Modelling forest development in the Mackenzie Basin under a changing climate

• Main Author: Hartley, Mary Isobel
• Format: Thesis
• Language: English
• Published: 1995
• Subjects: Mackenzie Basin
• Online Access: http://hdl.handle.net/2429/4190

The purpose of this study was to explore relationships between baseline climate conditions (1951- 1980), and forest composition and productivity, over the Mackenzie Basin at the forest inventory unit level, for use in the development of a forest productivity model. The Mackenzie Basin Forest Productivity model (MBFP model) was then constructed to project the climate-related forest attributes through climate change conditions, as predicted by global circulation models (GCMs). The tree species studied were black and white spruce (Picea mariana (Mill.) B.S.P. and Picea glauca (Moench) Voss.), jack pine (Pinus banksiana Lamb.), lodgepole pine (Pinus contorta Dougl.) trembling aspen (Populus tremuloides Michx.), and paper birch (Betulapapyrifera Marsh.). Only 18% of the area within the Mackenzie Basin had adequate forest inventory information for use in building the climate relationships and the MBFP model. The aggregation method used for multiple stand records within inventory units was described, with the transfer of information across scales recognized as an area of concern. Each species was assigned to age groups; productivities in the first three age groups were related to the baseline climate conditions (1951-80) using multiple linear regression techniques at the inventory unit level. The relative proportions of each species in each inventory unit were also related to the baseline climate conditions (1951-80) in a similar manner. The relationships for species productivity varied in R² values from 0.09 (MSE[sub e][sup 1/2] 5.83m³/ha) to 0.48 (MSE[sub e][sup 1/2] 4.04 m³/ha). The relationships for species' relative proportions in inventory units varied in R2 values from 0.14 (MSE[sub e][sup 1/2] 0.03) to 0.41 (MSE[sub e][sup 1/2] 0.16). The model was built using the GRASS GIS environment supported on the Linux operating system. Productivity, mortality (through surrounding conditions and fire), and establishment were represented in relation to climate in the model. The approaches used in modelling these processes were described and source code provided. Suggestions for calibrating the model to baseline climates provided by various Global Circulation Models (GCMs) were made and a design for a sensitivity analysis was given. Results from running the model were not provided due to limitations reached in the fire module imposed by the modelling environment. Overcoming these limitations was considered to be beyond the scope of this research. Forestry, Faculty of Graduate