Regional analyses assessing the vulnerabilities of forest ecosystems and the forest sector to climate change are key to considering the heterogeneity of climate change impacts as well as the fact ...that risks, opportunities, and adaptation capacities might differ regionally. Here we provide the Regional Integrated Assessment of climate change on Quebec's forests, a work that involved several research teams and focused on climate change impacts on Quebec's commercial forests and on potential adaptation solutions. Our work showed that climate change will alter several ecological processes within Quebec's forests. These changes will result in important modifications in forest landscapes. Harvest will cumulate with climate change effects to further alter future forest landscapes, which will also have consequences on wildlife habitats (including woodland caribou habitat), avian biodiversity, carbon budget, and a variety of forest landscape values for Indigenous peoples. The adaptation of the forest sector will be crucial to mitigate the impacts of climate change on forest ecosystem goods and services and improve their resilience. Moving forward, a broad range of adaptation measures, notably through reducing harvest levels, should be explored to help strike a balance among social, ecological, and economic values. We conclude that without climate adaptation, strong negative economic and ecological impacts will likely affect Quebec's forests.
At the landscape scale, one of the key indicators of sustainable forest management is the age-class distribution of stands, since it provides a coarse synopsis of habitat potential, structural ...complexity, and stand volume, and it is directly modified by timber extraction and wildfire. To explore the consequences of several landscape-scale boreal forest management strategies on age-class structure in the Mauricie region of Quebec, we used spatially explicit simulation modelling. Our study investigated three different harvesting strategies (the one currently practiced and two different strategies to maintain late seral stands) and interactions between fire and harvesting on stand age-class distribution. We found that the legacy of initial forested age structure and its spatial configuration can pose short- (<50 years) to medium-term (150-300 years) challenges to balancing wood supply and ecological objectives. Also, ongoing disturbance by fire, even at relatively long cycles in relation to historic levels, can further constrain the achievement of both timber and biodiversity goals. For example, when fire was combined with management, harvest shortfalls occurred in all scenarios with a fire cycle of 100 years and most scenarios with a fire cycle of 150 years. Even a fire cycle of 500 years led to a reduction in older forest when its maintenance was not a primary constraint. Our results highlight the need to consider the broad-scale effects of natural disturbance when developing ecosystem management policies and the importance of prioritizing objectives when planning for multiple resource use.
The effect of different harvesting practices on soil acid-base status was evaluated in black spruce (Picea mariana (Mill.) BSP) forests of Quebec by comparing soil from five pairs of whole-tree and ...stem-only harvested plots 3 years after harvest. Stem-only harvesting contributed to the enrichment of the exchangeable base cation pool, particularly in the forest floors of the pairs where whole-tree harvested plots showed the highest exchangeable Al3+. In the mineral soil, divergence between treatments was low, perhaps because these acidic soils were strongly saturated with Al3+ (about 90%), which did not favour cationic exchange reactions. Although the effects of treatment may not persist over time, improved base cation nutrition may benefit stands during the early stages of development. Over a forest rotation of about 85 years, the estimated loss of alkalinity due to whole-tree harvesting was estimated to be low (less than 20%) when compared with the effect of acidic deposition.
To determine the nature of the negative influence of Kalmia angustifolia L. on black spruce (Picea mariana (Mill.) BSP) seedling growth and foliar nutrient concentrations, the effect of proximity to ...Kalmia on spruce seedlings was studied on two Kalmia-dominated sites of contrasting soil characteristics in central Newfoundland. Spruce seedlings and the soil at the base of their stems were sampled, and spruce leader length and foliar N and P concentration, as well as various physicochemical soil characteristics, were determined. Path analysis was used to determine the strength of direct and indirect relationships among variables hypothesized to be causally linked. Path diagrams were generated based on current knowledge of nutrient cycling in boreal ecosystems and mechanisms previously hypothesized to account for the influence of Kalmia on black spruce. On the wetter and richer site, proximity to Kalmia was associated with reduced spruce growth and humus extractable NH
4
-N, suggesting nutrient competition. On the drier and poorer site, results were consistent with a direct negative effect of Kalmia on the N nutrition of spruce. On both sites, we also found evidence for a direct effect of Kalmia on spruce growth that is consistent with allelopathic effects on spruce function.
The cumulative impacts of human and natural activity on forest landscapes in Alberta are clear. Human activity, such as forestry and oil and gas development, and natural processes such as wildfire ...leave distinctive marks on the composition, age class structure and spatial configuration of the forest. Also, other processes such as climate change may be slowly and subtly modifying forest dynamics and may lead to important changes over time. Given the importance and ubiquitous nature of these cumulative impacts, a forest management plan that does not adequately take such impacts into account cannot be expected to adequately manage the forest, neither its components nor its processes. In order to address the question of cumulative impacts in the context of forestry, a landscape model was designed and built in order to simulate forestry, oil and gas, climate change, wildfire, and demographic change for the Whitecourt forest management area over a long time horizon. This paper presents the model and the forest landscape states it forecasted with cumulative impacts, and evaluates the fate of some key indicators of biodiversity and forest productivity. Simulations of harvesting as the only disturbance, the nearest analogue to the current approach to forest management planning, yield results that differ greatly, in every respect, from the results of simulations of harvesting combined with other disturbance agents. The simulation of multiple disturbance agents together allows for the detection of interactions among disturbance agents, and indeed, there are important interactions between the processes of fire and oil and gas. Results also show that climate and demographic change will intensify the impact of fire on the supply of timber and other values. Also, the continued development of petroleum resources will lead to an important erosion of the forest landbase. Overall, this paper makes a strong case for cumulative impacts assessment and the use of spatial and temporal stochastic modelling in forest management.
Kalmia angustifolia L. is an ericaceous shrub that frequently invades black spruce (
Picea mariana Mill.) clear-cuts in central Newfoundland. Field observations suggest that on many sites where
K. ...angustifolia grows, black spruce seedlings become chlorotic and stunted. Previous laboratory research has suggested that allelochemicals of
K. angustifolia affect the growth and development of black spruce as well as the growth of certain ectomycorrhizal (ECM) fungi associated with black spruce. Black spruce seedlings close to (<1 m) and far from (>1 m)
K. angustifolia were sampled from a clear-cut in central Newfoundland. The ECM community structure, degree of mycorrhizal infection, height, mass, root:shoot ratio, and the foliar concentrations of N, P, K, Ca, and Mg of spruce seedlings growing close to and far from
K. angustifolia were examined. Seedlings close to
K. angustifolia had significantly lower foliar concentrations of N and P, had a lower rate of mycorrhizal infection, and were more frequently associated with
Phialocephala dimorphospora Kendrick, a potential root pathogen of black spruce, than seedlings growing far from
K. angustifolia. There were positive linear relationships between black spruce foliar N concentration and total seedling height and biomass for seedlings growing away from
K. angustifolia, but not for seedlings in close proximity to
K. angustifolia. Hypotheses suggesting possible roles for nutrient competition, allelopathy, and
K. angustifolia's ability to increase the occurrence of the pseudomycorrhizal
P. dimorphospora on black spruce are proposed.
How different extracellular stimuli can evoke different spatiotemporal Ca2+ signals is uncertain. We have elucidated a novel paradigm whereby different agonists use different Ca2+-storing organelles ...(“organelle selection”) to evoke unique responses. Some agonists select the endoplasmic reticulum (ER), and others select lysosome-related (acidic) organelles, evoking spatial Ca2+ responses that mirror the organellar distribution. In pancreatic acinar cells, acetylcholine and bombesin exclusively select the ER Ca2+ store, whereas cholecystokinin additionally recruits a lysosome-related organelle. Similarly, in a pancreatic β cell line MIN6, acetylcholine selects only the ER, whereas glucose mobilizes Ca2+ from a lysosome-related organelle. We also show that the key to organelle selection is the agonist-specific coupling messenger(s) such that the ER is selected by recruitment of inositol 1,4,5-trisphosphate (or cADP-ribose), whereas lysosome-related organelles are selected by NAADP.
The development of a coherent system of criteria and indicators (C&I) requires collaboration and communication among scientists, government, the public, certifying organizations, and the forest ...industry. It also demands the integration of knowledge from many fields of study, which is foreign to the disciplinary nature of most forestry research. There needs to be greater effort to link groups of indicators and to favour those that are assimilative in nature. Modelling tools adapted to a multi-disciplinary approach and collaborative development will help to integrate knowledge from various fields and institutions. Specific challenges for implementation of C&I have been identified, including: leadership and vision in the evolution towards sustainable forest management (SFM); linking of grass-roots and higher level C&I initiatives; streamlining and co-ordinating different certification initiatives and agencies; technology transfer; and collaboration among disciplines.
The soil acid-based status of black spruce forests was examined as a function of different harvesting techniques. Soil was compared from five pairs of whole-tree and stem-only harvests. The ...enrichment of the exchangeable base cation pool occurred with stem-only harvesting. There was little difference between the treatments in mineral soil, possibly because the high levels of Al in these acidic soils inhibited cationic exchange reactions. While the treatment effects may not be sustained over time, the initial boost in base cation nutrition may improve early development.
At the landscape scale, one of the key indicators of sustainable forest management is the age-class distribution of stands, since it provides a coarse synopsis of habitat potential, structural ...complexity, and stand volume, and it is directly modified by timber extraction and wildfire. To explore the consequences of several landscape-scale boreal forest management strategies on age-class structure in the Mauricie region of Quebec, we used spatially explicit simulation modelling. Our study investigated three different harvesting strategies (the one currently practiced and two different strategies to maintain late seral stands) and interactions between fire and harvesting on stand age-class distribution. We found that the legacy of initial forested age structure and its spatial configuration can pose short- (<50 years) to medium-term (150-300 years) challenges to balancing wood supply and ecological objectives. Also, ongoing disturbance by fire, even at relatively long cycles in relation to historic levels, can further constrain the achievement of both timber and biodiversity goals. For example, when fire was combined with management, harvest shortfalls occurred in all scenarios with a fire cycle of 100 years and most scenarios with a fire cycle of 150 years. Even a fire cycle of 500 years led to a reduction in older forest when its maintenance was not a primary constraint. Our results highlight the need to consider the broad-scale effects of natural disturbance when developing ecosystem management policies and the importance of prioritizing objectives when planning for multiple resource use. PUBLICATION ABSTRACT
PDF