Forest Investment Account (FIA) - Forest Science Program
FIA Project Y073067

    Predicting development and productivity of southern interior mixed species stands through calibration and modeling
 
Project lead: Simard, Suzanne
Contributing Authors: Simard, Suzanne W.; Blenner-Hassett, Trevor
Imprint: Vancouver, B.C. : University of British Columbia, 2007
Subject: Forest Investment Account (FIA), SORTIE (Computer Program), Forest Management, Computer Programs, British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
Description:
This project best 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. In this project, we are calibrating the SORTIE-BC stand dynamics model for southern interior mixed stands. To do this, we are quantifying the growth response of juvenile trees (<10 cm dia.) growing under a range of light environments, characterizing the probability of juvenile tree mortality, and investigating the effects of competition on the growth and survival of adult trees (>10cm dia). Initially we will collect this information for paper birch, Douglas-fir and western larch. Our empirical data will be linked to SORTIE-BC. SORTIE-BC is a resource-mediated, spatially explicit, mixed-species forest model that makes population dynamic forecasts for juvenile and adult trees. It has a flexible user-interface that allows incorporation of a wide range of silvicultural strategies (e.g., clearcutting, understory protection, understory planting, diameter limit harvesting, shelterwood, single or group selection and variable retention). With the model, we can examine how complex stands respond to a wide range of silvicultural strategies, at different spatial scales and over different time periods, which is an impossible undertaking for traditional field-based research. This research will clearly aid the development of science-based policies, regulations and guidelines for the management of complex mixed species stands. Objectives: 1) To examine the growth response of young paper birch, Douglas-fir and western larch under a variety of light conditions. 2) To characterize the probability of juvenile paper birch, Douglas-fir and western larch mortality as a function of recent growth. 3) To determine the effects of competition on the growth and survival of adult paper birch, Douglas-fir and western larch trees. 4) To incorporate the collected information into the SORTIE-BC model using the methods and procedures of Kobie and Coates (1997) and Canham et al. (2004). 5) To validate the model growth and yield predictions using existing long-term measurement data. Approach: This study is being conducted in the ICH zone of the Southern Interior Forest Region. Southern interior mixtures are complex, and can include up to 12 tree species on a single site. We will initially sample southern interior paper birch, Douglas-fir, and western larch because we began collecting calibration data for these three species using FII funding in 2003/04. Once the model is calibrated for accurate growth projections of these three species, we will seek additional funding in future years to collect data for other southern ICH tree species (e.g., western redcedar, western hemlock). To determine the growth response of each test species to a variety of light conditions, we are collecting radial growth information from approximately 60 trees/species growing under different light conditions. We are also sampling live and dead saplings across a heterogeneous light environment to characterize the probability of juvenile mortality as a function of recent growth. To develop this relationship, stem cross sections are collected from approximately 40 living and 40 recently dead trees for each species. By sampling a variety of stand ages, we will be able to develop distance-dependent models to determine the effects of competition on growth and survival of adult trees (Canham et al., 2004). In each stand, a central transect 50-350 m long is established, and we number and record species, DBH and location of each tree with a DBH ? 10cm within 20 m of the transect center-line. In total 100-150 target trees are sampled for each species. Measurements: -Each sample tree is assessed for height and DBH to characterize the growth response of our test species to variations in light. The sample trees are cut down and a stem cross section collected 10 cm above the ground. The 10 most recent annual growth rings are measured using a Vellmex Micrometer. Hemispherical canopy photos are taken 1.5 m above the stump of each cut sample tree to quantify the level of available light. -To examine the probability of mortality as a function of recent growth, a stem cross section is removed from the chosen sample trees 10 cm above the ground. The 10 most recent annual growth rings are measured using a Vellmex Micrometer. A subsample of randomly placed quadrants is used to estimate the total number of live and dead individuals on each site. This information, along with the growth data collected from the disks, is required for maximum likelihood analysis. -To quantify effects of competition on the growth and survival of adult trees, stands of various ages are stem mapped. This is done using an Impulse LaserTM with the Mapstar Compass ModuleTM. All trees meeting the necessary requirements are mapped, tagged, and assessed for species and DBH. Target trees are cored and a Vellmex Micrometer used to determine the average radial growth (mm/yr) over the last 5yrs. Analyses: 1) The analysis of growth response data to variations in light will require the use of nonlinear regression to develop growth functions as described in Wright et al. 1998. 2) Maximum likelihood analysis, as described in Kobe and Coates 1997, will be used to determine the probability of mortality as a function of tree growth. 3) The analysis of the competition data will follow the techniques outlined by Canham et al. (2004). 4) Dave Coates will oversee the parameterization of the SORTIE-BC stand model. He has already conducted similar research for many tree species in northern BC. Once the model is updated with data collected for southern interior tree species, it will be used to predict the outcome of various silviculture management scenarios for mixed and pure stands (note, calibration of other ICH species has already been completed by Coates).
Related projects:  FSP_Y051067FSP_Y062067
Contact: Simard, Suzanne, (604) 822-1955, suzanne.simard@ubc.ca

    Deliverables:

Executive Summary (29Kb)

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Updated August 16, 2010 

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