Western Washington University Western CEDAR WWU Graduate School Collection WWU Graduate and Undergraduate Scholarship Winter 1990 Phellinus Weirii Root Rot of Douglas Fir in the Sehome Hill Arboretum: Distribution, Impact and Management Options William G. (William Gary) Cantrell Western Washington University Follow this and additional works at: https://cedar.wwu.edu/wwuet Part of the Environmental Sciences Commons Recommended Citation Cantrell, William G. (William Gary), "Phellinus Weirii Root Rot of Douglas Fir in the Sehome Hill Arboretum: Distribution, Impact and Management Options" (1990). WWU Graduate School Collection. 881. https://cedar.wwu.edu/wwuet/881 This Masters Thesis is brought to you for free and open access by the WWU Graduate and Undergraduate Scholarship at Western CEDAR. It has been accepted for inclusion in WWU Graduate School Collection by an authorized administrator of Western CEDAR. For more information, please contact [email protected]. PHELLINUS WEIRII ROOT ROT OF DOUGLAS FIR IN THE SEHOME HILL ARBORETUM: DISTRIBUTION, IMPACT AND MANAGEMENT OPTIONS by William G. Cantrell Accepted in Partial Completion of the Requirements for the Degree Master of Science Advisory Committee Master’s Thesis In presenting this thesis in partial fulfillment of the requirements for a master’s degree at Western Washington University, I agree that the Wilson Library shall make its copies freely available for inspection. I further agree that extensive copying of this thesis is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without my written permission. Date ^ ' <3 3 ~ Bellinsham, Washimton 98225 (206) 676-3000 MASTER'S THESIS In presenting this thesis in partial fulfillment of the requirements for a master's degree at Western Washington University, I grant to Western Washington University the non-exclusive royalty-free right to archive, reproduce, distribute, and display the thesis in any and all forms, including electronic format, via any digital library mechanisms maintained by WWU. I represent and warrant this is my original work, and does not infringe or violate any rights of others. I warrant that I have obtained written permissions from the owner of any third party copyrighted material included in these files. I acknowledge that I retain ownership rights to the copyright of this work, including but not limited to the right to use all or part of this work in future works, such as articles or books. Library users are granted permission for individual, research and non-commercial reproduction of this work for educational purposes only. Any further digital posting of this document requires specific permission from the author. Any copying or publication of this thesis for commercial purposes, or for financial gain, is not allowed without my written permission. Signature:_________William G. Cantrell Date: May 24. 2019 PHELLINUS WEIRII ROOT ROT OF DOUGLAS FIR IN THE SEHOME HILL ARBORETUM: DISTRIBUTION, IMPACT AND MANAGEMENT OPTIONS A Thesis Presented to the Faculty of Western Washington University In Partial Fulfillment of the Requirements for the Degree Master of Science William G. Cantrell Winter 1990 ABSTRACT This study examines the cause, distribution and impact of a forest pathogen within the 71 forested hectares of the Sehome Hill Arboretum in urban Bellingham, Washington. The causal agent was determined by the identification of cultures from deca5ring wood in douglas fir (Pseudotsuga menziesii (Mirbel) Franco) to be the root rotting basidiomycete Phellinus weirii (Muir.) Gilb. A ground survey of above­ ground symptoms was used to detect 31 infection centers covering 6.64 hectares (9.2% of the Arboretum) of symptomatic trees. Infra-red aerial photography was used to determine canopy cover for deciduous and evergreen species. A forest canopy survey was conducted to determine canopy dominance in each of 22 forested regions of the Arboretum. Basal area at breast height was used to establish dominance. Tree density and size-class distributions were used to predict future dominance in the presence of continuing Phellinus root rot infection. Seven management approaches were discussed. IV TABLE OF CONTENTS Page ABSTRACT iv LIST OF TABLES vii LIST OF FIGURES viii I. INTRODUCTION 9 An Overview of the Pathogen 10 II. STUDY AREA 16 Geology 18 Soils 19 Topography 20 Hydrology 21 Climate 21 III. METHODS 23 Field Identification of the Pathogen 23 Culture of the Pathogen 23 Ground Survey of Root Rot Infection Centers 23 Forest Canopy Survey 26 IV. RESULTS AND DISCUSSION 32 Field Observations of Symptoms 32 Confirmation of the Causal Agent 32 Macroscopic Characters of Cultures 32 Microscopic Characters of Cultures 33 Extent and Distribution of the Infection 35 Forest Canopy Survey 37 Stands of Low Susceptibility to Root Rot 43 The Highly Impacted Conifer Stands 48 The Least Impacted Conifer Stands 52 Management Options 57 Non-Interference 58 Dangerous Tree Survey 59 Species Manipulation 60 Swath Cutting 60 Stump Removal 61 Chemical Control 62 Biological Control 62 V Page V. CONCLUSIONS 64 VI. LITERATURE CITED 67 APPENDIX A Sample Data Sheet for the Root Rot Survey. 74 APPENDIX B Sample Data Sheet for the Forest Canopy 75 Survey. APPENDIX C A Susceptibility Scheme for Northwest 76 Conifers to Phellinus Root Rot. APPENDIX D Roppy disk containing vector data for maps Back included in this thesis. Cover VI LIST OF TABLES Page Table 1. Symptoms of five important forest 24 root diseases in the Pacific Northwest. From Root Diseases in Oregon and Washington Conifers. Table 2. Overall frequency of occurrence for 38 each of the major tree species in the Sehome Hill Arboretum. Table 3. Basal area of the most common trees in 40 the Sehome Hill Arboretum. Table 4. Tree density for the most common trees 40 in the Sehome Hill Arboretum. Table 5. Stand areas, area and fraction root rot, 42 area and fraction conifer cover for 22 stands in the Sehome Hill Arboretum. Table 6. Stand areas, area and fraction root rot, 44 area and fraction conifer cover. A) Stands of low Susceptibility to Phellinus root rot. B) Highly impacted conifer stands. C) Least impacted conifer stands. vii LIST OF FIGURES Page Figure 1. Location map for the Sehome Hill Arboretum. 17 Figure 2. Topography of Sehome Hill. 19 Figure 3. The transect lines used in the Phellinus 26 root rot ground survey. Figure 4. Digitized infra-red photograph showing 29 deciduous broad leaved tree species and conifers. This map was used to determine the forest stands to be sampled in the forest canopy survey. Figure 5. Map showing the forest canopy sampling stands. 30 Figure 6. Photograph of Phellinus weirii showing the 34 characteristic setal hyphae (450 X). Figure 7. The root rot infection centers on the 36 sampling grid. Figure 8. Location map for the stands of low 45 susceptibility to Phellinus root rot. Figure 9. Location map for the highly impacted 50 conifer stands. Figure 10. Location map for the least impacted 54 conifer stands. vm INTRODUCTION This thesis addresses the occurrence of numerous patches of dead and dying douglas fir (Pseudotsuga menziesii (Mirbel) Franco) within the forested acres of the Sehome Hill Arboretum. Despite the fact that the Sehome Hill Arboretum has been the object of numerous landscape plans, impact statements, and student papers (Western Washington State College 1974, Brewer 1978, Edwards 1978, Jones and Jones 1978, Miller 1978, Wild 1978, Bates 1979, Roberts 1982, Huxley College 1986) there has been no documentation of the tree decline. An Overview of the Pathogen The causal agent was determined by the identification of cultures from decaying wood of douglas fir to be the root rotting basidiomycete Phellinus weirii (Murr.) Gilb. The fungi was first described by Murrill (1914) from a collection on western red cedar (Thuja plicata Donn.), who classified it in the genus Poria. Gilbertson (1974) reclassified the fungus as a member of the genus Phellinus. Phellinus weirii is a member of an order of the Basidiomycotina in which the basidia are bom in a hymenium (layer of spore producing tissue) which is exposed before maturity (Watling 1982). Ainsworth et al. (1971) report the following taxonomic classification for the species: 9 Kingdom. .... Fungi Phylum.... ....Mycota Class...... .Basidiomycotina Order................Hymenochaetales Family...............Hymenochaetaceae Genus............... J^hellinus Species..............JPhellinus weirii Mounce et al. (1940) described the fungus on douglas fir and western hemlock (Tsuga heterophylla (Raf.) Sarg.) on Vancouver Island. They also described symptoms of the disease, macroscopic and microscopic culture characteristics, and the character of typical and incipient decay. Below is a summarized description of the fungi as provided by these authors: In late summer and early fall, sporophores (fruit-bodies) may be seen to develop on the underside of logs and in root crotches. The sporophores of Phellinus weirii are perennial, light in weight, and soft and fragile. In older specimens the pore layer is 6-10 mm. thick with 5-6 pores per mm. The spores are smooth, hyaline, broadly ellipsoid, becoming oblong ellipsoid, epiculate at maturity, 4.0-4.9 X 2.S-3.2 microns. Vegetative hyphae are brown, thin walled, with simple septa, sparingly branched, with the branches originating at a point median between two adjacent cross-walls. Setal hyphae (specialized structures distinguished from the 10 vegetative hyphae by thickened walls, slender appearance, pointed tip, and brown staining in KOH) are numerous. Phellinus weirii and other members of the Hymenochaetaceae do not form clamp connections (a lateral connection between adjacent cells of dikaryotic hypha ensuring each cell of the hypha will have two dissimilar nuclei). P. weirii exhibits the formation of heterokaryons (containing two or more genetically different nuclei per cell) with varying numbers of nuclei present (Hansen 1979a). Phellinus weirii exhibits physiological heterothallism, a system of sexual incompatibility with gene(s) ensuring that morphologically similar mates will be of different genotypes.