Evaluation of tree condition and tree safety assessment procedures in beetle-killed and fire-damaged lodgepole pine stands in central interior British Columbia

Abstract

This study quantified characteristics related to tree condition and deterioration in stands affected by the mountain pine beetle (MPB, Dendroctonus ponderosae) or wildfire. The stands evaluated were representative of a range of conditions present in the Sub-Boreal Spruce (SBS) zone in central interior British Columbia. The primary objective of the study was to evaluate the application and utility of theassessment procedure and safety thresholds outlined in the provincial Wildlife/Danger Tree Assessment Course (WDTAC). Stands dominated by lodgepole pine (Pinus contorta var. latifolia Englem.) that were affected by MPB or by wildfire were assessed in the Fort St. James, Nadina, Quesnel, Prince George, and Vanderhoof forest districts. Fifty-eight fixed radius study plots were delineated and 536 individual tree assessments were made. Forty-five trees were also destructively sampled to reveal internal tree condition and stem shell thickness. Using the WDTAC procedures, 16 trees (approximately 3% of those visually sampled and approximately 36% of those destructively sampled) were assessed as "dangerous." Notably, none of the beetle-killed trees sampled had specific defects or decay and deterioration patterns directly attributable to the MPB. The WDTAC procedures effectively detected danger trees among MPB-affected and fire-damaged lodgepole pine trees; the procedures appeared to be accurate, reliable, and consistent. This study demonstrates that as beetle and/or wildfire salvage continues, and where an increased risk of wildfire occurrence exists, application and use of the WDTAC criteria will help facilitate safe work practices in these situations.