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"Snow gone" (SGN) stage is one of the critical variables that describe the start of the official forest fire season in the Canadian Province of Alberta. In this paper, our objective is to evaluate the potential of MODIS-based indices for determining the SGN stage. Those included: (i) enhanced vegetation index (EVI), (ii) normalized difference water index (NDWI) using the shortwave infrared (SWIR) spectral bands centered at 1.64 μm (NDWI1.64μm) and at 2.13 μm (NDWI2.13μm), and (iii) normalized difference snow index (NDSI). These were calculated using the 500 m 8-day gridded MODIS-based composites of surface reflectance data (i.e., MOD09A1 v.005) for the period 2006-08. We performed a qualitative evaluation of these indices over two forest fire prone natural subregions in Alberta (i.e., central mixedwood and lower boreal highlands). In the process, we generated and compared the natural subregion-specific lookout tower sites average: (i) temporal trends for each of the indices, and (ii) SGN stage using the ground-based observations available from Alberta Sustainable Resource Development. The EVI-values were found to have large uncertainty at the onset of the spring and unable to predict the SGN stages precisely. In terms of NDSI, it showed earlier prediction capabilities. On the contrary, both of the NDWI's showed distinct pattern (i.e., reached a minimum value before started to increase again during the spring) in relation to observed SGN stages. Thus further analysis was carried out to determine the best predictor by comparing the NDWI's predicted SGN stages with the ground-based observations at all of the individual lookout tower sites (approximately 120 in total) across the study area. It revealed that NDWI2.13μm demonstrated better prediction capabilities (i.e., on an average approximately 90% of the observations fell within ±2 periods or ±16 days of deviation) in comparison to NDWI1.64μm (i.e., on an average approximately 73% of the observations fell within ±2 periods or ±16 days of deviation). [ABSTRACT FROM AUTHOR]

Examines the economic impact of policy changes in a forested region of the province of Alberta known as the Foothills Model Forest (FMF). Effects of policy changes in various sectors that are analyzed in terms of all sectors of the regional economy with particular emphasis on the forestry sector; Study that uses a computable general equilibrium (CGE) framework rather than a fixed-price framework to analyze economy-wide impacts of land use or forest policy changes; Application of this technique on a regional scale that is rare in the scientific literature; Model results that indicate that a decrease in forestry output somewhat offsets the positive economic impact generated by increased visitor activity; Failure to consider these trade-off impacts in the analysis that will result in erroneous conclusions; Outcomes from timely policy scenarios that are examined; Results from the CGE framework that suggest that policy makers face a greater degree of complexity than in current economic impact frameworks.

Reports that forest policymakers in Canada are considering the allowable cut effect (ACE) as a potential mechanism to provide tenure holders with incentives to practice enhanced forest management. To investigate the incentives created by the ACE, this paper estimates returns to ACE investments for a trembling aspen (Populus tremuloides Michx.) - white spruce (Picea glauca (Moench) Voss) mixedwood forest in Alberta. A timber supply model is used to optimize harvesting schedules to maximize net present values over a 200-year planning horizon. A number of scenarios are investigated with variations in intensity of silvicultural investments, beginning age-class distributions, levels of flexibility around the allowable annual cut (AAC), calculations of AACs based on coniferous and mixedwood volumes, and green-up constraints. In our simulations, it was difficult to find positive returns to the ACE. Positive returns only occurred when operating under harvesting constraints with a mature starting forest and AAC calculations that ignored deciduous volumes. In those limited cases where there were positive returns to the ACE, returns were higher for extensive, rather than intensive investments. Combining these results with other potential impediments to the ACE, previously identified in the literature, the probability of tenure holders having incentives to undertake ACE investments is low.

A wildland-urban interface is a complex and dynamic zone which makes it a very difficult and uncertain area in which to practice forestry. The difficulty stems from, among other things, lack of an effective two-way communication system between forestry organizations and the affected publics, and from the differential value systems and social standards held by the publics in the wildland-urban domain. The complexity of, and approaches to solving, forest management issues in West Bragg Creek, a wildlandurban setting in Alberta, are examined in this paper. The public consultation model is proposed and discussed as one strategy to minimize forest management conflicts in West Bragg Creek. [ABSTRACT FROM AUTHOR]

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Based on stem-mapped permanent sample plot data, percent stocking dynamics were modelled for four major tree species in the province of Alberta, Canada: trembling aspen (Populus tremuloides Michx.), white spruce (Picea glauca (Moench) Voss), lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) and black spruce (Picea mariana (Mill.) B.S.P.). Percent stocking was defined as the percentage of 10-m2 plots occupied by at least one tree with a minimum height of 1.3 m. The difference equation technique was applied for model fitting. Site index was a significant predictor in all models. Heterogeneous residual variances present in the aspen, white spruce and lodgepole pine models were corrected by applying a power-of-the-mean variance function. Serial correlation due to repeated measurements was considered through a linear log covariance structure. A percent stocking index, defined as the percent stocking at 50 years total age, was derived from the fitted percent stocking models and used for assessing species interactions in mixed-species stands. The presence of other species did not appear to affect percent stocking changes over time for aspen and black spruce. However, white spruce percent stocking was reduced when growing together with aspen, and lodgepole pine percent stocking was negatively affected by the presence of aspen, white spruce and black spruce. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of partial and clear-cut harvesting on forest floor physical, chemical, and biological properties, forest floor mesofauna, and nutrient cycling were investigated in conifer- and deciduous-dominated stands of Alberta's mixedwood boreal forest. Forest floor samples were collected 2.5 years after harvest from clearcuts, strip-cut corridors in a partial cut, green tree retention patches in a partial cut, and uncut control sites. Partial cuts showed intermediate decreases in annual litter input and NH[sub 4] -N between uncut and clear-cut sites of both the deciduous and conifer stands, as did microbial biomass, PO[sub 4] -P, mesofauna abundance (total, Acari, and Collembola), and fine root biomass in the conifer stands. In the deciduous stands, microbial biomass and fine root biomass in partial- and clear-cut treatments were not significantly different, but were significantly reduced compared with the uncut controls. Mesofauna abundance was reduced in the corridors of the partial-cut treatment compared with partial-cut patch, clear-cut, and uncut treatments. In both deciduous and conifer stands, NO[sub 3] -N was elevated in the partial-cut corridors and clearcuts compared with partial-cut patch and uncut treatments. Findings from this study show that negative impact to forest floor properties associated with clear-cut harvesting may be reduced in partial-cut harvesting systems.Les effets de la coupe à blanc et de la coupe partielle sur les propriétés physiques, chimiques et biologiques de la couverture morte, sur la mésofaune de la couverture morte et sur le recyclage des nutriments ont été étudiés dans des peuplements dominés soit par des conifères, soit par des feuillus, dans la forêt mixte boréale de l'Alberta. Des échantillons de la couverture morte ont été prélevés dans des sites coupés à blanc, dans les corridors de coupes partielles par bandes, dans les îlots de réserves de coupes partielles et dans des sites témoins non coupés deux ans et demi après la récolte. La coupe partielle a entraîné une diminution de l'apport annuel de litière et de N (NH[sub 4] ) intermédiaire entre les sites coupés à blanc et les sites non coupés dans les deux types de peuplements de même qu'une diminution de la biomasse microbienne, du P (PO[sub 4] ), de l'abondance de la mésofaune (totale, d'acariens et de collemboles) et de la biomasse des racines fines dans les peuplements résineux. Dans les peuplements feuillus, la biomasse microbienne et la biomasse de racines fines ne différaient pas significativement entre la coupe partielle et la coupe à blanc mais étaient significativement plus faibles que dans les sites témoins non coupés. L'abondance de la mésofaune dans les corridors de la coupe partielle était inférieure à celle observée dans la coupe partielle avec réserves, dans la coupe à blanc et dans les sites non coupés. Tant dans les peuplements résineux que feuillus, N (NO[sub 3] ) était plus élevé dans les corridors de la coupe partielle et dans la coupe à blanc que dans la coupe partielle avec réserves ou dans les sites non coupés. Les résultats de cette étude montrent que l'impact négatif de la coupe à blanc sur les propriétés de la couverture morte peut être minimisé avec des systèmes de coupe partielle.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Examines the ecological combining ability of three forest types in British Columbia and Alberta. Factors that are related to the stand volume of tree species; Effect of one species on the productivity of another species; Details of the forest policy in British Columbia; Analysis of vegetation and soil physics in British Columbia and Alberta.

This article presents an applied framework for selective precision in the insertion of superior data into hybrid regional models where regional purchasing coefficients are absent or unattainable. Due to the lack of regional-level data, crude top-down methods are the most frequently applied methods in Canadian regional studies. However, they may lead to inaccurate policy analysis where significant variation exists between the technical coefficients and trade flows of two economies. This article discusses an alternative, hybrid approach that involves the collection of region-specific information and therefore promises greater accuracy and validity of impact analysis. The robustness of the hybrid model is tested against the results derived from a synthetically regionalized model. The Foothills Model Forest (FMF) in west-central Alberta is used as a case study for the development of a sub-provincial economic database for the purpose of regional impact modeling. [ABSTRACT FROM AUTHOR]

Economic base analysis is a limited but useful tool for measuring forest dependence. It cannot measure the full range of forest values (e.g., subsistence, amenity, bequest, and existence values). However, economic base analysis utilizes widely available census data to provide accurate measures of communities dependent on industrial forest activity. This analysis includes Indian reserves and rural census subdivisions previously excluded in studies of economic base dependence. Economic base dependence measures are further improved by including a transfer payment sector. This paper presents findings of forest industry dependence measures using 1991 census data. Results show that including Indian reserves and other rural census subdivisions in the analysis increases the number of forest industry dependent places and population in the Prairie Provinces. The addition of the transfer payment sector to the economic base provides a more comprehensive account of the sources that contribute to the economic diversity of rural locations. These geographical and sectoral refinements to economic base calculations result in a more accurate accounting of forest industry dependence. [ABSTRACT FROM AUTHOR]

The ground beetle Pterostichus, melonarius (Coleoptera, Carabidae), of European origin, is abundant and wide-spread in the northern United States and southern Canada. Three field enclosures were used in a four-year experiment in Alberta, Canada, to examine whether the species is able to establish in natural aspen-poplar forest, and to test the hypothesis that it has an adverse effect on the native carabid assemblage. After introduction to the enclosures P. melanarius maintained breeding populations in them, establishing that the forest is suitable habitat for the species, and suggesting that the species will eventually invade from nearby populations Pterostichus melanarius had no negative effect on population size or body mass of the native carabid species. However, the two most abundant native species (Ptero-stichus adstrictus and P. pensylvanicus) appeared to be more active (measured as escape rate) in compartments where they co-occurred with P. melanarius. Although the three enclosures were just a few metres apart, one of them consistently yielded the highest densities of all carabid species. This difference was correlated with high abundance of earthworms and low liner accumulation. Relatively low densities of P. melanarius may explain the lack of negative interspecific interactions in forests, although such effects are suggested by data from urban and agricultural environments where P. melanarius is more abundant. [ABSTRACT FROM AUTHOR]