Canadian Forest Service Publications
Montane alternative silvicultural systems: ecophysiology of regenerating conifers. 1995. Mitchell, A.K.; Arnott, J.T. Pages 69-80 in J.T. Arnott, W.J. Beese, A.K. Mitchell, and J. Peterson, Editors. Montane alternative silvicultural systems (MASS), Proceedings: Workshop. June 7-8, 1995, Courtenay, British Columbia. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC, FRDA Report 238, copublished by the BC Ministry of Forests. 122 p.
Issued by: Pacific Forestry Centre
Catalog ID: 4226
CFS Availability: Order paper copy (free)
Coastal montane forests are becoming increasingly important sources of fiber supply in British Columbia. These high elevation sites are subject to harsh climatic conditions and short growing seasons that may reduce regeneration performance below expectations. Silvicultural alternatives to clearcutting that employ varying levels of overstory removal may provide means by which to mitigate these environmental extremes. In this study, physiological and morphological characteristics of Abies amabilis (Ba) and Tsuga heterophylla (Hw) planted under different silviculture systems treatments (CC, Clearcut; PC, Patch Cut; GT, Green Tree Retention; SW, Shelterwood; OG, Old Growth) were measured to compare acclimation of the two species to different overstory removal regimes. Physiological characteristics (net photosynthesis and chlorophyll fluorescence) were more responsive to the silviculture systems treatments than morphological ones (height growth, specific leaf area) but effects were small and inconsistent. Evidence of acclimation appeared first in chlorophyll fluorescence (Fo) in July and later in net photosynthesis in September. After one year, height growth and specific leaf area were not significantly affected by the treatments except in the old growth where light levels were extremely low. Western hemlock had greater acclimation to the treatments than amabilis fir but this did not confer a growth advantage.