Indexing Western Spruce Budworm Activity through Radial Increment Analysis

摘要

Past western spruce budworm (WSBW) activity in western Montana Douglas-fir (Pseudotsuga menziesii) forests was assessed through radial increment analyses of cores extracted as diameter breast height. A growth function defined as the cumulative sum of squared mean annual radial increment was graphically compared between WSBW host (Douglas-fir) and nonhost (ponderosa pine (Pinus ponderosa)) TREES. A hazard index that may reflect effects of WSBW on establishment of natural regeneration is proposed and may be suitable for analyses relating to WSBW activity to regeneration probability.