its foliage. Woody materials respond to environmental influences by gain- ing or losing moisture to eventually reach a state of moisture equilibrium with the environment. Temperature and relative humidity of the environment determine what the equilibrium condition of any one material will be (Brackebusch, 1975). But because temperature and relative humidity are constantly changing in the forest environment, it is likely that large wood residues seldom if ever reach a true moisture content equilibrium with their environment. Equilibrium moisture content is also affected by solar radiation and wind (Byram and Jemison, 1943). Solar radiational, temperature, and relative humidity differences between the partial cut and clearcut sites result in differences in evaporative demands on these sites. The filtering influence of the canopy cover in the partial cut prevents the direct solar insolation of logs on the ground, except during instances of sunflecks and thereby decreases the evaporative demand 129

(in terms of latent heat of evaporation). The greater evaporative demand corresponding to the greater net solar radiation on the clearcut site consequently results in generally lower moisture contents for the logs on this site compared with logs from the partial cut site. In addition, the presence of the partial cut canopy precludes some of the air movement beneath the canopy. The movement of air over the logs can further influence the moisture content of logs on the ground by affecting the rate of evaporation at the surface. The seasonal moisture content results for the three constant temperature treatments (Table 20) lacked any distinguishing pattern such as characterized the partial cut and clearcut results. The moisture content at the three temperatures remained relatively stable over time with generally small variations in the moisture content of samples between months. When woody materials are exposed to constant environments they will eventually attain a moisture equilibrium. According to U.S. Forest Products Laboratory (1974), Douglas-fir held in a 40% relative humidity environment at 15. 6°, 21. 10, and 26. 7°C should have reached equilibrium moisture contents of 11.3, 13.5, and 16. 5%, respectively. From the results in Table 20, it is clear that the average moisture contents were generally higher than their expected equilibriums, indicating that the logs had not attained their 130 theoretical equilibrium moisture contents by the time the study was terminated. Some of the logs, however, had nearly reached (in some instances surpassed) their theoretical equilibriums. It is possible that the other logs which deviated from the theoretical equilibrium moisture contents had reached their actual equilibrium moisture contents, but that they differed from log to log within and among treatments due to individual variability. Brackebusch (1975) points out that not all materials exposed to the same environment reach identical equilibrium moisture contents.

Table 20. Seasonal inner phloem moisture content trends in Douglas -fir logs infested with woodborers and held at three different constant temperatures, 1975-1976.

Average + S.E. Moisture Content (%)a Month 15. 6°C 21. 1 °C 26. 7oC

Sep -- 28.1+8.34 Oct 39.3+20.20 14.0+1.95 11.2+0.22 Nov 10.1+ 0.35 10.8+0.45

Dec 23.1+ 4.62 17.7+0.41..._ 17.8+2.35 Jan 25.6+1.90 16.7+4.07 16.6+1.13 Feb -- 19.4+0.87 20.3+1.31 Mar 21.2+0.43 27.5+5.82 19.9+1.96 Apr 26.6+2.95 - 26.1+3.26 May 17.0+2.52 22.5+1.48 25.7+5.45 aAverage percent of dry weight of four quadrants measured from each log. 131

The close relationship between the seasonal moisture content of the inner phloem of Douglas-fir logs and the seasonal precipitation trend is clearly shown in Table 21 for the 1976-1977 season on a clearcut in McDonald Forest. As mentioned earlier, the 1976-1977 season was unseasonally warm and dry in Oregon, and the effect of these abnormally xeric conditions on the moisture content of infested logs during this season is apparent from the results in Table 21. The moisture trends for the clearcut logs during the 1976-1977 season are considerably different from the moisture trends of the previous season in that there is a steady decrease in moisture content through the season until February, at which time moisture content increases to a peak in March, corresponding to the monthly precipitation trends during this period, and thereafter declines. When rainfall increased in February and March, the phloem moisture content increased, but dropped again in April with the onset of spring weather. By plotting the inner phloem moisture contents from all four quadrants on infested logs from the partial cut and clearcut in McDonald Forest through the 1975-1976 season, I determined the moisture content patterns within these logs which are helpful in explaining the ovipositional and larval developmental preferences for certain locations on the logs over others. 132

Table 21. Seasonal inner phloem moisture content trends in Douglas -fir logs infested with woodborers on a clearcut in McDonald Forest, Benton County, Oregon, 1976- 1977.

Average + S. E. Total Monthly Month Moisture Content (To) Precipitation (mm)

Sep 47.2+4.63 32.3 Oct 41.8+3.47 31.7 Nov 38.2+2.94 36.1 Dec 29.0+2.96 37.3 Jan 26.2+2.95 24.4 Feb 49.3+2.00 75.4 Mar 61.0+7.27 129.3 Apr 30.6+2.08 25.9 aAverage percent of dry weight of four quadrants measured from each log.

I found, from plotting the moisture contents of infested Douglas - fir logs that generally the lowest inner phloem moisture contents occurred in the south-top and south-bottom quadrants of partial cut logs (Figure 20) and in the south-top and north-top quadrants of the clearcut logs (Figure 21). These locations generally correspond to the site of greatest woodborer attack frequency and density (cf. Figures 7, 8, and 9) . With the logs lying in an east-west direction, I expected to find that the driest portion of the log would be that which received the greatest amount of incoming solar radiation (i. e. the top-half 133 250 tie 200 2

I- 1 50 0 0 w 100

(I) 50 01-1

0 OCT NOV DEC JAN FEB MAR APR 1975-76

V A SOUTH-TOP IJ NORTH-TOP SOUTH-BOTTOM NORTH-BOTTOM

Figure 20. Patterns of inner phloem moisture content in Douglas -fir logs infested with woodborers on a partial cut in McDonald Forest, Benton County, Oregon, 1975-1976 (values represent percent of dry weight sample). 134 250

SI Ne 200

150 w 100 cc

()I 50 1-10

OCT NOV DEC JAN FEB MAR APR 1975-76

v A SOUTH-TOP NORTH-TOP SOUTH-BOTTOM :4,:4-A.>x NORTH-BOTTOM

Figure 21. Patterns of inner phloem moisture content in Douglas- fir logs infested with woodborers on a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976 (values represent percent of dry weight sample). 135 and particularly the south-top quadrant), and indeed this was generally the case for the clearcut logs. Woodborer attacks were also heaviest at these locations (cf. Figures 7, 8, and 9). However, the driest portion of the partial cut logs proved to be the south-top and south- bottom quadrants. Although the reason that the south-bottom quadrant might be the next driest portion on the partial cut logs is not known for certain, this anomalous result might be partly explained by a consideration of the net solar radiation intensities that might be encountered by various areas on the logs. It is known (Reifsnyder and Lull, 1965), for example, that the quality of light that reaches the ground through a coniferous forest canopy is of the red and mostly infrared wavelengths, and that most of the light that enters below the canopy is diffused light, resulting from direct light being scattered by the canopy and skylight. Moreover, these authors point out that it is the net solar radiation that is responsible for evaporation and transpiration in forests, and not the air temperature. Considering these facts, it is conceivable that the vegetation characteristics and canopy configuration on the partial cut may be such that the low sun angles during the fall and winter insolate primarily the south side of the logs, thereby drying this portion of the logs more than any other. Without direct measurements of the net solar radiation received by various locations on these logs, 136 however, this would be difficult to prove. Furthermore, assuming that woodborers ovipositing on logs on the partial cut prefer warm- est bark sites for egg deposition, the results shown in Figures 7, 8, and 9 do not support the above hypothesis. More information is probably needed to satisfactorily explain these ambiguous results for the partial cut.

pH. The pH of bark is altered over time by primarily two factors; the degree of leaching of naturally occurring acids by precipitation, and the amount and kind of organic acids metabolically produced by anaerobic microorganisms in the absence of free oxygen (cf. Carlyle and Norman, 1941; James and Lejeune, 1952) that occur during the fermentation and biochemical decomposition of bark and wood by these organisms. I did not attempt to separate the effects of these factors, however, in the studies reported here. As phloem and sapwood begin to break down in dead woody material, fermentation and other chemical changes occur which result in the production and release of various highly water soluble acids (Bollen and Lu, 1970). Since these acids are so readily soluble in water, they are leached from bark during periods of rainfall. Bollen and Lu (1970) also showed that woody material increases in acidity as it undergoes fermentation during the initial stages of decomposition. Because pH changes over time (reflecting changes in the quality of the phloem), the state of the bark is of temporal 137 importance to the attack and utilization of residues by the flatheaded fir borer since it invades residues only during the first season the residues become available. Consequently, bark pH can be considered as a gross indicator of the relative nutritional status of bark and hence the suitability of the host for invastion by this insect. Inner phloem pH might also be directly involved in woodborer development although this biological activity has not been shown for woodborers. Results presented by Hendrickson (1965) suggest that "sour phloem" (a decay condition indicated by high phloem acidity which develops from microbial activity under anaerobic conditions) lowers brood size and survival of the Douglas-fir beetle.. I examined the consequence of changing acidity of the inner phloem over time on the survival of flatheaded woodborers, but the small numbers of individuals dying from unknown causes (Tables 18 and 19), of which pH might be included, prevented me from arriving at any specific conclusions regarding the possible effects of pH on the flatheaded fir borer survival. Changes that occur in the inner phloem pH of infested Douglas- fir logs on a partial cut and clearcut (Figure 22) indicate that the phloem increases in acidity after cutting until about February (for the clearcut) or March (for the partial cut), at which time the pH trends upward. This seasonal pattern corresponds inversely to the seasonal precipitation pattern (cf. Figures 13 and 22), and can be 138

5.00

10_4.50

4.00 OCT NOV DEC JAN FEB MAR APR 1975-76

PARTIAL CUT ME CLEARCUT

Figure 22. Seasonal inner phloem pH trends in Douglas -fir logs infested with woodborers on a partial cut and clearcut in McDonald Forest, Benton County, Oregon, 1975- 1976 (plotted values represent the average pH of four quadrants measured from each log). 139 negatively correlated with moisture content (Figure 23). It is also evident from Figure 22 that the inner phloem from partial cut logs is consistently more acidic than the clearcut logs through the season. This result is understandable considering that the partial cut logs maintain generally higher moisture contents than the clearcut logs, as shown above, and also that increased phloem moisture contributes to the development of sour-phloem by affecting an air-tight seal of intact bark (Hendrickson, 1965). The increased moisture content in partial cut logs probably also causes the soluble acids to be more readily leached from these logs than from the clearcut logs. The seasonal trends of inner phloem pH of logs held at the three constant temperatures (Table 22) show patterns similar to those of the partial cut and clearcut logs; the pH decreases initially in the season but then increases slightly in the spring. Unlike the field treatments, the constant temperature logs were not exposed to leaching of soluble acids by rainfall, but yet the results indicate similar seasonal pH patterns to those of the partial cut and clearcut logs. The seasonal pH trends are shown for the four quadrants of the partial cut logs (Figure 24) and for the four quadrants of the clearcut logs (Figure 25) during the 1975-1976 season. 140 6.00 r = -0.639

. 4. 5.00 . .. 4+ A 40 -e- * to, *0 410. Ia . , 40

e 4.00

3.00 0 20 40 60 eo 100 120 140 MOISTURE CONTENT (%)

Figure 23. Correlation between inner phloem pH and moisture content (percent of dry weight) of infested Douglas-fir logs from a partial cut and a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976, and from a second clearcut study on same site, 1976-1977. (Correlation coefficient highly significantly different from zero at P < 0.01. ) 141

Table 22. Seasonal inner phloem pH trends in Douglas -fir logs infested with woodborers and held at three different constant temperatures, 1975-1976.

Average + S. E. pHa Month 15.6°C 21.1°C 26.7°C

Sep 4.74+0.06 Oct 4.48+0.08 4.51+0.09 4.51+0.29 Nov 4.29+0.10 4.42+0.15 Dec 4.28+0.04 4.33+0.04 4.46+0.07 Jan 4.41+0.05 4.06+0.08 4.32+0.10 Feb 4.31+0.11 4.62+0.04 Mar 4.52+0.05 4.33+0.08 4.46+0.01 Apr 4.71+0.07 4.25+0.03 May 4.60+0.06 4.35+0.05 4.40+0.07 aAverage of readings from four quadrants measured from each log.

The partial cut logs (Figure 24) show that the lowest values of inner phloem pH alternate between north- and south-bottom quadrants, and the north-top quadrant through the season. No consistent trend can be seen from these results during the season. The results suggest that degradation of the inner phloem by microbial activity is not isolated or consistently greater in any given portion of the logs over the season, but rather appears to be somewhat more random. The phloem from the south-top portion of the logs, however, seems to show the least production of acids; probably resulting from less favorable microclimatic conditions for the organisms due 142 5.00

4.50

4.00

3.50 OCT NOV DEC JAN FEB MAR APR 1975-76

SOUTH-TOP U NORTH-TOP SOUTH-BOTTOM rwm NORTH-BOTTOM

Figure 24. Patterns of inner phloem pH in Douglas-fir logs infested with woodborers on a partial cut in McDonald Forest, Benton County, Oregon, 1975-1976. 143 to the fact that this quadrant is somewhat drier and probably warmer than the other log quadrants. The bottom-half of the clearcut logs (Figure 25), on the other hand, are nearly consistently characterized by the lowest pH levels. An exception to this is noted for the month of November. Also, except for the months of November and December, the north-bottom quadrant remained the most acidic over the season. These low pH trends can probably be accounted for by the more favorable temperature and moisture conditions which aid the development of anaerobic microorganisms occurring in the inner phloem of the lower-half of the clearcut logs. Considering all of the inner phloem pH results shown above, one can generally conclude that the rate of decay of the inner phloem is greater for the partial cut logs than for clearcut logs. This result is most clearly shown by the more acidic conditions developing over time in the partial cut logs when compared to the clearcut logs (cf. Figure 22). Factorial Analysis (Moisture Content and pH). Results of the moisture content significance tests for the 15. 60, 21. 10, and 26.7°C treatments (see appendix G -1) indicate that there is a significant difference (P < 0.05) in the mean moisture content between phloem types, sample treatments, and months, but not 144 5.00

4.50

4.00

}s:A

3.50 OCT NOV DEC JAN FEB MAR APR 1975-76

A SOUTH-TOP 1 I NORTH-TOP SOUTH-8017014 NORTH - BOTTOM

Figure 25. Patterns of inner phloem pH in Douglas-fir logs infested with woodborers on a clearcut in McDonald Forest, Benton County, Oregon, 1975-1976. 145 between sample positions (i.e. quadrants). There were no significant interactions between the various combinations of these factors. Under these three constant temperatures, we can expect significant variations in moisture content of the phloem to result from the main factor effects, and virtually none from any first- or second-order interactions of the factors. On the other hand, an examination of the significance test results for pH at these three temperatures (see appendix G-2) indicates the importance of factor interactions upon the variation of observed pH. The results indicate significant (P < 0. 05) phloem type X sample treatment, sample position X sample treatment, phloem type X sample month, and sample treatment X sample month interactions. In addition, several second-order interactions occurred. These significant interactions mean that the pH for a given factor level depends upon the level of the second factor, which may also depend on the level of a third factor, and vice-versa. The interpretation of interactions in factorial experiments such as these becomes increasingly difficult with each factor added. Close inspection of the intermeans for the factor interactions (appendix G-2) reveals that behairior of pH under different factor levels is somewhat erratic and provides little basis for explanation. The only generalizations I can make regarding the intermeans of these factor interactions is that there is an apparent overall effect of phloem type and sample 146 months on pH. In general, pH decreases from inner phloem to outer phloem and also decreases during the early months following cutting, but increases during the later months (i. e. through late winter and early spring). Results of the moisture content significance tests for the partial cut and clearcut field studies (see appendix H-1) indicate that interactions of the main factors are important sources of variation in the moisture content of logs exposed to the natural environment. Not only were all of the main factors (i. e. phloem type, sample position, sample treatment, and sample month) significant sources of variation in phloem moisture content, but significant sample position X sample treatment, phloem type X sample month, and sample treatment X sample month interactions were important as well. Examination of the intermeans for the quadrant X treatment interaction (appendix H-1) demonstrates the effect of position of the phloem sample on the log on moisture content of partial cut and clearcut logs. The moisture content continually increases for the partial cut logs from the south-top to south-bottom to north-bottom to north-top quadrants (see also Figure 20), whereas the moisture content for clearcut logs is lowest in the south-top and north-top quadrants (cf. appendix H-1 and Figure 21). These results further demonstrate the effect of solar insolation on the different areas of logs exposed under different field conditions. The apparent overall effect 147 of the weather (i. e. solar radiation and precipitation) on the moisture content of logs in the field is clearly demonstrated by examining the intermeans for the bark type X sample month and sample treatment X sample month interactions (appendix H-1). These results show that not only is the moisture content highest in the inner phloem, but that it also increases through the season, corresponding to precipitation trends as indicated in an earlier section. In addition, the mois - ture content of partial cut logs is generally higher throughout the season than for the clearcut logs. All main factor effects on the phloem pH of field exposed logs were found to be significant sources of variation by the analysis of variance (see appendix H-2). Also, the interactions of log quadrant with bark type and sample treatment with bark type proved to be significant. The intermeans for the bark type X quadrant interactions (appendix H-2) show that log quadrant affects inner phloem and outer phloem pH differentially. The lowest inner phloem pH occurred at the bottom half of field exposed logs, whereas the south- top and south-bottom portions of these same logs have the lowest outer phloem pH. The treatment X bark type comparison shows that the pH of the inner phloem of partial cut logs is relatively low and close to the outer phloem of these same logs, but the inner phloem and outer phloem pH of clearcut logs are much more widely 148 separated. The inner phloem pH of clearcut logs averaged considerably higher than the outer phloem of these same logs.

Temperature Studies. Temperature studies on infested and uninfested Douglas-fir logs were conducted periodically during 1976 and 1977. The studies examined the influence of solar insolation on the inner phloem temperature and moisture properties of logs on a simulated clearcut at the Entomology Farm on the OSU campus.

Four basic studies were undertaken: (1) To investigate the influence of cloud cover and relative bark thickness on inner phloem temperature; (2) to investigate the relationship between inner phloem temperature and ambient air temperature; (3) to investigate the assumed inner phloem temperature differences at the top and bottom of a log; and (4) to investigate the amelioration of temperature under the bark following cutting, and the response of bark moisture content to these changes in temperature. Two different days during November, 1976--one cloudy and one sunny--were monitored to investigate the effects of cloud cover on the temperatures that develop under the bark from the insolation of logs in an open area by solar radiation (Figure 26). Comparison of Figures 26A and B vividly illustrate that the influence of clouds on the temperature of the inner phloem of infested Douglas -fir logs 149 20 A

0_ 15MM THICK BARK

A 6MM THICK BARK (r:3 0 40 - o AMBIENT AIR Li - cr l-D 30 - cr I-1-1 20 a. - . 1 10-

0 10 2400 2400 HOURS

Figure 26. Diurnal temperature comparison of the inner phloem of two woodborer infested Douglas -fir logs and ambient air during a cloudy day (A) and a sunny day (B) in November, 1976 at Corvallis, Benton County, Oregon. 150 can be considerable. Cloud cover dramatically reduces the maximum temperatures that normally develop in the inner phloem on sunny days. Hence, the temperature response of Douglas-fir bark is considerably greater on sunny days than on cloudy days. Since plant material absorbs solar shortwave radiation, some of this energy is converted into thermal energy and causes the bark to increase in temperature. During cloudy days, however, a variable amount of energy from the sun is absorbed and scattered by the clouds so that the energy received at the earth's surface is reduced. List (1958) showed that the percent of clear-day radiation received by the earth varies from 15 to 85 percent, depending on type of cloud cover and optical airmass (i. e. the length of the sun's rays through the atmosphere based on the solar altitude). From List's results, it is obvious that cloud cover differentially affects the amount of clear-day radiation reaching the ground. Since the specific heat of wood is relatively high compared to other materials

-1 1 (0.42 cal g deg according to Hodgman et al. (1963)), logs may be considered "radiation sinks" in that a considerable amount of radiant energy must be absorbed by this material to produce a change in its temperature. In addition, the U S. Forest Products Labora- tory (1974) indicates that specific heat increases with moisture content and temperature because the specific heat of water is higher than that of dry wood, and the energy of absorption of wood increases 151 with temperature. Therefore, because of the high specific heat of wood and less solar energy available for absorption by the logs on cloudy days, the maximum temperature of the inner phloem will be much less under a cloudy sky than on a clear day as illustrated in Figure 26. It is also apparent from Figure 26 that the inner phloem temperature is much greater than the ambient air temperature external to the logs. This is due mostly to density differences of bark and air. Because of its low density, air is a good transporter of temperature (Geiger, 1971). The actual relationship of inner phloem temperature to ambient air temperature is shown by the curvilinear plot in Figure 27. Raw temperature data was fitted by the arctangent function of the form,

f (x) = b + c arctan. Tr d(x -a) , (7) Tt where a = "x" location of inflection point b = "y" location of inflection point c = step size (distance from the maximum point to the minimum point) d = slope of line at inflection point

The plot represents temperatures during both cloudy and sunny days since cloud cover was not noted while the temperature measurements were being recorded. Nevertheless, it illustrates the point that the 152

Y = 25.752 + 28.818 arctan [0.09513 ( X-12.6430 - 60 - r2 =0.626 C.) 50 -

40 -

10 -

0 0 10 20 30 AMBIENT AIR TEMPERATURE ( °C)

Figure 27. Relationship of the inner phloem temperature of Douglas-fir logs to ambient air temperature in Corvallis, Benton County, Oregon (plot represents daily maximum temperatures from November 14, 1976 to April 12, 1977). 153 the inner phloem is subject to considerably greater temperature fluctuations than the surrounding air, and is related to the surrounding air by the function (7) above. The biological significance of this result is that bark-feeding insects are subjected to temperatures considerably higher than that of the ambient air. The plot of the inner phloem temperatures for each °C of ambient air temperature observed (Figure 27), shows considerable variability. This variability can be partly explained on the basis of the differences in maximum inner phloem temperature of Douglas -fir logs on cloudy and sunny days (Figure 26). A better "fit" could probably have been obtained had I recorded and plotted the temperatures on cloudy days and sunny days separately, although the variables for either case would still have been curvilinearly related. The linear correlation between intensity of solar radiation and the amount by which subcortical temperature on the upper side of eastern white pine, Pinus strobus L. logs exceeds air temperature is given by Graham (1925). Although presented for a different species, Graham's (1925) correlation results provide a basis for discussing phloem temperature in terms of solar radiation. Accordingly, Graham is correct in stating tl ...that the intensity of solar radiation is a better index of subcortical temperature in logs than is air temperature. " He has shown that solar radiation and phloem temperature are linearly related and, consequently, can be directly compared. I have shown (Figure 154

27) that phloem temperature is curvilinearly related to ambient air temperature, and the two phenomena cannot be directly compared as a result. One final point to note regarding Figure 26 is that although thickness of the bark accounts for some variation in inner phloem temperatures, the temperature differences are not great enough to be statistically significant (P >0. 05), at least for the bark thicknesses I tested. Graham (1920, 1922, 1924, 1925) points out, however, that bark thickness is one factor that can influence subcortical temperature, and that bark, unless extremely thick, will have little "buffering" effect on temperature. The diurnal temperature trends and the magnitude of the temperature that developed under the bark of a 15 mm thick bark and a 6 mm thick bark were similar, regardless of whether clouds were present or not (Figure 26). Although I did not measure the inner phloem temperature of logs on a partial cut, differences in the ambient air temperature between this site and the clearcut site have been shown (see appendix

E). These results suggest that the inner phloem temperatures of the logs on the partial cut are lower. Moreover, the inner phloem temperatures of the partial cut logs probably display phloem temperature differences from the clearcut logs in a manner similar to the differences noted for the exposed logs on a cloudy day (Figure 155 26A) compared with the temperatures for the same logs on a sunny day (Figure 26B). The filtering of sunlight by the partial cut canopy could account for both qualitative and quantitative differences in the radiant energy that is encountered by the logs lying beneath the partial cut canopy, Reifsnyder and Lull (1965) point out, for example, that "while the forest canopy strongly reduces short-wave radiation, it depletes long-wave radiation very little.... " They go on to suggest that, "The reduction of short-wave radiation by 73 to 86 percent... is probably the greatest major effect of the forest on any climatic factor. " In view of this modifying influence of the partial cut canopy on solar radiation and the relationship between inner phloem temperature and ambient air temperature (Figure 27), it is without question that the inner phloem temperature of logs on the partial cut is lower than the inner phloem temperature for logs on the clearcut site, all other things being equal. Graham (1920, 1922, 1924) in fact, measured and reported increasingly lower subcortical temperatures in eastern white pine logs with increasing amounts of shading. Aside from the fact that relative temperature differences occur in the inner phloem of partial cut and clearcut logs, the most surprising element of my results is the fact that woodboring larvae, such as the flatheaded fir borer that develop in the inner phloem of 156 logs, are subjected to considerable fall and winter temperature extremes during the course of a 24-hour period. Diurnal tempera- oC ture fluctuation may account for as much as 26 or more difference in the inner phloem temperature over that of the ambient air. Hence, the flatheaded fir borers' undeniable ability to endure such temperature fluctuations is remarkable. West (1947) reports that fast-growing larvae of the California flatheaded borer can withstand oF exposure to a temperature of -15 ( -26. 1oC) for two hours in the laboratory, but incur mortality as high as 62. 5%. But, as he points out in a discussion on the low-temperature mortality of pre- 18, pupal M. californica in a progress report It would be expected that larvae 'hardened' in the field would be more resistant than these samples which were taken from logs not exposed to normal winter temperatures. Since to secure a bark temperature of -150F would necessitate considerably lower air temperatures, it is unlikely that significant mortality of prepupae would be of common occurrence in the field. To substantiate his remarks, he reported that very little mortality of pre-pupal brood occurred in infested trees examined in April, 1937 in northern California, where minimum temperatures for January, 1937 were recorded at -36.7°C for the infested area. The lowest ambient air temperature I recorded during the winter of 1975-76 at McDonald Forest occurred in February and reached a low of -3. 9°C.

18West, "The California and pine flatheaded borers, " 93 pp. 157

I was unable to find any reports on high-temperature related mortality for the flatheaded-fir borer, but Graham (1922, 1924) reported that adult Chrysobothris dentipes Germar can withstand temperatures up to 52oC before mortality occurs. I recorded inner phloem temperatures this high or higher in sun-exposed Douglas-fir logs (Figure 27). It is not known, however, whether the larval stages of this Chrysobothris sp. or M. drummondi can withstand prolonged exposure to temperatures of this magnitude. Vitg and Rudinsky (1957) reported that temperatures above 32-34°C were lethal to eggs and first-instar larvae of the Douglas-fir beetle when they were exposed for considerable periods. It is likely, however, that M. drummondi larvae can withstand even greater temperatures than those reported for the Douglas-fir beetle since they inhabit pre- dominantly the top sun-exposed portion of logs, and prefer clearcuts over partial cuts, as shown above. The Douglas-fir beetle, on the other hand, prefers cooler habitats such as the undersides of logs, and especially logs that are shaded. A Melanophila sp. with the common habit of flying to forest fires and breeding in the scorched logs, is reported to settle on surfaces ranging from 30.6° to 46. 5°C (Evans, 1971). Linsley and Hurd (1957) reported collecting other adult Melanophila spp. at a cement plant at air temperatures ranging from 45.6° to 56. 7°C. These authors also collected specimens resting on surfaces with temperatures ranging from 43. 3o to 48. 9°C. 158 It is apparent from these reports, that the Melanophila spp. beetles are capable of enduring high temperatures in the adult stage, and considering where they occur in the logs as larvae, they undoubtedly can tolerate the relatively high temperatures that develop in the inner phloem (Figure 27) as well. It is suggested that the reason woodboring larvae can endure exposures to high temperature under the bark is because exposures to daily maximum temperatures on sunny days are of relatively short duration (see Figure 26B). Save ly (1939) pointed out that daily maximum and minimum air temperatures do not usually last more than an hour. Accordingly, the daily maximum and minimum subcortical temperatures of logs are also transient in duration, since phloem temperature and air temperature are shown to be related (Figure 27). Craighead (1920) discovered that direct exposure of logs to sunlight could be used to control certain destructive tree-killing and woodboring insects because of the high lethal temperatures that sometimes develop within these logs. He indicated that the high temperatures that develop depend on the locality, the condition of the sky, and the angle of the sun's rays. Graham (1920), based on his experiments, added that color, structure, thickness, and surface of the bark; air movements, evaporation from the surface layers of the bark; and proximity to other absorbing or radiating surfaces are also important factors in influencing the temperatures 159 under the bark of logs. The bark characteristics described by Graham (1920) are relative factors which, from the standpoint of physics, influence three important thermal properties of bark, namely: (1) thermal conductivity, (2) specific heat (related to heat capacity), and (3) thermal diffusivity. These three properties, functioning in combination, ultimately determine the temperature within the bark for each level of energy input. Furthermore, certain of these properties are also influenced by the density and moisture content of the material (U. S. Forest Products Laboratory, 1974). In view of the significance of so many variable factors that in one way or another influence the temperature under the bark of logs, it is understandable how phloem temperature variations within logs as well as between logs could result.

In another study conducted on November 19, 1977 at the Oregon State University Entomology Farm, I investigated the inner phloem temperatures at the top and bottom of an infested Douglas- fir log over a 24-hour period (Figure 28). The results show that the top portion of the log is consistently warmer than the bottom portion of the same log. It also indicates that the inner phloem temperature at the bottom of the log follows a diurnal trend much like that of the ambient air. These results are similar to the phloem temperature trends reported for the top and bottom of eastern white pine logs by Graham (1925). Although it was shown above (Table 13) that rate of 160

TOP A BOTTOM 0 AMBIENT AIR

2300

HOURS

Figure 28. Diurnal temperature comparison of the inner phloem at the top and bottom of a woodborer infested Douglas - fir log and ambient air on November 19, 1977 at Corvallis, Benton County, Oregon. 161 development of the flatheaded fir borer was faster at the tops of clearcut logs than at the bottoms, the difference 'was not statistically significant. However, these differences are accounted for by differences in the rate of accumulation of heat units based on the temperatures that develop in the upper and lower sides of these logs. The amelioration of inner phloem temperature is rapid after cutting, and is accompanied by a rapid drying of the inner bark as well (Appendix A). Gaumer and Gara (1967) similarly reported a rapid drying of the inner phloem after initial cutting,of loblolly pine, Pinus taeda L. The inner phloem of the Douglas -fir logs in my study (Appendix A) showed a continual drying trend during periods of warm weather as indicated by the decreasing moisture content corresponding to warm inner phloem temperatures over the first week following cutting. Ensuing rains followed for about two weeks, however, during which time the moisture content was recharged, and the temper - atures substantially decreased. After 21 days from cutting, warm weather returned to heat the bark and decrease the moisture content once again. These results indicate that the moisture content of the inner phloem of logs is inversely related to phloem temperature, although no attempt at the mathematical definition of this relationship has been made. This result is not too suprising, considering that a portion of the radiant energy that insolates the logs on the ground is used to evaporate water, while another portion heats the log (cf. Fowler, 1974; Reifsnyder and Lull, 1965). 162

Beetle-Microclimate Interactions

In view of the results of the investigations reported in this dissertation, solar radiation is probably the most important element affecting the development of woodborers as well as the predisposition and maintenance of the microclimate of its host. The most important ways that solar radiation is manifested with regard to this study are the following: (1) Energy stored as heat or converted in the metabolic process by the developing larvae and measured by accumulated degree-days for development; (2) sensible heat energy used to heat the air and measured in terms of the ambient air temperature; ( 3) energy used to heat the log and measured in terms of the inner phloem temperature; and (4) energy used in evaporation of water from the bark (latent heat of vaporization), and measured in terms of decreases in inner phloem moisture content of the logs. The various effects of the microclimate on the flatheaded fir borer and on the various properties of the host are summarized in the following paragraphs. Effect on Woodborer Distribution. Geiger (1971) pointed out that insects (and other animals) adjust themselves, both in terms of their distribution and species, to the microclimatic differences of the habitat in which they live. Various microclimates can occur within the relatively small area of the bark of logs on the ground. 163 Temperature as well as moisture differences develop in logs heated by the sun such that a gradient of gradually decreasing temperatures and increasing moisture contents develop circumferentially from the top of the logs to the bottom. These differences, for the most part, ameliorate the microclimate of the bark so that portions of the bark are more favorable for one insect species than for another. Graham (1922, 1925) indicates that moisture content is an important factor affecting insects in logs. He showed that the distribution of two species of Cerambycidae correspond to moisture differences in the logs. Similarly, the distribution of the buprestid woodborers in my studies results partly from moisture differences in the bark. The drier portions of the bark are favored over wetter portions (cf. Table 13 and Figure 21). In earlier results on the distribution of M drummondi and Chrysobothris spp. (Figure 7), I showed that these species clearly favor the top portion of logs over the bottom. Figure 28 illustrates that the top of the log is warmer than the bottom due to the direct solar insolation of the former, and maintains the lowest inner phloem moisture content (Figure 21) and the highest pH as well (Figure 25), at least for the clearcut logs. The pH, however, is partly dependent upon the moisture content, since the anaerobic conditions required by the decomposing microorganisms are induced by excessive moisture. Moisture content of the bark is recharged by precipitation, but depleted through 164 evaporation of water by solar radiation, which further results in an increased temperature of the bark. It is apparent from the above, that the various factors of weather and host interact, probably in ways much more complex than I describe, to precondition and maintain different microclimates within a log that not only influence the distribution of insects within the log, but probably the initial attractiveness of the logs to insects as well. Certain microclimates are favored by one or more insect species over others because of the ability of the microclimates to meet the insects' relative energy budget requirements. The flatheaded fir borer and the Chrysobothris complex favor the top and upper sides of logs over other locations, whereas the Douglas-fir beetle, whenever galleries were encountered, were located on the lower-sides or under-sides of logs where the microclimate is cooler and damper. Every organism requires the exchange of energy in one form or another for life processes. According to Gates (1968), energy is transferred by the environment through climate, to and from all living organisms by one or more of the following processes: radiation, convection or conduction of heat, or mass transport of water vapor or other fluids. The energy gained by an insect within the bark through the conduction of heat into the bark from the solar and terrestrial radiation incident on the surface, is lost from the 165 organism by heat conduction, by gas exchange, and by some evaporative cooling with the loss of moisture. As Gates (1968) points out, the sum total of all energy transferred must balance, and if an organism is to survive, it can neither gain nor lose net energy over an extended period of time. Moreover, he indicates that the climatic niche for a plant or animal can be predicted in terms of the temperature extremes (hot and cold) it can endure. The short- term transient conditions of extreme hot or cold temperatures that can develop within the bark (cf. Figures 26 and 27) are countered by an insect by cooling, warming, or drawing on its fat reserves for energy, or altering its metabolic rate so it either conserves or expends more energy. In extreme cases, some insects may go into diapause to conserve energy during the unfavorable periods. Thus it is apparent from this discussion that solar radiation and its temperature component have an overall effect on the microclimate of the host and on the energy budget of the flatheaded fir borer and the Chrysobothris app. beetles developing within their favored microclimate- -the tops of logs where the environment is warmer and drier. Effect on Food Quality. Phloem- and xylem-feeding insects have different requirements for food. The relative quality of the food for insects feeding in the bark or phloem is an important limiting factor for their growth and development. The differences in food requirements for insects working in freshly cut logs were given by Graham (1922). Graham also pointed out that the maximum length 166 of the insects' development period is limited by the length of time that its food remains in a usable condition. The flatheaded fir borer, for example, probably belongs to the first group described by Graham (1922) (although I would not entirely rule out the possibility of symbiotic microorganisms in the digestive tract of these insects). This beetle will only attack materials during the first season they become available, and requires as a rule only one year to complete development to adult. They are therefore very exacting in their requirements for food. The relative pH of the inner phloem indicates, in a crude sense, the quality of this material as I indicated earlier. The higher pH values recorded for the top portion of the clearcut logs (Figure 25) indicate that this portion is of relatively higher quality than the bottom, since the sugars and proteins have not been completely decomposed to intermediary alcohols, acids, and other components by microbial transformations (cf. Bollen, 1969). The quality of the inner phloem at the bottom of the logs from my study, although relatively less nutritious than the inner phloem at the top (owing to the development of sour phloem), had not reached the state of decay that would cause it to become nutritionally limiting to the insect's development. This was indicated from the results of Table 13 in which development occurred at both the top and bottom of these logs,

apparently unimpeded. 167

The temperature and moisture conditions that characterize the microclimate at the different locations within the inner phloem of logs preconditions the log for the development of sour phloem. The rate at which sour phloem develops in the phloem at the bottom of logs is faster than at the top because of the microclimatic differences indicated by phloem temperature and moisture content. The moisture content is especially important in this regard since it induces the anaerobic conditions required for the fermentation process. Effect on Rate of Development. Davidson (1944), and various other authors mentioned above, clearly established the relationship between temperature and the rate of development of insects. I have shown in my studies (Figures 11 and 12) that the rate of beetle development is faster on the clearcut site than on the partial cut site, because the two sites differed in their rate of accumulated degree-days as estimated from ambient air temperatures (cf. Figures 13 and 14). The more complete insolation of logs on the clearcut site by solar radiation allowed heat units to be added to the bark more quickly than on the partial cut. Consequently, the larvae developing within the bark of logs on the clearcut were able to utilize this available energy more quickly in their metabolic process to

speed development. In fact, the metabolic rate of the larvae from clearcut logs likely exceeded the metabolic rate of the larvae from 168 the partial cut, since temperature influences the rate of insect metabolism (Chapman, 1971). The role of the microclimate, and especially radiation, in relation to insect development is of considerable importance as indicated above. It is particularly important to consider the physical conditions that exist in the species' niche, because not only do these conditions affect the development, but as Wellington (1950) showed they can greatly influence the insect's behavior as well. Thus, insect behavior should be analyzed in terms of the changes in the physical condition of the insect habitat. Moreover, air temperature does not always reflect the temperature that the insect experiences in its particular habitat. Relatively large changes in the temperature under the bark, for example, may correspond to only subtle differences or changes in air temperature (cf. Figures 26 and 27). These microclimatic changes that occur at the site of the insect are therefore probably the most important ones to consider, rather than the changes in air temperature when assessing the behavior or development of woodborers. Effect on Mortality. The microclimate, as I observed it on the partial cut and clearcut during these studies, was apparently never severe enough during this period to produce a mortality that I could measure. However, for the purposes of this study, the microclimatic influences on woodborer mortality may not be as important as the influences on log or site preference for oviposition and 169 habitat for larval development, based on my results. Alternatively, the sample intensity or method of evaluation I employed may not have been sensitive enough to detect this type of mortality. At any rate, an estimated 8. 0% of unknown mortality (which may have been caused by adverse microclimate or other conditions described above) occurred on the clearcut (Table 16) and 3. 1% on the partial cut (Table 17). The greater percent mortality on the clearcut resulted from a larger total number of individuals upon which the percentage was based, than occurred on the partial cut. Assuming this unknown mortality was caused by adverse microclimate, which components of the microclimate within the host might account for it? As I indicated in an earlier section, high acidity has been implicated in the mortality of bark beetle brood in some studies (e.g. Hendrickson, 1965). I would not expect this to be an important mortality for the flatheaded fir borer, however, since this species favors the tops of logs and clearcuts for development which are less likely to be highly acidic. The moisture contents under these conditions seldom remain excessively high long enough for sour phloem to develop. The optimal regulation of water and salt content in insect tissue is essential for their development and survival. The evaporative demand can significantly influence the balance of water and salt in terrestrial insects, although it may not be as great for 170 subcortical insects. Losses of water from the tissues of insects must be kept to a minimum and must be offset by water gained from other sources if they are to survive (Chapman, 1971). It would seem, however, that critical moisture deficits are uncommon for woodboring larvae developing in forest residues under natural conditions. Only under the extreme drying conditions of sub-normal rainfall and unusually high temperatures during the developmental stages would desiccation likely occur. Extremely high moisture content causes mortality by drowning, since larvae are unable to exchange gases during respiration. On the other hand, low moisture content is really a result of sustained high temperatures, and it is actually the temperature acting through reduced moisture content that causes the mortality by desiccation. Even under adverse temperature conditions, however, woodborers surely have a minimum moisture requirement, where the replacement of water from phloem tissues would at least equal the loss of moisture by the insect. Since close inspection of Tables 18 and 19 reveal that this unknown mortality occurs primarily in the top half of the logs where moisture is the lowest, but unlikely limiting from the measurements I obtained, it seems reasonable to suggest that this mortality (at least in the tops of the logs) resulted from low- or more likely high-lethal temperatures. This explanation is supported further by the results of Craighead (1920). He found that high subcortical temperatures in 171 infested logs exposed to direct sunlight for two weeks resulted in 90% mortality of the several species of Chrysobothris larvae and larvae of a cerambycid that were in these logs. Microclimate of logs, or the altering of the microclimate of logs through manipulation, can result in woodborer mortality. Unfavorable alterations in the microclimate of logs infested by woodborers might be brought about naturally by protracted warm weather and drought, although this has not been shown in my studies.

Estimation of Insect-Caused Deterioration

The estimation of insect-caused deterioration in ecological studies is difficult to achieve from the standpoint of quantifying the volume or surface area amount of wood or bark utilized. The difficulty of exposing the gallery for measurement and the lack of an adequate method for obtaining accurate and precise measurements have been the greatest impediments to the successful estimation of wood utilization and deterioration by insects. The insect-caused deterioration studies mentioned at the beginning of this dissertation made little attempt at estimating volume or surface area amount of wood or bark utilized by insects, due to the reasons mentioned

above. Hosking and Knight (1976) measured the volume of the galleries of Pityokteines sparsus (Le Conte) by estimating part of the gallery 172 as a cone until the latter part of final instar feeding, and the remainder of the gallery until pupation as a cylinder. They determ- mined the density of the frass from galleries by oven-drying and weighing a known volume of material determined by liquid displace- ment. They do not, however, present any of their results except in terms of caloric conversions of the measured material. The method they used, although theoretically sound, has some practical limitations. The gallery does not widen, through the first part, in a manner of continuously increasing circumference. Anthropo- morphically speaking, it would require a considerable degree of skill on the part of the larva to produce such an accurate replica of a cone. More likely, the gallery widens as they assumed, but not as linearly divergent as a perfect cone. It may be parallel in some places, and it may even narrow occasionally. Another source of error is to consider the last part of a gallery as a perfect cylinder, which it is not. These kinds of errors are additive in their overall effects on volume and will therefore give an inaccurate estimate of gallery volume. In addition, the frass may be packed more loosely in some portions of the gallery and more tightly in other portions. The density determined on all the frass from the gallery will give only an average density value over the entire gallery length, while the actual densities of short sections of the gallery frass may vary considerably. This would also 173 introduce error. When summed together, all of the sources for error would lead to an inaccurate and biased estimate of gallery volume. My approach led to the development of a method for measuring the gallery surface area amount based on the length of the flatheaded fir borer gallery (Figures 16 and 17). This method is accurate in estimating gallery surface area (r 2 = 0. 99), and lends itself well to field studies since only the length of the gallery is required in order to predict the gallery surface. This method should prove useful to the land manager in conducting biodeterioration surveys in Douglas- fir residues, as it will allow him to quantify one measure of insect- deterioration which has, until the present, escaped estimation. 174

VII. SUMMARY AND CONCLUSIONS

The patterns of distribution of the flatheaded fir borer and the Chrysobothris spp. in Douglas-fir logs were similar. The top-half of logs were preferred over the bottom-half by these woodborers. Statistical tests revealed that the mean number of larvae distributed over the top-half of logs were significantly different (P < 0.05) from mean distributions over the bottoms of logs for both groups. Larval densities for both groups were highest in the tops of logs as well. The top-half of the Douglas-fir logs sampled contained 76.8% of the total number of M. drummondi found and 80. 7% of the total number of Chrysobothris spp. found in all the log quadrants combined. Based on the distribution results for M. drummondi, I would include them with the Group I insects described by Graham (1922), since they can tolerate the extremes of temperature that are required for their development. The bark area on the logs most favored by the flatheaded fir borer was the south-top quadrant which received the greatest intensity of solar radiation. In addition, the mean number of flatheaded fir borers found in the south-top quadrant was significantly different than the mean number in the north-top quadrant at the P < 0. 05 level. Temperature and moisture differences within the bark around the logs are believed to affect the distribution of the flatheaded 175 woodborers within logs. A negative correlation was found between where the beetles were located within logs and the moisture contents of the inner phloem at these sites. However, moisture content alone accounted for little more than a quarter of the variation observed in the location of beetles in the inner phloem of Douglas -fir logs on a clearcut. It was suggested that a much larger portion of the variation in beetle location in the bark is due to differences in bark temperature, although this hypothesis could not be tested from my data. Results of a correlation analysis of beetle attack with bark thickness and log diameter revealed these relationships were neither significant nor close for either the flatheaded fir borer or the Chrysobothris spp. These results concurred with those of others reported in the literature. I did note, however, that the attack by M. drummondi was more closely related to bark thickness than to log diameter, while the converse was true for the Chrysobothris spp. The reason for this is because M. drummondi develops nearly exclusively in the phloem where the thickness of the bark is crucial to its development and survival. The Chrysobothris spp., on the other hand, spends most of its development period in the sapwood where the diameter of the log is more critical for its success. The rate of M. drummondi development under clearcut conditions was not significantly greater than under partial cut conditions 176 at the P = 0.05 level, but was significant at the P < 0.10 level. The relative rate of development of the flatheaded fir borer varied from treatment to treatment according to the following order: clearcut > partial cut > 26. 7°C > 21. 1°C > 15. 6°C. From these results, it was concluded that the microclimatic conditions represented by the clearcut are optimal for development. Also evident from these results is the fact that rate of development increases as temperature increases. This finding concurs with the findings of several other workers on forest insects. Development of M. drummondi larvae at all three of the constant temperature rearings had progressed to the third (pre-pupal) instar by January, but failed to develop further indicating the presence of a diapause. Unseasonally warm weather during the 1976-1977 season did not significantly affect the rate of M. drummondi development (P > 0.05) when compared to the development rate of this insect from the 1975-1976 season. Differences in the rate of development of the flatheaded fir borer on the partial cut and clearcut sites are attributed to differences in the accumulation of heat units between these sites. The faster development of the woodborers on the clearcut site corres - ponded to a faster rate of accumulated heat units than on the partial cut site. The greatest accumulative exposure of degree-days on both the partial cut and clearcut sites occurred during the months 177 of May through October. Little accumulative exposure occurred after October due to the beginning of the "rainy season" in western Oregon at this time. Larval development rates for the flatheaded fir borer varied between the tops and bottoms of logs on a clearcut. The tops of logs showed a slightly faster rate of development over the bottoms, although the rates were not statistically significant (P >0.05). A statistical comparison of the mean percent mortalities of the five different treatments over the season indicated that the differences between treatment mortalities were highly significant (P <0.01). However, a priori comparisons of differences in overall mortality between constant temperature rearings and field treatments, and between partial cut and clearcut lacked statistical significance (P >0.05). Of the mortality factors identified, parasitism was the greatest followed in descending order of importance by unknown causes, resinosis, and predation. These factors accounted for 29. 2% M. drummondi mortality, and 29. 7% Chrysobothris spp. mortality. Parasitism of both woodborer groups was caused by A. longifemoralis, C. brunneri, P. minor, and D. fartus, but A. longifemoralis occurred most often. The predators observed in my studies were F. lecontei preying on M. drummondi and T. virescens var. chlorodia on the Chrysobothris complex. Point estimates of M. drummondi mortality for the total population from all causes 178 revealed that 19. 9% occurred on the clearcut and 29. 6% on the partial cut. These findings indicate that the largest proportion of individuals of the flatheaded fir borer survived to adulthood on the clearcut. Measurements of gallery surface area and length were used to develop an accurate, predictive linear regression model of the amount of inner phloem surface area exposed by the feeding activities of flatheaded fir borer larvae. Measurements of gallery length. can be used to predict the surface area amount of the flatheaded fir borer gallery by employing the equation,

LOG Y = -2. 598 + 1. 503 LOG X, (8)

2) with a resulting coefficient of determination (r of 0.991. The inner phloem moisture content of Douglas -fir logs exposed to the natural environment was correlated with monthly precipitation. The relationship between moisture content and precipitation was positive and relatively close (r = 0.88). These findings supported the conclusion by Brackebusch (1975), that precipitation is an important factor affecting the gain and loss of moisture by logs on

the ground. Moisture content of logs on the partial cut was higher throughout the season than of logs on the clearcut. The partial cut logs also maintained lower levels of pH than clearcut logs due to the production and leaching of acids from the bark that resulted from 179 anaerobic fermentation by microorganisms. Moisture differences between sites are caused by differences in the intensity and spectral distribution of solar radiation reaching the forest floor of the partial cut and clearcut. Logs lying in an east-west direction on a south- facing slope had the lowest moisture contents and acidity at the tops of logs on a clearcut and on the south-side of logs on a partial cut. Inner phloem pH was negatively correlated with moisture content. The correlation coefficient was significant, but not really high ( -0. 63). In a factorial analysis of variance of several factors influencing the moisture content and pH of logs held at three constant temperatures, significant (P < 0. 05) main effects of phloem types, treatment, and months were found for moisture content. The pH of the bark, however, depended upon several different interactions of the various factors. Main factor interactions were also important to moisture content and pH of logs on a clearcut and partial cut as well. Phloem temperature investigations conducted on a simulated clearcut at the OSU Entomology Farm revealed that cloud cover dramatically reduces the maximum temperature of the inner phloem

of logs. These differences result from the reduction of solar short- wave energy by the clouds. Also, the inner phloem temperature is higher than the air surrounding the logs; especially on clear days. Phloem temperature is related to ambient air temperature by an 180 arctangent function. These two temperature variables cannot be directly related, however, since they are described by a non-linear function. A bark thickness difference of 9 mm influences the temperature under the bark, but not significantly (P >0.05). Beetle larvae feeding in the inner phloem are subjected to considerable temperature extremes, as shown by my results. It is suggested that the reason woodboring larvae can endure such relatively high exposures to temperature is because the length of these exposure periods is relatively short. Differences in inner bark temperature are found around logs. The tops of logs are warmer than the bottoms. The temperature at the bottom of logs followed a pattern similar to the air temperature. The inner phloem temperatures of logs ameliorates rapidly after cutting and is also accompanied by rapid drying of the phloem. The results reported above indicate the importance of the microclimate to the flatheaded fir borer's distribution and energy requirements for development. The relevance of the microclimate to the insect's survival is viewed in terms of the relative duration of extreme conditions of temperature and moisture content of the bark that beetles can endure. Short-term extremes in these factors can be tolerated, but prolonged exposures are likely to be lethal, based on the reports of others. Microclimate can also have an indirect effect on the suitability 181 of the host for woodborers in relation to food quality. The microclimate, operating through high moisture contents, can induce anaerobic fermentation of the bark by certain microorganisms such that the phloem material becomes nutritionally altered. It was not ascertained in this study, however, whether nutritionally altered phloem is in any way detrimental or limiting to larval growth. On the basis of the findings reported here as well as the reports of others it is clear that solar radiation as manifested by temperature is the most important microclimatic factor affecting the rate of insect development. Considering the temperature and rate of development differences between the partial cut and clearcut, it is also evident that the clearcut site represents the optimal microclimatic conditions for development and survival of the flatheaded fir borer. The development and distribution results further suggest that logs and residues on a clearcut are the usual and preferred habitats for M. drummondi and also for the Chrysobothris complex. Insect-caused deterioration is initiated on clearcut sites by the flatheaded fir borer and closely followed by the Chrysobothris

complex. These species are compatible in their habitation of Douglas-fir residues since the former feeds nearly exclusively in the inner phloem, whereas the latter spends a brief time in the inner phloem initially, but then enters the sapwood, thereby avoid - ing competition for food and growing space. The flatheaded fir 182 borer's ecological role in forest residue deterioration is threefold: 1) It initiates the biodeterioration of residues in the nutrient cycling process; 2) it reduces the bark of forest residues directly by its feeding activities; and 3) it opens the inner bark for the entrance of decay microorganisms and other insects that further reduce the volume of this material. The Chrysobothris group also has this threefold ecological role in the decomposition of the sapwood. In view of the habitat preference, development rate, and ecological significance in the decomposition of forest residues by flatheaded woodborers, it might be possible to speed the biological utilization of accumulated residues resulting from logging activities or the actions of weather or natural catastrophies by manipulating these residues. It is conceivable, for example, that residues resulting from thinnings, or sanitation and improvement cuttings could be more rapidly and efficiently utilized by beneficial insects such as the flatheaded woodborers to speed insect-related deterioration, if they were moved into a clearcut or some other clearing where they would be exposed to maximum solar radiation. This measure would also reduce the possibility of the buildup of pest insect populations, or potential hazards from disease, or fire. But this would only be possible where such action would be compatible with the overall management objectives for the site, and was not 183 economically unfeasible or impractical. Althou.gh there is need for more information in this regard, the results of the present studies suggest that further research on insects in relation to residues, and especially the manipulation of these materials to speed their decomposition by insects, offer some intriguing possibilities for the future. 184

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McCambridge, W. F. 1974. Influence of low temperature on attack, oviposition, and larval development of mountain pine beetle, Dendroctonus ponderosae (Coleoptera:Scolytidae). Can. Entomol. 106:979-984. McGhehey, J. H. and W. P. Nagel. 1969. The biologies of Pseudohylesinus tsugae and P. grandis (Coleoptera: Scolytidae) in western hemlock. Can. Entomol. 11:269-279.

McMullen, L. H. 1976. Effect of temperature on oviposition and brood development of Pissodes strobi (Coleoptera: Curculionidae). Can. Entomol. 108:1167-1172.

Mirov, N. T. 1961. Composition of gum turpentines of pines. U.S. Dep. Agr. Tech. Bull. No. 1239. 158 pp.

Moore, G. E. 1970. Isolating entomogenous fungi and bacteria, and tests of fungal isolates against the southern pine beetle. J. Econ. Entomol. 63:1702-1704. 193

Muesebeck, C. F. W. , K. V. Krombein, and H. K. Townes. 1951. Hymenoptera of America north of Mexico. Synoptic catalog. U. S. Dep. Agr. Monogr. 2. 1420 pp. Nelson, G. H. and R. L. Westcott. 1976. Notes on the distribution, synonymy, and biology of Buprestidae (Coleoptera) of North America. Coleopt. Bull. 30:273 -284. Panshin, A. J. and C. de Zeeuw. 1970. Textbook of wood technology (3rd ed.). McGraw-Hill Book Co., New York. 705 pp. Parmelee, F. T. 1941. Longhorned and flatheaded borers attacking fire-killed coniferous timber in Michigan. J. Econ. Entomol. 34:377-380. Prebble, M. L. 1933. The larval development of three bark beetles. Can. Entomol. 65:145-150. Reid, R. W. 1962. Biology of the mountain pine beetle, Dendroctonus monticolae Hopkins, in the East Kootenay Region of British Columbia. I. Life cycle, brood development, and flight periods. Can. Entomol. 94:531-538. Reifsnyder, W. E. and H. W. Lull. 1965. Radiant energy in relation to forests. U.S. Dep. Agr. Tech. Bull. No. 1344. 111 pp. Richmond, H. A. and R. R. Lejeune. 1945. The deterioration of fire-killed white spruce by wood-boring insects in Northern Saskatchewan. Forest. Chron. 21:168-192. Rohlf, F. J. and R. R. Sokal. 1969. Statistical tables. W. H. Freeman and Co., San Francisco. 253 pp. Ross, D. A. 1968. Wood- and bark-feeding Coleoptera of felled spruce in interior British Columbia. J. Entomol. Soc. British Columbia. 65:10-12. Rowe, K. and J. A. Barnes. 1976. Statistical Interactive Program- ming System (SIPS) command reference manual. Oregon State Univ. Dep. of Statistics, Statis. Comput. Rep. No. 3 (October). 66 pp. 194

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Shenefelt, R. D. 1943. The genus Atanycolus Foerster in America north of Mexico. Res. Stud. State Coll. Wash. 11:51-163.

Sidor, C. 1970. On the polyhedral virus disease of larvae of Melanophila picta Pall. (Coleoptera, Buprestidae). VIIth Int. Congr. Plant Prot. September 21-25, Paris, pp. 559. (Engl. sum. of paper).

Sidor, C. 1971. Virus diseases of some economically important harmful insects. Topola No. 83-85, pp. 65-69. (in Serbo- Croatian; Engl. title and sum.). Sloop, K. D. 1937. A revision of the North American Buprestid beetles belonging to the genus Melanophila (Coleoptera, Buprestidae). Univ. Calif. Publ. Entomol. 7:1-20. 195

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Vita, J. P. and J. A. Rudinsky. 1957. Contribution toward a study of Douglas -fir beetle development. Forest Sci. 3: 156-167. Walters, J. and L. H. McMullen. 1956. Life history and habits of Pseudohylesinus nebulosus (Leconte) (Coleoptera: Scolytidae) in the interior of British Columbia. Can. Entomol. 88:197-202. Wang, J. Y. 1960. A critique of the heat unit approach to plant response studies. Ecology 41:785-790. Wellington, W. G. 1950. Effects of radiation on the temperatures of insectan habitats. Sci. Agr. 30:209-234. West, A. S. 1941. Biological notes on two species of Melanophila. J. Econ. Entomol. 34:43-45. West, A. S. 1947. The California flatheaded borer (Melanophila californica Van Dyke) in ponderosa pine stands of Northeastern California. Can. J. Res. 25:97-118. Wickman, B. E. 1964. A comparison of radiographic and dissection methods for measuring siricid populations in wood. Can. Entomol. 96:508-510. Wickman, B. E. 1965. Insect-caused deterioration of windthrown timber in Northern California, 1963-1964. U. S. Dep. Agr. Forest Serv. Res. Pap. PSW-20, 14 pp. Wickman, B. E. 1966. Use of radiography to detect mortality of California flatheaded borers in pine bark. J. Econ. Entomol. 59:1028-1030. Wickman, B. E. 1969. Wood borers attracted to turpentines in windthrown timber in northern California. U. S. Dep. Agr. Forest Serv. Res. Note PSW-195. 4 pp.

Wickman, B. E. 1976. Phenology of white fir and Douglas-fir tussock moth egg hatch and larval development in California. Environ. Entomol. 5:316-322. Wollerman, E. H., C. Adams, and G. C. Heaton. 1969. Con- tinuous laboratory culture of the locust borer, Megacyllene robiniae. Ann. Entomol. Soc. Amer. 62:647-649. 197

Wright, E. and W. B, Bonen- 1961, Microflora of Douglas-fir forest soil, Ecology 42:825 8284 Wright, E. and K. H. Wright. 1954. Deterioration of beetle-killed Douglas-fir in Oregon and Washington. A summary of findings to date. U.S. Dep. Agr. Forest Serv. Res. Pap. PNW-10. 12 pp. Wright, K. H. and G. M. Harvey. 1967. The deterioration of beetle-killed Douglas-fir in western Oregon and Washington. U. S. Dep. Agr. Forest Serv. Res. Pap. PNW-50. 20 pp. Zethner-Miller, O. and J. A. Rudinsky. 1967. On the biology of Hylastes nigrinus (Coleoptera:Scolytidae) in western Oregon. Can. Entomol. 99:897-911. APPENDICES 198

a TOP A BOTTOM 30

03 ,... - 25 ocr cl rx a.w 20 - wI 1--

t1111151511 t i ilillit23 HOURS AFTER CUTTING

Appendix A-1. Changes in inner phloem temperature at the top and bottom of a Douglas-fir log in a simulated clearcut during the first 24 hours following cutting on September 2, 1977. 199 a TOP A BOTTOM 55

10 7 14 21 28 DAYS AFTER CUTTING

Appendix A-2. Changes in inner phloem temperature at the top and bottom of a Douglas-fir log in a simulated clearcut during the first month following cutting on September Z, 1977. 200

O TOP A BOTTOM 240 ce

2 Li 200 2 0 0

160 I0 120 23 HOURS AFTER CUTTING

Appendix A-3. Changes in inner phloem moisture content at the top and bottom of a Douglas-fir log in a simulated clearcut during the first 24 hours following cutting on September 2, 1977. 201

0 TOP A BOTTOM 125 0'1 ae z w 100 0z

Dcr 75 to 1-1 I 50. 7 14 21 28 DAYS AFTER CUTTING

Appendix A-4. Changes in inner phloem moisture content at the top and bottom of a Douglas-fir log in a simulated clearcut during the first month following cutting on September 2, 1977. 202

HOURS AFTER CUTTING

Appendix A-5. Changes in inner phloem pH at the top and bottom. of a Douglas-fir log in a simulated clearcut during the first 24 hours following cutting on September 2, 1977. 203

5.50- o TOP A BOTTOM

41. 5.00-0

I0 4.50-

4.00 a r 0 7 14 21 28 DAYS AFTER CUTTING

Appendix A-6. Changes in inner phloem pH at the top and bottom of a Douglas-fir log in a simulated clearcut during the first month following cutting on September 2, 1977. 204 Appendix B. Summary of Tele-Thermometer--Laboratory Recorder operation and voltage divider network construction (Robert D. Bronson, School of Engineering, Oregon State University, Corvallis, Oregon, December 31, 1976).

The Tele-Thermometer probe has a negative resistance characteristic (i.e., as temperature increases, probe resistance decreases). A bridge circuit is used to derive the output of the Tele-Thermometer. For the Model 418 probe, the bridge circuit o is balanced at approximately 50 C. Thus, this is the point where the voltage measurement across the Tele-Thermometer output terminals is zero. As temperature is decreased, a negative voltage is observed at the output terminals. The zero-offset on the recorder is set such that the recorder needle is at the extreme right edge of the chart for zero input (i. e. , full scale deflection for zero input). The negative input from the Tele-Thermometer then has the effect of reducing the needle deflection toward zero as temperature is decreased. The characteristic curve of the Tele-Thermometer output voltage versus temperature was obtained experimentally. (It should be noted at this point that the voltages shown on the characteristic curve actually represent negative values.) The maximum output (over the desired range of operation) is approximately 160 my. Since the recorder provides only decade scale increments, it was 205 desirable to scale the input to obtain nearly full scale deflection for the 0-160 my range. This was achieved by adding a voltage divider network using the input resistance of the recorder. The size of resistors to be used in this voltage divider circuit were determined experimentally, yielding the following arrangement:

470K 27K

Tele-Thermometer Output

Recorder R = Recorder Amplifier Input Resistance 206

Appendix C. Buprestids captured in flight at McDonald Forest, Benton County, Oregon, during the summer, 1976.

Dates of No. No. Total Species Capture Males Females

Anthaxia aenescens Casey May 1-Aug. 22 45 28 73

A. deleta deleta Leconte July 24-Sep. 7 1 4 5

275 A. expansa Leconte May 1-Sep. 11 170 105

Melanophila drurnmondi Kirby May 1-Sep. 25 105 115 220

Chrysobothris pseudotsugae Van Dyke May 10-Sep. 25 66 78 144

C. laricis Van Dyke May 26-Sep. 7 34 13 47

C. caurina Horn June 28 0 1 1

0 1 1 C. Sylvania, Fall Aug. 15

19 Buprestas aurulenta Linnaeus June 18-Sep. 11 1 18

B. lecontei Saund July 24-Sep. 11 3 2 5

3 B. langi Mannerheim Aug. 15-Aug. 29 0 3

Chrysophana placida Leconte June 18-Sep. 7 1 5 6

Chalcophora angulicollis Leconte May 26 1 0 1 Appendix D-1. Example of FORTRAN plotting program used to produce Figure 8.

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PRoWIAr oATACXtIocft=6',719;ooTPuT.A4/5^11ArE11= luIS roRTRA4 rrOCPAu PLOTS A HISTOGoAu or 'WY nArA 14Av1, A IAXTHou or 4 C SUOJECTI tt.E. Aol 5 cnuCITIoUS tt4E, tRrAtur.flT7.1, TOP ',till' 'OMIT C DATA is SET Ht, rottnutUr; ormirot COlou I C ronx,O;o1C XGA0 t )(TAO 2 C XI r. )(Liu, 1 YLAB Tr OYONIT CISIO1132.C131.Crit. C En, , 0234

CNSti gC414 2G cl7t.r.,;77,?.(71s1.c114

uUFRFT riny = Tur. CRFOOFOCY ,14EOF Oil PO- Y-A,(IS. = UMIITP or soorrcri los c 414 , THE uuourp ur cnum[rtous tun c 51 XI.Ar,(TIT . TOE l/IFIEt TO OF. PLACE(' ON TUT x-AXIS tOloEn TrTE ',tors rop coDottjoHlul lEACU )(LAO MIST OE 1 tO C'IAnACTrps. APO SrACIS1 TuE xt_Ars MUST un, cxrr:c0 C YtAO t THE lft1FL TO OF eLAccu ON Tor Y-AXIS toOST OE < 10 in C. ClihrACTEcTS Arin srAccsl. rlyuutr Tor uuuncr or cuArAerrqs Auo SPACTS IN TNT r EAOEt f. CPPSIO1, THE NTU CQUOIIPUT Or THE nth SUPJECT. Tursr vArurs C CAN nE EMT' IUTECC.RS OR REAL foOluE01.

cououuirrrrIcour.wforuoriGur,xcAP(5).rtAn111,uruutrft) 01 5100 ric.hr ICOlET! wturu=s. uEllut-h. hn REA, .,r,lAxeus,ur. t0otxrAqt1).1-1.w.;1 c) REA3 21ortvim.t-1,i1 tg roRlATIAtro TORAATIT/Ita, Appendix D-1 (Continued) 45 REM) ,NYONI 00 11 I= 1.NC REA 9 ", (F11.11 . 1,1.(1;1 30 CONTINUE CALL 1115111 T INC, MS .F.F1Axl 50 STOP ENO

!, L.A-WM CM STORAGI USED .16? 3 '.1:0995

SUMROHT INf 14ISTPLI 73/74 IS (RACE FIN 4.64452 15/02/15. 11.53.29 PAGE

SOOR9UTINE HISIPITINCoNi.F,FIAX1 011F1SION F45.41.1A9121 CO4HON/PLI/ICOPF.4101H.HFIGHT.XLA015/.YlA0111.NYOUITII, N-NI*NC 5 C OEF INF THE SCALING, FACTORS

XFACI=U10fo/ (nms) YFACF=HE IGHT/ 1FM AX1 10 XMIN=1. NIN=0. C C START THE PLO) C 15 CALL PLOTTP(11C00E1 CALL SIZEU41011112.,HEIG11T02.1 CALL SCALEIXFACT.YFACT.1.,1..XHIN.YHINI

C LAPEL THE Y AXIS 20 X=XHIN-0.65/XFAC1 CENFER=FLOAllNYUNI11.0.115/2. Y=F9AX/2.-CEUTEP/YFACT CALL SYHOOLIX.Y00..0.16.30,YLAB1 25 XPOS=XHIN-0:16 /X FACI Y=1"11H INC=FHAX/5. IFIINC .1.1. 11 INC=1 CALL PLotiAntu,r4m0.01 Appendix D-1 (Continued)

30 HAx,FmAx 00 1 1=1,11AX,1110 J=1-I ENCOOE14,7oNOUI J 7 F0014'1(141 35 Y.J CALL PL0I1X010,Y,1.6) CALL SY090LIXPOS,Y#0,,9.16.A,Nogi A CALL rLOEIXM10,3,0,0) 11-(1.E0.HAX) GO TO 9 40 cucnotAA.r.notlii '/AX y=oAx CALL rio,(xmlnor,t,o) CALL synooL(APoso,04,1,1600mo1 C 45 C DRAW FITE 01510GRA0 C 9 X=X4IN Y=Y410 00 29 I=LINC 50 GALL SY110011X.Y010-0.57YEACT.O.,0.44,10.XLA0(111 00 10 J=1,4S CALL 01011A,V010.0.01 Y.FIlt11 CALL PL011X.Y.10) 55 X=XT,5 CALL PLOTTX.Y,I,01 CALL PLOI1X.Y010,1,01 ENC00E111700i1.A01 20r FORIATIII) 60 CALL SY00011X-.5.Y410-.31Z7YFACE.P.i0.16.1AA91 CALL PLOT-IA.1,010.0.0) X.X..5 10 CONTINUE 29- XzX11; 65 CALL PLOTIX.Y010.1.01 CALL pLortxntoommt,ut CALL s'onoLtxntot2.5o/xfAct, FnAx.c.,o.00,ti.ttoi SOUIN-TOP1 CALL 51040LIX01017.507XEACI,FNAX-0.25/Y7ACts0..0.00414.1402. 50010- *0011041 70 CALL 31.1.1(11_ WI IN 112 :51 /*FACT TFMAX-C a5P/YFAC 1.1 0 e 14 I 1 4113 NOIMI 90110M1 CALL SVOIOLTOTIN 2.507KEACTiFNAX-0.75/YEACT.0..0.P8.11.1104 NORIO- TOP) CALL PLOTEND 75 RETURN END

4100011 CM STORAGE USIO .501 SECONDS Appendix D-2. Example of FORTRAN plotting program used to produce Figure 13.

PKOGRAN 114144U 7i/74 OP 1 =) tRiWf (Tu 4.61452 rifa,?./12. 17.56.14 PAGE

1 rRoGRAY IIKR11111Nrot=64/400Mtv0i=64/40,CAPFIC,61

i. sit or nAlA 4,aAYS, 0F.F1Nr. till. WOO RC AO 11 IHIO 111E ARPAYS

5 of firt,3101. 7A frill I) .,(voil ,yros 1;7) oft AI1(12) ARM ,4Y107:10),Yx1'11 'S 61,1.A0,(14),), 1),Y1tIII,r2tw.y DATA OATA Y1/14.11,15fiC.,135J,,15d..,.,IP9T.,310.,154.,5t.,50.,160,45u./ DATA Y2/1711.,1.474.5,11r2.0.7fill.,1100.,129.5,1.31.5.51.,50.5,165.5 10 ",503.5/ 0ATA y1/155C.,11551.0550..1556.,12;0.,150,150.,21,0.,0.,450.,850./ DATA Vi/t919.,?302.5,2,715.2231.5,1.4755,3,13.,153.5,2,4.5.40,05 .5,99 If RFAJ ,1111111 15 OFFINT *0, PoYS1CAT PROPCqTTES OF TOT PLOT. 1. CALL PlaryPt(31 CALL GlYPC16411111F1 20 CALL 517F115.,10.1 Ulpft1=7.4 11FIGH1,,11.17r, XNA4,11.. Xr114,1. 25 YMPOO. )113111S=2.5

AF1lC1n140111/0.0AN-X41141 10 VIACTrAt1601/1Y0Ax-yAINI CALL SCATFAXFACT,YFAGT,XPIAi0BIAS00111I,YH141 C C ORAN FOE AXIS.

15 CALL Ax15.(xfltil,x(lAx,(miu,yriluoadt..,(11(1,0.,5e0.,n,4) (ALL FLoflx(11,350J.,0,d) rp=3noo.

00 15 1.1,1 ypryP*56). :All PieTtxP.1,,I,,i1 YTICi=Y1-154. 1)0 16 J=1,9 CA11. PlOfIXP,Y1165,i,51 1(11c5=vTICS15.1. Appendix D-2. (Continued) 16 CONTINUE 15 CON I 'NUE CALL PLOIIAN111,5010..1,61 C 51 I IF_FINE PO5111016 FU;/ 1.111E1_3, A.I0 LAtlEL THE X-AX IS. XPOiIih.,011N-11.25/AFACI XING.° .425 110 ?u 1.2,11 55 XP3S 111 - 011111/(114(/ (FACT A ING,X11; /0.675 in CON( INUC XP031121,-,XIIIIII 2. 906/AFACT VP0111)=Yti1/1-0.312/yract yrns(e1=rtitii-0./112/YFACI XLA0111. AI AP. X1.411?), 311 /Ill XL A9131..111/111G XL A0(1.1..Nisro 69 X169191= RION XLA 1161=01110v iati xtritt)(91= 111111) 70 XL A9(131=31111AA XL A9111.1 .311A0P, XL* )1121.7141975-/6 00 PI 1.1.11 CALL SY1371L XPOSII 1 .YPOSIII .0 ..0. 16, 1. XL A1311/ 1 75 3 CONTINUE CALL 3711001 I XPOS 1121 YPO5 (21 ..0 .16 .1. XlAD) 12/ 1 C C PEF PIC P05) 110N3 FOR LA0ELS. Al10 LALIFL 1111 C AO YL Alf 11= UN YLA7121= 115/10 11411111.41110.10 YLA914)=5111566 TLA1151.4112140 95 3LA0161. 4112500 VLA1171.19111100 ENC00E13:!, 35,1 AGYI 35 FOR1A1 132WIONIIIL flIERmAL UNITS ADOVF 10 CI XYP9.11/ ,W11111-0. ?5/X1601 9i) X71'11312) ,X11111-6. 562/KF ACT xvrostil .xtilti-u. 656/ X1 ACT XYPOS 141 rx"1111-.1. 719 /.(F ACT Yrn5151 rXIIIII-u. Ti I/XF ACT X7P1317,1=4.1111-6. 75/XFACI 95 X 714.15 1 7/ --A I 719 /XFAG1 XYPOS la) -x,i111-a. 9.0,/xFAcr yxPostit ,rmill-u.nri/yFnct Appendix D -2. (Continued)

YPIC=500 00 1"2. 7 Ild YYP03111=Y111,11Y DIC-.1.1 7A /Yr AI 1 YIPIG =Y INC 50 n 11 C,9111 114111 CALL SY119011XY,41S111 yxyns I II ,t .t .11., 1. YL A0 1 I I CALL SYNaOLIAYFUS121Y(FOS12).C.A.1(.3YLA0IE11 105 1/0 50 1= II 7 CALL SY110L 1 AYP13 II / Yi"r1S111 .0 11),4, YLAril 1/ I PP141 4 Y PO S (1 ) PRINT . YA 1'03 I II PPI4I YLAIII I I 110 51 CON 11101E CALL SYNOUL 1 AY PO 5151 Yol)S111 .1 .1(1, .32 ft_ V/ YI CALL SYIIi0L I (Y1)1(11.35)).-d.L 70/YFACI,C 0. 16 .1.YLAU It I/ CALL SY11101 101114-9. 5 WO-ACT 1.970/Y14;1 ,O. Ivito()) CALL ;Y1144 (XV /1);(7) 463,', . -ti.;78/yrAcI ,9. 16. 3. 3142b01 115 CALL SY11011,(YI'll3l21 50111.-0 .11711/YFACT Z11( CALL SY'1401. 1 AYPOSIA10351),14-0. /IYVACI .9) .10 .1C. 1118,11,111--PFCIPI 1AT 10 111111

C 0L01 riff C0/vrs. tZd CAI. I 0AS0E CALL t 111E1 X .Y1 td .111 CALL LINE IX Y, III CALL VEC IOPF 125 CALL 1.111E1/(0( .111 CALL 1.114E1A Y .111

rt or pRic 11,1 Al ION NI SIOGPAI. C 130 Xxl4CsAtilr4,6.63125/XFACT XX. (i1111 CALL PLO f (xX o..0. (11 Y11) =RA(N11) TALL P101ixAYILIt 1.01 155 xx.,X.o01.125,/xFAc I CALL 0Lul(xx.Y111, 1,J) CALL PLOT 1/01, 150;' tl .01 CALL 11.011X1111111500a 1 U) CALL 1'101 I XX 111C, 3500. '10/ 150 CALL P1011XX1111), YHA 1,01 XXINC2rX.1111C 1) .0 1125/AF AC1 CALL PLOIIAAIIIC2Y (II 111) CALL PL011 XX 111(32 ,1500 *1.'7'1 XX 1.IC 1=XXINC ?1/.131Z5/XFAC 1'.5 CALL P101 (X% 111C3 .35110 tlL) CALL PLO IL AkINC3,11111 .1,01 Appendix D-2. (Continued) 00 60 K=2,11 GALL PlOWP0S(K1.125/0ACI,1500.,u,0 APOSIKI=XPOS1K14.125/ACACT till y1k =k11104K1 CALL PLOI1A1,0S(KI.Y1K1,1,61 xx=XP0SIKtiu.25/xFACI CALL PLOWA,41K1,1.11 CALL 14.011xx,3,503..1,u1 t5i CALL pLotcApoSIKI,1540,1,C1 IF MK) .L0. 5500.1) CO 10 6( XX10,;=,(11S0(1...1.13126/AFACI AC0rvi1=e.63125/xFACI CALL PLOIAAK106,151d.,t01 160 CALL 11.011KAI0C,U1K1,1,i1 A41062,4410Ct4c00ii CALL Pt6i(xxIt1G2.reci,1,0) CALL PLO(AAI1tC2.)5J6.,i,t1 AX1063=5A10C2x6INfil t65 CALL 11011x41;1C3,SiUa.,1,t1 CALL el0fiXxl0C1,1f1,(1,1,01 )0(11,164=4410C:1sxC)t1S1 CALL P1.0145A10C4,4141,1,1 CALL Pt0llAxINC4,35u,.,10.1 t10 xx10C5=SA1064.C111Sf CALL PL01tAx10Gi,150!',"1,1.1 CALL ULLII IAA I 161.1.61 1,1Gu = Aalia CALI 1'101 I p.A 111,.:6, I (K1 L;Al L PLO (AA Ii(t..(1.1610 i C .441ILL:;-4411-4L6s-ACJW51 CAI PIC)) xx trio./ I:J., L.,. 1 C..LL 1XA (K1 I Li) ell141INLII

1'1.01 LIJ'AI:a Allll L ALL S 1- Or( LF6Li41/.

IA=tmlpt Yt=tri0-1.1/5/1FACI Luti AA *6 .t,/ Me I VI A4:1- L.ALL OAiL CALL Ilt)). (AA. CV , API CALL )01. (Pi_ CIS* i2.:1/ Ci s V VIA'. 01. 1AL Cull 1 1J Xn=4:1444 At ( Al- LL1Sz AA IL .b/A AC T CALL 611:1,1KS CALL IIALA A ,Y , XPL YPL 051 CAI L SY10(1t 4),L iFit J. L Z,J/ Af ACi V T ,J.1.11,1111CLI A/alit / CALL PLC) it N1.1 SUIP 040 Appendix D -2. (Continued)

stm.ou'inc nnx '3/74 nPf=0 TRAGF FIN 4.644,2 74/02/12. 17.56.15 PAGF

sumiourm poxixxoy,xyLus.yPLu3) cALL-PLoyoxxoy,A.0) CALL PLOIIXPLUS,YY.1,0/ CALL PLoltxrLus.YrLos.1,01 5 CALL FLortxxoPLus,1.0) CALL PlOTIXY,Y,01461 ENOREfURN .062,5714289714 451.4124158209 2.514J86616843E+253 -.12714215714286 1453..128 )5@21 8.0450772.17898E 4254 -.1271423,714146 1953.412115821 4.537671274418E272 -.07142857142857 2453.4324151121 1. 484054808601E274 -.12714289714286 2453.432835421 4.554991514293F-291 215

Appendix E. Temperature and precipitation records for McDonald Forest study sites, Benton County, Oregon, from June 1975 through May 1977.

Mean Monthly Maximum Ambient Air Temperatures (0C) Total Monthly Partial Cut Clearcut Precipitation ( mm) Month 1975 1976 1975 1976 1977 1975 1976 1977

Jan 8.1 8.8 11.8 5.334 0.762

Feb 7.9 8.9 13.5 5. 842 2. 794

Mar 9. 1 12.2 11.3 3.556 4.064

Apr 12.4 16.9 19.5 1.778 0.762

May 17.0 22.3 19.6 1.016 2.794

June 20.2 18. 3 24.2 23. 8 1. 016 0. 508

July 24.2 24.3 29. 3 30.4 0. 508 0. 762

Aug 22.4 22.2 24.7 28.3 1.270 1.778

Sep 26.1 22.9 31.4 29.9 0.000 1.016

Oct 13.4 18.8 16.8 24.8 3.556 1.016

Nov 9.4 14.4 9.3 16.0 4. 572 1.270

Dec 7.7 8.0 8.7 5.334 1.270 216

Appendix F. Comparison of mean mortality of Chrysobothris spp. within four quadrants of Douglas-fir logs exposed to five environmental conditions, 1975-1976.

a Meant C. L. Percent Mortality by Quadrant Environmental Condition South-Top South-Bottom North-Bottom North-Top

Clearcut 31.2+17.1 69. 8+31.2 75. 0+44. 1 33. 0+19. 7

Partial cut 56. 0+33. 7 100.0+ 0 0. 0 50.0+88. 1

oC 26. 7 58. 3+35. 4 23. 2+24. 4 16. 7+17. 6 33.3+41.7

0 21.1 C 31.3+15.5 50. 0+88. 1 38. 9+34. 6 17. 5+21. 5

0 15.6 C 50.0+88. 1 75.0+44. 1 33. 3 +10.2 33.3 +10. 2 a95% confidence limits for means computed in arcsine transformed scale (Arcsine 1,;) and back-transformed to original scale for reporting here. 217

Appendix G-1. Factorial analysis of variance table and intermeans of main factor effect levels and first-order interactions of factors on phloem moisture content for 15.60, .210, and 26.7°G cQnstant temperature studies.

ANALYSIS OF: VAKIANCE FOrt InOI.STJrtE LINE SOjKCF. OF VAK1ATION DF MEAN SUJA4i. BARICTY1-"E 1.9569E 03 3 5.07463E 01 C. 2) (41 LIA DKA N T 3) BAART`lr'E*QUADKA NT 3 0.06015E 01 -4) Tri EA TYJEN 2 1.916o6C 02 5) 2 b.4'vi09c. Ul 6') U0A DKA N T L-(1E:A Tiv.t...N 6 4.6b93.01 7) 'ithAii:ST7-1-"L*1JADKANT* 6 3056241. 3 2.75175E 02 C o) MON T1-16 1:3ARISn?i*MONTAS 3 1 .22715Z 02 10 )- QUADAANT*MONTr16 _ 9 613900E 01 ( 1 1 ) SArthT sr? r7.*QtJADiiANT*MONT1-16. 9 37639E 01 ( 1 2 ) T MEN * 0 TH.S. 6 b65.317F. 01 13) SAKATYr"-.2.*TKEATXEN*MONTI-IS 6 53b666E 01 1 b 6.4736.3t.: 01 C ) 00A DriAN 7*-razA ThEN *til ON ThS 15) .3ArCAT`i?ii...*00ADi-LANT* TrtEATMEN*P-JONTHS I b 5. 5b0551. J1

TOTAL

BA-KAT E

VALUE Fm".E0 inEAN OF MOISTUKE 1.000000E 00 72 *2.062063E 01 2.000000E 00 72 1 .3246-61E.

LIA DriA N T

'VALJE FK.E141 iv;EAN OF MOISTJAi: 1'.00000Q 00 36 1 656944E 01 2.000000E 00 36 1 636056E 01 3.000000E 00 36 . 1 .60 7-22E 01 4.000000E UU" 36 1.669167'z: 01 218

Appendix G-1. (Continued)

00ADRANT

JALjE MEAN OF MO/STU z4.E 1.00030JE JO 1.000000E 00 to 1.9433i3E 01 2.000000E 00 lc 1.1a770:. j1 3.-000000E JO 10 1.932-22E 31 4.000030E lo 2.460000E-01 2.JOUOUJE 0 1.000000E JO 10 1..370536E 31 a.j0000JE 00 10 1.3633,3,3E 31 3.030030E. 30 lo 01 4.0000U0E 00 10. 1.870Jj3E 31

:INTE.iMEANS.."NEATMEN,3A:E*T:5.EA1-EN.,3jALO:i_ANT4cTa,E.ATN.

T.-LA

IAL i,i-EAN OF MOISTJnE 1.000JjOE 30 40 1.91500E 0.1 2'.003JUJE 33 1.58729E 01 -,i.J3j000E 00 46. 1.63717E 31

T;IZATMEN

VALjE MEAN OF L4.:01.73-zi.E 1.003030E 06 1000063E OJ 444 ..-2.4117E 01 .UJ00JJ 03 1.74167E 01 3.0L)0030-e. JO '2.4 1-.74167E 01 2.000000E 'JO

. 1.003030Z Jj 24 1.417503 E 01 2.30000JET 24 1.255417-E 01 3.003j6JE Jj 24 .1....i31607E. 31 219 Appendix C 1. (Continued) .,1JADFLAN

TrEA T zT.0,1

VALUE F1k E:51 MEAN OF MOI6TJ:1.E 1.000000E JO 1.jjj0jJE JJ 12 1.715030E J1 2.0jJJOjE JO 12 1.450633E-01 3.J00jJOE JU 12 1.60500,0E j1 8.0003jJE JJ 1.JOJOJOE 0J. 12 1.767500E 01 2.000,300E" "JO 12 1.599167E 01 3.Jj00JOE OJ 12 1.587500E 31 3.000300E Jd 1.0066JJE 00 12 1.775060E 01 8.JUJJJjE 00 12 1.446333E 01 3.j000JOIE 00 12 1.605633E. 01 4.0JJ000E 33 1.0d0JJOE JO 8.36.3J33 E j1 2.JOJOJOE 00 14 1.61063jE j1 3.000000E dti 12 1..610.333 E 31

MONTI-1.6

"%ALOE OF MOI6TjE 1.000JJOE JJ 4.015(533 E 8.00j000E JJ 1.10375jE 01 3.JOJOOJE JO 1.6954.17E.J1 4..000JjOE JO 24 1-575417E 01

73AT'irJE MONT-mi

HiALjE M=AN OF MONTj,--.8:-. 1.J03033 E 03 1.J0J000E JO 12 8.635603E J1 8.JOJJJOE JO 18 1.J74167E 31 3.000000E 30 18 1 .'D33J3t. 31 4.000000E 30 14 1.9666-67E 01 8.00000JE JO 1.JOJOJOE JJ 18 1.425633E 31 2.jOUOJJE JO 12 1.13j3j3E 31 J.J.JUJJOE JJ 18 1.4.3.7560E. j 1 h4 .000000i OU 12 1.164167E 31 220 Appendix G-1. (Continued)

1.110ADriANT trIONTHS

ALOE FisZL,1 iv,ZAN OF iv:GIST-J:4.E 1.000000E 00 1.000JJUE -00 6 1.621667E 01 a.u.uuuouE JO 6 1.160Jd0E 01 J.000000Z 00 6 172,63.3jE 01 '4.000000Z U0 6 1.331667E UL 2.000000E. 00 1.000000Z 00 6 1.66;i3jJE J1 2.000UOUL Od 6 1.166UJ0E 01 :i.000000E 03 .6 1.566000Z 01 4.000000Z. OU 6 1.661667E 01 3.ocauouE UO 1.060000E JO 6 1.6663.33Z 01 2.000000E J1/41 6 11033.53E 01 3.000000Z 00 6 1.7J.3.3'3 E 01 4.000000E 00 6 .1.7iJo3.3.3::: jl 4.000000Z 00 1.000000E 00. 6 3.0900a0E j1 2.000000Z 00 6 9.666667Z 30 3.000000E JO 6 1.745600E 01 4.000000E 00 6 1.30uo00 a ut 221 Appendix G-2: Factorial analysis of.variance table and intermeans of main factor effect levels and first-order interactions of factors on phloem pH for 15. 60, 21. 1°, and 26. 7°.c constant temperature studies.

ANAL IS 1 S OF VA:UANCE FOR' LINE SOURCE OF VAii. IAT I ON DF EAN SL,10AAE

1) BARii.TY?E 1 6.97400E '00 2 ) QUADRANT. 3 _6.14246E-02 C 3) BARKTYPE*QUAD(Q.ANT 3 - 3.13711E-02 C 4) .THEATMEN 2 1.69924E-02 C 5) SAR.KTYPE*TREA TMEN 2 7.53132E-02 C 6 ) UADAANT*TREATMEN 6 4.35561E-02 . 7) BARXT`f?E,*QUADRANT* TREATMEN. 6 2.06141E-02 C 6) MONTHS -3 1 .45309E-01 C 9) 3ARKTYPE*MONTR5. 3 . 7.1.5724E -02 C 10) .QUADRANT*MONTRS 9 2.36031E-02 ( 11) OARXTIPE*QUADRANT*MONTES., 9 3.76050E-02 ( 12) TAEATmEN*mONTHS 6 1 .17192E-01 ( 13 ) 3AR.i.C.T1?E*THE.4TMEN*isviONTI-iS .6 6.77724E-02. C 1 4 )*---Q UA ORAN T * THEA TMEN *MONTHS 16 2.5367-3E -U2 C 13 ) SARATstlE*AD-ri.ANT* TRE-ATI,:EN*MONTRS b 1 .56055E -02

TOTAL

3AliXTYPE

VALUE F RE MEAN OF H 1.000000E '00 72 4.394722E 00- 2.000000E 00 72 3 . 954563E1 00

Q UA D RA N T

VALUE FHEL11 MEAN OF i-,11 1.000.000E 00 36 4.139444E 00 2.000000E 00 36 4.139167E 00 3.000000E 00 36 4.202222E. 00 4.000000E 00 36 4.217776E 00 222 Appendix G-2. (Continued)

L4UA0riANT

VALUE FiU MEAN OF 1.000000E 00 1.000000E CO 1o' 4.332776E 00 2.000000E 00 10 4.340556E 00 3.000000E 00 16 4.42d669E 00 4.000000E 00 16 4.476667E JO 8.000000E 00 1.000000E 00 lo 3.946111E. 00 8.000000E 00 16. 3.937776E 00 3.op0000z 00' lo 3.975556E. 00 4.000000E 00 lo 3.96cco9E CIL)

:INTEHMEANS4T".:7.-EAD\TMEN,3ATY:=E*7::EATMEN,UADri.ANTAT:%EN

-TAZATMt:N

VALJE MEAN OF L.000000E 00 . 46 4.196250E 00 2.000000E 00 4d 4.1570o3E 00 3.000000E JO Lid 4.170623E 00

84Ft.T1?6

VALUE FRE., 4,21.-AN OF as 1.000000E 00 -1.000000E 00- 24 4.449563E 00 2.000000E 00 24- 4.333333E 00 3.000000E 00. 24 4.401250E 00 2.000600E 00 1.000000E 00 24 3.942917E 00 .2.000000E 00 24 3.960n33E QJ 3.000000E 00 24 ..3.940000E JO 223

Appendix .G -2. (Continued) 0JADrtANT TREATMEN

VALUE Raid ,IEAN OF ae 1.000000E-03 - 1.000000E 00 4.15633E 00 2.000000E 30 12 4.156333E 00 3.0000U0 00 12 4.064167E 00 2.000000E 30 1-000000E 00 12 4.131667E 00 2.000000E 00 12_ 4-064167E JO 3.000000E 00 12 4.821667E JO 3.000000E 30 1.000000E 00 12 4.237500E JO 2.000000E 00, 12 4.161667E JO 3.000000E 00 12 4.217500E 30 4.0000006 00 1.000000E 00 12 4.250000E JO 2.000000E 00 4.224167E 33 3.000000E 00 12 4.174167E 03

MONTHS

VALITE OF Ph 1.000000E 00 24 4.275417: 00 2.000000E 00 24 4.133333E 00 3.000000E 00 24 4.16';563E 00 4.000000E JO 24 4,066333E JO

\IALUE :714.7.1 MEAi,; OF 1.000000E,J0 1.000000E 00 12 4.4641673 33 2.000000E 00 12 4.0167E 00

3.000000E. JO is . 4.356333E 00 4.000000E 30 12 4-865000E 00 8.000000E 36 -1.000600E 30 12 4.066667E JO 2.000000E 12 3.657600E 30 3'4000000E 03 12 4.020633E 00 4.000000E 00 12 3.671667E 00 224

Appendix G-2. Continued)

!Ili.JADaANT IONThS

VALUE FRCS. MEAN OF Ph 1.000000E'00 1.000000E 30 6 4.270003E 00 2.000000E 00 6 3.70000E 30 3.000600E JO 6 4.215333E. JO - 4.0.00000E 00 15- 4.051567E: 30 -2.000300Z 00 1.00.0000E 00 -6 4.2133J5E 00 2.000000E 00_ 6 4.055333E 00 3.000000E 00 6 4.150000E 00 4. 0000006 00 6 4.e30000E 00 3.000000E 00 1.000000E 00 6 4.865333E 00 2.000000E 00 6 4.831567E 00 3.000000E 00 6 4.15333E Jd. 4.000000E 00 5 4.143.337E 33 4.300000E 00 l'.0000GOE 00 6 4..360000E 00 2.000000E JO 6 4.273333E 30 3.000000E 00 6 4.151667E 00 4.000000E 60 6 4.035333E 30 225

Appendix G-2. (Continued)

- TREA T MEN MONT:LS

VAL:JE F-itza MEAN OF g-rt 1 .000003E 00 1 .00.0000E 00 5 4.292503E. 00 2.003000E 30 5 4.30500E 3.000000E. 30 6. -4.376250E- 00 4.000000E 03 5 4;I..36250E 33 2.000000E 00 .000000E 00 5 4.221250f 00 2 .00O0.00E. 00 6 4.133750Z 00 3-.000000E d 4.140660E JO 4.00.0000E 00 5 3-972500E 03. 3.000000E. 00 000000E 00 4.312500E 00 2.000000E: 00 4.163750E 00 a.a00000.E. 00 6 4.352560E 03 4.003000E 30 4.076250E 00 226 Appendix H-1. Factorial analysis. of. variance table and intermeans of main factor effect levels and, first-order interactions of factois on phloem moisture content for the partial cut and clearcut, field 'studies.

ANALYSIS OF VARIANCE FOR. MOISTU kE . rEAN SQUArIE LINE SOURCE OF VARIATION OF 1 1.16067E 05 ( 1) BARhTYPE 3 3.41175E 03 2) QUADRANT 02 BARKT '1? El.QUADRANT 3 7.66435E ' ( 3) 03 4) THEA T MEN 1. 3.463662 1 6-.15600E 02 C 5) BARATYPF.*T'REA TMEN 3. 2.29111E 08 C 6) (1LIAD.RANT*TRE.A TMtEN C 7) 3ARATYPE44,10ADRANT* 3 4-.14393E 02 . T REA T MEN .3 5 . 63494E 03 8 ) MONTHS 3 5'.24992E 03 . '9) BARicTTPE *tviONTRS 9 .4.06666E 0',2 ( 10 ) CIUADRANT*MONTHS 9 4 13704F. 02 ( 11) BAR.KTYPE*OUADi-S-ANT*MONTHS. 03 12 ) TREA TI.:EN*MONTHS 3 3.2671.0E 3 3.65034E Q2 C 13 ) 3ARXTYg E*TREATIEN*MONTHS 02 *1-1-i F.N mrty: ON THS 9 3.21329E C 14) JA Dit.AN

. ( 15 ) BARATI2-'1:-.10.1IADZ-RANT* 02 TREATMEN*MONTHS 9 3.11.773E

TOTAL 63

BAR itTi? F.

VALgE FREQ MEAN OF MOISTURE 1.000000E 00 1.069771E 02 2.000000Z 00 . 3.972917E 01

QUADRANT

VALUE FRE(.1 MEAN OF moisTuaz 1.000000E 00 24 6.000 033E 01 2.000000E 00 24 7._.251667E-01 3.000000E 00 24 0.901667E 01 4.060000E 00 24 7 567063E 01 227

Appendix H-1. (Continued)

SARXTY?E (.43ADAANT

VAL.JE FREU MEAN OF moiTuaz. 1.000000i 00 1.000000E 00 -12 b- 929167£.31 -2.000000E 00 la 1.026633E 02 3.000000E 00 12 1.297333E 02

-4.000000E 60 _ 7,12 1.1-40000E. 02 2.300000E 00 1.000000E 00 12 3.072500E 01 .2.000000E 00 12 4.215000E 01? 3.000000E 00. 12 4.630000E 01 4.000000E 00 12 3.774157E 01

:INTE1i.MEAN3,TREATMEN,13Aa.iiTY:JE*T..i.EATMENJUALAANT*7-::EATME6

THEATXEN

VALUE Faia MEAN 07 MOISTURE 1.000000E 00 46 6.037706E 01 2.000000E 00 4o 5.632917E 01

3ARATYPE "TREATMEN

VALUE FREll MEAN 07 MOI3TU32 1.000000E JO 1.000000E 00 24 1.175333£ 2.000000E 00 24. 1.004206E 02 2.000000E 00 1.000000E 00 24. 4.322063E 01 2.000000E 00 24 3.523'750E-01 228

Appendix H-1. (Continued)

elJADAANT TAZATEN

VALUE FTial MEAN OF MOIOT-jE, 1.000003E 00 1.000000E 00 la 6.674167E 01 2..000300E ia. 5.327500E 31 2.000000E.00 r.000000E. 33 12. 6.929.167E 01 a.00000aa 00 12 7574167E. 01 3.00p0ooz 00 1.000000E' 00 12 9.085633E 01 2.000000E 00 12 6.777500E 31 4.000300E 00 1.000000E 00 12 9.521667E. 01 2.000000E 00 12 3.652500E 01

:INTEii:MEANS,MONTHS,3AiiATE*MONTitS'ajAiDaANT*MONT:i6

MONT:Li

V.AL:JE FREQ MEAN OF MOI5TU:ii 1,000000E 00 16 4.436675E 01 2.000000E 00 16 6.045625.E 01 3.oaooa0 z 00 16 7.3'.-)5625Z 01 4.000000E 00 16 6.599375E 31

BAil:ATYL--;E ,MONT:16'

VALUE FREia. MEAN OF MOISTJ:i.E 1.000000E 00 1.030000E 00 6 5.620000E 31 2.000000E 30 6 6.357500E 01 3.000000E 00 6 9.650000E 01 4.000000E_-00 1.233625E 02 2.000000E 00 1.000000Z. 00 6 3.253750E, 01 2.000030E 00 6 3.733750E 31 3-000030E 00 o 4.91266E 01 4-000000E. JO 6. 4.662500E 01 Appendix H-1. (Continued) 229

,.31JADRANT MONTHS

VALUE FHE3 MEAN OF MOISTJ:i.E .1.000000E 00 1.000000E JO 4 4.295000E 01 2.000000E 00 4 5.347500E 01 3.000000E JO 4 5.070000E 01 4.000000E 00 4 6.697500E 01 .2.000000E 00 1.000000E 00 4 4-467500E 01 2.000000E 00 4 6.7-45000E 01 3.000600E oa 4 7.635000E 01 4.00(1000E 00 4 6.527500E 01 3.00000GE 00 1.000000E UJ 5.6050UQ3 01 2.000000E 00 k. 6.257600E 01 3.000003 oo. 4 9.437500E 01 4.00.0000E 00 4 1.002250E 32 4.000000E 00 1.000000E. 00 4 3.160000E 61, a.ou000JE oo 4 6.132500E. 01 3.000000E 00 4. 7.240000E 01 4.000000E 00 4 6.950000E 01

T AEA T MEN MONTHS

VALUE Fii.ZU. MEAN alz. MOi3T0HE 1.000000E 00 1.000000E oo 0 ?..001250E 01 2.000000E 00 b 6.405000E 01 3.000000E 00 6 9.067500E 01 4.000000E 00 1.092675E 02 2.000000E 00 1.000000E JO 5 6.272500E J1 8.000000E 00 6 6.666250E 31 3.000000E 00 6 5.703750E 01 4.000000E 00 5 6.270000E 01 230 Appendix H -2. Factorial, analysis of variance table and intermeans of, main factor effect levels and firSt-order interactions of factors on phloem pH for the partial cut and clearcut field stadies.

ANALYSIS OF VARIANCE. FOR PH LINE SOIJACE OF VARIATION DF MEAN SQ UA 1 C 1) 13ARKTYPE .2.16901E 00 3 ,2.07018E -01 C 2) QUADRANT 3 2.05057E -01 C 3) 3AARTYPE*UUADRANT 1. 3.25501E-01 C 4) TREATNEN 1 3 5892 6E-01' C 5) 13AAATYPE*TREATMEN 6) QUADRANT*THEATMEN 3 t:5 . 9 5 7 6 E 0 2 C 7) BAARTYIJEQUADeLANT* 3 4.47326E-03 TREATMEN.. .3 cs) MONTHS 1.37022E -01 3 2.54269E-02 C 9) SARATYPEMONTMS 9 4.56535E -02. C 10) QUADRANT*MONTHS 2.81641E -02 C 11) BA'AXTYPE*QUADFLANT*MONTHS 9 C 12) THEATMEN*MONTHS 3 I .0,9019E-01 9.1.7085E-02 C 13) 3ARETYPE*THEATMEN*MONTHS 9 5.60169E-32 C 14) QUADAANT*THEATMEN*MONT17iS 15) BAAKTPE*QUADAANT* TREAMEN*MONTHS 9 3.3d391E-02

TOTAL 63

SARATYPE

VALUE FREQ mEAN OF .4-,H 1.000000E 00 48 4.360625E 00 2.000000E 00 48 4 .064000E 00

QUA N T

VALUE MEA N OF 1.000000E 00 24 4.312500E 00 2.000000E 00 24 4.087083E 00 3.000'000E 00 24 4.224583E 00. 4.000000E 00 24 ' 4.217063E 0O 231 Appendix.H-2. (Continued)

3A&AT Ye E. 0.0ADziANT

VALUE. F1iEU MEAN OF ?1-1 1.000000E 00 1.000000,L00 12 4.590633E 00 2.000000E 00 12 4.177500E 00 3.000000E 00 12 4.300000E 00 4.0000003 00 la 4.374167E 00 2.000000E 00 1.000000E 00 12 4.03-4167E 30 2.030000E OG 12 3.996667E 30 3.600000E 30 12 4.149167E 30 4.000000E 00 12 4.060000E 00

:INTEi,11.'rEANS,THEATI,IEN,6,Aiii41Ti?E*1"EATE:N...:ADIIANT*1-7LEATMEN

TALATMEN

VALUE F:1E MEAN'OF Ph 1.000000E 00 46 4.152063E. 00 2.000000E JO 46 4.866542E 30

iltEATMEN

VALUE FREQ MEAN OF r'-ri 1.000000E 33 1.000000E 00 4.241250E,00 2.000000E 00 4:41 4.4000UE 00 2.000000E. 00 1.000000E 00 24 4.062917E JO 0 ti t..10'LLE.- 33 24 4.067u63E 00 232

Appendix H-2. (Continued) UA DriANT iLEN

wiLua FREU MEAN OF ?h 1.000000a00 .1.000000E 00 12 4.,233.333E 03 "2.300000E 00 12 4.391667E 00 2.000000i: 00 1.000000E 00 12 3.973333E 00 2.000400E 00 4.200633E 00 3.000000E 00 1.000000E 00 12 4.853:333E 00 2.000000E. ti0 1 ;) 4.195633E 03 4.000000E 00 1.0000-00E OQ 12 -4..146333E 00 2.00.0000E 12 4.265633E JO :IN2EhMEANS,MONTh6,3AFLATY?E*MO6THADANT*i,:0NTh3

:MONThS VALE MEAN OF ?h 1.000000E 00 4.266750E 33 2.000000E 00. 4.336675E 00 3.000000E 00 4.105625E 30 4.000000E 00 4.145000E 00

3AF,KTY?E. MONThS

VALLiE iilEAN OF 1.000000E 00 1.000066E 00 4.456750E 30 2.000000E 00 4.437560E 00 3.000000E 00 4.277500E 00 '4.000000E 00 4.276750E 00: 2..000000E O0_ 1.000000E oa 4.076750E OP 2.000000E 00 4.836250E 00 3.000006E 00 3.933750E 00 4.000000E 30 .4. 0112503 30 233 Appendix H -2. . (Continued) ',.4iJADRANT i,IONTI-IS

VALUE FREU MEAN OF PH 1.000000E _JO 1-.300000E 00 4 .4.497500E 00 2.0000001:: 00 4 4.390000E 00 3.000000E 00 4 4.205600E 00 4.000000E 00 4 4.162500E 00 2.000000:Z.00 1.000000E 00 4 4.067500E 00 2.000000E 00 4 4.235000E 00 3.000000E 00 4 4.042.56UE 00 4.000000E 00 4 3.662500E 00 3.000000E 00 1.000000E 00 4 4.177500E 00 2.0000.00E 00 4 4,430000 00 3.000000.E J0 4 4.067500E 30 4.000000E- Oj 4 4.372500E 00 4.000000E 30 1.000000E 30 4 4.332500E 00 2..000000E JJ 4 4.292500E JO 3.300003E 00 4 4.-iit)70-Ji: 4.000000E 00 4 4.16830uZ uJ

raz.A ;MEN MONTHS .

VALUE FAE:1 MEAN OF Sri 1.000000E 30 1.000000E 00 4.148250E 00 2.000000E uu 4.195000E 00 3.000,000E 00 6 4.006260E 00 4.000000E 00 6 4.165000E 30 2.000000E 00 1.000000E JO 6 4.391250E 0J 2.000000E 00 0 4.470753E Oj 3.000000E 00 6 4.183000E- 4.000000E 00 b 4.103000E 00