Forest Investment Account (FIA) - Forest Science Program
FIA Project L077016

    Long-Term Sub-Boreal Mixedwood Studies
Project lead: Hawkins, Chris (University of Northern British Columbia)
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
The Sub-boreal Mixedwood Studies LTRI is comprised of seven existing mixedwood stands in the sub-boreal spruce (SBS) biogeoclimatic zone with variable paper birch or trembling aspen densities, and incorporates both historic (30+ years) and new data. In 2001, the UNBC Mixedwood program took over the maintenance and management of four research sites from the Ministry of Forests and has incorporated these sites into its sub-boreal mixedwood study (FSP Y062350). Between 2000 and 2005, three additional research sites were established at Sinclair Mills, Walker Creek and on the Coalmine Forest Service Road. The four inherited sites are located at Spey Creek, Raft Creek, and two near Vama Vama Creek. The management of these complex stands will lead to enhancements in biodiversity and to the value added sector. Information on growth and yield and wood quality is lacking for mixedwood stands. Research at this LTRI addresses these two broad themes as well as economic analyses of various management scenarios. The current study utilizes growth measurements, quality assessments, and models to determine: A) optimal threshold deciduous levels in mixed species stands, B) the influence of deciduous species in areas of White Pine Weevil (WPW) attack, C) timber quality of fast-grown spruce and birch grown at variable densities, D) growth and yield of variable density, fast-growing mixed species stands, and E) the wood quality of 30+ year old spruce developed under open-grown/high WPW attack and under aspen/low WPW attack. The study site at Spey Creek is part of a large opening that includes a sizeable area of 35 year old paper birch. The dense coniferous understory is dominated by white spruce and subalpine fir with a minor component of Douglas-fir and lodgepole pine. A completely randomized design with four treatments: 1) control; 2) 1200 birch sph; 600 birch sph; and, 4) remove all birch and other broadleaf trees, was replicated 4 times. Understory conifers were thinned to 1200 sph in all treatments. Following thinning, permanent sample plots (pspís) 0.16 ha (40 m x 40 m) were established at the centre of each main plot and all trees (paper birch and conifers) in each plot were number-tagged, and the stand was mapped. The Raft Creek study site is a large and relatively uniform area of pure paper birch that was selected for an underplanting experiment. A completely randomized design was established with five levels of canopy closure i. e. densities of paper birch (0, 300, 600, 1000 and control) and was underplanted with 4 conifer species: Douglas-fir, white spruce, subalpine fir, and lodgepole pine at 3 m spacing. Each of the treatments was replicated three times. The main treatment plots are 70 m x 70 m with a 40 m x 40 m psp in the centre (20m x 20m subplot for each conifer species). The Vama Vama Creek site was established in 1999. It is predominantly lodgepole pine and aspen with lesser amounts of spruce and subalpine fir. The experiment is a completely randomized design with six aspen densities (0, 300, 1200, 2500, 5000, and control) replicated three times. Birch within 1.5 m of conifers were cut, but aspen within 1.5 m of conifers were not cut if they were required to meet the treatment density. Treatment plots measure 50 m? 50 m with a circular 0.01 ha (radius 5.64 m) psp in an aspen patch nearest the plot centre. A second site near Vama Vama Creek, called Cozens Vama Vama, was operationally planted in 1970 and the research trial was established in 1983 to look at overstory and WPW attack. The trial has three treatments applied in 50 x 150 m plots: completely brushed, side shade, and unbrushed. The trial is replicated 3 times and all trees are stem mapped. Mixed species 5.64 m temporary sample plots were also established in 2002. The Sinclair Mills study site was established in 2000 to investigate the impact of birch overstory on white pine weevil (WPW) attack, conifer growth, and free growing specifications. The stand was logged in winter 1987-88, broadcast burned in spring 1988, and planted in the spring of 1989. The trial consists of 38 - 70 x 70 m plots with variable spruce and birch densities. The trial encompasses 4 broad treatments: (1) control Ė 3 plots; (2) historical glyphosate treatment - 3 plots; (3) 8 - variable spruce density plots with constant birch density (1200 sph); and (4) 24 - variable birch density plots (3 replicates of each) with total spruce retention. The variable spruce density plots were created with brush saws. A 30 m x 30 m plot centered in each treatment unit contains the psp. The Walker Creek site was established during the winter of 2003-04. The stand is a 15 year old aspen-spruce mixture located in the ICHwk3. The research trial was designed to replicate density manipulation treatments at Sinclair Mills. Twenty - 70 m x 70 m treatment plots were established with 30 m x 30 m psp areas centered within. Variable density treatments were randomly assigned to each plot, and thinning was undertaken in summer 2004: 1)0 sph aspen and birch ; 2)500 sph; 3)1100 sph; 4)1800 sph; and 5) 2500, each replicated four times. Four 5.64 m pspís were established in control areas where no birch or aspen removal occurred. During the 2005/06 field season, we observed that many of the wooden posts marking the locations of permanent sample plots at the LTRI sites were either missing or damaged, and tags at older sites had fallen off sample trees. Also, since the UNBC Mixedwood program took over the management of the MoF LTRI sites, associated historic electronic and paper data files were provided to the program. These files are numerous and are not in any organized format. This Letter of Intent is submitted to propose funding to 1) maintain the sites with established pspís (replace approximately 650 wooden posts with more permanent metal and pvc posts, replace missing or damaged tags); and 2) incorporate historic and current data, reports, extension notes, maps, analysis files, and photographs in database format and to document the contents of the numerous paper and various electronic files which have been turned over to the program. As a result of the proposed activities, the permanent infrastructure of the sites will be maintained for the benefit of existing and future experiments. The knowledge assets associated with this LTRI can be documented, converted into a format accessible to current and future researchers, and will be housed on the UNBC server to protect them. The experimental results potentially realized through study at these LTRI sites support the following Forest Science Board Timber Growth and Value Program Themes: 1) 1.0 Basic research on tree growth and stand development, 1.1 Complex stands including partial cutting, variable retention, a) species interactions; 2) 2.0 Design and analysis of silvicultural systems, 2.1 Complex stands including partial cutting, variable retention and development, a) evaluation of the results of partial cuts and the effects on stand establishment, early growth and yield and response to management practices b) monitoring of the impact of various stand treatment regimes on regeneration; 3) 3.0 Growth and yield modeling/predictions 3.1 Complex stands including partial cutting variable retention a) Interior BEC zones (ESSF, MH, SBS); and 3.2 Wood quality. Remeasurement Description This year, the project has received LTRI funding to maintain the research sites and construct a data base of historical files (L077016). This remeasurement request is to conduct Leaf Area Index (LAI) measurements at three of the seven project sites. Repeat LAI measurements have been collected at three research sites (Raft Creek, Spey Creek, and Vama Vama Creek) in 1996, 2004, 2005 and 2006 (FRBC, FII, FSP). Preliminary analysis of LAI results from these sites have provided important and relevant information regarding the contribution of competition from overtopping deciduous canopies, and potential for use in modeling future growth. Dr. Phil Comeau (University of Alberta) has published results of Spey Creek measurements1 and will be examining results of 2004 and 2005 measurements. Collection of LAI at Sinclair Mills, Walker Creek, and Cozenís Vama Vama sites would further enhance the current study findings and help meet project objectives. We propose to collect LAI measurements both while deciduous leaves are present (summer measurements), and after leaf senescence to determine the LAI contribution from deciduous overstory only and the contribution from conifer trees. This proposal request is for the FY 2006/2007. If future measurements are assessed to be necessary, further funding sources will be requested as part of the complete project funding (FSP full proposal request). Project funding has been approved for FY 2006/2007 (FSP-Y073090) to collect tree measurements, soil samples and to conduct vegetation surveys at the project sites. The experimental results potentially realized through study at these LTRI sites support the following Forest Science Board Timber Growth and Value Program Themes: 1.0 Basic research on tree growth and stand development, 2.0 Design and analysis of silvicultural systems, 3.0 Growth and yield modeling/predictions Outcomes of this LTRI will be applicable to the northern interior and results of existing and potential experiments could apply to other regions throughout the province.


Annotated Bibliography (86Kb)
Itemized File List (0.2Mb)
Cozens Vama Vama (0.4Mb)
Raft Map (0.2Mb)
Sinclair Mills Map (5.9Mb)
Spey Creek Map (83Kb)
Vama Vama Map (0.8Mb)
Walker Creek Map (0.1Mb)

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Updated April 29, 2011 

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