Model Of Forest Dynamics Research Articles

Residual vegetation importance to net CO2 uptake in pine-dominated stands following mountain pine beetle attack in British Columbia, Canada

An unprecedented epidemic of mountain pine beetle (MPB: Dendroctonus ponderosae) has resulted in extensive mortality of lodgepole pine (Pinus contorta var. latifolia) across British Columbia. The goal of this study was to quantify the contribution of residual live vegetation to forest-level daytime gross ecosystem photosynthesis (GEP) as measured by EC flux-towers in two lodgepole pine-dominated forests during and/or after MPB-attack. Diurnal foliar net photosynthesis (pn) of residual live herb, shrub, and tree foliage was measured periodically at both sites throughout the growing seasons of 2007, 2008, and 2009. There were no consistent trends in pn across years at either site for conifer or broadleaf components. The weighted average growing season pn of all components, normalized for LAI of the component, were similar to the average growing-season flux-tower estimates of GEP. Non-rectangular hyperbolic relationships between instantaneous values of pn and photosynthetically active radiation (Q) provided the best-fit models for pn. These relationships were used to scale up to stand level by using half-hourly values of Q, and measurements of the leaf area of vegetation components to provide modelled estimates of the vertical stand components and their summed ecosystem-scale net photosynthesis (PN ECOSYSTEM). PN ECOSYSTEM was similar to GEP at MPB-06 for both half-hourly and daily averages. At MPB-03, daily average estimates of PN ECOSYSTEM agreed very well with GEP estimates, but half-hourly averages were consistently underestimated in the morning compared to GEP in all 3years. Understory non-tree species (termed broadleaf vegetation component) were responsible for the majority (65–68%) of PNECOSYSTEM at MPB-03, and about one-third (33–35%) at MPB-06. Thus, residual vegetation, and particularly broadleaf species, is very important to growing-season CO2 uptake in MPB-attacked pine stands in central British Columbia and cannot be neglected in larger scale modelling of forest carbon dynamics in these locations. Management of forests in this region should take into account the importance of CO2 uptake by live residual vegetation in helping to mitigate forest management impacts on rising atmospheric CO2 concentrations.

Joint simulation of stand dynamics and landscape evolution using a tree-level model for mixed uneven-aged forests

A century and more after a major reforestation program, large areas in the French Southern Alps have moved to a landscape mosaic of old pine plantations and new, heterogeneous and uneven-aged, mixed stands. These conditions are challenging foresters in silvicultural practices and management choices. The aims of this study are to understand, analyze, model, and simulate the ongoing phenomena, and to propose a decision-making tool. An individual-based forest dynamics model considering recruitment, growth, and mortality (as related to the spatial arrangement of stands and species, to site conditions and competition) and a simulation system including spatial sampling are designed and calibrated to allow simulation of both silviculture treatments at the stand level and management strategies at the forest or landscape level. By keeping track of the trees while simulating at the forest level, they offer an alternative to upscaling strategies and a suitable tool for prediction of stand and forest characteristics in situations influenced by strong driving forces such as colonization and forest maturation. This approach is a straightforward means for adjusting forest management to trends such as expansion of shade-tolerant species; as spatial and temporal variation in site conditions are accounted for, it is also a promising way towards predicting their warming-induced upward shift.

Biodiversity protection and economics in long term boreal forest management — A detailed case for the valuation of protection measures

Increased protection of forest biodiversity implies reduced income from timber production both for society and forest owners, and consistent analysis of the relationships between biodiversity benefits and corresponding costs is important both for forest managers as well as policy makers. Using a complex dynamic forest optimization model, we analyse impacts on economy and biodiversity of forest management restrictions implemented to protect biodiversity. A reference scenario is compared to two preservation regimes based on 1) the current Norwegian forest certification system and 2) an expert judgement designed to put strong emphasis on biodiversity protection in boreal forests. Economic impacts are expressed as net present value and harvesting level, while impacts on forest structure are expressed by a vector of variables including old forest proportions, growing stock, number of retention trees, size of buffer zones and amount of dead wood. A rather detailed description of forest structure and biodiversity measures represents the main improvements compared to previous analyses. Different restrictions result in 10–45% decrease in economic value of the forest compared to no restrictions. The most costly measures are found to be 50% increased rotation and keeping old-growth proportions higher than 20%.

Size-Specific Tree Mortality Varies with Neighbourhood Crowding and Disturbance in a Montane Nothofagus Forest

Tree mortality is a fundamental process governing forest dynamics, but understanding tree mortality patterns is challenging because large, long-term datasets are required. Describing size-specific mortality patterns can be especially difficult, due to few trees in larger size classes. We used permanent plot data from Nothofagus solandri var. cliffortioides (mountain beech) forest on the eastern slopes of the Southern Alps, New Zealand, where the fates of trees on 250 plots of 0.04 ha were followed, to examine: (1) patterns of size-specific mortality over three consecutive periods spanning 30 years, each characterised by different disturbance, and (2) the strength and direction of neighbourhood crowding effects on size-specific mortality rates. We found that the size-specific mortality function was U-shaped over the 30-year period as well as within two shorter periods characterised by small-scale pinhole beetle and windthrow disturbance. During a third period, characterised by earthquake disturbance, tree mortality was less size dependent. Small trees (<20 cm in diameter) were more likely to die, in all three periods, if surrounded by a high basal area of larger neighbours, suggesting that size-asymmetric competition for light was a major cause of mortality. In contrast, large trees (≥20 cm in diameter) were more likely to die in the first period if they had few neighbours, indicating that positive crowding effects were sometimes important for survival of large trees. Overall our results suggest that temporal variability in size-specific mortality patterns, and positive interactions between large trees, may sometimes need to be incorporated into models of forest dynamics.

Using stochastic simulation to evaluate competing risks of wildfires and fuels management on an isolated forest carnivore

Natural resource managers are often challenged with balancing requirements to maintain wildlife populations and to reduce risks of catastrophic or dangerous wildfires. This challenge is exemplified in the Sierra Nevada of California, where proposals to thin vegetation to reduce wildfire risks have been highly controversial, in part because vegetation treatments could adversely affect an imperiled population of the fisher (Martes pennanti) located in the southern Sierra Nevada. The fisher is an uncommon forest carnivore associated with the types of dense, structurally complex forests often targeted for fuel reduction treatments. Vegetation thinning and removal of dead-wood structures would reduce fisher habitat value and remove essential habitat elements used by fishers for resting and denning. However, crown-replacing wildfires also threaten the population’s habitat, potentially over much broader areas than the treatments intended to reduce wildfire risks. To investigate the potential relative risks of wildfires and fuels treatments on this isolated fisher population, we coupled three spatial models to simulate the stochastic and interacting effects of wildfires and fuels management on fisher habitat and population size: a spatially dynamic forest succession and disturbance model, a fisher habitat model, and a fisher metapopulation model, which assumed that fisher fecundity and survivorship correlate with habitat quality. We systematically varied fuel treatment rate, treatment intensity, and fire regime, and assessed their relative effects on the modeled fisher population over 60 years. After estimating the number of adult female fishers remaining at the end of each simulation scenario, we compared the immediate negative effects of fuel treatments to the longer-term positive effect of fuel treatment (via reduction of fire hazard) using structural equation modeling. Our simulations suggest that the direct, negative effects of fuel treatments on fisher population size are generally smaller than the indirect, positive effects of fuel treatments, because fuels treatments reduced the probability of large wildfires that can damage and fragment habitat over larger areas. The benefits of fuel treatments varied by elevation and treatment location with the highest net benefits to fisher found at higher elevations and within higher quality fisher habitat. Simulated fire regime also had a large effect with the largest net benefit of fuel treatments occurring when a more severe fire regime was simulated. However, there was large uncertainty in our projections due to stochastic spatial and temporal wildfires dynamic and fisher population dynamics. Our results demonstrate the difficulty of projecting future populations in systems characterized by large, infrequent, stochastic disturbances. Nevertheless, these coupled models offer a useful decision-support system for evaluating the relative effects of alternative management scenarios; and uncertainties can be reduced as additional data accumulate to refine and validate the models.

Historical biogeography of the Brazilian Atlantic forest and the Carnaval-Moritz model of Pleistocene refugia: what do phylogeographical studies tell us?

The present study uses published phylogeographical studies to test the Carnaval–Moritz (CM) model of forest dynamics in the Atlantic forest of Brazil. The model predicts that a large forested area in the north–central region of this biome has remained stable during the last glacial maximum, and only relicts in its current southernmost distributions. All available sequences for phylogeographical studies on vertebrates on the Atlantic forest were obtained from GenBank. All datasets consisted of mitochondrial sequences and were submitted to the same analyses, including time of divergence and migration rates between phylogeographical lineages, as well as historical demography analyses, including neutrality tests and Ne estimates. The species studied showed different degrees of phylogeographical structure. Two contact zones are defined: one very heterogeneous in south-east Brazil that was largely congruent with the CM model and one around the Doce river further north. Population genetics analyses showed a smaller effective number on southern population, and most of these southern populations showed evidence for recent demographic expansion. These features are also in agreement with the CM model. Additionally, divergence/expansion events dated back to the Pleistocene epoch in all but one organism. According to hierarchical approximate Bayesian computation analysis, most of the data can be attributed to a single event. The results highlight the need for more finescale studies in the Atlantic forest. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104, 499–509.

A system of nonlinear simultaneous equations for crown length and crown radius for the forest dynamics model SORTIE-ND

A system of equations was developed to predict crown length (CL) and crown radius (CRAD) for trees in structurally complex stands. The equations address two problems that often arise in crown allometry. First, relationships between the main stem and the crown are likely to change with intertree competition. Therefore, explicit measures of density were used along with main stem measurements as explanatory variables. Second, the physiological relationship between CL and CRAD is often overlooked when modeling crowns. This relationship is incorporated through the use of a simultaneous system of equations. Parameters were estimated using nonlinear three-stage least squares (N3SLS) in which first-stage equation estimates of CRAD are used to estimate CL and vice versa in the second and third stages of N3SLS. The equations were fitted and validated for four species: lodgepole pine (Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson), hybrid spruce (Picea engelmannii Parry ex Engelm. × P. glauca (Moench) Voss), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco), and trembling aspen (Populus tremuloides Michx.). The intent is to use the equations as alternatives to the crown equations in the spatially explicit forest growth model SORTIE-ND that use only main stem variables in estimating crowns over time.

Validation of a multispecies forest dynamics model using 50-year growth from Eucalyptus forests in eastern Australia

One of the key problems confronting ecological forecasting is the validation of computer models. Here we report successful validation of a forest dynamics model Ecosystem Dynamics Simulator (EDS), adapted from the JABOWA-II forest succession model. This model and many variants derived from it have successfully simulated growth dynamics of uneven-aged mixed forests under changing environment with a moderate amount of input data. But rarely are adequate time-series data available for quantitative model validation. This study tested the performance of EDS in projecting the tree density, tree diameter at breast height ( dbh), tree height, basal area and aboveground biomass of uneven-aged, mixed species sclerophyll forests in St. Mary state forests of eastern Australia. The test data were collected between 1951 and 2005. Every tree was uniquely numbered, tagged and measured in consecutive re-measurements. Projected growth attributes were compared with those observed in an independent validation dataset. The model produced satisfactory projections of tree density (91.7%), dbh (92.3%), total tree height (82.8%), basal area (89.3%) and aboveground biomass (87.6%) compared to the observed attributes. These results suggest that the EDS model can provide reasonable capability in projecting growth dynamics of uneven-aged, mixed species sclerophyll forests.

Simulated nitrogen deposition affects wood decomposition by cord-forming fungi

Anthropogenic nitrogen (N) deposition affects many natural processes, including forest litter decomposition. Saprotrophic fungi are the only organisms capable of completely decomposing lignocellulosic (woody) litter in temperate ecosystems, and therefore the responses of fungi to N deposition are critical in understanding the effects of global change on the forest carbon cycle. Plant litter decomposition under elevated N has been intensively studied, with varying results. The complexity of forest floor biota and variability in litter quality have obscured N-elevation effects on decomposers. Field experiments often utilize standardized substrates and N-levels, but few studies have controlled the decay organisms. Decomposition of beech (Fagus sylvatica) blocks inoculated with two cord-forming basidiomycete fungi, Hypholoma fasciculare and Phanerochaete velutina, was compared experimentally under realistic levels of simulated N deposition at Wytham Wood, Oxfordshire, UK. Mass loss was greater with P. velutina than with H. fasciculare, and with N treatment than in the control. Decomposition was accompanied by growth of the fungal mycelium and increasing N concentration in the remaining wood. We attribute the N effect on wood decay to the response of cord-forming wood decay fungi to N availability. Previous studies demonstrated the capacity of these fungi to scavenge and import N to decaying wood via a translocating network of mycelium. This study shows that small increases in N availability can increase wood decomposition by these organisms. Dead wood is an important carbon store and habitat. The responses of wood decomposers to anthropogenic N deposition should be considered in models of forest carbon dynamics.

Co-dominance and succession in forest dynamics: The role of interspecific differences in crown transmissivity

Forests that are composed of two or more tree species with similar ecological strategies appear to contradict the competitive exclusion principle. Beech–maple communities are a well-known example of such a system. On a local scale, a number of mechanisms have been proposed to explain the coexistence of these two species. These are reciprocal replacement, external factors that favour alternatively one or the other species and demographic stochasticity. This paper presents and analyses a simple mathematical model that shows that external factors are not an essential requirement for coexistence. Rather, coexistence requires interspecific differences in light transmissivity through the crowns of adult trees. However, all the three mechanisms mentioned above can be interpreted within the framework of the model. Furthermore, many models of forest dynamics make use of shade tolerance as a key feature in describing successional dynamics. Despite its importance, however, shade tolerance does not have a commonly accepted quantitative definition. Here, a simple scheme is proposed where the relationship between shade tolerance, individual traits (growth and survival) and successional status is defined. This might have important implications in understanding the overall dynamics. Theoretical results have been compared with a number of studies carried out in North American forests. In particular, coexistence in beech–maple communities and the relation between shade tolerance and successional status in a beech–hemlock–birch community have been discussed.

Importance of colonization and competition in forest landscape response to global climatic change

The tree species composition of a forested landscape may respond to climate change through two primary successional mechanisms: (1) colonization of suitable habitats and (2) competitive dynamics of established species. In this study, we assessed the relative importance of competition and colonization in forest landscape response (as measured by the forest type composition change) to global climatic change. Specifically, we simulated shifts in forest composition within the Boundary Waters Canoe Area of northern Minnesota during the period 2000–2400 AD. We coupled a forest ecosystem process model, PnET-II, and a spatially dynamic forest landscape model, LANDIS-II, to simulate landscape change. The relative ability of 13 tree species to colonize suitable habitat was represented by the probability of establishment or recruitment. The relative competitive ability was represented by the aboveground net primary production. Both competitive and colonization abilities changed over time in response to climatic change. Our results showed that, given only moderate-frequent windthrow (rotation period = 500 years) and fire disturbances (rotation period = 300 years), competition is relatively more important for the short-term ( 100 years), colonization became relatively more important. However, if more frequent fire disturbances were simulated, then colonization is the dominant process from the beginning of the simulations. Our results suggest that the disturbance regime will affect the relative strengths of successional drivers, the understanding of which is critical for future prediction of forest landscape response to global climatic change.

Projecting impacts of human disturbances to inform conservation planning and management in a dryland forest landscape

Systematic approaches to conservation planning and management require spatially explicit information on the dynamics of multiple disturbance processes, but progress in providing such information has been limited to date. Here we examine the use of a spatially explicit model of forest dynamics (LANDIS-II), incorporating a range of ecological processes, to examine the impacts of different types of disturbance on a dryland forest landscape in Central Chile. The model was parameterized using spatial data and results of a field survey, in which 21 native tree species were recorded, and one invasive exotic ( Acacia dealbata). Seven disturbance scenarios were simulated, with different combinations of fire, browsing and tree cutting. Model results indicated relatively little impact of disturbance on forest cover but substantial differences in forest structure, with relatively old-growth forest stands (>120 years old) being virtually eliminated from the landscape in scenarios with both browsing and cutting. Tree species richness tended to be lower in those scenarios without disturbance, highlighting potential trade-offs between forest structure and species richness. Spread of A. dealbata was projected only to occur in the presence of fire when combined with browsing and/or cutting. These interactive effects of different forms of disturbance illustrate the value of process-based modeling approaches for exploring the spatial dynamics of multiple disturbance processes, but highlight the difficulty of identifying an optimum disturbance regime that would enable conservation objectives to be achieved. It is suggested that process-based models should form part of an analytical ‘toolkit’ to support the practical implementation of systematic conservation planning approaches.

Modeling impacts of fire severity on successional trajectories and future fire behavior in Alaskan boreal forests

Much of the boreal forest in western North America and Alaska experiences frequent, stand-replacing wildfires. Secondary succession after fire initiates most forest stands and variations in fire characteristics can have strong effects on pathways of succession. Variations in surface fire severity that influence whether regenerating forests are dominated by coniferous or deciduous species can feedback to influence future fire behaviour because of differences in forest flammability. We used a landscape model of fire and forest dynamics to explore the effects of different scenarios of surface fire severity on subsequent forest succession and potential fire activity in interior Alaska. Model simulations indicated that high levels of surface fire severity leading to a prolonged phase of deciduous forest dominance caused a reduction in landscape flammability and fewer large fire events. Under low surface fire severity, larger patches of contiguous conifer forest promoted fire spread and resulted in landscapes with shorter fire return intervals compared to scenarios of high surface severity. Nevertheless, these negative feedbacks between fire severity, deciduous forest cover, and landscape flammability were unable to fully compensate for greater fire activity under scenarios of severe climate warming. Model simulations suggest that the effects of climate warming on fire activity in Alaska’s boreal forests may be partially but not completely mitigated by changes in fire severity that alter landscape patterns of forest composition and subsequent fire behaviour.

Estimating gap lifetime and memory from a simple model of forest canopy dynamics

Gap formation and closure represent important disturbance events in forests, but the processes involved are still poorly understood. We use models, which we and others previously developed, to make long-term predictions of tropical forest gap dynamics based on Barro Colorado Island data. We first fit the models to the data by comparing their discrete Fourier transforms, and we propose a definition for the lifetime of a gap and predict a large-gap lifetime typically to be less than 50 years. We find that the gap lifetime diverges logarithmically for large-gap sizes. We examine the ‘memory’ of spatial gap patterns via spatiotemporal correlations and find a correlation time of about 160 years, suggesting that present gap patterns could have long-lasting effects on forest spatial patterns.

Simulating the potential for ecological restoration of dryland forests in Mexico under different disturbance regimes

Examining the potential for ecological restoration is important in areas where anthropogenic disturbance has degraded forest landscapes. However, the conditions under which restoration of degraded tropical dry forests (TDF) might be achieved in practice have not been determined in detail. In this study, we used LANDIS-II, a spatially explicit model of forest dynamics, to assess the potential for passive restoration of TDF through natural regeneration. The model was applied to two Mexican landscapes under six different disturbance regimes, focusing on the impact of fire and cattle grazing on forest cover, structure and composition. Model results identified two main findings. First, tropical dry forests are more resilient to anthropogenic disturbance than expected. Results suggested that under both a scenario of small, infrequent fires and a scenario of large, frequent fires, forest area can increase relatively rapidly. However, forest structure and composition differed markedly between these scenarios. After 400 years, the landscape becomes increasingly occupied by relatively shade-tolerant species under small, infrequent fires, but only species with both relatively high shade tolerance and high fire tolerance can thrive under conditions with large, frequent fires. Second, we demonstrated that different forms of disturbance can interact in unexpected ways. Our projections revealed that when grazing acts in combination with fire, forest cover, structure and composition vary dramatically depending on the frequency and extent of the fires. Results indicated that grazing and fire have a synergistic effect causing a reduction in forest cover greater than the sum of their individual effects. This suggests that passive landscape-scale restoration of TDF is achievable in both Mexican study areas only if grazing is reduced, and fires are carefully managed to reduce their frequency and intensity.

Forest processes from stands to landscapes: exploring model forecast uncertainties using cross-scale model comparison

Forest management practices conducted primarily at the stand scale result in simplified forests with regeneration problems and low structural and biological diversity. Landscape models have been used to help design management strategies to address these problems. However, there remains a great deal of uncertainty that the actual management practices result in the desired sustainable landscape structure. To investigate our ability to meet sustainable forest management goals across scales, we assessed how two models of forest dynamics, a scaled-up individual-tree model and a landscape model, simulate forest dynamics under three types of harvesting regimes: clearcut, gap, and uniform thinning. Althougth 50–100 year forecasts predicted average successional patterns that differed by less than 20% between models, understory dynamics of the landscape model were simplified relative to the scaled-up tree model, whereas successional patterns of the scaled-up tree model deviated from empirical studies on the driest and wettest landtypes. The scale dependencies of both models revealed important weaknesses when the models were used alone; however, when used together, they could provide a heuristic method that could improve our ability to design sustainable forest management practices.

Cost-effectiveness of dryland forest restoration evaluated by spatial analysis of ecosystem services

Although ecological restoration is widely used to combat environmental degradation, very few studies have evaluated the cost-effectiveness of this approach. We examine the potential impact of forest restoration on the value of multiple ecosystem services across four dryland areas in Latin America, by estimating the net value of ecosystem service benefits under different reforestation scenarios. The values of selected ecosystem services were mapped under each scenario, supported by the use of a spatially explicit model of forest dynamics. We explored the economic potential of a change in land use from livestock grazing to restored native forest using different discount rates and performed a cost-benefit analysis of three restoration scenarios. Results show that passive restoration is cost-effective for all study areas on the basis of the services analyzed, whereas the benefits from active restoration are generally outweighed by the relatively high costs involved. These findings were found to be relatively insensitive to discount rate but were sensitive to the market value of carbon. Substantial variation in values was recorded between study areas, demonstrating that ecosystem service values are strongly context specific. However, spatial analysis enabled localized areas of net benefits to be identified, indicating the value of this approach for identifying the relative costs and benefits of restoration interventions across a landscape.

New Development in Study of the Faustmann Optimal Forest Harvesting

Abstract Chinese forest resources have become very scarce in the face of rapid economic growth demand, while the reform of collective forest right system is in full swing across the country. It will directly affect the regeneration level of forest resources and the diverse ecological value functions. In this article, the mainstream model paradigm of forest economics, that is, the basic framework of the Faustmann model and its evolution process are made in a more detailed explanation, especially the extended model including considered silvicultural effort, tax subsidies, risk dynamic management, and forest regeneration factors are made in more detailed explanations. This article concludes with the future further research directions of forest economics, including the design of dynamic models that includes considered uneven-aged forest management, non-timber goods and services, dynamic forest models. The research reflects the general trend of interdisciplinary and cross-border.

Regeneration niches and functional traits of three common species in subtropical dune forest

South African coastal dune forests are young, highly disturbed subtropical communities where conventional models of forest dynamics may be challenged. We tested predictions from the gap-phase regeneration model by comparing seedlings of three common species representing contrasting regeneration strategies: Acacia karroo as a ruderal, Celtis africana as a coloniser of forest gaps, and Diospyros natalensis as a late-successional species. We grew seedlings under contrasting light and nitrogen levels in a greenhouse and in the field for 1 year to compare their growth and survival rates, allocation and photosynthetic traits. Species’ growth rates generally followed the expected order: Acacia>Celtis>Diospyros, but Acacia responded strongly to light and Celtis responded strongly to nitrogen, leading to cross-overs in growth rates. The plasticity of allocation and photosynthesis did not clearly differentiate the strategies, although it was greater in the light-demanding species. Acacia and Celtis tended to survive better in Acacia stands than in forest plots. Leaf-level light compensation points (LCPs) were similar for the three species in most conditions, but auxiliary data suggest Diospyros has a lower whole-plant LCP than Acacia. Growth rates and LCPs were lower than most of those reported for primary-forest species in the literature, suggesting an unusual degree of shade-tolerance in this habitat. We discuss reasons why variation in shade-tolerance may be less important here than in the prevailing model for forest regeneration and suggest other biotic factors that may help differentiate regeneration niches.

A geospatial model of forest dynamics with controlled trend surface

This paper proposes a method of controlled trend surface to simultaneously account for large-scale spatial trends and non-spatial local effects. With this method, a geospatial model of forest dynamics was developed for the Alaska boreal forest from 446 constantly monitored permanent sample plots. The geospatial component of this model represented large-scale spatial trends in recruitment, diameter growth, and mortality. The model was tested on two sets of validation plots which represented temporal and spatial extensions of the current sample coverage. The results suggest that the controlled trend surface model was generally more accurate than both the non-spatial and conventional trend surface models. With this model, we mapped the forest dynamics of the entire Alaska boreal region by aggregating predicted stand states across the region. It was predicted that under current conditions of climate and natural disturbances, most of the Alaska boreal forest region may undergo a major shift from deciduous-dominant to conifer-dominant, with an average increase of 0.33 m 2 ha year −1 in basal area over the Twenty-First Century.