A present philosophy in forest management planning is to emulate natural disturbances. This philosophy is based on the assumption that all living organisms have adapted to the patterns and process created by natural disturbances, and that if we can reproduce similar conditions, biodiversity will be maintained (Hunter 1993; Swanson et al. 1993; Bunnell 1995). Before the arrival of western civilization in the boreal landscape, natural disturbances played a leading role in shaping forest dynamics. The purpose of this report is to provide Tembec-Chetwynd Pulp Mill with a pre-industrial forest condition (PIC) analysis for the Dawson Creek Timber Supply Area (TSA) that may be used to guide forest management decisions. The PIC analysis includes a description of fire history and a comparison of species composition, age class and patch size between pre-industrial and current time periods.
In the mid 1990?s, forest management in BC began to emulate natural disturbances. The Biodiviersity Guidebook (1995) was a first attempt at describing forest landscapes as they have been shaped by nature and was used to direct forest management in the Prince George Forest Region. As more information became available for the northeastern part of the Province, Natural Disturbance Units (NDU) began replacing Natural Disturbance Types (NDT) used by the Biodiversity Guidebook. NDUs were created based on differences in stand development, landscape pattern (temporal and spatial) and disturbance processes. A total of nine NDUs were created for the Prince George Forest Region (Delong 2002) and are used as the basis for describing the pre-industrial condition for the Dawson Creek TSA. Depending on the NDU, some disturbance factors have a stronger influence than others. Overall, wildfire is the most influential natural disturbance factor in the Dawson Creek TSA (Delong 2002). Of the six NDU?s in the TSA, five have stand replacement fires as the foremost disturbance type. Only the Wet Trench ? Mountain NDU is dominated by small-scale gap replacements caused by disturbance agents such as insects, disease and wind.
In the Boreal Foothills NDU, stand-replacing fire cycles are estimated to occur every 120 years for the valley portions and 150 years for the mountain portions. In the Boreal Plains NDU, fire cycles are estimated to be 100 years in the upland portions. In the Omineca NDU, fire is a key disturbance factor with stand-replacement disturbance cycle of 120 years for the valley and 300 years for the mountain portions. In the Wet Trench, the fire cycle varies depending on the site conditions with stand-replacement disturbance cycles estimated to be 800 years in the mountain portions. Data from the MOFR Fire Protection Branch for the Dawson Creek TSA indicate that, since 1922, the majority of all fires have been smaller than 100 hectares but that these fires make up less than five percent of the total area burned. On the other hand, there have been relatively few fires greater than 1000 hectares, yet these make up over 75% of the total area burned in the Dawson Creek TSA.
Results for species composition indicate that the current composition is quite similar to preindustrial species composition. Overall, the current TSA forest composition showed a slight increase in deciduous species and a slight decrease in coniferous species as compared to the preindustrial condition. These slight changes are likely due to the fact that less than 10% of the forested landbase has been harvested or silviculture management activities in the past 50 years. Slight changes in species could also be attributed to a variety of activities including natural fire patterns, fire suppression, and forest management practices.
Results for age-class distribution indicate that, in the current Dawson Creek TSA and Tembec operating areas, there are fewer stands 40 years and younger and 250 years and older than in preindustrial times. Currently, there are more stands older than 100 years o ...
Timberline Natural Resource Group Ltd.. 2009. Pre Industrial Condition Report For The Dawson Creek TSA - Tembec Chetwynd. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2009MR078
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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