Age Class Structure - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

Age Class Structure

The Experts below are selected from a list of 13815 Experts worldwide ranked by ideXlab platform

Age Class Structure – Free Register to Access Experts & Abstracts

Werner A Kurz – One of the best experts on this subject based on the ideXlab platform.

  • accounting of forest carbon sinks and sources under a future climate protocol factoring out past disturbance and manAgement effects on Age Class Structure
    Environmental Science & Policy, 2008
    Co-Authors: Hannes Bottcher, Werner A Kurz, Annette Freibauer
    Abstract:

    Today, forests in the northern hemisphere are a sink for carbon dioxide (CO2) from the atmosphere, partly due to changes in forest manAgement practice and intensity. Parties of the Kyoto Protocol had the option to elect to account for direct human-induced carbon (C) sources and sinks from land manAgement activities since 1990. The effect of AgeClass Structure of a forest landscape resulting from past practices and disturbances before the reference year 1990 should be excluded, but methods for “factoring out” the effects of this AgeClass legacy on carbon emissions and removals are lacking. The legacy effect can be strong and can even overwhelm effects of post-1990 manAgement. It therefore needs to be “factored out”, i.e., removed from the direct human-induced post-1990 effects. In this study we examine how the contributions to forest biomass carbon stock changes of (1) past (pre-1990) disturbances and harvest and (2) recent (post-1990) changes in forest manAgement can be differentiated in present and future observable carbon dynamics in manAged forest ecosystems. We also calculate the consequences of different accounting rules for the magnitude and direction of accountable C stock changes in European countries in the period 2013-2017. Different accounting approaches are compared in terms of applicability and their ability to provide incentives for manAgement changes to increase carbon sinks and reduce carbon sources. We demonstrate implications of the various ways of accounting for a sample of European countries with different initial AgeClass Structures. The current forest AgeClass distribution in countries determines whether and how many credits can be created by the various accounting approaches. We suggest an approach that includes a dynamic, forward-looking baseline as reference and list options to define such a baseline. Accounting of recent manAgement change against such a baseline factors out the contribution of the legacy effect to accounting results and only rewards the effect of recent changes in forest manAgement practices in support of climate change mitigation. We demonstrate that relatively simple, state-of-the-art forest models can factor out effects of past practices and past disturbances on present and future carbon stock changes. Factoring out of past practice effects is thus technically feasible but the numerical results are highly dependent on the choice of baseline which will be subject to negotiation. It is possible, however, to select a dynamic baseline that represents “business-as-usual”, and to isolate and account for only the changes in manAgement. Changes in accounting rules will always be advantAgeous for some countries and disadvantAgeous for others, but using a dynamic “business-as-usual” baseline effectively removes the legacy of pre-1990 AgeClass effects, and thus overcomes one of the acknowledged shortcomings of the current accounting approach.

  • could increased boreal forest ecosystem productivity offset carbon losses from increased disturbances
    Philosophical Transactions of the Royal Society B, 2008
    Co-Authors: Werner A Kurz, G Stinson, G J Rampley
    Abstract:

    To understand how boreal forest carbon (C) dynamics might respond to anticipated climatic changes, we must consider two important processes. First, projected climatic changes are expected to increase the frequency of fire and other natural disturbances that would change the forest AgeClass Structure and reduce forest C stocks at the landscape level. Second, global change may result in increased net primary production (NPP). Could higher NPP offset anticipated C losses resulting from increased disturbances? We used the Carbon Budget Model of the Canadian Forest Sector to simulate rate changes in disturbance, growth and decomposition on a hypothetical boreal forest landscape and to explore the impacts of these changes on landscape-level forest C budgets. We found that significant increases in net ecosystem production (NEP) would be required to balance C losses from increased natural disturbance rates. Moreover, increases in NEP would have to be sustained over several decades and be widespread across the landscape. Increased NEP can only be realized when NPP is enhanced relative to heterotrophic respiration. This study indicates that boreal forest C stocks may decline as a result of climate change because it would be difficult for enhanced growth to offset C losses resulting from anticipated increases in disturbances.

  • Accounting of forest carbon sinks and sources under a future climate protocol—factoring out past disturbance and manAgement effects on AgeClass Structure
    Environmental Science & Policy, 2008
    Co-Authors: Hannes Bottcher, Werner A Kurz, Annette Freibauer
    Abstract:

    Abstract Today, forests in the northern hemisphere are a sink for carbon dioxide (CO2) from the atmosphere, partly due to changes in forest manAgement practice and intensity. Parties of the Kyoto Protocol had the option to elect to account for direct human-induced carbon (C) sources and sinks from land manAgement activities since 1990. The effect of AgeClass Structure of a forest landscape resulting from past practices and disturbances before the reference year 1990 should be excluded, but methods for “factoring out” the effects of this AgeClass legacy on carbon emissions and removals are lacking. The legacy effect can be strong and can even overwhelm effects of post-1990 manAgement. It therefore needs to be “factored out”, i.e., removed from the direct human-induced post-1990 effects. In this study we examine how the contributions to forest biomass carbon stock changes of (1) past (pre-1990) disturbances and harvest and (2) recent (post-1990) changes in forest manAgement can be differentiated in present and future observable carbon dynamics in manAged forest ecosystems. We also calculate the consequences of different accounting rules for the magnitude and direction of accountable C stock changes in European countries in the period 2013–2017. Different accounting approaches are compared in terms of applicability and their ability to provide incentives for manAgement changes to increase carbon sinks and reduce carbon sources. We demonstrate implications of the various ways of accounting for a sample of European countries with different initial AgeClass Structures. The current forest AgeClass distribution in countries determines whether and how many credits can be created by the various accounting approaches. We suggest an approach that includes a dynamic, forward-looking baseline as reference and list options to define such a baseline. Accounting of recent manAgement change against such a baseline factors out the contribution of the legacy effect to accounting results and only rewards the effect of recent changes in forest manAgement practices in support of climate change mitigation. We demonstrate that relatively simple, state-of-the-art forest models can factor out effects of past practices and past disturbances on present and future carbon stock changes. Factoring out of past practice effects is thus technically feasible but the numerical results are highly dependent on the choice of baseline which will be subject to negotiation. It is possible, however, to select a dynamic baseline that represents “business-as-usual”, and to isolate and account for only the changes in manAgement. Changes in accounting rules will always be advantAgeous for some countries and disadvantAgeous for others, but using a dynamic “business-as-usual” baseline effectively removes the legacy of pre-1990 AgeClass effects, and thus overcomes one of the acknowledged shortcomings of the current accounting approach.

Andrew Fall – One of the best experts on this subject based on the ideXlab platform.

  • Forest Age Structure as indicator of boreal forest sustainability under alternative manAgement and fire regimes: A landscape level sensitivity analysis
    Ecological Modelling, 2006
    Co-Authors: M.p. Didion, Marie-josée Fortin, Andrew Fall
    Abstract:

    Effective forest ecosystem-based manAgement requires a thorough understanding of the interactions between anthropogenic and natural disturbance processes over larger spatial and temporal scales than stands and rotation Ages. Because harvesting does not preclude fire, it is important to evaluate the combined effects of harvesting and fire on forest Age Structure, a coarse indicator of forest ecosystem state. We performed a sensitivity analysis of landscape scale effects of forest manAgement (strategy, harvest rate and access cost) and fire regime (fire return interval and extent) in terms of combined impacts on forest stand AgeClass Structure on a study area of 3.5 million hectares of boreal forest of Quebec. A series of scenarios were simulated over 500 years and replicated 30 times using a previously reported spatially explicit landscape model. Within the parameter space of our sensitivity analysis, we found that harvest rate, fire return interval and manAgement strategy were the most significant parameters affecting stand AgeClass distribution across the landscape. The former are not so surprising, given that they combine to produce an overall disturbance rate, but the latter shows that the resulting impact on AgeClass Structure can be influenced to some degree through manAgement objectives. A harvesting strategy of clearcutting for sustained timber supply, using a harvest rotation based on minimum merchantable Age (approximately 100 years in this analysis), creates a trend for the stand AgeClass distribution away from the expected range of natural variation for the study area. Within the scope of our simulations, alternative manAgement strategies with extended harvest rotation Age proved the most robust forest manAgement practice to absorb variations in fire regime.

  • Consequences of various landscape-scale ecosystem manAgement strategies and fire cycles on AgeClass Structure and harvest in boreal forests
    Canadian Journal of Forest Research, 2004
    Co-Authors: Andrew Fall, Marie-josée Fortin, Daniel Kneeshaw, Stephen H Yamasaki, Christian Messier, Luc Bouthillier, Cheryl Smyth
    Abstract:

    At the landscape scale, one of the key indicators of sustainable forest manAgement is the AgeClass distribu- tion 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 AgeClass Structure in the Mauricie region of Quebec, we used spatially explicit simu- lation modelling. Our study investigated three different harvesting strategies (the one currently practiced and two differ- ent strategies to maintain late seral stands) and interactions between fire and harvesting on stand AgeClass distribution. We found that the legacy of initial forested Age Structure and its spatial configuration can pose short- (

  • consequences of various landscape scale ecosystem manAgement strategies and fire cycles on Age Class Structure and harvest in boreal forests
    Canadian Journal of Forest Research, 2004
    Co-Authors: Andrew Fall, Marie-josée Fortin, Daniel Kneeshaw, Stephen H Yamasaki, Christian Messier, Luc Bouthillier, Cheryl Smyth
    Abstract:

    At the landscape scale, one of the key indicators of sustainable forest manAgement is the AgeClass distribu- tion 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 AgeClass Structure in the Mauricie region of Quebec, we used spatially explicit simu- lation modelling. Our study investigated three different harvesting strategies (the one currently practiced and two differ- ent strategies to maintain late seral stands) and interactions between fire and harvesting on stand AgeClass 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 distur- bance 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.

Annette Freibauer – One of the best experts on this subject based on the ideXlab platform.

  • accounting of forest carbon sinks and sources under a future climate protocol factoring out past disturbance and manAgement effects on Age Class Structure
    Environmental Science & Policy, 2008
    Co-Authors: Hannes Bottcher, Werner A Kurz, Annette Freibauer
    Abstract:

    Today, forests in the northern hemisphere are a sink for carbon dioxide (CO2) from the atmosphere, partly due to changes in forest manAgement practice and intensity. Parties of the Kyoto Protocol had the option to elect to account for direct human-induced carbon (C) sources and sinks from land manAgement activities since 1990. The effect of AgeClass Structure of a forest landscape resulting from past practices and disturbances before the reference year 1990 should be excluded, but methods for “factoring out” the effects of this AgeClass legacy on carbon emissions and removals are lacking. The legacy effect can be strong and can even overwhelm effects of post-1990 manAgement. It therefore needs to be “factored out”, i.e., removed from the direct human-induced post-1990 effects. In this study we examine how the contributions to forest biomass carbon stock changes of (1) past (pre-1990) disturbances and harvest and (2) recent (post-1990) changes in forest manAgement can be differentiated in present and future observable carbon dynamics in manAged forest ecosystems. We also calculate the consequences of different accounting rules for the magnitude and direction of accountable C stock changes in European countries in the period 2013-2017. Different accounting approaches are compared in terms of applicability and their ability to provide incentives for manAgement changes to increase carbon sinks and reduce carbon sources. We demonstrate implications of the various ways of accounting for a sample of European countries with different initial AgeClass Structures. The current forest AgeClass distribution in countries determines whether and how many credits can be created by the various accounting approaches. We suggest an approach that includes a dynamic, forward-looking baseline as reference and list options to define such a baseline. Accounting of recent manAgement change against such a baseline factors out the contribution of the legacy effect to accounting results and only rewards the effect of recent changes in forest manAgement practices in support of climate change mitigation. We demonstrate that relatively simple, state-of-the-art forest models can factor out effects of past practices and past disturbances on present and future carbon stock changes. Factoring out of past practice effects is thus technically feasible but the numerical results are highly dependent on the choice of baseline which will be subject to negotiation. It is possible, however, to select a dynamic baseline that represents “business-as-usual”, and to isolate and account for only the changes in manAgement. Changes in accounting rules will always be advantAgeous for some countries and disadvantAgeous for others, but using a dynamic “business-as-usual” baseline effectively removes the legacy of pre-1990 AgeClass effects, and thus overcomes one of the acknowledged shortcomings of the current accounting approach.

  • Accounting of forest carbon sinks and sources under a future climate protocol—factoring out past disturbance and manAgement effects on AgeClass Structure
    Environmental Science & Policy, 2008
    Co-Authors: Hannes Bottcher, Werner A Kurz, Annette Freibauer
    Abstract:

    Abstract Today, forests in the northern hemisphere are a sink for carbon dioxide (CO2) from the atmosphere, partly due to changes in forest manAgement practice and intensity. Parties of the Kyoto Protocol had the option to elect to account for direct human-induced carbon (C) sources and sinks from land manAgement activities since 1990. The effect of AgeClass Structure of a forest landscape resulting from past practices and disturbances before the reference year 1990 should be excluded, but methods for “factoring out” the effects of this AgeClass legacy on carbon emissions and removals are lacking. The legacy effect can be strong and can even overwhelm effects of post-1990 manAgement. It therefore needs to be “factored out”, i.e., removed from the direct human-induced post-1990 effects. In this study we examine how the contributions to forest biomass carbon stock changes of (1) past (pre-1990) disturbances and harvest and (2) recent (post-1990) changes in forest manAgement can be differentiated in present and future observable carbon dynamics in manAged forest ecosystems. We also calculate the consequences of different accounting rules for the magnitude and direction of accountable C stock changes in European countries in the period 2013–2017. Different accounting approaches are compared in terms of applicability and their ability to provide incentives for manAgement changes to increase carbon sinks and reduce carbon sources. We demonstrate implications of the various ways of accounting for a sample of European countries with different initial AgeClass Structures. The current forest AgeClass distribution in countries determines whether and how many credits can be created by the various accounting approaches. We suggest an approach that includes a dynamic, forward-looking baseline as reference and list options to define such a baseline. Accounting of recent manAgement change against such a baseline factors out the contribution of the legacy effect to accounting results and only rewards the effect of recent changes in forest manAgement practices in support of climate change mitigation. We demonstrate that relatively simple, state-of-the-art forest models can factor out effects of past practices and past disturbances on present and future carbon stock changes. Factoring out of past practice effects is thus technically feasible but the numerical results are highly dependent on the choice of baseline which will be subject to negotiation. It is possible, however, to select a dynamic baseline that represents “business-as-usual”, and to isolate and account for only the changes in manAgement. Changes in accounting rules will always be advantAgeous for some countries and disadvantAgeous for others, but using a dynamic “business-as-usual” baseline effectively removes the legacy of pre-1990 AgeClass effects, and thus overcomes one of the acknowledged shortcomings of the current accounting approach.

Julie Morand-ferron – One of the best experts on this subject based on the ideXlab platform.

  • Urbanization is associated with differences in Age Class Structure in black-capped chickadees (Poecile atricapillus)
    Urban Ecosystems, 2020
    Co-Authors: Dovid Y. Kozlovsky, Catherine A. Jarjour, Julie Morand-ferron
    Abstract:

    Urbanization has a tremendous impact on the environment from landscape features to distribution of food resources. Such drastic environmental changes can result in community, population, and individual differences between urban and non-urban animals. Urbanization has been associated with differential mortality and reproduction and therefore, differences in Age Structure may also be expected across urban gradients. Additionally, many traits studied along urban gradients, such as morphology, can also differ across Age Classes, and as such, Age is an important factor to consider. Despite this, differences in Age Structure along urbanization gradients have only rarely been examined. Here, we use black-capped chickadee ( Poecile atricapillus ) Age, morphological, and feeder visitation data to address whether Age Structure, morphology, and Age-related winter survival differ across a gradient of urban land use in and around Ottawa, ON. We test the hypothesis that urbanization is associated with higher proportions of juveniles, because of an increased exploratory tendency by juveniles against the hypothesis that urbanization favors higher proportions of adults because of a slower pace of life. We further hypothesize that urban chickadees will be smaller than non-urban ones, because anthropogenic environments will attract both younger and worse quality individuals. We found that urban environments were associated with significantly higher proportions of first year individuals and these proportions remained stable from late fall through all of winter. We did not, however, find evidence that Age related differences explained variation in morphology. Instead variation in morphology was small and inconsistently associated with both urbanization and Age. The results stand in contrast to results for two species of European birds. The present study calls for using broadly available but under-exploited data to better understand urbanization-related differences in Age Structure and its implications for population-level processes such as disease transmission and information flow.

Hannes Bottcher – One of the best experts on this subject based on the ideXlab platform.

  • accounting of forest carbon sinks and sources under a future climate protocol factoring out past disturbance and manAgement effects on Age Class Structure
    Environmental Science & Policy, 2008
    Co-Authors: Hannes Bottcher, Werner A Kurz, Annette Freibauer
    Abstract:

    Today, forests in the northern hemisphere are a sink for carbon dioxide (CO2) from the atmosphere, partly due to changes in forest manAgement practice and intensity. Parties of the Kyoto Protocol had the option to elect to account for direct human-induced carbon (C) sources and sinks from land manAgement activities since 1990. The effect of AgeClass Structure of a forest landscape resulting from past practices and disturbances before the reference year 1990 should be excluded, but methods for “factoring out” the effects of this AgeClass legacy on carbon emissions and removals are lacking. The legacy effect can be strong and can even overwhelm effects of post-1990 manAgement. It therefore needs to be “factored out”, i.e., removed from the direct human-induced post-1990 effects. In this study we examine how the contributions to forest biomass carbon stock changes of (1) past (pre-1990) disturbances and harvest and (2) recent (post-1990) changes in forest manAgement can be differentiated in present and future observable carbon dynamics in manAged forest ecosystems. We also calculate the consequences of different accounting rules for the magnitude and direction of accountable C stock changes in European countries in the period 2013-2017. Different accounting approaches are compared in terms of applicability and their ability to provide incentives for manAgement changes to increase carbon sinks and reduce carbon sources. We demonstrate implications of the various ways of accounting for a sample of European countries with different initial AgeClass Structures. The current forest AgeClass distribution in countries determines whether and how many credits can be created by the various accounting approaches. We suggest an approach that includes a dynamic, forward-looking baseline as reference and list options to define such a baseline. Accounting of recent manAgement change against such a baseline factors out the contribution of the legacy effect to accounting results and only rewards the effect of recent changes in forest manAgement practices in support of climate change mitigation. We demonstrate that relatively simple, state-of-the-art forest models can factor out effects of past practices and past disturbances on present and future carbon stock changes. Factoring out of past practice effects is thus technically feasible but the numerical results are highly dependent on the choice of baseline which will be subject to negotiation. It is possible, however, to select a dynamic baseline that represents “business-as-usual”, and to isolate and account for only the changes in manAgement. Changes in accounting rules will always be advantAgeous for some countries and disadvantAgeous for others, but using a dynamic “business-as-usual” baseline effectively removes the legacy of pre-1990 AgeClass effects, and thus overcomes one of the acknowledged shortcomings of the current accounting approach.

  • Accounting of forest carbon sinks and sources under a future climate protocol—factoring out past disturbance and manAgement effects on AgeClass Structure
    Environmental Science & Policy, 2008
    Co-Authors: Hannes Bottcher, Werner A Kurz, Annette Freibauer
    Abstract:

    Abstract Today, forests in the northern hemisphere are a sink for carbon dioxide (CO2) from the atmosphere, partly due to changes in forest manAgement practice and intensity. Parties of the Kyoto Protocol had the option to elect to account for direct human-induced carbon (C) sources and sinks from land manAgement activities since 1990. The effect of AgeClass Structure of a forest landscape resulting from past practices and disturbances before the reference year 1990 should be excluded, but methods for “factoring out” the effects of this AgeClass legacy on carbon emissions and removals are lacking. The legacy effect can be strong and can even overwhelm effects of post-1990 manAgement. It therefore needs to be “factored out”, i.e., removed from the direct human-induced post-1990 effects. In this study we examine how the contributions to forest biomass carbon stock changes of (1) past (pre-1990) disturbances and harvest and (2) recent (post-1990) changes in forest manAgement can be differentiated in present and future observable carbon dynamics in manAged forest ecosystems. We also calculate the consequences of different accounting rules for the magnitude and direction of accountable C stock changes in European countries in the period 2013–2017. Different accounting approaches are compared in terms of applicability and their ability to provide incentives for manAgement changes to increase carbon sinks and reduce carbon sources. We demonstrate implications of the various ways of accounting for a sample of European countries with different initial AgeClass Structures. The current forest AgeClass distribution in countries determines whether and how many credits can be created by the various accounting approaches. We suggest an approach that includes a dynamic, forward-looking baseline as reference and list options to define such a baseline. Accounting of recent manAgement change against such a baseline factors out the contribution of the legacy effect to accounting results and only rewards the effect of recent changes in forest manAgement practices in support of climate change mitigation. We demonstrate that relatively simple, state-of-the-art forest models can factor out effects of past practices and past disturbances on present and future carbon stock changes. Factoring out of past practice effects is thus technically feasible but the numerical results are highly dependent on the choice of baseline which will be subject to negotiation. It is possible, however, to select a dynamic baseline that represents “business-as-usual”, and to isolate and account for only the changes in manAgement. Changes in accounting rules will always be advantAgeous for some countries and disadvantAgeous for others, but using a dynamic “business-as-usual” baseline effectively removes the legacy of pre-1990 AgeClass effects, and thus overcomes one of the acknowledged shortcomings of the current accounting approach.