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Browse subject: forest ecology
Number of records: 1425

European Forest Institute
About this Resource: The European Forest Institute's (EFI) mission is to conduct, promote and cooperate in the research of forests, forestry and forest products at the pan-European level, and to make the results of the research known to all interested parties, notably in the areas of policy formulation and implementation, in order to promote the conservation and management of forests for producing goods and services in a sustainable way. The website divides into three sections. EFI describes its' organization, its' activities, and offers a news service. Research emphasis concentrates on: forest ecology and management; forest products; markets and socioeconomics; policy analysis, forest resources and information. EFI is currently advancing seven database services from this website; while most is open, certain parts may be limited to EFI members and partners. These services include: EFIDAS (the European Forestry Information and Data Analysis System); EFISCEN (the EFI Forest SCENario Project); DFDE (the Database of Forest Disturbances in Europe); the Database on Forest Capacities in 18 European Countries; CIS (the Certification Information Service); the Forest Research Network; FINE (the Forest Information Services Network for Europe) and EFIS (the European Forest Information System). EFI offers details on publications; mostly descriptive, pointers identify: research reports, working papers, proceedings, discussion reports, internal papers and related documents.

Longleaf Alliance
About this Resource: The Longleaf Alliance was established in 1995 with the express purpose of coordinating a partnership between private landowners, forest industries, state and federal agencies, conservation groups, researchers, and other enthusiasts interested in managing and restoring longleaf pine forests for their ecological and economic benefits. The page provides conference and other activity and event information, as well as award information and member information such as how to become a member. The website is also a resource for basic longleaf pine forest information and how to manage and restore these forests. There is educator information, job listings, current event information, and a forum for discussion. There is also a video entitled "Partners in Action" that can be watched.

Ecoforestry
About this Resource: Ecoforestry is a journal of the Ecoforestry Institute and can be found at this site. The site offers tables of contents for Winter 2003 and previous issues. Some articles are available to read online as well. Subscription rates are listed as is information on how to subscribe to the journal.

Finnish Forest Research Institute
About this Resource: Established in 1917, the Finish Forest Research Institute (Metla) is a signifigant resource realtive to Finland's forests. The website accomodates both English and Finish speaking audiences. Metla provides organizational background for site visitors, with staff introductions and descriptions of research, experiments, services and products. The Institute is making its' publications accessible in full-text and there is an explanation of the METINFO services. A sitemap faciliates site navigation and Metla places emphasis on currency by highlighting news items. The Finnish Forest Research Institute reports to Finland's Ministry of Agriculture and Forestry. The journal "Silva Fennica" is full-text accessible - beginning in 1998 (with pdf formatting), abstracts date back to 1994. The "Working Papers of the Finnish Research Institute" was launched in 2004.

Visible and invisible effects of hurricanes on forest ecosystems: an international review
About this Resource: Hurricanes have visible and invisible effects on forests. The visible effects are dramatic, noticeable over the short-term and relatively well documented in the literature. Invisible effects are less understood as they require well-focused research both in the short- and long-term time scales. This review of the literature on hurricane effects focuses on the Neotropics and the temperate zone of North America. The material is organized according to a heuristic model that distinguishes between immediate effects (0 to 3 years), immediate responses (0 to 20 years), trajectories of responses (0 to 100 years) and long-term legacies (>100 years). It is suggested that the ecological role of hurricanes involves six principal effects: 1. they change the ecological space available to organisms; 2. they set organisms in motion; 3. they increase the heterogeneity of the landscape and the variability in ecosystem processes; 4. they rejuvenate the landscape and its ecosystems and redirect succession; 5. they shape forest structure, influence their species composition and diversity and regulate their function; and 6. they induce evolutionary change through natural selection and ecological creativity through self-organization. A new approach to hurricane research will study hurricanes at the same scale at which they operate (i.e., across latitudes and longitudes and over disturbed and undisturbed landscapes). This research will require networks of observation platforms located along expected hurricane paths to facilitate forest structure and functioning observations across gradients of hurricane frequency and intensity. This research will also require use of remote sensing and automated wireless technology, hardened to survive hurricane-strength winds and floods to assure real time measurements of the characteristics of hurricanes and ecosystem responses. No progress will be forthcoming in the understanding of hurricane effects if we do not learn to quantify objectively the energy dissipation of hurricanes on the full grid of affected forests as the hurricane passes over a landscape.

Douglas-Fir Beetle Response to Artificial Creation of Down Wood in the Oregon Coast Range.
About this Resource: Douglas-fir beetle populations were monitored before and after thinning and felling of trees to create down wood in an 88-year-old Douglas-fir plantation in the Oregon Coast Range. Treatments included an unthinned control, thinning to a target of 75 trees/ha, and thinning to a target of 150 trees/ha. Actual mean tree densities on the plots after thinning were 406, 102, and 154, for the control, 75 trees/ha, and 150 trees/ha treatments, respectively. Fifty trees/ha were felled and left on all thinned plots to create down wood for ecological values. Catches in pheromone-baited traps indicated that the local beetle population increased for 1 year in response to felling and leaving large diameter trees in partial shade. Douglas-fir beetle entrance holes and brood were significantly more abundant on the sides of felled trees and wood borers were significantly more abundant on the upper surface suggesting that treatments that provide maximum exposure of felled trees will create the least favorable habitat for Douglas-fir beetles. However, there were no differences in Douglas-fir beetle entrance holes or brood densities in felled trees between the two thinning intensities. Douglas-fir beetle-caused tree mortality was significantly higher on thinned plots with residual felled trees compared with unthinned controls, although infestation levels were low on all plots (<2 trees/ha). The small increase in beetle-caused tree mortality associated with leaving felled trees would be unlikely to interfere with resource management objectives. These results are applicable to mature, managed forests west of the Cascades with relatively low Douglas-fir beetle populations. In different regions and stand types, or under different environmental conditions, beetle populations could increase to higher densities, remain at high densities longer, and cause higher levels of tree mortality.

Krasnoyarsk Center for Forest Protection
About this Resource: The expertise of the Center is mainly in the ecological monitoring of large forests, including forecasting of mass outbreaks of forest insect pests and infectious diseases caused by phytopathogenic microbes. This site provides general information about the organization, a colored guide to insect pests of Siberian forests, and maps showing population density of the major pests.

Global Forest Information System
About this Resource: GFIS is an Internet gateway to forest information resources from around the world. Users can locate maps, datasets, web resources, journal articles, books and other resources relevant to their forest information needs.","GFIS is an internet gateway that provides access to various types of information resources through partnerships with information providers. GFIS search facilities (in the style of commonly used Internet search facilities), allows the user to locate forest related information through a single entry point based on the different search options.","* An updated version of a previous GFIS metadata search provides users with the ability to search the catalogues of information resources (a total of 130,000 metadata records) provided by GFIS partners. The metadata search allows users to search all metadata fields for specific terms or phrases.","* Browsing is a way of navigating among categories and their subcategories to pinpoint the resources that you want to search. GFIS offers browsing among selected information sources from its partners, organized by key types of resources.","* A GFIS Online resource search service uses the Google Web APIs, which is an experimental and free program. The Google API currently makes it possible to carry out 1,000 queries per day with a maximum of 10 keywords. Each query is confined to one single domain.","To describe the content of this information GFIS uses a standardized metadata format and provides conversion facilities for metadata submitted in other formats. In addition a universally accepted terminology facilitates the search operations and the respective results.

Potential water yield reduction due to forestation across China
About this Resource: It is widely recognized that vegetation restoration will have positive effects on watershed health by reducing soil erosion and non-point source pollution, enhancing terrestrial and aquatic habitat, and increasing ecosystem carbon sequestration. However, the hydrologic consequences of forestation on degraded lands are not well studied in the forest hydrology community as a whole. China has the largest area of forest plantations in the world now, and the hydrologic consequences of massive forestation are unknown. We applied a simplified hydrological model across the diverse physiographic region to estimate the potential magnitude of annual water yield response to forestation. Our study suggests that the average water yield reduction may vary from about 50 mm/yr (50%) in the semi-arid Loess Plateau region in northern China to about 300 mm/yr (30%) in the tropical southern region. We conclude that forestation in China that often involves a combination of tree planting and engineering (e.g., terracing) may have even a higher potential to greatly reduce annual water yield in headwater watersheds, especially in the semi-arid Loess Plateau region. However, the forestation area is relatively small for most large basins with mixed landuses in China, thus the regional effects of forestation on water resource management may not be of major concern. Comprehensive science-based evaluation of roles of forests on regulating regional water resources is critical to the current forestation endeavors in China.

Atlantic Forestry Centre
About this Resource: The Atlantic Forestry Centre is one of five CFS research centers that plays a role in regional and national forestry research programs. Their website provides information on several ongoing research subject areas. These research areas include biodiversity, biotechnology, climate change, ecology, entomology, forest fires, forest conditions, forest management, pathology, silviculture, and socio-economics.

Forest Value Orientations in Australia: An Application of Computer Content Analysis
About this Resource: This article explores the expression of three forest value orientations that emerged from an analysis of Australian news media discourse about the management of Australian native forests from August 1, 1997 through December 31, 2004. Computer-coded content analysis was used to measure and track the relative importance of commodity, ecological and moral/spiritual/aesthetic forest value orientations. The number of expressions of these forest value orientations followed major events in forest management and policy, with peaks corresponding to finalization of Regional Forest Agreements and conflicts over forest management. Over the time period analyzed, the relative share of commodity value orientation decreased and the shares of the ecological and moral/spiritual/aesthetic value orientations increased. The shifts in forest value orientations highlight the need for native forests to be managed for multiple values and the need for continued monitoring of forest values.

Fates of live trees retained in forest cutting units, western Cascade Range, Oregon
About this Resource: Live trees, standing dead trees, and downed logs have been retained in some forest harvest sites in the Pacific Northwest to fulfill various ecological objectives. To assess the fates of retained trees following partial cutting of mature forests in the central western Cascade Range in Oregon, we inventoried standing live and dead trees and toppled trees in 21 cutting units in 1993 and 2001. In 1993, 1-10 years after cutting, an average of 65% of the initially retained trees (average of counts for all sites) were alive and standing, 12% had been toppled or topped by wind, 13% had become snags by natural processes, and 10% were converted to snags by management action, including cutting, blasting, girdling, and inoculation with fungi. By 2001, when cutting-unit ages ranged from 9 to 18 years, 54% of the retained trees were alive and standing, 10%-21% had been toppled or topped by wind, 11%-22% had become snags by natural processes, and 14% had been converted to snags by management action. The highest levels of mortality occurred at sites with abundant intentional snag creation and (or) prescribed fire following harvest. The rate of mortality due to windthrow declined over time, possibly because the remaining trees were more windfirm.

Forest Resource Environmental Educational Network | University of Minnesota
About this Resource: A coalition composed of state and federal agencies that are working with and include the University of Minnesota, and various forest product companies in Minnesota; F.R.E.E. (the Forest Environmental Education Network) is facilitating the dissemination of educational information about forest resources and their products. Educational resources are provided for teachers and children. Includes research resources as well.

Environment and Natural Resources : Tennessee Extension Service
About this Resource: Resources centered on environmental and natural resource matters, from the University of Tennessee. Clustered around the following: news and highlights, educational programs and services, departmental units and web services and publications.

Forest Environmental Investments and Implications for Climate Change Mitigation
About this Resource: Forest environmental conditions are affected by climate change, but investments in forest environmental quality can be used as part of the climate change mitigation strategy. A key question involving the potential use of forests to store more carbon as part of climate change mitigation is the impact of forest investments on the timing and quantity of forest volumes that affect carbon storage. Using an economic optimization model, we project levels of U.S. forest volumes as indicators of carbon storage for a wide range of private forest investment scenarios. Results show that economic opportunities exist to further intensify timber management on some hectares and reduce the average timber rotation length such that the national volume of standing timber stocks could be reduced relative to projections reflecting historical trends. The national amount of timber volume is projected to increase over the next 50 yr, but then is projected to decline if private owners follow an economic optimization path, such as with more forest type conversions and shorter timber rotations. With perfect foresight, future forest investments can affect current timber harvest levels, with intertemporal linkages based on adjustments through markets. Forest investments that boost regenerated timber yields per hectare would act to enhance ecosystem services (e.g., forest carbon storage) if they are related to the rate of growth and extent of growing stock inventory.

The ecology of forest insect invasions and advances in their management
About this Resource: Invasions by nonindigenous forest insects can have spectacular effects on the biodiversity, ecology, and economy of affected areas. This introduction explores several critical issues that are generally relevant to invasions by forest insects to provide an extended background for this special issue of the Canadian Journal of Forest Research and highlights the key findings of the papers included in the issue. The topics covered address new information about (1) the role of cargo shipments as invasion pathways for the arrival of insects such as wood borers and bark beetles, (2) biogeographical effects that can influence the ecological and economic impact of insects feeding on exotic tree species, (3) the influence of biodiversity on impacts of forest insects and on the invasibility of ecosystem, and (4) recent advances in the detection, monitoring, and management of invasive species and native pests, including DNA barcoding for identification, the use of pheromones for monitoring and mating disruption, and biological control. These findings are likely to become even more important with elevated prevalence of invasions as a result of increasing global trade and international travel. Avenues of international communication and cooperation among scientists should be encouraged to enhance the sharing of information about biological invasions and to find solutions to this alarming problem.

Modeling trade-offs between fire threat reduction and late-seral forest structure.
About this Resource: Evaluating the effects of managing for one forest resource in terms of associated impacts on other resources is not easy. Yet methods to identify potential trade-offs among forest resources are necessary to inform people about the implications of management options on public land. This paper uses a case study from a forest reserve in the northwestern United States to quantify trade-offs between fire threat (FT) and late-seral forest (LSF) structure at stand and landscape levels. Simulation of forest dynamics was done with and without silvicultural treatments. A landscape optimization algorithm maximized FT reduction subject to constraints on amount of LSF structure and total area treated. Results suggest that compatibility between the two objectives is possible at the landscape level when LSF structure is about 45% or less of the total reserve area. Conflict can exist between them at the stand level and when more area is required to be in LSF structure in the reserve landscape.

Forestry AgNIC
About this Resource: This web site provides significant information, resources, associations, databases, and links on forestry and the related sciences such as agroforestry, wilderness management, and outdoor recreation.

Forest fragmentation and edge effects from deforestation and selective logging in the Brazilian Amazon
About this Resource: Forest fragmentation results from deforestation and disturbance, with subsequent edge effects extending deep into remaining forest areas. No study has quantified the effects of both deforestation and selective logging, separately and combined, on forest fragmentation and edge effects over large regions. The main objectives of this study were to: (1) quantify the rates and extent of forest fragmentation from deforestation and logging within the Brazilian Amazon, and (2) contextualize the spatio-temporal dynamics of this forest fragmentation through a literature review of potential ecological repercussions of edge creation. Using GIS and remote sensing, we quantified forest fragmentation - defined as both increases in the forest edge-to-area ratio and number of forest fragments - and edge-effected forest occurring from these activities across more than 1.1millionkm² of the Brazilian Amazon from 1999 to 2002. Annually, deforestation and logging generated ~32,000 and 38,000km of new forest edge while increasing the edge-to-area ratio of remaining forest by 0.14 and 0.15, respectively. Combined deforestation and logging increased the edge-to-area ratio of remaining forest by 65% over our study period, while generating 5539 and 3383 new forest fragments, respectively. Although we found that 90% of individual forest fragments were smaller than 4km², we also found that 50% of the remaining intact forests were located in contiguous forest areas greater than 35,000km². We then conducted a literature review documenting 146 edge effects and found that these penetrated to a median distance of 100m, a distance encompassing 6.4% of all remaining forests in our study region in the year 2002, while 53% of forests were located within two km of an edge. Annually deforestation and logging increased the proportion of edge-forest by 0.8% and 3.1%, respectively. As a result of both activities, the total proportion of edge-forest increased by 2.6% per year, while the proportion within 100-m increased by 0.5%. Over our study period, deforestation resulted in an additional ~3000km² of edge-forest, whereas logging generated ~20,000km², as it extended deep into intact forest areas. These results show the large extent and rapid expansion of previously unquantified soft-edges throughout the Amazon and highlight the need for greater research into their ecological impacts.

Mountain Pine Beetle-Induced Changes to Selected Lodgepole Pine Fuel Complexes within the Intermountain Region
About this Resource: The mountain pine beetle (Dendroctonus ponderosae Hopkins) is a forest insect that infests lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) forests in the Intermountain West. The often widespread mortality caused by the mountain pine beetle has been suggested to result in significant changes to stand structure, composition, and total fuel loading; however, little quantitative information that documents these changes is available. We examined mountain pine beetle-induced changes to ground, surface, and aerial fuels in lodgepole pine stands during current epidemics and 20 years after an epidemic. Results indicated that there were statistically significant increases in the amounts of fine surface fuels in recently infested stands, i.e., those stands <=5 years past peak mortality. In the previously infested stands, there were large increases in the amounts of dead woody fuels in all but the smallest size classes, with a 7.8-fold increase in down woody fuels >=7.62 cm in diameter. Live shrubs and the amount of subalpine fir (Abies lasiocarpa Nutt.) regeneration were also significantly greater in the postepidemic stands. The net result of epidemic mountain pine beetle activity was a substantial change in species composition and a highly altered fuels complex in which large dead woody fuels and live surface fuels dominate.

A link between hurricane-induced tree sprouting, high stem density and short canopy in tropical dry forest.
About this Resource: The physiognomy of Caribbean dry forest is shorter, denser and contains a greater proportion of multi-stemmed trees than other neotropical dry forests. Our previous research, conducted after Hurricane Georges in 1998, has shown that dry forest trees sprout near the base following hurricane disturbance, even if the trees have not incurred structural damage. However, for these hurricane-induced sprouts to contribute to the physiognomy of the forest, they must grow and survive. We followed sprout dynamics and stem mortality on 1,407 stems from 1998, after Hurricane Georges, until 2005. The number of surviving sprouts and the proportion of sprouting stems decreased during the 7-year period, but the sprouting rate was still 3-fold higher and the proportion of sprouting stems 5-fold higher than before the hurricane. Mortality of non-sprouting stems (15.4%) was about the same as for sprouting stems (13.9%) after 7 years. The mean length of the dominant sprout surpassed 1.6 m by 2005, with over 13% of the dominant sprouts reaching subcanopy height. Sprout growth and survival varied among species. These results demonstrate that, despite some thinning, hurricane-induced sprouts survive and grow and that the unique physiognomic characteristic of Caribbean dry forests is related to hurricane disturbance.

Root dynamics in an artificially constructed regenerating longleaf pine ecosystem are affected by atmospheric CO2 enrichment
About this Resource: Differential responses to elevated atmospheric CO2 concentration exhibited by different plant functional types may alter competition for above- and below ground resources in a higher CO2 world. Because C allocation to roots is often favored over C allocation to shoots in plants grown with CO2 enrichment, below ground function of forest ecosystems may change significantly. We established an outdoor facility to examine the effects of elevated CO2 on root dynamics in artificially constructed communities of five early successional forest species: (1) a C3 evergreen conifer (longleaf pine, Pinus palustris Mill.); (2) a C4 monocotyledonous bunch grass (wiregrass, Aristida stricta Michx.); (3) a C3 broadleaf tree (sand post oak, Quercus margaretta); (4) a C3 perennial herbaceous legume (rattlebox, Crotalaria rotundifolia Walt. ex Gemel); and (5) an herbaceous C3 dicotyledonous perennial (butterfly weed, Asclepias tuberosa L.). These species are common associates in early successional longleaf pine savannahs throughout the southeastern USA and represent species that differ in life-form, growth habit, physiology, and symbiotic relationships. A combination of minirhizotrons and soil coring was used to examine temporal and spatial rooting dynamics from October 1998 to October 1999. CO2-enriched plots exhibited 35% higher standing root crop length, 37% greater root length production per day, and 47% greater root length mortality per day. These variables, however, were enhanced by CO2 enrichment only at the 10-30 cm depth. Relative root turnover (flux/standing crop) was unchanged by elevated CO2. Sixteen months after planting, root biomass of pine was 62% higher in elevated compared to ambient CO2 plots. Conversely, the combined biomass of rattlebox, wiregrass, and butterfly weed was 28% greater in ambient compared to high CO2 plots. There was no difference in root biomass of oaks after 16 months of exposure to elevated CO2. Using root and shoot biomass as a metric, longleaf pine realized the greatest and most consistent benefit from exposure to elevated CO2. This finding suggests that the ability of longleaf pine to compete with sand post oak, a common deciduous tree competitor, and wiregrass, the understory herbaceous species, in regenerating ecosystems may be significantly enhanced by rising atmospheric CO2 concentrations.

Late Holocene forest dynamics, volcanism, and climate change at Whitewing Mountain and San Joaquin Ridge, Mono County, Sierra Nevada, CA, USA
About this Resource: Deadwood tree stems scattered above treeline on tephra-covered slopes of Whitewing Mtn (3051 m) and San Joaquin Ridge (3122 m) show evidence of being killed in an eruption from adjacent Glass Creek Vent, Inyo Craters. Using tree-ring methods, we dated deadwood to AD 815-1350 and infer from death dates that the eruption occurred in late summer AD 1350. Based on wood anatomy, we identified deadwood species as Pinus albicaulis, P. monticola, P. lambertiana, P. contorta, P. jeffreyi, and Tsuga mertensiana. Only P. albicaulis grows at these elevations currently; P. lambertiana is not locally native. Using contemporary distributions of the species, we modeled paleoclimate during the time of sympatry to be significantly warmer (+3.2°C annual minimum temperature) and slightly drier (-24 mm annual precipitation) than present, resembling values projected for California in the next 70-100 yr.

Double sampling may improve the efficiency of litterfall estimates
About this Resource: The effort required for an extensive litterfall measurement campaign can be prohibitive. We propose a double sampling approach, in which a large set of traps is used in each stand to estimate total litterfall, and only a subset of these traps is sorted to the relevant components. We examine its feasibility using data from a regional litterfall study of eastern white pine (Pinus strobus L.), in which the variables of interest were biomass of foliar litterfall from pine and nitrogen content of foliar litterfall from all vegetation. Double sampling was more efficient than simple random sampling but only if every trap received a rapid presorting to remove twigs and cones. The optimal strategy when pine foliar litterfall biomass was the target variable was to conduct full sorting on 33% of the traps. When foliar litterfall N was the target, sorting only 20% of the traps was optimal. Holding time costs constant, the variance of estimated pine foliar litterfall biomass could be reduced by 18%, whereas that for foliar litterfall N could be reduced by 49%. Alternately, when variance was held constant, the time cost could be reduced by 17% for pine foliar litterfall biomass or 44% for foliar litterfall N.

Assessing the effects of vegetation types on carbon storage fifteen years after reforestation on a Chinese fir site
About this Resource: Forest ecosystems play a significant role in sequestering carbon (C) in biomass and soils. Plantations established in subtropical China since the 1980s, mainly of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) in monocultures, have proved to be major C sinks. However, information is lacking about whether mixing Chinese fir with broadleaved tree species will increase stand growth and C sequestration. We address this question by comparing a pure Chinese fir plantation and two mixed plantations established in 1990 at Huitong Experimental Station of Forest Ecology, Hunan Province, China. The mixed plantations include Chinese fir and either Kalopanax septemlobus (Thunb.) Koidz or Alnus cremastogyne Burk., planted at 4:1 ratios. We found that total C storage was 123, 131 and 142Mgha⁻¹ in the pure plantation, mixed plantation with K. septemlobus, and mixed plantation with A. cremastogyne, respectively. The mixed plantation with A. cremastogyne increased C storage in biomass relative to the pure Chinese fir plantation (P <0.05). No significant difference was detected between mixed plantations. Soil C storage did not differ among these plantations, ranging from 67.9±7.1 to 73.3±9.1Mgha⁻¹, which accounted for about 55% of the total C pools. Our results indicated that as the mixture of Chinese fir and broadleaved species will increase both biomass C and soil C storage over pure Chinese fir, and will do it, within 15 years of planting.

Swedish University of Agricultural Sciences, Department of Forest Resource Management and Geomatics
About this Resource: The Department of Forest Resource Management and Geomatics focuses on education and research in the fields of statistics, forest management planning, remote sensing, forest inventory, and environmental monitoring. Courses are offered in statistics, computer science, forest management planning, forest inventry, remote sensing, GIS, and environmental monitoring. There is information about the program on the site. There are links to the Swedish National Forest Inventory and the National Inventory of Landscapes in Sweden, which is a national program for the monitoring of biodiversity.

Effects of reduced-impact logging and forest physiognomy on bat populations of lowland Amazonian forest
About this Resource: 1. As human population size increases, demand for natural resources will increase. Logging pressure related to increasing demands continues to threaten remote areas of Amazonian forest. A harvest protocol is required to provide renewable timber resources that meet consumer needs while minimizing negative effects on biodiversity and ecosystem services. Reduced-impact logging (RIL) may be a viable option to achieve these goals. 2. Effects of RIL (18 m³ ha⁻¹) and forest physiognomy were assessed for populations of bats from Amazonian terra firme forest in Brazil at 20-42 months postharvest. 3. Based on 64 512 meter-hours of netting, 1468 bats were captured representing 47 species, 30 genera, four families and five feeding ensembles. Five species (one nectarivore and four frugivores) responded to management in a consistent manner: four were more abundant in logged forest and one was more abundant in undisturbed forest. Ten species (one nectarivore, two gleaning animalivores and seven frugivores) responded to forest physiognomy in a consistent manner: nine were more abundant in closed-canopy sites and one was more abundant in gaps. Three species (all frugivores) exhibited idiosyncratic responses to management that were contingent on physiognomy. 4. Using qualitative measures (changes in status from common to rare, or from present to absent), RIL elicited negative responses from 16 species, mostly rare taxa. After accounting for differences in total number of collected individuals, control forest harboured seven to 15 more rare species than did forest subjected to RIL. 5. Synthesis and applications. In the short term, RIL generally did not negatively affect populations of abundant bats. In contrast, reductions in abundance or local extirpation in response to RIL generally characterized uncommon or rare species. Arrangement of RIL sites in a matrix of undisturbed forest may allow source-sink dynamics to mitigate effects of RIL on rare or sensitive species and enhance sustainability at a regional scale.

Managing forest disturbances and community responses: Lessons from the Kenai Peninsula, Alaska.
About this Resource: Managing forest disturbances can be complicated by diverse human community responses. Interviews and quantitative analysis of mail surveys were used to assess risk perceptions and community actions in response to forest disturbance by spruce bark beetles. Despite high risk perception of immediate threats to personal safety and property, risk perceptions of broader threats to community and ecological well-being were found to be more likely to influence participation in community action. Results imply that increased dialogue between resource managers and local community residents contributes to broader risk assessment and prioritization of risk mitigation strategies. Identifying community risk perceptions, tapping into local capacities for action, and accepting controversy facilitate sound decisionmaking and give voice to local concerns regarding risk mitigation after forest disturbance.

British Columbia Forest Service Research Branch
About this Resource: The Home Page link for the Ministry of Forests (British Columbia, Canada). Features publications, software and project information on a variety of forestry and environmental topics: biometrics, climate, growth and yields, fire ecology, silviculture, stand management, wildlife habitat. Describes the Branch's mission and history. Offers a link into the Library.

Healthy Forests Initiative | USDA-FS
About this Resource: The Healthy Forests Initiative, enacted as a consequence of the Healthy Forests Restoration Act of 2003, is designed to improve the health of our nation's forests and rangelands. This website furnishes background on the Initiative; it also provides details of examples where improvements are being made. Documentation related to the science behind the Initiative is included; there are fact sheets available; along with guidance documents as to how the Initiative improves efforts related to work associated with endandgered species, environmental assessments and related endeavors. The website is also a source for news; it identifies accomplishments; is a source for communication materials and also links to additional sites related to the Initiative.

Regional Height-Diameter Equations for Major Tree Species of Southwest Oregon.
About this Resource: Selected tree height and diameter functions were evaluated for their predictive abilities for major tree species of southwest Oregon. Two sets of equations were evaluated. The first set included four base equations for estimating height as a function of individual tree diameter, and the remaining 16 equations enhanced the four base equations with alternative measures of stand density and relative position. The inclusion of the crown competition factor in larger trees (CCFL) and basal area (BA), which simultaneously indicates the relative position of a tree and stand density, into the base height-diameter equations increased the accuracy of prediction for all species. On the average, root mean square error values were reduced by 45 cm (15% improvement). On the basis of the residual plots and fit statistics, two equations are recommended for estimating tree heights for major tree species in southwest Oregon. The equation coefficients are documented for future use.

Using glomalin as an indicator for arbuscular mycorrhizal hyphal growth: an example from a tropical rain forest soil.
About this Resource: Glomalin concentrations of extra-radical arbuscular mycorrhizal (AM) hyphae were estimated by deploying hyphal in-growth cores containing glomalin-free sand in field soils in a tropical forest and in pot cultures. In field soils, glomalin was 0.044 +/- 0.013 microgram m(-1) hyphae. In pot cultures glomalin concentrations were lower (range 0.0068-0.036 microgram m(-1)), and varied significantly among species. Using this technique, preliminary estimates of extraradical AM hyphal production on Inceptisols were 1.91 Mg ha(-1)yr(-1) and on Oxisol were 1.47 Mg ha(-1) yr(-1), but they could range between 0.9-5.7 Mg ha(-1) yr(-1). These rates of hyphal production are approximately 10% (range 5-33%) of estimated above ground primary production of the forest.

Composition and carbon dynamics of forests in northeastern North America in a future, warmer world
About this Resource: Increasing temperatures, precipitation extremes, and other anthropogenic influences (pollutant deposition, increasing carbon dioxide) will influence future forest composition and productivity in the northeastern United States and eastern Canada. This synthesis of empirical and modeling studies includes tree DNA evidence suggesting tree migrations since the last glaciation were much slower, at least under postglacial conditions, than is needed to keep up with current and future climate warming. Exceedances of US and Canadian ozone air quality standards are apparent and offset CO2-induced gains in biomass and predispose trees to other stresses. The deposition of nitrogen and sulfate in the northeastern United States changes forest nutrient availability and retention, reduces reproductive success and frost hardiness, causes physical damage to leaf surfaces, and alters performance of forest pests and diseases. These interacting stresses may increase future tree declines and ecosystem disturbances during transition to a warmer climate. Recent modeling work predicts warmer climates will increase suitable habitat (not necessarily actual distribution) for most tree species in the northeastern United States. Species whose habitat is declining in the northeastern United States currently occur in Canadian forests and may expand northward with warming. Paleoecological studies suggest local factors may interact with, even overwhelm, climatic effects, causing lags and thresholds leading to sudden large shifts in vegetation.

Informed multi-objective decision-making in environmental management using Pareto optimality
About this Resource: 1. Effective decision-making in environmental management requires the consideration of multiple objectives that may conflict. Common optimization methods use weights on the multiple objectives to aggregate them into a single value, neglecting valuable insight into the relationships among the objectives in the management problem. 2. We present a multi-objective optimization procedure that approximates the non-dominated Pareto frontier without the use of weightings, allowing for visualization of the trade-offs among objectives. The non-dominated Pareto frontier is approximated by the simultaneous optimization of a vector objective function; two vector objective functions are defined as non-dominated if improvement with respect to one objective is at the detriment of another objective. 3. We demonstrate the method with a case study for the optimum distribution of forest fuels treatments that reduce the impact of fire on a forest. The multiple objectives are to protect habitat of an endangered species, protect late successional forest reserves and minimize the total area treated. In the comparison of three optimization searches, the number of non-dominated solutions increases with the dimensions of the objective space, but with only two objectives the search is ineffective in minimizing fire impact in the different landscape types. Key challenges include the extensive computation time required to approximate the non-dominated set, and reducing the number of solutions that are analysed in detail. 4. Synthesis and applications. The multi-objective optimization program presented can be adapted to other environmental management problems, and easily incorporates a wide range of quantifiable objectives. This tool provides decision-makers with a set of alternatives that estimates the full range of trade-offs among multiple objectives and provides a common ground from which dialogue can come to an informed compromise and decision in environmental management problems.

Canadian Forestry Links
About this Resource: This directory points to links related to Canadian forestry. Organizational links are identified by the following arrangements: government, universities, associations companies and forest publications. The topical indexes relate to: biodiversity, forest genetics, forest products, forest fires, forest management, silviculture, sustainable forestry, soils, insects and disease and geographical information systems.

Poplar plantation has the potential to alter the water balance in semiarid Inner Mongolia
About this Resource: Poplar plantation is the most dominant broadleaf forest type in northern China. Since the mid-1990s plantation was intensified to combat desertification along China's northwestern border, i.e., within Inner Mongolia (IM). This evoked much concern regarding the ecological and environmental effects on areas that naturally grow grass or shrub vegetation. To highlight potential consequences of large-scale poplar plantations on the water budget within semiarid IM, we compared the growing season water balance (evapotranspiration (ET) and precipitation (PPT)) of a 3-yr old poplar plantation (Kp₃) and a natural shrubland (Ks) in the Kubuqi Desert in western IM, and a 6-yr old poplar plantation (Bp₆) growing under sub-humid climate near Beijing. The results showed that, despite 33% lower PPT at Kp₃, ET was 2% higher at Kp₃ (228 mm) as compared with Ks (223 mm) in May-September 2006. The difference derived mainly from higher ET at the plantation during drier periods of the growing season, which also indicated that the poplars must have partly transpired groundwater. Estimated growing season ET at Bp6 was about 550 mm and more than 100% higher than at Kp₃. It is estimated that increases in leaf area index and net radiation at Kp₃ provide future potential for the poplars in Kubuqi to exceed the present ET and ET of the natural shrubland by 100-200%. These increases in ET are only possible through the permanent use of groundwater either directly by the trees or through increased irrigation. This may significantly change the water balance in the area (e.g., high ET at the cost of a reduction in the water table), which renders large-scale plantations a questionable tool in sustainable arid-land management.

Forest History Society, Environmental History Bibliography
About this Resource: The Environmental History Bibliography contains over 35,000 annotated citations to books, articles, and dissertations dealing with the utilization, management, and appreciation of forest-related resources. The Bibliography contains citations published from 1633 to the present and is updated quarterly.

Habitat classification modeling with incomplete data: pushing the habitat envelope
About this Resource: Habitat classification models (HCMs) are invaluable tools for species conservation, land-use planning, reserve design, and metapopulation assessments, particularly at broad spatial scales. However, species occurrence data are often lacking and typically limited to presence points at broad scales. This lack of absence data precludes the use of many statistical techniques for HCMs. One option is to generate pseudo-absence points so that the many available statistical modeling tools can be used. Traditional techniques generate pseudo-absence points at random across broadly defined species ranges, often failing to include biological knowledge concerning the species-habitat relationship. We incorporated biological knowledge of the species-habitat relationship into pseudo-absence points by creating habitat envelopes that constrain the region from which points were randomly selected. We define a habitat envelope as an ecological representation of a species, or species feature's (e.g., nest) observed distribution (i.e., realized niche) based on a single attribute, or the spatial intersection of multiple attributes. We created HCMs for Northern Goshawk (Accipiter gentilis atricapillus) nest habitat during the breeding season across Utah forests with extant nest presence points and ecologically based pseudo-absence points using logistic regression. Predictor variables were derived from 30-m USDA Landfire and 250-m Forest Inventory and Analysis (FIA) map products. These habitat-envelope-based models were then compared to null envelope models which use traditional practices for generating pseudo-absences. Models were assessed for fit and predictive capability using metrics such as kappa, threshold-independent receiver operating characteristic (ROC) plots, adjusted deviance, and cross-validation, and were also assessed for ecological relevance. For all cases, habitat envelope-based models outperformed null envelope models and were more ecologically relevant, suggesting that incorporating biological knowledge into pseudo-absence point generation is a powerful tool for species habitat assessments. Furthermore, given some a priori knowledge of the species-habitat relationship, ecologically based pseudo-absence points can be applied to any species, ecosystem, data resolution, and spatial extent.

Patterns and general characteristics of severe forest dieback from 1950 to 1995 in the northeastern United States.
About this Resource: US national and state forest insect and disease surveys provide plentiful information on forest dieback. These data, however, have not been quantified and analyzed systematically to address outstanding questions on the etiology of dieback. This study quantified long-term (1950-1995) trends in the severity of dieback on Acer saccharum Marsh., Fraxinus spp., Betula spp., and Picea rubens Sarg. in US northern hardwoods. A numeric index (0-10 scale) of the severity and extent of dieback was applied using key words frequently found in the surveys. The 18 episodes identified showed considerable variability among species at the local scale, yet systematic, repetitive patterns of dieback at the scale of the region and multidecadal time frame. Six dieback characteristics were evident: episodes showed abrupt onset and subsidence, endured 13.6 years on average, were cyclical, with a frequency of 22.3 years between recurrence, and averaged about two-thirds of maximum possible severity. In contrast to the perception that dieback is happenstance and chaotic, this study supports the hypothesis that, by addressing issues of spatial scale and long-term population dynamics, coherent, generic patterns emerge that are cyclic and predictable. Limitations and advantages of the approaches were discussed in terms of meeting needs of the US Forest Health Monitoring Program for innovative approaches to the analysis of the voluminous field data being assembled nationwide. By developing a quantitative database, environmental correlation and modeling of dieback now become possible.

Historical disturbance regimes as a reference for forest policy in a multiowner province: a simulation experiment
About this Resource: Using a landscape simulation model, we examined ecological and economic implications of forest policies designed to emulate the historical fire regime across the 2 x 10⁶ ha Oregon Coast Range. Simulated policies included two variants of the current policy and three policies reflecting aspects of the historical fire regime. Policy development was guided by the management intentions of four owner groups: forest industry, nonindustrial private, state, and federal. Fire severity was emulated with green-tree retention standards; fire frequency was emulated with annual harvestable area restrictions; and fire extent was emulated with harvest-unit size regulations. Simulated disturbance-based policies produced age-class distributions closer to the estimated historical range than those created by the current policy. Within 100 years, proportions of younger forests were within the historical range, while older forests moved closer to, but remained below, historical conditions. In the near term, disturbance-based policies produced annual harvest volumes 20%-60% lower than those produced by the current policy. However, relative costs of disturbance-based policies diminished over time. Our results suggest that if expediting a return to historical age-class distributions at a provincial-scale was a goal, then public lands would be needed to provide large patches of old forest. In addition, this experiment illustrated that distributing costs and benefits of conservation policies equitably across multiple private landowners is a significant challenge.

Overstory and understory development in thinned and underplanted Oregon Coast Range Douglas-fir stands
About this Resource: Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests managed for timber in western Oregon frequently lack structure and diversity associated with old-growth forests. We examined thinning effects on overstory and understory development for 8 years after treatment. Three 30- to 33-year-old Oregon Coast Range plantations were partitioned into four overstory treatments: unthinned (approximately 550 trees/ha) and lightly (approximately 250 trees/ha), moderately (approximately 150 trees/ha), and heavily (approximately 75 trees/ha) thinned. Within each overstory treatment, two understory treatments were established: underplanted with Douglas-fir and western hemlock (Tsuga heterophylla (Raf.) Sarg.) or not underplanted. Thinning increased overstory stem growth, crown expansion, and retained crown length. Thinned overstory canopies began to close rapidly the third year after thinning, decreasing % skylight by approximately 2%/year, whereas % skylight in unthinned stands increased slightly. All seedlings planted in unthinned stands died, whereas eighth year survival in thinned stands averaged 88%. Natural regeneration densities and distributions were highly variable. Understory shrub cover was reduced by harvesting disturbance but recovered by the fifth year. Thinning increased understory plant species diversity, and no shrub species were lost. Thinning to low densities and underplanting has the potential to accelerate development of multilayered stands characteristic of old-growth Douglas-fir forests.

Spatial complementarity of forests and farms: accounting for ecosystem services
About this Resource: Our article considers the economic contributions of forest ecosystem services, using a case study from Flores, Indonesia, in which forest protection in upstream watersheds stabilize soil and hydrological flows in downstream farms. We focus on the demand for a weak complement to the ecosystem services-farm labor-and account for spatial dependence due to economic interactions, ecosystem processes, and data integration. The estimated models have theoretically expected properties across eight different specifications. We find strong evidence that forest ecosystem services provide economically substantive benefits to local people and that these services would be substantially undervalued if spatial dependence is ignored.

Headwater riparian forest-floor invertebrate communities associated with alternative forest management practices
About this Resource: Headwater streams and their riparian zones are a common, yet poorly understood, component of Pacific Northwest, USA, landscapes. We describe the ecological importance of headwater stream riparian zones as habitat for forest-floor invertebrate communities and assess how alternative management strategies for riparian zones may impact these communities. We compared community composition of forest-floor invertebrates at increasing distances along trans-riparian (stream edge to upslope) transects in mature forests, clearcuts, and riparian buffers of 30-m width with upslope clearcuts. Invertebrates were collected using pitfall traps in five replicate blocks of three treatments each in the Willamette National Forest, Oregon, USA. We measured microclimate and microhabitat variables at pitfall locations. Despite strong elevation and block effects on community composition, community analyses revealed a distinct “riparian” invertebrate community within 1 m of the stream edge in mature forest treatments, which was strongly related to cool, humid microclimate conditions. Invertebrate community composition in buffer treatments was far more similar to that of mature forests than to clearcuts; a pattern mirrored by microclimate. These results suggest that, within our study sites, forest-floor invertebrate distributions are strongly associated with microclimate and that riparian buffers of 30-m width do provide habitat for many riparian and forest species. Riparian reserves may serve as effective forest refugia and/or dispersal corridors for invertebrates and other taxa, and their incorporation into watershed management plans likely will contribute to meeting persistence and connectivity objectives.

Variable-retention harvests in the Pacific Northwest: A review of short-term findings from the DEMO study
About this Resource: In the Pacific Northwest (PNW) region of the contiguous United States, retention of live (green) trees in harvest units is an integral part of forest management practices on federal lands, yet the ecological benefits that result from various levels or patterns of retained trees remain speculative. The Demonstration of Ecosystem Management Options (DEMO) study was established to address these informational gaps. The experimental design consists of six treatments, each 13ha in size, replicated at six locations (blocks) in western Washington and Oregon. Treatments represent strong contrasts in retention level (15-100% of original basal area) and pattern (trees dispersed vs. aggregated in 1-ha patches) in mature Douglas-fir (Pseudotsuga menziesii) forests. A wide variety of ecological responses and public perceptions of visual quality have been examined; this paper provides a comprehensive review of the short-term (1-7 years) results of these studies. Level of retention had a strong effect on many responses. At 15% retention, regardless of pattern, microclimate, ecological responses, and public perceptions of visual quality did not differ from those measured in the “clearcut” areas of aggregated treatments. In contrast to level of retention, pattern of retention had limited effect on most measures of biological response. Small changes within forest aggregates were balanced by large changes in adjacent harvested areas, thus on average, responses within aggregated treatments were comparable to those in dispersed treatments. Nevertheless, retaining trees in 1-ha aggregates provided several benefits over dispersed retention. Aggregates greatly reduced damage to and mortality of residual trees (particularly at lower levels of retention) and provided short-term refugia for forest organisms sensitive to disturbance or environmental stress (e.g., bryophytes and late-seral herbs). However, aggregates were susceptible to edge effects (e.g., elevated light and temperature), which may compromise their ability to serve as sources for recolonization of adjacent harvested areas. Collectively, our findings suggest that retention levels >15% are needed to effectively retain sensitive plants and animals, ameliorate harsh microclimatic conditions, and gain public acceptance of retention harvests in these forests. A combination of relatively large (>=1ha) aggregates and dispersed trees at levels considerably greater than current minimum standards in the PNW may be the most effective strategy for sustaining a broad array of forest values in managed stands.

Reconciling divergent interpretations of quaking aspen decline on the northern Colorado Front Range
About this Resource: Ecologists have debated over the past 65 years whether quaking aspen (Populus tremuloides Michx.) has or has not declined in abundance, vigor, or regeneration in western North America. Many studies have provided divergent interpretations of the condition of aspen forests, leading to difficulty in translating this ecological information into management recommendations. To reconcile these contrasting conclusions and to test the hypothesis that multiple types of aspen decline and persistence occur simultaneously on heterogeneous landscapes, we assessed 91 aspen stands across the northern Colorado Front Range to determine the range of ecological conditions that underlie aspen decline or persistence. Approximately 15% of aspen forest area in our sample exhibited dieback of mature stems coupled with a lack of young trees indicative of declining stands, most often at lower elevations where elk browsing is heavy and chronic, and where effects of fire exclusion have been most significant. However, 52% of the area sampled had multiple cohorts indicative of self-replacing or persistent stands. Conifer dominance was increasing in over 33% of all aspen forest area sampled, most often at high elevations among lodgepole pine (Pinus contorta var. latifolia Englem. ex Wats.) forests. Reconstructions of relative basal area and density of aspen and lodgepole pine in these stands suggest cyclical dominance of these species, where conifers gradually replace aspen over long fire intervals, and aspen vigorously re-establish following stand-replacing fires. The diversity of ecological contexts across the northern Colorado Front Range creates a variety of aspen dynamics leading to decline or persistence, and no single trend describes the general condition of aspen forests in appropriate detail for managers. Active management may be useful in preserving individual stands at fine scales, but management prescriptions should reflect specific drivers of decline in these stands.

Fine-scale variability in growth-climate relationships of Douglas-fir, North Cascade Range, Washington.
About this Resource: Information about the sensitivity to climate of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is valuable because it will allow forest managers to maximize growth, better understand how carbon sequestration may change over time, and better model and predict future ecosystem responses to climatic change. We examined the effects of climatic variability on the growth of Douglas-fir along an elevational gradient in the North Cascade Range, Washington (USA), at annual timescales during the 20th century. Multivariate analysis and correlation analysis were used to identify climate-growth relationships. Mid-elevation chronologies were negatively correlated with growing season maximum temperature and positively correlated with growing season precipitation. In contrast, high-elevation chronologies were positively correlated with annual temperatures and negatively correlated with previous-year winter Pacific Decadal Oscillation index. Projected increases in summer temperatures will likely cause greater soil moisture stress in many forested ecosystems. The potential of extended summer drought periods over decades may significantly alter spatial patterns of productivity, thus impacting carbon storage. It is likely that the productivity of Douglas-fir in the Cascade Range will decrease at sites with shallow, excessively drained soils, south- and west-facing aspects, and steep slopes and will increase at high-elevation sites.

Landscape assessment of tree communities in the northern karst region of Puerto Rico
About this Resource: The northern karst of Puerto Rico is a unique formation that contains one of the island's largest remaining forested tracts. The region is under ever-increasing human pressure, but large portions of it are being considered for conservation. Forest classification of the region is at a coarse scale, such that it is considered one vegetation type. We asked whether there were distinct tree assemblages which would necessitate targeted conservation strategies to ensure their protection. We examined tree species and communities across the region at three different major topographic positions along mogotes, or haystack-shaped hills. We found distinct tree communities on hilltops and valleys, with significantly more non-native species in valleys and significantly more endemic species on hilltops and hillsides. At a landscape level, we identified at least four different communities within each topographic position. Two mogote top communities were separated geographically (west and south) within the region, while two others co-occurred in the east-central part of the region. Mogote side and valley communities were less distinct geographically. Temperature, elevation, and precipitation were important variables in separating some communities, suggesting that abiotic stress may play an important role in the distribution of some species. In contrast, the lack of geographic separations of other communities suggested that variables such as soil conditions, land use and biotic interactions such as dispersal limitation may also be important. Conservation planning strategies should target the south, west, and east-central areas that harbor distinct mogote top plant communities to ensure protection of the widest range of tree species and communities in the karst region.

Diversity-invasibility across an experimental disturbance gradient in Appalachian forests
About this Resource: Research examining the relationship between community diversity and invasions by nonnative species has raised new questions about the theory and management of biological invasions. Ecological theory predicts, and small-scale experiments confirm, lower levels of nonnative species invasion into species-rich compared to species-poor communities, but observational studies across a wider range of scales often report positive relationships between native and nonnative species richness. This paradox has been attributed to the scale dependency of diversity-invasibility relationships and to differences between experimental and observational studies. Disturbance is widely recognized as an important factor determining invasibility of communities, but few studies have investigated the relative and interactive roles of diversity and disturbance on nonnative species invasion. Here, we report how the relationship between native and nonnative plant species richness responded to an experimentally applied disturbance gradient (from no disturbance up to clearcut) in oak-dominated forests. We consider whether results are consistent with various explanations of diversity-invasibility relationships including biotic resistance, resource availability, and the potential effects of scale (1 m2 to 2 ha). We found no correlation between native and nonnative species richness before disturbance except at the largest spatial scale, but a positive relationship after disturbance across scales and levels of disturbance. Post-disturbance richness of both native and nonnative species was positively correlated with disturbance intensity and with variability of residual basal area of trees. These results suggest that more nonnative plants may invade species-rich communities compared to species-poor communities following disturbance.

Trembling aspen response to a mixed-severity wildfire in the Black Hills, South Dakota, USA.
About this Resource: Trembling aspen (Populus tremuloides Michx.) regeneration dynamics including sprout production, growth, and clone size were measured to determine the effects of fire on small aspen clone persistence following a mixed-severity wildfire in the Black Hills, South Dakota. Four years postfire, 10 small, isolated aspen clones per low and high fire severity classes were compared with 10 unburned clones. Regardless of severity, fire did not cause an increase in the area occupied by individual aspen clones. Clones affected by high severity fire had the greatest suckering response producing an average of 31 930 sprouts.ha(-1); more than double the sprout density in unburned clones and 67% greater than the sprout density in clones affected by low severity fire. Sprout growth in high severity clones was 135% and 60% greater than sprout growth in unburned and low severity clones. The succession of these clones to more shade-tolerant ponderosa pine was delayed in clones affected by high severity fire as high severity fire caused significant pine mortality within and surrounding the clone, whereas, without further disturbance, pine encroachment and dominance will likely continue in clones affected by low severity fire.

Forest dynamics in Oregon landscapes: Evaluation and application of an individual-based model
About this Resource: The FORCLIM model of forest dynamics was tested against field survey data for its ability to simulate basal area and composition of old forests across broad climatic gradients in western Oregon, USA. The model was also tested for its ability to capture successional trends in ecoregions of the west Cascade Range. It was then applied to simulate present and future (1990-2050) forest landscape dynamics of a watershed in the west Cascades. Various regimes of climate change and harvesting in the watershed were considered in the landscape application. The model was able to capture much of the variation in forest basal area and composition in western Oregon even though temperature and precipitation were the only inputs that were varied among simulated sites. The measured decline in total basal area from tall coastal forests eastward to interior steppe was matched by simulations. Changes in simulated forest dominants also approximated those in the actual data. Simulated abundances of a few minor species did not match actual abundances, however. Subsequent projections of climate change and harvest effects in a west Cascades landscape indicated no change in forest dominance as of 2050. Yet, climate-driven shifts in the distributions of some species were projected. The simulation of both stand-replacing and partial-stand disturbances across western Oregon improved agreement between simulated and actual data. Simulations with fire as an agent of partial disturbance suggested that frequent fires of low severity can alter forest composition and structure as much or more than severe fires at historic frequencies.