Increased retention trees in openings, such as wildlife tree patches or variable retention, leads to increased edges compared to clearcuts. This study is designed to examine the effects of retained forest edge on the growth of regenerating trees in Coastal BC. Seven large scale (~100 ha) and three smaller scale (~40ha) experimental areas have been established across Western Forest Products landbase. Within these experimental areas sector plots have been established to examine the effects of forest edge on growth. By edge we mean an ecotone between forest and harvested area. The sector plots are designed to sample across the edges; trees are placed into 2m sections within the sector plots. The sector plots overcome the edge effect biases entailed by establishing traditional fixed area of prism plots.
As part of this project we request assistance in 1) measuring a portion of these sites (two sites, OP38250 (a hemlock/cedar group amount experiment) remeasurement after 5 years (30%, 20% and 10% retention, a clearcut and retained area), and MH4902 (a Douglas-fir mixed retention experiment remeasurement after 3 years (10% group, 5% group+5% dispersed and clearcut). 2) continued examination of the statistical properties of sector sampling Any funding shortfall for the 2 planned sites will be made up by Western Forest Products. The experimental sites were established on homogenous areas, have clearcut and uncut controls and up to 3 treatments comprised of different types and levels of variable retention (Beese et al. 2005). Categories are group retention, group size, dispersed retention, group removal and mixed retention. There are generally 3 treatments per site from low to higher levels of retention, and an uncut and a clearcut area, all randomly allocated. Within these experimental areas permanent long-term sector plots (Iles and Smith 2006) have been established to examine the effects of forest edge on growth. In dispersed experiments, clearcuts and uncut areas 0.1ha sector plots with a central angle of 36 degrees are established randomly. For group retention or group removal treatments four 9 degree sectors tied to a central 'pivot-point' are established with random angles in a minimum of 3 patches per treatment. At each experiment plots generally cover about 2ha. Each site permanently monitors 3000- 5000 planted trees, 2000+ tagged natural regeneration trees and 500-2500 retained trees measured on a 1,2,3,5,8 and 10 year cycle.
The experiments are long-term (20 years+). As part of this project we request assistance in measuring a portion of these sites. Note that requested funds will only cover a portion of the actual cost for these sites; in-kind funding will make up the short-fall. We also request assistance with funding a partial data analysis of information collected up to and including 2007-2008 from the two sites and a test of the FORGE model predictions of seedling growth versus actual data. Analysis will include an analysis of retained trees, planted and natural regeneration growth responses across variable retention edges, linked to light, temperature and moisture gradients, which have also been collected from the sites.
Smith, Nick J.. 2008. Effects of variable retention on planted and natural regeneration in Coastal BC. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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