The overall focus of this project is to provide information about management practices and ecosystem function in conifer/broadleaf forests of the southern interior wet-belt. The research activities and budget in 2005/06 supported completing research on three of the six conifer/paper birch mixtures experiments that comprise this continuing project: (1) Site Preparation Study, (2) Soil Transfer Study, and (3) Birch/Conifer Thinning Study. For the Site Preparation Study, a journal article and extension note initiated in 2004/05 was completed and will be submitted for publication in 2006. For the Soil Transfer Study, a journal article and extension note summarizing data collected in 2004/05 was prepared and will be submitted for publication in 2006. The activities for these two component studies were done at no further cost to the project, representing an efficient investment for FSP. Most of the research activities and budget in 2005/06 focused on the Birch/Conifer Thinning study, the third of the integrated studies. Here we investigated understory vegetation responses to thinning, providing critical information for silviculture treatments effects on biodiversity and habitat supply. An extensive literature search revealed no publications on sprouting responses of broadleaf species, and few on understory vegetation responses, to broadleaf density gradients within even-aged conifer plantations. Here we had the opportunity to fill this knowledge gap at low cost. Thinning treatment effects on abundance and diversity of understory species have relevance to habitat quality for wildlife species (Bunnell and Kremsater 1990; Carey and Johnson 1995), soil quality for healthy, not pathogenic, soil biotic communities (Marshall 2000), and nutrient inputs for Douglas-fir regeneration (Trofymow et al., 1991). This information is becoming of vital importance in British Columbia as we focus more on mixed species management and require information for habitat supply models. Forestry managers in the province are challenged to concentrate their efforts on sustaining and increasing timber production and wood quality, while at the same time maintaining ecosystem function and species diversity of complex stands. The Birch/Conifer Thinning study provided an opportunity to examine how manipulating birch density within the mixed broadleaf/conifer stand in the highly productive interior cedar-hemlock wet-belt forests would affect the composition and development of understory species.
Simard, Suzanne W.. 2006. Effect of young stand silviculture on conifer/broadleaf mixtures in seral ICH forests of southern interior BC. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2006MR287