Showing papers in "Canadian Journal of Forest Research in 2010"
TL;DR: The resilience and vulnerability of permafrost to climate change depends on complex interactions among topography, water, soil, vegetation, and snow, which allow permaf frost to persist at mean annua...
Abstract: The resilience and vulnerability of permafrost to climate change depends on complex interactions among topography, water, soil, vegetation, and snow, which allow permafrost to persist at mean annua...
480 citations
TL;DR: A synthesis was carried out to examine Alaska’s boreal forest fire regime and found that during the 2000s, an average of 767 000 ha·year–1 burned, 50% higher than in any previous decade since the 1940s.
Abstract: A synthesis was carried out to examine Alaska’s boreal forest fire regime. During the 2000s, an average of 767 000 ha·year–1 burned, 50% higher than in any previous decade since the 1940s. Over the...
344 citations
TL;DR: In the boreal forests of interior Alaska, feedbacks that link forest soils, fire characteristics, and plant traits have supported stable cycles of forest succession for the past 6000 years, but the loss of resilience in individual stands may foster resilience at the landscape scale.
Abstract: In the boreal forests of interior Alaska, feedbacks that link forest soils, fire characteristics, and plant traits have supported stable cycles of forest succession for the past 6000 years. This high resilience of forest stands to fire disturbance is supported by two interrelated feedback cycles: (i) interactions among disturbance regime and plant-soil-microbial feed- backs that regulate soil organic layer thickness and the cycling of energy and materials, and (ii) interactions among soil conditions, plant regeneration traits, and plant effects on the environment that maintain stable cycles of forest community composition. Unusual fire events can disrupt these cycles and trigger a regime shift of forest stands from one stability do- main to another (e.g., from conifer to deciduous forest dominance). This may lead to abrupt shifts in forest cover in re- sponse to changing climate and fire regime, particularly at sites with intermediate levels of moisture availability where stand-scale feedback cycles are only weakly constrained by environmental conditions. However, the loss of resilience in individual stands may foster resilience at the landscape scale, if changes in the landscape configuration of forest cover types feedback to stabilize regional patterns of fire behavior and climate conditions. Resume´ : Dans la foret boreale de l'interieur de l'Alaska, les retroactions qui relient les sols forestiers, les caracteristiques des incendies et celles de la vegetation ont assurele maintien des cycles de succession forestiere pendant les 6000 dernie `- res annees. Cette grande resilience des peuplements forestiers face aux perturbations causees par le feu est le resultat de deux cycles interreliesd e retroactions : (i) les interactions entre le regime de perturbations et les retroactions entre les plantes, le sol et les microbes qui controlent l'epaisseur de l'horizon organique du sol et le recyclage de l'energie et des materiaux et (ii) les interactions entre les conditions du sol, les caracteristiques de la regeneration des plantes et les effets des plantes sur l'environnement qui maintiennent la stabilitedes cycles de composition des communautes forestieres. Les incendies inhabituels peuvent perturber ces cycles et declencher un changement de regime des peuplements forestiers d'un domaine de stabiliteaun autre (p. ex., d'une foret dominee par des coniferes aune foret dominee par des feuillus). Cela peut entraoˆner des changements abrupts dans le couvert forestier en reponse aux changements climatiques et a la modifica- tion du regime de feux, particulierement dans les stations avec un niveau intermediaire de disponibiliteen eau oules cy- cles de retroaction a l'echelle du peuplement sont assujettis seulement faiblement aux conditions environnementales. Cependant, la perte de resilience de peuplements particuliers peut favoriser la resilience a l'echelle du paysage si les chan- gements dans la configuration des types de couvert forestier al'echelle du paysage ont un effet de retroaction qui stabilise les patrons regionaux du comportement du feu et des conditions climatiques. (Traduit par la Redaction)
329 citations
TL;DR: The longleaf pine (Pinus palustris mill) forest ecosystems of the US southeastern Coastal Plain, among the most biologically diverse ecosystems in North America, originally covered over 24 × 106 h...
Abstract: The longleaf pine (Pinus palustris Mill.) forest ecosystems of the US southeastern Coastal Plain, among the most biologically diverse ecosystems in North America, originally covered over 24 × 106 h...
191 citations
TL;DR: Forest structure, as measured by the physical arrangement of trees and their crowns, is a fundamental attribute of forest ecosystems that changes as forests progress through a series of stages as mentioned in this paper.
Abstract: Forest structure, as measured by the physical arrangement of trees and their crowns, is a fundamental attribute of forest ecosystems that changes as forests progress through suc;cessional stages. W...
160 citations
TL;DR: In this article, the authors consider the mode of tree competition, which can be size-asymmetric when growth is limited by light or size symmetric when belowground resources are sca...
Abstract: Current individual tree growth models rarely consider the mode of tree competition, which can be size-asymmetric when growth is limited by light or size-symmetric when belowground resources are sca...
154 citations
TL;DR: The resilience of Alaska’s boreal forest system to rapid climatic change is assessed, including reduced effects of upland permafrost on regional hydrology, expansion of boreal Forest into tundra, and amplification of climate warming because of reduced albedo ( shorter winter season) and carbon release from wildfires.
Abstract: This paper assesses the resilience of Alaska’s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth of dominant tree species, plant disease and insect out...
153 citations
TL;DR: In this paper, the role of moss in ecosystem succession, productivity, and decomposition was examined in the boreal forests of Alaska, where moss abundance showed a unimodal distribution with time since fire.
Abstract: Shifts in moss communities may affect the resilience of boreal ecosystems to a changing climate because of the role of moss species in regulating soil climate and biogeochemical cycling. Here, we use long-term data analysis and liter- ature synthesis to examine the role of moss in ecosystem succession, productivity, and decomposition. In Alaskan forests, moss abundance showed a unimodal distribution with time since fire, peaking 30-70 years post-fire. We found no evi- dence of mosses compensating for low vascular productivity in low-fertility sites at large scales, although a trade-off be- tween moss and vascular productivity was evident in intermediate-productivity sites. Mosses contributed 48% and 20% of wetland and upland productivity, respectively, but produced tissue that decomposed more slowly than both nonwoody and woody vascular tissues. Increasing fire frequency in Alaska is likely to favor feather moss proliferation and decrease Sphagnum abundance, which will reduce soil moisture retention and decrease peat accumulation, likely leading to deeper burning during wildfire and accelerated permafrost thaw. The roles of moss traits in regulating key aspects of boreal per- formance (ecosystem N supply, C sequestration, permafrost stability, and fire severity) represent critical areas for under- standing the resilience of Alaska's boreal forest region under changing climate and disturbance regimes. Resume´ : Des changements dans les communautes de mousses peuvent alterer la resistance des ecosystemes boreaux aux changements climatiques a cause du role des especes de mousses dans la regulation du pedoclimat et le recyclage biogeo- chimique. Dans cette etude, nous avons eu recours al'analyse de donnees a long terme et a une synthese de la litterature pour etudier le role des mousses dans la succession, la productiviteet la decomposition dans les ecosystemes. Dans les fo- rets de l'Alaska, l'abondance des mousses a une distribution unimodale dans le temps avec un maximum qui survient 30- 70 ans apres un feu. Nous n'avons pas trouved'indice agrande echelle demontrant que les mousses compensent la faible productivitedes plantes vasculaires dans les stations afaible productivite ´. Par contre, un compromis entre la productivite ´
146 citations
TL;DR: Based on individual tree damage data dating back to the gale "Lothar" (winter 1999) in Baden-Wurttemberg, Germany, a statistical model was developed to estimate the risk of storm damage for individ...
Abstract: Based on individual tree damage data dating back to the gale “Lothar” (winter 1999) in Baden-Wurttemberg, Germany, a statistical model was developed to estimate the risk of storm damage for individ...
123 citations
TL;DR: It is widely accepted that N limits primary production in temperate forests, although colimitation by N and P has also been suggested, and on some soils, Ca and base cations are in short supply.
Abstract: It is widely accepted that N limits primary production in temperate forests, although colimitation by N and P has also been suggested, and on some soils, Ca and base cations are in short supply. I ...
112 citations
TL;DR: In this paper, the authors evaluated k-nearest neighbor imputation models incorporating LiDAR data to predict tree-level inventory data (individual tree height, diameter at breast height, and species) across a 12,100-ha study area in northeastern Oregon, USA.
Abstract: Sustainable forest management requires timely, detailed forest inventory data across large areas, which is difficult to obtain via traditional forest inventory techniques. This study evaluated k-nearest neighbor imputation models incorporating LiDAR data to predict tree-level inventory data (individual tree height, diameter at breast height, and species) across a 12 100 ha study area in northeastern Oregon, USA. The primary objective was to provide spatially explicit data to parameterize the Forest Vegetation Simulator, a tree-level forest growth model. The final imputation model utilized LiDAR-derived height measurements and topographic variables to spatially predict tree-level forest inventory data. When compared with an independent data set, the accuracy of forest inventory metrics was high; the root mean square difference of imputed basal area and stem volume estimates were 5 m2·ha–1 and 16 m3·ha–1, respectively. However, the error of imputed forest inventory metrics incorporating small trees (e.g., q...
TL;DR: In this paper, regression analysis was applied to quantify the relationship between the late summer water table depth and tree stand volume, mean monthly summertime precipi- tation (Ps), drainage network condition, and latitude.
Abstract: Ditch networks in drained peatland forests are maintained regularly to prevent water table rise and subsequent decrease in tree growth. The growing tree stand itself affects the level of water table through evapotranspiration, the mag- nitude of which is closely related to the living stand volume. In this study, regression analysis was applied to quantify the relationship between the late summer water table depth (DWT) and tree stand volume, mean monthly summertime precipi- tation (Ps), drainage network condition, and latitude. The analysis was based on several large data sets from southern to northern Finland, including concurrent measurements of stand volume and summer water table depth. The identified model demonstrated a nonlinear effect of stand volume on DWT, a linear effect of Ps on DWT, and an interactive effect of both stand volume and Ps. Latitude and ditch depth showed only marginal influence on DWT. A separate analysis indicated that an increase of 10 m 3 � ha -1 in stand volume corresponded with a drop of 1 cm in water table level during the growing sea- son. In a subsample of the data, high bulk density peat showed deeper DWT than peat with low bulk density at the same stand volume.
TL;DR: In this paper, the effects of recent trends and future climate change projections on the boreal eco- system of interior Alaska and relate changes in ecosystem services to Athabascan subsistence are described.
Abstract: Subsistence harvesting and wild food production by Athabascan peoples is part of an integrated social-ecologi- cal system of interior Alaska. We describe effects of recent trends and future climate change projections on the boreal eco- system of interior Alaska and relate changes in ecosystem services to Athabascan subsistence. We focus primarily on moose, a keystone terrestrial subsistence resource of villages in that region. Although recent climate change has affected the boreal forest, moose, and Athabascan moose harvesting, a high dependence by village households on moose persists. An historical account of 20th century socioeconomic changes demonstrates that the vulnerability of Athabascan subsistence systems to climatic change has in some respects increased while at the same time has improved aspects of village resil- ience. In the face of future climate and socioeconomic changes, communities have limited but potentially effective mitiga- tion and adaptation opportunities. The extent to which residents can realize those opportunities depends on the responsiveness of formal and informal institutions to local needs. For example, increases in Alaska's urban population coupled with climate-induced habitat shifts may increase hunting conflicts in low-moose years. This problem could be mi- tigated through adaptive co-management strategies that project future moose densities and redirect urban hunters to areas of lower conflict. Resume´ : La recolte de subsistance et la production de nourriture sauvage par le peuple athapascan fait partie d'un sys- teme socio-ecologique integrede l'interieur de l'Alaska. Nous decrivons les effets des tendances recentes et des projec- tions de changements climatiques a venir sur l'ecosysteme boreal de l'interieur de l'Alaska et nous relions les changements dans les services de l'ecosysteme ala subsistance des athapascans. Nous mettons principalement l'accent sur l'orignal, une ressource terrestre de subsistance cledes villages de cette region. Bien que les changements climatiques re ´- cents aient affectela foret boreale, l'orignal et la recolte d'orignaux par les athapascans, les menages des villages conti- nuent adependre fortement de l'orignal. Un compte rendu historique des changements socioeconomiques survenus au 20 e siecle demontre que la vulnerabilitedes systemes de subsistances des athapascans aux changements climatiques a acer- tains egards augmentealors que des aspects de la resilience des villages se sont ameliores durant la meme periode. Face aux changements climatiques et socioeconomiques a venir, les communautes ont des possibilites d'adaptation et d'atte ´- nuation limitees mais potentiellement efficaces. Dans quelle mesure les residants peuvent concretiser ces possibilitesd e´- pend de la capacitede reaction des institutions formelles et informelles aux besoins locaux. Par exemples, des augmentations de la population urbaine de l'Alaska couplees a des changements d'habitat induits par le climat peuvent augmenter les conflits de chasse les annees durant lesquelles l'orignal est peu abondant. On pourrait attenuer ce probleme par des strategies de cogestion adaptative qui predisent la densitedes orignaux et redirigent les chasseurs urbains vers des zones moins conflictuelles. (Traduit par la Redaction)
TL;DR: In this paper, the authors evaluated fuel treatments in dry forests and found that fuel treatments are effective in reducing fuel accumulations in wildfire fires, but there have been few opportunities to evaluate treatment efficacy in wildfires.
Abstract: To address hazardous fuel accumulations, many fuel treatments are being implemented in dry forests, but there have been few opportunities to evaluate treatment efficacy in wildfires. We documented ...
TL;DR: In this paper, LiDAR measurements of canopy structure can be used to classify forest stands into structural stages to study spatial patterns of canopy structures, identify habitat, or plan management actions.
Abstract: LiDAR measurements of canopy structure can be used to classify forest stands into structural stages to study spatial patterns of canopy structure, identify habitat, or plan management actions. A key assumption in this process is that differences in canopy structure based on forest age and elevation are consistent with predictions from models of stand de- velopment. Three LiDAR metrics (95th percentile height, rumple, and canopy density) were computed for 59 secondary and 35 primary forest plots in the Pacific Northwest, USA. Hierarchical clustering identified two precanopy closure classes, two low-complexity postcanopy closure classes, and four high-complexity postcanopy closure classes. Forest de- velopment models suggest that secondary plots should be characterized by low-complexity classes and primary plots char- acterized by high-complexity classes. While the most and least complex classes largely confirmed this relationship, intermediate-complexity classes were unexpectedly composed of both secondary and primary forest types. Complexity classes were not associated with elevation, except that primary Tsuga mertensiana (Bong.) Carriere (mountain hemlock) plots were complex. These results suggest that canopy structure does not develop in a linear fashion and emphasize the im- portance of measuring structural conditions rather than relying on development models to estimate structural complexity across forested landscapes.
TL;DR: In this paper, the authors investigated the relative contribution of two tree-driven mechanisms, litter mixing and litter quality, to decomposition rate. But the authors focused on the decomposition of trees.
Abstract: Litter quality is often considered the main driver of decomposition rate. The objective of this study was to investigate the relative contribution of two other tree-driven mechanisms, litter mixing...
TL;DR: It was found that soil horizon was the factor by which fungal communities were most strongly structured and that pre- dictable turnover in upland fungal species occurred through succession, and the capacity of individual taxa in these hyperdiverse communities to respond strongly to resource inputs and changes in other abiotic environmental parameters such as temperature.
Abstract: This paper outlines molecular analyses of soil fungi within the Bonanza Creek Long Term Ecological Research program. We examined community structure in three studies in mixed upland, black spruce (Picea mariana (Mill.) BSP), and white spruce (Picea glauca (Moench) Voss) forests and examined taxa involved in cellulose degradation at one upland site. We found that soil horizon was the factor by which fungal communities were most strongly structured and that pre- dictable turnover in upland fungal species occurred through succession. Communities from consecutive summers were not significantly different, indicating that interannual variation was small in relation to differences between forest types and soil horizons, yet the community at a seasonal study site underwent significant changes within a year. In each study, my- corrhizal fungi dominated the community. Fungi rather than bacteria appeared to dominate ( 13 C)cellulose degradation, with strongest growth in taxa that were not dominant members of the untreated community, including members of the ge- nus Sebacina. Overall, our results point to considerable interannual resilience juxtaposed with narrow niche partitioning and the capacity of individual taxa in these hyperdiverse communities to respond strongly to resource inputs and changes in other abiotic environmental parameters such as temperature. Our data double the cumulative total of fungal sequences in GenBank and together achieve a better picture of fungal communities here than for any other ecosystem on earth at this time. Resume´ : Cet article decrit les analyses moleculaires effectuees sur les champignons du sol dans le cadre du programme de recherche a long terme en ecologie de Bonanza Creek. Nous avons etudiela structure des communautes par le biais de trois etudes portant sur des forets mixtes en milieu sec, d'epinette noire (Picea mariana (Mill.) BSP) et d'epinette blanche (Picea glauca (Moench) Voss) et nous avons etudieles taxons impliques dans la degradation de la cellulose dans une sta- tion seche. Nous avons trouveque l'horizon du sol etait le facteur preponderant dans la structuration des communautes fongiques et que le renouvellement previsible des especes fongiques en milieu sec se produisait par l'entremise de la suc- cession. Les communautes presentes d'un eteal'autre n'etaient pas significativement differentes indiquant que la variation interannuelle etait faible comparativement aux differences entre les types de foret et les horizons du sol. Par contre, la communautepresente sur le site d'une etude saisonniere a subi des changements significatifs a l'interieur d'une annee. Dans chaque etude, les champignons mycorhiziens dominaient la communaute ´. Les champignons plutot que les bacteries semblaient dominer la degradation de la ( 13 C)cellulose; la plus forte croissance a eteobservee parmi les taxons qui n'etaient pas des membres dominants de la communautenon traitee, incluant des membres du genre Sebacina. Globale- ment, nos resultats font ressortir la grande resilience interannuelle juxtaposeead'etroites niches ecologiques ainsi que la capacitede taxons particuliers dans ces communautes hyper diversifiees de reagir fortement aux apports de ressources et a la variation d'autres parametres environnementaux. Nos donnees viennent doubler le total cumulatif de sequences fongi- ques dans GenBank et ensemble donnent ace jour une meilleure image des communautes fongiques ici que dans n'im- porte quel autre ecosysteme ailleurs dans le monde. (Traduit par la Redaction)
TL;DR: Sirex noctilio Fabricius has a long history as an invasive insect species in pine plantations throughout the Southern Hemisphere and has been recently discovered in North America, where it is uncertain how this insect will behave in pine ecosystems.
Abstract: Sirex noctilio Fabricius has a long history as an invasive insect species in pine plantations throughout the Southern Hemisphere and has been recently discovered in North America, where it is uncertain how this insect will behave in pine ecosystems. To assess the impact and attack behavior of S. noctilio, forest surveys and measurements from attacked and unattacked trees were taken in nine Pinus resinosa Ait. and Pinus sylvestris L. plantations in New York, USA, and Ontario, Canada. There was a trend of S. noctilio attacking suppressed trees with smaller live crowns and reduced growth. Some S. noctilio attacks were also found in dominant crown classes but at a lower rate than overtopped or intermediate classes. Sirex noctilio appeared to have more of an impact in P. sylvestris forests, as they attacked more stems (9%–18%) and higher basal area (1.6–5.5 m2/ha) than P. resinosa stands (3%–8% of stems and 0.4–2.4 m2/ha). Dead trees with signs of Siricidae and dead from other causes were also quantified, and ...
TL;DR: In this paper, the relationship between stand age and either complexity or carbon storage and sequestration, especially trade-offs between the two, are not well characterized, and they quantified these relationships in clearcut-origin, unmanaged pine and aspen chronosequences ranging from 130 years in northern Minnesota.
Abstract: Forest managers are seeking strategies to create stands that can adapt to new climatic conditions and simultaneously help mitigate increases in atmospheric CO2. Adaptation strategies often focus on enhancing resilience by maximizing forest complexity in terms of species composition and size structure, while mitigation involves sustaining carbon storage and sequestration. Altered stand age is a fundamental consequence of forest management, and stand age is a powerful predictor of ecosystem structure and function in even-aged stands. However, the relationship between stand age and either complexity or carbon storage and sequestration, especially trade-offs between the two, are not well characterized. We quantified these relationships in clearcut-origin, unmanaged pine and aspen chronosequences ranging from 130 years in northern Minnesota. Complexity generally increased with age, although compositional complexity changed more over time in aspen forests and structural complexity changed more over time in pine stands. Although individual carbon pools displayed various relationships with stand age, total carbon storage increased with age, whereas carbon sequestration, inferred from changes in storage, decreased sharply with age. These results illustrate the carbon and complexity consequences of varying forest harvest rotation length to favor younger or older forests and provide insight into trade-offs between these potentially conflicting management objectives.
TL;DR: Wood density, radial cell diameter, cell wall thickness, and specific fibre surface were highly heritable, indicating that significant genetic gains could be expected in tree improvement programs, although cambial age at selection may stro...
Abstract: We investigated the genetic control of wood properties as a function of cambial age to enable improvement of juvenile wood attributes in white spruce (Picea glauca (Moench) Voss). Increment cores w...
TL;DR: The relative importance of density, acoustic velocity, and microfibril angle (MFA) for the prediction of stiffness and strength has not been well established for Douglas-fir (Pseudotsug... as discussed by the authors.
Abstract: The relative importance of density, acoustic velocity, and microfibril angle (MFA) for the prediction of stiffness (MOE) and strength (MOR) has not been well established for Douglas-fir (Pseudotsug...
TL;DR: Empirical models for predicting the production of wild mushrooms in pine forests in the South-Central Pyrenees using forest stand and site characteristics as predictors are developed.
Abstract: Multiple-use forestry requires comprehensive planning to maximize the utilization and sustainability of many forest resources whose growth and productivity are interconnected Forest fungi represen
TL;DR: In this article, fire suppression has facilitated the spread of red maple (Acer rubrum L.), a fire-sensitive, yet highly adaptable species, in historically oak-dominated forests of the eastern United States.
Abstract: Fire suppression has facilitated the spread of red maple (Acer rubrum L.), a fire-sensitive, yet highly adaptable species, in historically oak-dominated forests of the eastern United States. Here, ...
TL;DR: Aspects of the tree mortality regime were characterized for old-growth conifer forests in Mount Rainier National Park, Washington, USA, using individual tree records from a network of permanent forest research plots, consistent with a predisposing role of decay fungi in trees that die due to mechanical damage.
Abstract: Aspects of the tree mortality regime were characterized for old-growth conifer forests in Mount Rainier National Park, Washington, USA, using individual tree (stems ≥5 cm diameter at breast height ...
TL;DR: In this paper, the authors used the ecosystem demography model in conjunction with a stochastic model of HWA spread to predict the impact of the HWA infestation on the current and future forest composition, structure, and carbon dynamics in the eastern United States.
Abstract: The hemlock woolly adelgid (HWA; Adelges tsugae Annand) is an introduced insect pest that threatens to decimate eastern hemlock (Tsuga canadensis (L.) Carriere) populations. In this study, we used the ecosystem demography model in conjunction with a stochastic model of HWA spread to predict the impact of HWA infestation on the current and future forest composition, structure, and carbon (C) dynamics in the eastern United States. The spread model predicted that on average the hemlock stands south and east of the Great Lakes would be infested by 2015, southern Michigan would be reached by 2020, and northeastern Minnesota by 2030. For the period 2000–2040, the ecosystem demography model predicted a mean reduction of 0.011 Pg C·year–1 (Pg C = 1015 g C), an 8% decrease, in the uptake of carbon from eastern United States forests as a result of HWA-caused mortality, followed by an increased uptake of 0.015 Pg C·year–1 (a 12% increase) in the period 2040–2100, as the area recovers from the loss of hemlock. Overal...
TL;DR: This paper integrates dendrochronological, demographic, and experimental perspectives to improve understanding of the response of white spruce tree growth to climatic change.
Abstract: This paper integrates dendrochronological, demographic, and experimental perspectives to improve understanding of the response of white spruce (Picea glauca (Moench) Voss) tree growth to climatic v...
TL;DR: The fruit body inventory underestimated fungal diversity in comparison with the culture-free denaturing gradient gel electrophoresis analysis that also detected inconspicuous but important species inhabiting decaying wood.
Abstract: We investigated the fungal communities inhabiting decaying logs in a seminatural boreal forest stand in relation to host tree species, stage of decay, density, diameter, moisture, C to N ratio, Klason lignin content, and water- and etha- nol-soluble extractives. Communities were profiled using denaturing gradient gel electrophoresis fingerprinting of the rDNA ITS1 region coupled with sequencing of fungal DNA extracted directly from the wood. In addition, polypore fruit bodies were inventoried. Logs from different tree species had different fungal communities and different physicochemical properties (e.g., C to N ratio, density, ethanol extractives, and diameter). Ascomycetes comprised a larger portion of com- munities inhabiting deciduous birch (Betula spp.) and European aspen (Populus tremula L.) logs compared with those liv- ing on coniferous Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.). A relationship between mycelial community structure and density of decaying spruce logs suggested a succession of fungi with mass loss of wood. The fruit body inventory underestimated fungal diversity in comparison with the culture-free denaturing gradient gel electrophoresis analysis that also detected inconspicuous but important species inhabiting decaying wood. Resume´ : Nous avons etudieles communautes de champignons lignicoles dans les billes en decomposition dans un peu- plement forestier boreal semi-naturel en relation avec l'espece d'arbre hote, le stade de decomposition, la densite ´, le dia- metre, l'humidite ´, le rapport C aN, le contenu en lignine Klaxon ainsi que les produits d'extraction solubles dans l'eau et solubles dans l'ethanol. Le profilage des communautesaeteeffectueal'aide d'une technique d'empreinte genomique de la region ITS1 de l'ADNr par electrophorese en gel de gradient denaturant coupleea u sequencage de l'ADN fongique ex- trait directement du bois. De plus, les fructifications des polypores ont eteinventoriees. Les billes de differentes especes d'arbres contenaient differentes communautes fongiques et avaient differentes proprietes physico-chimiques (p. ex. le rap- port C aN, la densite ´, les produits d'extraction a l'ethanol et le diametre). Les ascomycetes constituaient une plus grande proportion des communautes lignicoles dans les billes des essences feuillues comme le bouleau (Betula spp.) et le peuplier europeen (Populus tremula L.) comparativement aux communautes lignicoles des essences resineuses comme l'epicea commun (Picea abies (L.) Karst.) et le pin sylvestre (Pinus sylvestris L.). Une relation entre la structure des communautes myceliennes et la densitedes billes d'epiceae n decomposition indiquait qu'il y avait une succession de champignons en lien avec la perte de masse du bois. L'inventaire des fructifications sous-estimait la diversitefongique comparativement a ` l'analyse par electrophorese en gel de gradient denaturant qui ne necessitait pas de mise en culture et qui detectait aussi les especes lignicoles dans le bois en decomposition qui, quoiqu'importantes, passent inapercues. (Traduit par la Redaction)
TL;DR: The results show that spatial aggregation is a dominant pattern of species in the Changbaishan temperate forests, however, the percentage of significantly aggregated species decreases with spatial scale, especially for rare species.
Abstract: Studying spatial distributions of species can provide important insights into processes and mechanisms that maintain species richness. We used the relative neighborhood density Ω based on the avera...
TL;DR: In this paper, the development of spatial surfaces describing variation in productivity across broad landscapes at a fine resolution would be of considerable use to forest managers as decision support tools to optimise forest management.
Abstract: Development of spatial surfaces describing variation in productivity across broad landscapes at a fine resolution would be of considerable use to forest managers as decision support tools to optimi...
TL;DR: The modeled effects of constructed defensible fuel profile zones and group se- lection treatments on crown fire potential, flame length, and conditional burn probabilities across 11 land allocation types for an 18 600 ha study area within the northern Sierra Nevada, California are reported.
Abstract: Across the western United States, decades of fire exclusion combined with past management history have con- tributed to the current condition of extensive areas of high-density, shade-tolerant coniferous stands that are increasingly prone to high-severity fires. Here, we report the modeled effects of constructed defensible fuel profile zones and group se- lection treatments on crown fire potential, flame length, and conditional burn probabilities across 11 land allocation types for an 18 600 ha study area within the northern Sierra Nevada, California. Fire modeling was completed using FlamMap and FARSITE based on landscape files developed with high-resolution aerial (IKONOS) imagery, ground-based plot data, and integrated data from ARCFUELS and the Forest Vegetation Simulator. Under modeled 97th percentile weather condi- tions, average conditional burn probability was reduced between pre- and post-treatment landscapes. A more detailed simu- lation of a hypothetical fire burning under fairly severe fire weather, or ''problem fire'', revealed a 39% reduction in final fire size for the treated landscape relative to the pre-treatment condition. To modify fire behavior at a landscape level, a combination of fuel treatment strategies that address topographic location, land use allocations, vegetation types, and fire regimes is needed. Resume´ : Partout dans l'ouest des Etats-Unis, des decennies d'exclusion du feu combinee aux pratiques d'amenagement passees ont contribuea la situation actuelle caracterisee par de vastes superficies de peuplements de coniferes tolerants a l'ombre qui sont de plus en plus sujets ades feux de severiteelevee. Ici, nous rapportons les effets de la construction de coupe-feu ombrages et de traitements de jardinage par groupe sur le potentiel de feu de cime, la longueur de flamme et les probabilites de brulage conditionnel parmi 11 types d'affectation des terres dans une aire d'etude de 18 600 ha situee dans la partie septentrionale de la Sierra Nevada, en Californie. La modelisation du feu a eterealiseeal'aide de FlamMap et de FARSITE sur la base de fichiers de paysage elaboresapartir de l'imagerie aerienne (IKONOS) a haute resolution, de donnees terrain provenant de placettes echantillons et de donnees integrees provenant de ARCFUELS et du Simulateur de vegetation forestiere. Sur la base de conditions meteorologiques modelisees au 97 e percentile, la probabilitemoyenne de brulage conditionnel etait reduite en comparant les paysages pre ´- et post-traitement. Une simulation plus detaillee d'un feu hypothetique brulant dans des conditions meteorologiques assez severes, ou un feu problematique, a reveleque la di- mension finale du feu etait reduite de 39 % dans le cas du paysage traiterelativement a la situation anterieure au traite- ment. Pour modifier le comportement du feu al'echelle du paysage, il faut avoir recours a une combinaison de strategies de traitement des combustibles qui tiennent compte de la situation topographique, de l'affectation des terres, du type de vegetation et du regime des feux. (Traduit par la Redaction)