Canada’s forest sector must maintain wood supply, carbon storage, biodiversity, and social values as climate change and other global stressors increase the risk of disturbance and threaten forest resilience. Climate-Smart Forestry (CSF) offers an important framework for integrating adaptation, mitigation, and socio-economic objectives, but practitioners often lack spatial decision support tools that connect stand-level actions to landscape-scale resilience under uncertain future conditions. We introduce DIVERSE, a pan-Canadian research partnership working across 22 managed-forest landscapes (>20 Mha) to implement and test the Functional Complex Network (FCN) approach as a spatially explicit, resilience-oriented planning method aligned with CSF. FCN represents landscapes as networks of stands and combines functional trait diversity and redundancy with network properties, including connectivity, centrality, and modularity, to identify where diversification, conservation, or spatial reconfiguration can enhance resilience while limiting ecosystem-wide risk. We summarize DIVERSE’s six integrated research themes and operational products: (1) vulnerability and trait baselines; (2) climate-adaptation guidance for species and seed sources; (3) FCN-based resilience assessment and prioritization; (4) climate and management scenario testing through landscape simulation; (5) socio-economic feasibility analyses; and (6) operational field experiments. DIVERSE will evaluate where and when FCN can improve the robustness of forest management in Canada and support the long-term sustainability of future Canadian forests.

An increased shift in climate change contributes to accelerated forest dieback around the world. Forest dieback is the process of a forest ecosystem suffering from disease, with mortality rates increasing among trees, potentially leading to the death of the ecosystem. Dieback can be caused through a variety of biotic and abiotic factors such as climate change, land use change, pests, pathogens, and invasive species. Balsam fir trees (Abies balsamea) in eastern North America are particularly vulnerable to dieback. Increased temperatures associated with climate change hinder their tree germination, growth, and competitiveness in an ecosystem. It has been determined that limiting forest dieback damage can be performed by monitoring forest conditions and identifying symptoms such as yellowing of leaves, delayed growth, and reduced stem and twig growth. Diversification was determined to be one of the primary methods of reducing the damage caused by forest dieback. Other methods that were found included decreasing deforestation and limiting the effects of climate change within an ecosystem. These strategies can be applied to balsam fir trees, although the efficacy of mitigation strategies would need to be explored long term.

Forest models can be developed from empirical relationships between stand attributes, including age, and yield. Empirical growth and yield (G&Y) models remain popular with forest managers for their simplicity and utility. It is important to apply models at the spatial levels at which they were developed to avoid the fallacy of disaggregation. This study attempted to determine whether regionally aggregated G&Y curves perform adequately when applied at the sub-regional scale, and if not, if their application can be modified to better model a mesoscale forest. We studied a mesoscale forested watershed in Nova Scotia, Canada, to determine if regional G&Y curves could predict stand merchantable volume (MV) using data available from a photogrammetric provincial forest inventory for initial stand conditions. Initial results demonstrated that curves significantly underestimated stand MV compared to 700 forest cruise point observations throughout the study area. Curves were reassigned based on observations and local knowledge, and subsequently generated estimates of stand MV not significantly different from observations. We found that while regional growth models are not ideal for mesoscale application, when properly calibrated through field observations, they can offer insights into current conditions and the future potential of a forest with minimal additional data collection required.

Governments increasingly collaborate with residents and nongovernment organizations (NGOs) in urban forest management because of the underlying belief that these groups improve the delivery of local forest services. However, in practice, the successes, challenges, and outcomes vary drastically by collaborative arrangement; solely documenting positive outcomes in NGO-government collaborations may hinder the ability to mitigate their associated downsides rather than biasing collaborative behaviours towards success. This study draws on the experiences of urban forest professionals across nine Canadian cities who have participated in or observed NGOs and local governments engage in collaborative urban forest management. We employed semi-structured interviews with 32 participants from three groups: leaders of NGOs, municipal government officials, and urban forest experts who have observed the two parties interact. Our results demonstrate that the addition of NGOs in municipal forest management is associated with positive outcomes and the characteristics of relationships, individual personnel, and community support contribute to their success. We also characterize the barriers that collaborators are tasked with navigating in order to achieve positive outcomes, including high employee turnover, siloed departments, competing priorities, shifting politics, and precarious funding and contracts. Our recommendations for successful NGO-government collaborations include arming stakeholders with a thorough knowledge of civic processes, diversifying political relationships, fostering “champions” among a greater number of involved parties, and participating in longer-term contracts and funding agreements. Further, involved parties should ensure they work towards the equitable distribution of the benefits and outputs of urban forest collaborations. Moving forward, because of the insular nature of NGO-government collaborations and a low capacity among NGOs to share the outputs of these collaborations, we recommend researchers continue to study the successes and shortcomings under varying governance arrangements so that groups may benchmark their collaborative activities against others and determine the most effective means of participating in co-management.

While forest management commonly seeks to increase carbon (C) capture and sequestration, in some settings, a high density of C storage may be detrimental to other land uses and ecosystem services. We study a forested, drinking-water-supply watershed to determine the effects of forest management on C storage with the implicit understanding that greater storage of C will lead to increased quantity of carbon exported hydrologically into a source-water reservoir. Using a custom implementation of CBM-CFS3, a Canadian model to simulate C transformations and movement in forested systems, and a custom forest disturbance and management model, we simulate various management scenarios and their C outcomes. The largest forest C pool, mineral soils, is very slow to change and manipulating DOC export through this pool would likely not be feasible within human management timescales. Other pools, in which C has lower residence time and from which C is more readily mobilized, are a more promising area for future research into hydrologic DOC export under varying management regimes. Our findings indicate that management activities can serve to reduce forest C storage, but further research is required to connect these outcomes to hydrologic export.

During a time of rapid urban growth and development, it is becoming ever more important to monitor the carbon fluxes of our cities. Unlike Canada's commercially managed forests that have a long history of inventory and modelling tools, there is both a lack of coordinated data and considerable uncertainty on assessment procedures for urban forest carbon. Nonetheless, independent studies have been carried out across Canada. To improve upon Canada's federal government reporting on carbon storage and sequestration by urban forests, this study builds on existing data to develop an updated assessment of carbon storage and sequestration for Canada's urban forests. Using canopy cover estimates derived from ortho-imagery and satellite imagery ranging from 2008 to 2012 and field-based urban forest inventory and assessment data from 16 Canadian cities and one US city, this study found that Canadian urban forests store approximately 27,297.8 kt C (- 37%, + 45%) in above and belowground biomass and sequester approximately 1497.7 kt C year-1 (- 26%, + 28%). In comparison with the previous national assessment of urban forest carbon, this study suggested that in urban areas carbon storage has been overestimated and carbon sequestration has been underestimated. Maximizing urban forest carbon sinks will contribute to Canada's mitigation efforts and, while being a smaller carbon sink compared to commercial forests, will also provide important ecosystem services and co-benefits to approximately 83% of Canadian people.

The Acadian Forest Region is a temperate-boreal transitional zone in eastern North America which provides a unique opportunity for understanding the potential effects of climate change on both forest types. Leaf phenology, the timing of leaf life cycle changes, is an important indicator of the biological effects of climate change, which can be observed with stationary timelapse cameras known as phenocams. Using four growing seasons of observations for the species Acer rubrum (red maple), Betula papyrifera (paper/white birch) and Abies balsamea (balsam fir) from the Acadian Phenocam Network as well as multiple growing season observations from the North American PhenoCam Network we parameterized eight leaf emergence and six leaf senescence models for each species which span a range in process and driver representation. With climate models from the Fifth Phase of the Coupled Model Intercomparison Project (CMIP5) we simulated future leaf emergence, senescence and season length (senescence minus emergence) for these species at sites within the Acadian Phenocam Network. Model performances were similar across models and leaf emergence model RMSE ranged from about 1 to 2 weeks across species and models, while leaf senescence model RMSE ranged from about 2 to 4 weeks. The simulations suggest that by the late 21st century, leaf senescence may become continuously delayed for boreal species like Betula papyrifera and Abies balsamea, though remain relatively stable for temperate species like Acer rubrum. In contrast, the projected advancement in leaf emergence was similar across boreal and temperate species. This has important implications for carbon uptake, nutrient resorption, ecology and ecotourism for the Acadian Forest Region. More work is needed to improve predictions of leaf phenology for the Acadian Forest Region, especially with respect to senescence. Phenocams have the potential to rapidly advance process-based model development and predictions of leaf phenology in the context of climate change.

Climate change leads to an increased frequency of severe weather events as well as stressful growing conditions. Together these changes may impact the resilience of ecosystems. To keep track of such effects, conservation managers monitor the "ecological integrity" or coherence of ecosystem processes, such as the cycling of carbon and water. Networked phenocams can produce near-continuous observations of leaf function in the context of climate change, capturing declines due to disturbance or stress. Here we explore the application of phenocams to detect responses to disturbance and stress using 14 examples from the PhenoCam Network. We selected these previously published and new examples to include a variety of disturbances in the form of hurricanes, a windstorm, frost, insect defoliation, and stress due to drought. Frost and herbivory disturbances led to both reductions and extensions in the duration of the rising section of the greenness curve, while hurricanes generally led to reductions in the duration of the plateau section and entire leaf-on period. We found that changes of at least +/- 20% in the duration of the rising section in the seasonal greenness curve, +/- 20% in the duration of the plateau section following the seasonal greenness peak, and +/- 10% in the duration of the entire leaf-on period were a reliable signal of leaf functional declines due to disturbance or stress. If such declines become increasingly frequent and severe as a consequence of climate change, this could impact ecological integrity through interruptions to ecosystem processes. Comparing the duration of these periods in a given year to the average for other years with these thresholds resulted in average true detection rates of 86% and false-positive detection rates of 11% when sampling from probability density functions of 344 broadleaf and needleleaf PhenoCam site-years. Here we show that phenocams are powerful ecological integrity monitoring tools, which can be efficiently applied to quantify dynamic responses to disturbance or stress.

Urban forests provide a myriad of social, environmental, and economic benefits that help make cities desirable and safe places to live. However, despite their importance, urban forests are often inequitably distributed, with marginalized populations having disproportionately low access to them and their associated benefits. For this reason, understanding the distribution and change of urban forests is key to achieving their equitable presence and management. Though urban forest equity is becoming a well researched topic, few studies address the equity of urban forest change and most existing equity studies assess only canopy cover. This study addresses these gaps by examining the relationship between changes in Toronto’s urban forest over a ten-year period and its frequency with four indicators of population marginalization. Diameter growth rate, mortality rate, and establishment rate were used to quantify change, while basal area per hectare and stems per hectare were used to quantify frequency. The indicators of marginalization used in this study were residential instability, economic dependency, ethnocultural composition and situational vulnerability, from the Canadian Index of Multiple Deprivation. Bivariate correlation, multiple linear regression, and geographically weighted regression were used to determine if there was a relationship between each urban forest variable and each indicator of marginalization. Bivariate cluster analysis was also used to identify areas in Toronto with the highest occurrences of urban forest inequity. Significant correlations are found between several indicators of marginalization with diameter growth rates, establishment rates, and both frequency measures. Furthermore, areas in Toronto with the highest establishment rates were also the areas with the highest tree frequency before this change analysis. Ultimately, this study suggests that changes in Toronto’s urban forest are not helping to resolve its inequity, but reveals that understanding urban forest change can provide insights into potential perpetrators of existing inequities that may help cities address them.

Urban forests are being threatened by rapid urbanization, biodiversity crises, and climate variability. In response, governments are increasingly collaborating with the public for solutions to these mounting challenges. Non-governmental organizations (NGOs) are dominant players in these collaborations because of their ability to supplement governments' expertize and resources and bring social and ecological issues to the forefront of civic agendas. Despite their growing visibility in urban forest management, there is a lack of attention directed to the forms and range of NGO relationships. This study focuses on addressing this gap and examining collaborations between local governments and NGOs in urban forest programming by characterizing their components including mandates, relationship ties, accountability, resource exchange, and power dynamics. We collected data using semi-structured interviews with three groups: leaders of NGOs, municipal government officials in an urban forest or public works departments, and urban-forest experts who have observed their interactions. The participants represent 32 individuals in nine Canadian cities. Our results indicate that NGO-government collaborations have relational ties and accountability processes that are both formal and informal in nature. Formality in collaborations is often associated with the amount of funding, proximity to government, or size of the NGO. In addition, our findings suggest that NGOs present an opportunity for local governments to supplement their resources and capacity. While the strength and formality of collaborations may be a product of NGO size and budgets, public servants should not hesitate to engage smaller, grassroots NGOs to realize their public service mandates. Characterizing the components of these governance processes provides a benchmark for practitioners participating in similar public-civic interactions and arms them with the knowledge to navigate collaborative decision-making.

Forest bioenergy production can represent a renewable energy supply while benefiting the forest sector. However, greenhouse gas (GHG) reductions are often not immediate. The point of carbon parity where bioenergy starts delivering GHG benefits may be years to decades in the future. This study examined the life-cycle emissions associated with bioenergy production at combined heat-and-power (CHP) projects in Nova Scotia, Canada. We examined the effects and sensitivities of different feedstock mixes of chips from harvested roundwood and mill residues, the implementation of intensive and extensive silviculture strategies, and different market/supply-chain assumptions around additionality and product substitution. We found contrasting GHG outcomes for bioenergy, depending largely on additionality assumptions and biomass type. When primary biomass (roundwood) was used as the feedstock type, carbon parity was achieved within four to nine years when pulp and paper products were substituted, whereas carbon parity was achieved in 86–100 years or longer when biomass harvests were additional. Net GHG benefits were achieved in 10 years with the use of secondary biomass (mill residues) as the bioenergy feedstock, although they were delayed when at lower energy conversion efficiencies. Adoption of more intensive silvicultural practices (plantations) reduced the time to carbon parity because of increased yields, although uncertainties in long-term soil carbon storage exist. Study Implications: Our analysis shows that the use of forest biomass in local CHP facilities can deliver GHG benefits in the short term but there is substantial variability. Carbon parity times were the longest with the use of additional primary biomass feedstocks (i.e., roundwood) but were substantially reduced when biomass harvests substituted harvests for pulp and paper products and when secondary biomass (i.e., mill residues) was used. This study highlights the nuance of different forest management dimensions (e.g., silviculture) while also presenting novel findings on the importance of assumptions around biomass harvesting being additional to current practices or a substitution for declines in traditional forest products.

The Acadian Forest Region is a temperate-boreal transitional zone in eastern North America. Therein, both forest types are vulnerable to environmental changes due to their proximity to biogeographical range limits. Using four growing seasons of phenocam-derived leaf phenology observations for the species Acer rubrum, Betula papyrifera, and Abies balsamea from across the Acadian Phenocam Network as well as multiple growing season observations from the North American PhenoCam Network we parameterized eight leaf emergence and six leaf senescence models for each species which together span a range in process and driver representation. With climate models from the Fifth Phase of the Coupled Model Intercomparison Project (CMIP5) we simulated future patterns in leaf emergence, senescence, and season length (senescence minus emergence) for these species at sites within the Acadian Phenocam Network. Model performances were similar across models. By the late 21st century, leaf emergence could be about two to three weeks earlier for both boreal and temperate species. The timing of leaf senescence may become continuously delayed for boreal species like Betula papyrifera and Abies balsamea, though remain relatively constant for temperate species like Acer rubrum. This has important implications for carbon uptake, nutrient resorption, ecology, and ecotourism for the Acadian Forest Region. Phenocams have the potential to rapidly advance process-based model development and predictions of leaf phenology in the context of climate change.

Urban forestry, as the name implies, is a branch of forestry that deals with trees and woodlands in urban areas. Practice in urban forestry may have its foundations in the nineteenth century, but the moniker of urban forestry launched in earnest in the 1970s largely through the contributions of Eric Jorgensen, a professor at the University of Guelph on Ontario, Canada. Urban forestry combines long traditions of science and management in the fields of arboriculture (management of individual trees), silviculture (management of stands of trees), and forestry (management of larger woodlands comprised of many stands). Urban forestry, according to Jorgensen (see Konijnendijk, et al. 2006, cited under Definitions) is “a specialized branch of forestry and has as its objectives the cultivation and management of trees for their present and potential contribution to the physiological, sociological and economic well-being of urban society” (p. 95). This bibliography concentrates on the ecology of urban forests. Given that ecology is the study of organisms and their relationships with the biotic and abiotic environments, one instantly recognizes the fundamental ecological nature upon which urban-forest studies must rest. No trees in the urban ecosystem—whether in the heart of downtown or in the peri-urban outskirts of the town or city, or indeed anywhere between—escape the influence of humans, especially their built infrastructure. So urban forestry as a science and practice cannot help but rest firmly on the foundation of urban forest ecology. However, scoping this domain of science is fraught with pitfalls because the boundaries are unclear, broad, and porous. Much of forest ecology in general pertains to all forests, not just hinterland forests nor timber-producing forests. Equally complicating the scoping problem are the numerous intense relationships between people and trees which justify the notion that urban forests are best understood as social-ecological systems with vital economic and technical dimensions. Hearty thanks to K. E. Turner and C. Ordóñez Barona for assistance in identifying relevant literature, and to an anonymous reviewer for revisions suggestions.

Ecological forestry is based on the idea that forest patterns and processes are more likely to persist if harvest strategies produce stand structures, return intervals, and severities similar to those from natural disturbances. Taylor et al. (2020) reviewed forest natural disturbance regimes in Nova Scotia, Canada, to support implementation of ecological forestry. In this follow-up paper, we (i) review the use of natural disturbance regimes to determine target harvest rotations, age structures, and residual stand structures; and (ii) describe a novel approach for use of natural disturbance regimes in ecological forestry developed for Nova Scotia. Most examples of ecological forestry consider only the local, dominant disturbance agent, such as fire in boreal regions. Our approach included: (i) using current ecological land classification to map potential natural vegetation (PNV) community types; (ii) determining cumulative natural disturbance effects of all major disturbances, in our case fire, hurricanes, windstorm, and insect outbreaks for each PNV; and (iii) using natural disturbance regime parameters to derive guidelines for ecological forestry for each PNV. We analyzed disturbance occurrence and return intervals based on low, moderate, and high severity classes (<30, 30–60, and >60% of biomass of living trees killed, respectively), which were used to determine mean annual disturbance rates by severity class. Return intervals were used to infer target stand age-class distributions for high, moderate, and low severity disturbances for each PNV. The range of variation in rates of high severity disturbances among PNVs was from 0.28%·year–1 in Tolerant Hardwood to 2.1%·year–1 in the Highland Fir PNV, equating to return intervals of 357 years in Tolerant Hardwood to 48 years in Highland Fir PNVs. As an example, this return interval for the Tolerant Hardwood PNV resulted in target rotation lengths of 200 years for 35% of the PNV area, 500 years for 40%, and 1000 years for 25%. The proposed approach of determining natural disturbance regimes for PNV communities and calculating target disturbance rates and corresponding harvest rotation lengths or entry times appears to be a feasible method to guide ecological forestry in any region with a strong ecological land classification system and multiple disturbance agents.

Urban trees provide people with a range of ecosystem services. Trees planted along streets have been a large focus of urban forest research and practice, and municipalities invest significant resources in their survival. However, the optimal spacing of street trees is not addressed in the scientific literature, and existing municipal street tree spacing standards are highly variable and poorly enforced. In this study, we examine variability in crown shape and size for street trees to test for possible interaction effects at closer spacings. We measured variability in crown diameters both parallel and perpendicular to street tree rows to test whether changes in crown dimensions can be explained by interaction effects with neighbouring trees, and whether crown interactions lead to a reduction in total crown projection area (i.e., canopy cover). We measured the crown dimensions and diameter at breast height of 1,338 street trees in Halifax, Canada. We used two-way analysis of variance to test whether crown shape and crown projection area were affected by crown interactions and spacing. We found that the effect of narrower spacing and interactions (i.e., crowns touching/overlapping) among trees translated to crowns extending away from the direction of interaction. We also found that these changing crown dimensions were associated with increases in canopy cover. Urban forest ecosystems are a vital resource for the increasingly urban population. There is a need for empirical research on spacing standards and practices that investigate their influence on the supply of ecosystem services, such as stormwater retention, air pollution removal, and cooling.

Models of forest growth and yield (G&Y) are a key component in long-term strategic forest management plans. Models leveraging the industry-standard “empirical” approach to G&Y are frequently underpinned by an assumption of historical consistency in climatic growing conditions. This assumption is problematic as forest managers look to obtain reliable growth predictions under the changing climate of the 21st century. Consequently, there is a pressing need for G&Y modelling approaches that can be more robustly applied under the influence of climate change. In this study we utilized an established forest gap model (JABOWA-3) to simulate G&Y between 2020 and 2100 under Representative Concentration Pathways (RCP) 2.6, 4.5, and 8.5 in the Canadian province of Newfoundland and Labrador (NL). Simulations were completed using the province’s permanent sample plot data and surface-fitted climatic datasets. Through model validation, we found simulated basal area (BA) aligned with observed BA for the major conifer species components of NL’s forests, including black spruce [Picea mariana (Mill.) Britton et al.] and balsam fir [Abies balsamea (L.) Mill]. Model validation was not as robust for the less abundant species components of NL (e.g., Acer rubrum L. 1753, Populus tremuloides Michx., and Picea glauca (Moench) Voss). Our simulations generally indicate that projected climatic changes may modestly increase black spruce and balsam fir productivity in the more northerly growing environments within NL. In contrast, we found productivity of these same species to only be maintained, and in some instances even decline, toward NL’s southerly extents. These generalizations are moderated by species, RCP, and geographic parameters. Growth modifiers were also prepared to render empirical G&Y projections more robust for use under periods of climate change.

The urban forest is a valuable ecosystem service provider that is garnering increasing attention in environmental research and municipal planning agendas. However, because of its location in heavily built-up and densely-settled environments, the urban forest is vulnerable. The purpose of this dissertation is to conceptualize, assess, and analyze urban forest ecosystems and their vulnerability at multiple spatial and temporal scales. An urban forest ecosystem classification framework that integrates biophysical, built, and human components is developed. Subsequent classification of ecosystems at the neighbourhood scale reveals the spatial arrangement of several social-ecological interactions. Such information is valuable to ecosystem-based decision support while also informing future vulnerability research. The investigation of ecosystem vulnerability began with the development of a theory-based conceptual framework. Urban forest vulnerability is defined as the likelihood of decline in ecosystem service supply and its associated benefits for human populations, urban infrastructure, and biodiversity. It is comprised of exposure, sensitivity, and adaptive capacity, which describe the built environment and associated stressors, urban forest structure, and the human population, respectively. This framework is applied using empirical field research in Toronto, Canada to explore the processes of vulnerability and their influence on ecological change. Results indicate that there are several significant predictors of urban forest decline and mortality, and emphasize the importance of applying diverse metrics to describe the built environment and urban forest structure at fine spatial scales. Vulnerability assessment and analysis at much broader spatial and temporal scales, using a spatially-explicit assessment approach and ecological modelling of alternative management and disturbance scenarios, is further investigated. This latter research emphasizes the importance of aligning scales of management with ecosystem function and the long-term influence of management intervention on ecological conditions. The multiple scales of investigation and methodological approaches developed in this study provide complementary opportunities to synthesize and apply existing theory in novel settings while also generating new theories pertaining to the processes of urban ecosystem change and decline. The intention of this study is to contribute to the understanding of urban forest ecosystems and their vulnerability, while also providing practical knowledge and tools for the sustainable management of this resource.

Forest ecosystem resilience is of considerable interest worldwide, particularly given the climate crisis, biodiversity loss, and recent instances of zoonotic diseases linked to deforestation and forest loss. Novel, digital-based technologies are also increasingly ubiquitous. We provide a more comprehensive understanding of how these new technologies are being used for forest management in different sectors and contexts, and discuss potential implications and future research needs for forestry researchers, managers, and policymakers. We carried out a literature database search and scoping review to collect peer-reviewed articles from 2010 to 2020, and developed a forest-technology classification to identify hardware and/or software technologies and techniques, methodology used, forest management application(s), spatial and temporal context, subsequent challenges and limitations, and opportunities. A qualitative analysis revealed a strong emphasis on remote sensing-based innovations for forest monitoring, planning, and management, where machine-learning techniques also play an important role in data collection, processing, and analysis. Data fusion approaches are also becoming more common, enabled by open-source data sets and data sharing practices. More emerging technologies and applications include virtual/augmented environments for understanding human-nature relationships and behavior patterns, automated workflows for forestry operations, and urban green infrastructure mapping and ecosystem services assessments via social media and mobile tracking applications. The continued adoption of digital-based tools will likely bring about new research questions about forest ecosystems as dynamic social, ecological, and technological landscapes, and future work should more closely examine how forestry researchers, managers, and stakeholders can anticipate and adapt to both environmental and technological uncertainty change in a forest-ecosystem context.

Climate has a considerable influence on tree growth. Forest managers benefit from the empirical study of the historic relationship between climatic variables and tree growth to support forest management frameworks that are to be applied under scenarios of climate change. Through this research, we have utilized long-term permanent sample plot records, historic climate data sets, and linear mixed modelling techniques to evaluate the historic influence of climatic variables on the growth rates of major boreal tree species in Newfoundland and Labrador, Canada. For the commercially significant spruce and fir forests of the province, we found growing degree-days (GDD) to negatively correlate with tree productivity in warmer regions, such as much of Newfoundland (±1350 GDD), but positively correlate with growth in cooler regions, such as those in Labrador (±750 GDD). With respect to precipitation, environmental moisture was not on average a limiting factor to species productivity in the province. These dynamics have implications for the productivity of the spruce–fir forests of the study area when considered alongside contemporary climate projections for the region, which generally entail both a warmer and wetter growing environment.

In response to the global climate crisis, the Nova Scotia Department of Lands and Forestry is using the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) and associated methodologies to assess the carbon dynamics of the provincial forestry sector. The CBM-CFS3 bases simulations on a range of studies and national forest inventory plots to predict carbon dynamics using merchantable volume yield curves. Nova Scotia has also maintained thousands of permanent forest sample plots (PSPs) for decades, offering the opportunity to develop empirical, province-specific carbon models. This study used PSP tree measurements and allometric equations to compute plot-level forest carbon models from the PSP dataset and compared their output to that of the CBM-CFS3 model. The PSP-based models were stratified into five forest types and predict the carbon for seven carbon pools as a function of the plot age. Predictions with the PSP- and CBM-CFS3 models were compared to observed PSP data at the plot level and compared against each other at the stand and landscape level. At the plot level, the PSP-derived models predicted carbon closer to the observed data than the CBM-CFS3 model, the extent of over- or under-estimation depending on the carbon pool and forest type. At the stand scale, the CBM-CFS3 model predicted forest carbon to within 3.1–17.6% of the PSP method on average. Differences in predictions between the CBM-CFS3 and PSP models decreased to within 2.4% of the PSP-based models at the landscape level. Thus, the implications of using one method over the other decrease as the prediction scale increases from stand to landscape level, and the implications fluctuate as a function of the forest type and age.