Historically, forest management in British Columbia has focussed on the production of merchantable conifers planted predominantly in monoculture stands. Current and future challenges for British Columbia forest management include the mid-term timber supply shortage caused in part by numerous natural disturbances. Paper birch (Betula papyrifera Marsh.) and other broadleaf species present a possible solution to supplement volume loss and both alleviate the mid-term timber supply shortage and establish mixedwood stands capable of withstanding natural disturbances. Paper birch is found throughout British Columbia in pure and mixed stands. Paper birch is a pioneer species that establishes quickly following largescale disturbances such as wildfire or logging. Its ability to regenerate at high densities leads to strong intraspecific competition, and early and intense selfthinning influences crown development. In British Columbia’s Interior Cedar– Hemlock (ICH) forests, paper birch can dominate early stand succession (Peterson et al. 1997). Paper birch ranks highly as a nurse crop species as its canopy transmits more light to the understorey than other deciduous species (Perala and Alm 1990). In British Columbia, particularly in the ICH, paper birch could be used as a nurse crop to facilitate growth of naturally regenerating and economically appealing conifer species, such as Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), interior spruce (Picea engelmannii Parry × glauca [Moench] Voss), western redcedar (Thuja plicata D. Don.), and western hemlock (Tsuga heterophylla) without inhibiting early growth (Simard and Hannam 2000). Management of paper birch stand densities could be used to influence species diversity and natural regeneration by altering the amount of sunlight that reaches below the canopy. This Extension Note provides a summary of recently published results from a long-term experiment designed to follow paper birch response to thinning.
George Harper, Marie-Eve Leclerc. 2020. Effects of pre-commercial thinning on growth and diversity of paper birch leading stands 25 years following thinning. FLNRORD. EN123