Forest Investment Account (FIA) - Forest Science Program
FIA Project Y073065

    Effect of young stand silviculture on conifer/broadleaf mixtures in seral ICH forests of Southern Interior BC
Project lead: Simard, Suzanne
Contributing Authors: Simard, Suzanne W.; Hope, Graeme D.; Vyse, Alan; Hagerman, Shannon M.; Sachs, Donald L.; Heineman, Jean L.; Mather, W. Jean; Zimonick, Barbara J.
Imprint: Vancouver, B.C. : University of British Columbia, 2007
Subject: Forest Investment Account (FIA), Forest Management, British Columbia, Interior, Site Preparation
Series: Forest Investment Account (FIA) - Forest Science Program
This project fits the FSP 'Timber Growth and Value' program, '1.0 Basic Research on tree growth and stand development' theme and '1.1 Complex stands' topic. The combination of six fully replicated conifer/paper birch mixtures experiments on sixteen different sites in young stands within the Interior Cedar Hemlock and Interior Douglas-fir zones of the southern interior represents an extensive research program. The six experiments are: 1) Regeneration of birch/conifer mixtures (established in 1992), 2) Site preparation for Armillaria root disease (established in 1992), 3) Crop-tree response to brushing at various radii (established in 1995), 4) Birch/Douglas-fir thinning study (established in 1999), 5) Birch/spruce thinning study (established in 1992), 6) Birch/Douglas-fir vegetation management study (established in 1986). Objectives and Methods: The FSP project in 2004/05 includes four of these integrated studies, all of which are designed to provide information about effects of management practices on interspecific interactions, growth and yield, stand development, and ecosystem function in conifer/broadleaf forests of the southern interior wet-belt. Following is a brief description of the four component studies: a) Site Preparation Study The specific objectives are: (1) to determine the effects of different intensities of stumping and soil disturbances on long-term changes in soil physical and nutrient properties, and long-term growth of lodgepole pine, hybrid spruce, and paper birch; and (2) to identify causal relationships between soil properties altered by disturbance and long-term growth of different species. The study is in the ICHmw subzone and uses a randomized block design with three replicate sites (Adams, Malakwa, and Hidden Lake) and four treatments (control, stumps inverted in place, stumps carefully removed, stumps and forest floor removed). Each treatment plot is further split into three tree species (lodgepole pine, interior spruce, and paper birch). In 2004/05, we planned to collect 10-year soil chemical and bulk density samples at one of the three sites (the other two sites had already been sampled). We were to collect samples for determination of bulk density and total C, N, and S, available P, and pH. Five composite samples per plot were collected for soil chemistry and 10 individual samples per plot for bulk density within each of the 24 sub-plots throughout the site. Foliar nutrient samples will also be collected from 30 trees per subplot. This new data will be combined with existing 10-year data and analyzed using ANOVA and ANCOVA, where appropriate, to test for differences in soil physical and chemical properties between silviculture treatments. Relationships between soil properties and forest productivity will be investigated using multiple regression and multivariate techniques. b) Soil Transfer Study The specific objectives of this experiment are: (1) to determine the effects of soil transfer from different forest tree species on growth and survival of planted Douglas-fir and paper birch, and on soil chemical and microbial characteristic, (2) to determine the effect of grass removal on survival and growth of Douglas-fir seedlings, and (3) to determine the effect of painting the root collar on mortality and sunscald of paper birch. This study was established at Malakwa on a single study site that had experienced repeated plantation failure for the past 12 years. Three blocks were installed at the site in 2002 and an equal mix of Douglas-fir and paper birch was planted. Four treatment factors were applied in a 2x3x2x2 factorial design. The treatment factors/levels were: species (Douglas-fir or paper birch); soil inoculum (none, soil transferred from beneath a mature birch tree, or soil transferred from Douglas-fir); grass competition (all vegetation completely removed from a 1 m x 1m plot centered on the planted tree, or no vegetation removed); and sun scald protection (protection or no protection applied). Each of these treatments was replicated 6 times in each block. In 2004/05, we planned to measure seedling survival, biomass, and foliar nutrients, as well as soil moisture content, and available nitrogen. The root systems were to be assayed for arbuscular mycorrhizae abundance and ectomycorrhizal types and diversity. Data will be analyzed using a mixed model ANOVA for a factorial experiment in a randomized block design with three replicates and six subsamples. c) Crop-tree response to manual and chemical brushing at various radii (Radii Study)- The specific objectives of this experiment are: (1) to determine the effect of a range of brush-free radii on survival, growth, and disease or insect incidence of lodgepole pine, (2) to examine the effects of these treatments on the diversity and abundance of the plant community, and (3) to identify appropriate birch-free radii where conifer productivity is maximized without adverse effects on forest health or diversity. The experiment is located on a single study site at Rushton Creek in the Kamloops Forest District. It is one experiment of several established on a range of sites to examine the effects of point brushing around crop-trees. Other experiments in this study have been testing responses of Douglas-fir and paper birch crop-trees to similar treatments. The Rushton Creek experiment involves lodgepole pine crop-trees to which six different birch-free radii treatments, ranging from 0 m to 2.5 m, were applied using a motor-manual method or a chemical method. The 2x6 factorial set of treatments was applied in a completely randomized design with 22 replicates. Five-year data was collected at Rushton Creek with previous FII funding. Crop-tree growth and survival, and target birch response, were analyzed using two-way ANOVA and planned contrasts. In 2004/05, we will publish in a refereed journal on the 5-year growth and survival response of lodgepole pine to these treatments. This publication completes the series of three publications funded by FII, including articles on Douglas-fir and paper birch responses. d) Birch/Conifer Thinning Study - The primary objective of this study is to determine paper birch density reduction effects on the growth, nutrition, and Armillaria infection of understory Douglas-fir. A second objective is to identify birch density threshold that maximize conifer productivity. The study is located in four mesic Douglas-fir plantations in the ICH in the Adams River drainage. The clearcut study sites originally had a minimum density of 7,000 stems ha-1 paper birch, had been mechanically site prepared with slash burning, and planted with Douglas-fir. Five density treatments were replicated four times in a randomized block design. The five treatments represent a gradient in paper birch density, decreasing from the control to 4444, 1111, 400 and 0 stems ha-1 paper birch. Douglas-fir density was not manipulated and averaged 1190 stems ha-1. The birch density treatments were achieved by manually cutting the paper birch at the root collar. In 2004, we planned to collect five-year post-treatment growth response of Douglas-fir and paper birch, record the incidence of Armillaria ostoyae, analyze the data, report the results in peer-reviewed literature, and extend the results. At the time measurements were made, the sites and plots were also to be maintained. Data analysis will include ANOVA or ANCOVA, LSD tests, and planned contrasts.
Related projects:  FSP_Y051065FSP_Y062065


Can. J. For. Res. 35:843-859
Can. J. For. Res. 36:2486-2496
FEM 214:251-265
FEM 242:625-635
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Updated August 16, 2010 

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