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This paper describes a modelling research approach for the proposed new study of the interaction of fire and mountain pine beetle via forest age structure. This approach is theoretical and provides an analysis of how the stability of forest age-distributions is related to fire regimes. Starting with the derivation of the theoretical negative expone...
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Context 1
... Forest regeneration occurs immediately after stands are burned. Two well known probability distributions were then obtained: the negative exponential distribution and the geometric distribution: where x is stand age in years, and f(x) is the relative frequency of forest stands with age x. Figure 1 shows the two probability distributions with the same p value. The negative exponential distribution has been used in the presentation of the age class distribution theory and has received wide attention, because of its simple mechanism of generation as well as the convenience in computation and plotting as a descending straight line on semi-logarithmic paper. ...
Citations
... Among these species, MPB has the most devastating impact on forest dynamics and has been in an outbreak phase for the last several years in British Columbia (British Columbia Ministry of Forests 2003). With the climate warming in western Canada, this species has rapidly expanded its infestation area into northern British Columbia and western Alberta where lodgepole pine is distributed (Alberta Sustainable Resource Development 2004; Li and Barclay 2004;Li et al. 2005a). In this chapter, however, we focus on fire and harvest regimes. ...
Increased human activities have changed global ecosystems that include the dynamics of carbon (C) stocks in forest lands,
which are determined by the sizes of living biomass, dead woody materials and soil C pools. This study focuses on C dynamics
in living biomass that has been used in international reporting. Based on the forest conditions of Fort A La Corne (FALC)
in central Saskatchewan, Canada and Miyaluo in Sichuan Province, P.R. China, this study employed a strategic model to simulate
C stock dynamics under various combinations of forest fire and harvest alternatives. Our simulation results suggest that the
forest C sink size is less likely to be sustained with a simple strategy of complete protection against all disturbances.
Changes in the C sink size are largely attributed to the dynamics of forest age distribution. Forest management options that
keep forests within a certain range of mean forest age could result in both higher mean annual increment (MAI) and C sequestration
rates than the default and average values used by the Intergovernmental Panel on Climate Change (IPCC). The specific range
of mean forest age will be region-specific, depending on the tree species composition and physical conditions. Our simulation
results suggest that, in most cases, the FALC forests will function as C sinks except when the fire cycle becomes very short;
hence, the area has the potential to positively contribute to the C sink. For Miyaluo forests, a strategy of regulated harvest
activities can enhance the C sink.
... The British Columbia Ministry of Forests Prognosis BC development team is currently developing a growth and yield model linked to a fuel and snag dynamics modelling system that will be able to help resource and fire managers determine impacts of mountain pine beetle outbreaks, particularly on timber supply and making salvage decisions . Li & Barclay (2004) and Li et al. (2005) used a theoretical modelling approach to study the interaction of fire and mountain pine beetle via forest age structure. The results of their simulation suggest that the temporal dynamics of lodgepole pine forests susceptible to mountain pine beetle attack are complex and depend on the fire history of the stand for areas that are experiencing large and irregular stand-replacement fires ( Li et al. , 2005 ). ...
... The results of their simulation suggest that the temporal dynamics of lodgepole pine forests susceptible to mountain pine beetle attack are complex and depend on the fire history of the stand for areas that are experiencing large and irregular stand-replacement fires ( Li et al. , 2005 ). A stable lodgepole pine forest age-distribution might never be achieved if the landscape is subjected to large and irregular fire disturbances ( Li & Barclay, 2004 ). ...
1 Natural and recurring disturbances caused by fire, native forest insects and pathogens have interacted for millennia to create and maintain forests dominated by seral or pioneering species of conifers in the interior regions of the western United States and Canada.
2 Changes in fire suppression and other factors in the last century have altered the species composition and increased the density of trees in many western forests, leading to concomitant changes in how these three disturbance agents interact.
3 Two- and three-way interactions are reviewed that involve fire, insects and pathogens in these forests, including fire-induced pathogen infection and insect attack, the effects of tree mortality from insects and diseases on fuel accumulation, and efforts to model these interactions.
4 The emerging concern is highlighted regarding how the amount and distribution of bark beetle-caused tree mortality will be affected by large-scale restoration of these fire-adapted forest ecosystems via prescribed fire.
5 The effects of fire on soil insects and pathogens, and on biodiversity of ground-dwelling arthropods, are examined.
6 The effects of fire suppression on forest susceptibility to insects and pathogens, are discussed, as is the use of prescribed fire to control forest pests.
