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Forest succession is a dynamic process of progressive compositional development of ecological communities of species following natural or anthropogenic disturbance. Despite a rich history of conceptual frameworks, models, and empirical advances, the complex interactions among climatic conditions, disturbances, edaphic factors, and silvicultural treatments still challenge our ability to accurately predict forest succession, hindering application to forest management. Our goal was to improve understanding of forest succession in the managed boreal forests of North America by clarifying advances in knowledge and limitations in our understanding. We reviewed 152 peer-reviewed papers to: (i) document conceptual developments in forest succession; (ii) summarize drivers of North American boreal forest succession, including changes to forest composition and successional trajectories given climate change; and (iii) discuss the implications of the synthesized information for boreal forest management. While the element of stochasticity is expected to increase under climate change, successional dynamics are anticipated to remain predominantly deterministic. Southern boreal forests are at increased risk of mortality due to warming-driven drought and increased fires. Following disturbance, regeneration is likely to favor deciduous hardwoods. In boreal mixedwoods, increased fires would promote jack pine, and also black spruce on hydric and xeric sites. Dynamics of the northern boreal will depend on the balance between precipitation and evapotranspiration. Forest management must carefully select prescriptions to promote forest regeneration and composition that consider the long-term effects of changing climate and disturbance regimes. For instance, combining retention cut with mechanical site preparation would maintain site productivity and reverse open black spruce stand development in northern boreal stands. Our work shows that multiple disturbances have compounding effects on forest development, but further work is needed to better define thresholds for synergistic and buffering interactions. Modeling of boreal forest succession can be improved by incorporating more of the influential factors, but this is often limited by the lack of data. This information will guide the development of forest management strategies by exploring combinations of prescribed fire and variable intensity selection cutting systems to reproduce the effects of multiple interacting natural disturbances under climate change on successional dynamics. [ABSTRACT FROM AUTHOR]

Traditionally, forest management has focused on forestry-related practices whereas other industries have been managed separately. Forest management requires the integration of all natural resource development activities, along with other anthropogenic and natural forest disturbances (e.g., climate change, pollution, wildfire, pest disturbance) to understand how human activities can change forested ecosystems. The term cumulative effects has been used to describe these attempts to integrate all disturbances to develop an understanding of past, current, and future impacts on environmental, social, and economic components of the system. In this review, we focus on the science required to understand the past, current, and future impacts of the cumulative effects of anthropogenic and natural disturbances on forested ecosystems or their components. We have primarily focused on the terrestrial system with an emphasis on northern forests in Canada. Our paper is not intended to be a comprehensive review of all cumulative effects science but a synthesis of the challenges and approaches currently being used. Central repositories were identified as an approach to deal with issues of availability of remotely sensed data on anthropogenic and natural disturbances. Data integration projects, open data, and well-designed large-scale data collection efforts are needed to provide sufficient data on environmental responses to cumulative effects. As well, large-scale integrated, modularized ecosystem models are needed to bring stressor and environmental response data together to explore responses to, and interactions between, multiple stressors to project these effects into the future and to identify future data collection needs. [ABSTRACT FROM AUTHOR]

Loss of global forest, and in particular forest that has little human disturbance, is a standard against which we measure progress to conserve Earth's forests. The value of intact forest landscapes has taken hold in the global psyche. We provide a brief history of the intact forest landscape concept and discuss how this has moved to an operational definition used as a global and regional metric of forest conservation. We distinguish between a conceptual intact forest landscape and an operational definition. For the purposes of this paper we will use the term IFL to mean the operational definition and intact forest landscapes to mean the conceptual idea. We provide an overview of the science that supports the value of intact forest landscapes in a Canadian boreal context and analyse issues with using a standard operationalized IFL definition to both measure and promote conservation of forests at global and regional scales. We found many arguments for protecting large, intact forest landscapes that are relevant to the Canadian boreal forest, including conservation of biodiversity, ecological processes and ecosystem services, existence values, application of the precautionary principle, and the need for scientific benchmarks. But it is clear that the standard operational IFL size threshold of 50 000 ha in the boreal forest is inadequate to meet these broad conservation objectives. However, the concept of intact forest being large enough to allow for all natural processes and biodiversity is likely not logistically feasible in Canada's managed boreal forest. The scale at which the most extensive processes (e.g., fire and insects) occur and species (e.g., woodland caribou) function is likely too large. Management options incorporating local knowledge of conservation needs and the specifics of ecosystem function and composition are more likely to be effective in conservation than rigid IFL requirements. A standardized approach is useful for global tracking of IFLs but it is not the best approach to meet more regional forest conservation goals. Intact forest landscapes have exceptional value but should be managed in the context of integrated land use planning that includes protected areas, sustainable forest management, species at risk management, and ecosystem restoration. [ABSTRACT FROM AUTHOR]

Urban forest naturalization has gained momentum within municipal planning and non-governmental organizations. As the interest in naturalization increases, so does the impetus for exploring its conceptual and practical dimensions. Naturalization is a form of ecological restoration with prominent social dimensions. One motivation is reintegrating the urban forest to a greater extent into its surroundings, increasing the habitat available for native species. However, naturalization is not always desirable, as we may want to use and modify certain areas for cultural purposes, or feasible, as some species may be unable to establish in an urban setting. This paper examines the concepts underlying naturalization and how they influence naturalization decisions and goals. It then provides a framework for urban forest naturalness and explores potential applications of naturalness assessments in urban forest management. The framework outlines 37 different biotic and abiotic dimensions of naturalness that can help urban forest decision-makers visualize and manage the urban forest through understanding its individual parts and thus the whole. If a site is weak in particular dimensions, actions can be directed to increase the naturalness of these components. Similarly, some dimensions may be of more interest than others, such as increasing habitat suitability for a particular species. We then offer real and hypothetical examples of applying the framework to urban forest management. The benefits of a naturalized urban forest are many. It provides habitat for native species and has an important role as a biological teaching tool for urban residents. In developing this framework, we hope to expand the discussion on naturalization beyond simply planting native species and ceasing mowing to positioning urban forests in a broader landscape. [ABSTRACT FROM AUTHOR]

Much of Canada's terrestrial biodiversity is supported by boreal forests. Natural resource development in boreal forests poses risks to this biodiversity. This paper reviews the scientific literature to assess the effects of natural resource development on terrestrial biodiversity in Canadian boreal forests. We address four questions: (1) To what extent have Canadian boreal forests changed due to natural resource development? (2) How has biodiversity responded to these changes? (3) Will the biodiversity of second-growth forests converge with that of primary boreal forests? (4) Are we losing species from boreal forests? We focus on trees, understory plants, insects, fungi, selected mammals, and songbirds because these groups have been most studied. We review more than 600 studies and found that changes in community composition are prevalent in response to large-scale conversion of forest types, changes in stand structures and age distributions, and altered landscape structure resulting from forest management and habitat loss associated with other developments such as oil and gas, hydroelectric, and mining. The southern boreal forest has been more highly impacted than the north due to more extensive forest management and the cumulative effects of multiple forms of development. There is abundant evidence that most species are not in danger of being extirpated from the boreal forest due to these anthropogenic changes. A few species, including woodland caribou ( Rangifer tarandus) and grizzly bear ( Ursus arctos), have, however, undergone long-term range contractions. Significant gaps in our ability to assess the effects of natural resource development on biodiversity in the boreal zone are the lack of long-term spatial and population data to monitor the impact of forest changes on ecosystems and species. [ABSTRACT FROM AUTHOR]