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

Climate change interacts with ecological processes leading to changes in tree and forest growth rate, biome shifts and species composition, all of which are influenced by disturbances. This study explores future overarching climate trends of eight of Canada's ecozones containing managed forests. For the 2071 to 2100 period, climate projections indicate a warming trend of up to an additional 5.5 °C and an overall increase in annual precipitation. Future trends suggest marked contrast between coastal and interior forests and polarization between western and eastern forests. Warmer temperatures, accumulating degree-days above 5 °C and frost-free days suggest longer and drier growing seasons and greater risk of drought particularly in moisture-limited areas such as montane cordillera, taiga shield and boreal shield ecozones. Warmer temperatures and rising precipitation combined with less snow suggest shorter and wetter future winters. This indicates greater risk of rain-on-snow and freeze-thaw events, flooding and landslides particularly in coastal ecozones. We discuss how these projections are likely to result in shifts in dominant species and abundance, which when coupled with the cumulative effects of future disturbances, is likely to alter future forest dynamics and impact harvestable wood volumes for Canada's forestry industry. [ABSTRACT FROM AUTHOR]

Modifications to the environment around a weather station or changes in instrument result in discontinuities or shift in weather data. This paper asks the often ignored questions such as, “what are the impacts of inhomogenized data?” and “does using homogenized weather data affect the conclusions of environmental research?” To answer these questions, we used the Canadian Forest Fire Weather Index (CFFWI) System for our studies. Weather station data are used to calculate wildfire danger indices. The homogenized data and raw (inhomogenized) observations for sixteen weather stations spread across Canada were used to calculate the CFFWI indices. The sixteen weather stations were further divided into three subset of stations based on the length of the accessible data during the fire season (April to end of September). The first set included stations that covered just 27 years of data and the second data sets had 49 years of data, while the third set included only five stations with the longest time period of 66 years. The majority of the stations, as measured by the Wilcoxon signed-rank test, rejected the null hypothesis (difference between the pairs follows a symmetric distribution around zero). The rejection rate increases to 100% as the length of data record increases from 27 to 66 years. Homogenization of 66 years data reduced the indices values approximately 0.7–8.4% and also reversed the long-term trend in some stations such as Kapuskasing. [ABSTRACT FROM AUTHOR]

Background Forest based climate mitigation emerged as a key component of the Paris Agreement, and thus requires robust science to reduce uncertainties related to such strategies. The aim of this study was to assess and compare the cumulative effects on carbon dynamics of forest management and climate change on boreal and northern temperate forest sector in eastern Canada for the 2020–2100 period. Methods We used the spatially explicit forest landscape model LANDIS-II and its extension Forest Carbon Succession, in conjunction with the Carbon Budget Model for Harvested Wood Products framework. We simulated the dynamics of forest composition and carbon flows from forest ecosystems to wood products and their substitution effect on markets under increasing climate forcing, according to a tonne-year approach. Simulations were conducted for a series of forest management scenarios based on realistic practices principally by clearcut in the boreal territory and continuous-cover forestry in the northern temperate one. These scenarios included: i) a business-as-usual scenario (BaU), representing the current management strategy, ii) increased harvesting by 6.3% to 13.9%, iii) increased conservation (i.e. reduced harvesting by 11.1% to 49.8%), iiii) and a scenario representing the natural evolution of the forest landscape (i.e. without any management activity). Results Our study revealed that increasing harvesting levels had contrasting effects on the mitigation potential in northern temperate (enhance net sequestration) and boreal forest sector (enhance net emissions) in comparison to the BaU from 2040 onwards, regardless of the future climate. Carbon storage in wood products and the substitution effect were not sufficient to offset carbon emissions from ecosystems. Moreover, climate change had a strong impact on the capacity of both landscapes to act as carbon sinks. Northern temperate landscapes became a net source of carbon over time due to their greater vulnerability to climate change than boreal landscapes. Conclusions Our study highlights the need to consider the initial landscape characteristics in simulations to maximize the mitigation potential of alternative forest management strategies. The optimal management solution can be very different according to the characteristics of forest ecosystems. This opens the possibility of optimizing management for specific forest stands, with the objective of maximizing the mitigation potential of a given landscape. [ABSTRACT FROM AUTHOR]

Forest monitoring studies show contrasting trends in tree growth rates since the mid‐twentieth century. However, due to their focus on annual and decadal dynamics, they provide limited insight into the effects of long‐term climatic variability on tree growth. Here, we relied on a large tree‐ring dataset (∼2,700 trees) of two common North American shade‐intolerant tree species, trembling aspen (Populus tremuloides Michx.) and jack pine (Pinus banksiana Lambert), to assess their lifespan‐long growth dynamics in the mixedwood forests of Québec. We also determined how the environmental conditions of the stands influenced tree growth. We observed a significant increase in the radial growth rate of trembling aspen during the study period, while the jack pine decline was not significant. Over the whole study region, the trees growing in sites with lower competition, and those at the lower sections of the terrain slope experienced more of the positive effects of temperature on growth rates. Our study suggests that the tree growth response to climate warming may be species‐specific and will vary across the boreal mixedwoods. Key Points: Climate warming impacts long‐term tree growth in the boreal mixedwoodsGrowth response to climate warming is species‐specificStand conditions modulate the tree growth responses to climate [ABSTRACT FROM AUTHOR]

• Forests are experiencing the cumulative negative impacts of multiple disturbances. • Community forestry in British Columbia has gained experience over 20 years. • Lessons from community forestry can serve to enhance the resilience of forests. • Area-based tenure fosters long-term forest health and community well-being. • Community forests shift mindsets towards a dynamic and holistic view of the forest. Forests around the world are experiencing the cumulative effects of rapid social and environmental change. Building resilience in the forestry sector has thus become of major importance in many countries, including Canada. While British Columbia (BC) generates the highest revenue from the forestry sector in Canada, the planning and management of forests in this province face several limitations that hinder the application of resilience thinking in a fully integrated way that accounts not only for ecosystem processes but also the close interconnection between forests and people. Community forestry in BC provides experience gained over 20 years that can form the basis for a more holistic, long-term approach to enhance the resilience of forested landscapes. Based on interviews with managers of 5 case study community forests (CFs), and a survey of all CFs in BC over three consecutive years, we present pilot practices to manage forests for resilience at the stand- and landscape-levels. Findings show that these practices mainly focus on (1) age and species diversification, (2) introduction of more drought-tolerant species, (3) systematic long-term monitoring of productivity and forest health, (4) wildfire risk management, and (5) introduction of enhanced silviculture such as thinning, rehabilitation and fertilization. Between 2016 and 2018, 38 CFs in BC invested more than CAD 4.5 million in enhanced silvicultural practices using their own funds. The area-based tenure of CFs motivated not only long-term planning and investment, but also shifted the mindset among residents towards a more multi-functional and dynamic view of the forest. Building adaptive capacity and social license, CFs foster a future where forest health and community well-being are compatible. These lessons can be scaled to BC and other forested landscapes in Canada and around the world. Scaling mechanisms include: (1) facilitating knowledge exchange; (2) increasing multi-stakeholder collaboration; (3) replication and mainstreaming of effective practices; (4) rethinking the forest tenure system; and (5) systematic research and monitoring to learn from pilot studies that could inform strategic interventions with landscape-scale impact. Multi-functional forests which are increasingly affected by climate change and novel disturbances could particularly benefit from the insights shared in this paper to build social-ecological resilience. [ABSTRACT FROM AUTHOR]

Abstract: Canada's forests are shaped by disturbances such as fire, insect outbreaks, and droughts that often overlap in time and space. The resulting cumulative disturbance risks and potential impacts on forests are generally not well accounted for by models used to predict future impacts of disturbances on forest. This study aims at projecting future cumulative effects of four main natural disturbances, fire, mountain pine beetle, spruce budworm and drought, on timber volumes across Canada's forests using an approach that accounts for potential overlap among disturbances. Available predictive models for the four natural disturbances were used to project timber volumes at risk under aggressive climate forcing up to 2100. Projections applied to the current vegetation suggest increases of volumes at risk related to fire, mountain pine beetle, and drought over time in many regions of Canada, but a decrease of the volume at risk related to spruce budworm. When disturbance effects are accumulated, important changes in volumes at risk are projected to occur as early as 2011–2041, particularly in central and eastern Canada. In our last simulation period covering 2071–2100, nearly all timber volumes in most of Canada's forest regions could be at risk of being affected by at least one of the four natural disturbances considered in our analysis, a six‐fold increase relative to the baseline period (1981–2010). Tree species particularly vulnerable to specific disturbances (e.g., trembling aspen to drought) could suffer disproportionate increases in their volume at risk with potential impacts on forest composition. By 2100, estimated wood volumes not considered to be at risk could be lower than current annual timber harvests in central and eastern Canada. Current level of harvesting could thus be difficult to maintain without the implementation of adaptation measures to cope with these disturbances. [ABSTRACT FROM AUTHOR]

Abstract: In many forested ecosystems, it is increasingly recognized that the probability of burning is substantially reduced within the footprint of previously burned areas. This self‐limiting effect of wildland fire is considered a fundamental emergent property of ecosystems and is partly responsible for structuring landscape heterogeneity (i.e., mosaics of different age classes), thereby reducing the likelihood of uncharacteristically large fires in regions with active fire regimes. However, the strength and longevity of this self‐limiting phenomenon is not well understood in most fire‐prone ecosystems. In this study, we quantify the self‐limiting effect in terms of its strength and longevity for five fire‐prone study areas in western North America and investigate how each measure varies along a spatial climatic gradient and according to temporal (i.e., annual) climatic variation. Results indicate that the longevity (i.e., number of years) of the self‐limiting effect ranges between 15 yr in the warm and dry study area in the southwestern United States to 33 yr in the cold, northern study areas in located in northwestern Montana and the boreal forest of Canada. We also found that spatial climatic variation has a strong influence on wildland fire's self‐limiting capacity. Specifically, the self‐limiting effect within each study area was stronger and lasted longer in areas with low mean moisture deficit (i.e., wetter and cooler settings) compared to areas with high mean moisture deficit (warmer and drier settings). Last, our findings show that annual climatic variation influences wildland fire's self‐limiting effect: drought conditions weakened the strength and longevity of the self‐limiting effect in all study areas, albeit at varying magnitudes. Overall, our study provides support for the idea that wildland fire contributes to spatial heterogeneity in fuel ages that subsequently mediate future fire sizes and effects. However, our findings show that the strength and longevity of the self‐limiting effect varies considerably according to spatial and temporal climatic variation, providing land and fire managers relevant information for effective planning and management of fire and highlighting that fire itself is an important factor contributing to fire‐free intervals. [ABSTRACT FROM AUTHOR]

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

The potential of forests and the forest sector to mitigate greenhouse gas ( GHG) emissions is widely recognized, but challenging to quantify at a national scale. Mitigation benefits through the use of forest products are affected by product life cycles, which determine the duration of carbon storage in wood products and substitution benefits where emissions are avoided using wood products instead of other emissions-intensive building products and energy fuels. Here we determined displacement factors for wood substitution in the built environment and bioenergy at the national level in Canada. For solid wood products, we compiled a basket of end-use products and determined the reduction in emissions for two functionally equivalent products: a more wood-intensive product vs. a less wood-intensive one. Avoided emissions for end-use products basket were weighted by Canadian consumption statistics to reflect national wood uses, and avoided emissions were further partitioned into displacement factors for sawnwood and panels. We also examined two bioenergy feedstock scenarios ( constant supply and constrained supply) to estimate displacement factors for bioenergy using an optimized selection of bioenergy facilities which maximized avoided emissions from fossil fuels. Results demonstrated that the average displacement factors were found to be similar: product displacement factors were 0.54 tC displaced per tC of used for sawnwood and 0.45 tC tC−1 for panels; energy displacement factors for the two feedstock scenarios were 0.47 tC tC−1 for the constant supply and 0.89 tC tC−1 for the constrained supply. However, there was a wide range of substitution impacts. The greatest avoided emissions occurred when wood was substituted for steel and concrete in buildings, and when bioenergy from heat facilities and/or combined heat and power facilities was substituted for energy from high-emissions fossil fuels. We conclude that (1) national-level substitution benefits need to be considered within a systems perspective on climate change mitigation to avoid the development of policies that deliver no net benefits to the atmosphere, (2) the use of long-lived wood products in buildings to displace steel and concrete reduces GHG emissions, (3) the greatest bioenergy substitution benefits are achieved using a mix of facility types and capacities to displace emissions-intensive fossil fuels. [ABSTRACT FROM AUTHOR]

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

Climate change is threatening our ability to manage forest ecosystems sustainably. Despite strong consensus on the need for a broad portfolio of options to face this challenge, diversified management options have yet to be widely implemented. Inspired by functional zoning, a concept aimed at optimizing biodiversity conservation and wood production in multiple-use forest landscapes, we present a portfolio of management options that intersects management objectives with forest vulnerability to better address the wide range of goals inherent to forest management under climate change. Using this approach, we illustrate how different adaptation options could be implemented when faced with impacts related to climate change and its uncertainty. These options range from establishing ecological reserves in climatic refuges, where self-organizing ecological processes can result in resilient forests, to intensive plantation silviculture that could ensure a stable wood supply in an uncertain future. While adaptation measures in forests that are less vulnerable correspond to the traditional functional zoning management objectives, forests with higher vulnerability might be candidates for transformative measures as they may be more susceptible to abrupt changes in structure and composition. To illustrate how this portfolio of management options could be applied, we present a theoretical case study for the eastern boreal forest of Canada. Even if these options are supported by solid evidence, their implementation across the landscape may present some challenges and will require good communication among stakeholders and with the public. [ABSTRACT FROM AUTHOR]

Forests of Canada The forests of Canada are located across much of the country. GreenHouse Gas Emissions One of the key causes of climate change has been the rise in GreenHouse Gases (GHG), mainly Carbon Dioxide (CO2). By Canadian province/territory, five top GreenHouse Gas emitters in 2017 were Alberta, Ontario, Quebec, Saskatchewan and British Columbia, these together released 91% of Canada's national total GHG emissions. [Extracted from the article]