Forest roads are an important part of forest management, both in terms of cost and impact on surrounding ecosystems. Existing tools to simulate the construction of forest roads have been designed for tactical or operational planning purposes, for relatively small areas (<10 000 ha) and small-scale topographic information. Hence, no forest road simulation tool properly exists to assist forest landscape ecology and management research. Here, we present the Forest Roads Simulation (FRS) extension for the LANDIS-II model—a spatially explicit landscape simulation model of forest succession and disturbances. The FRS extension simulates forest road networks via a least-cost path algorithm accounting for landscape structure, decision inputs, and forest road types. We demonstrate the accuracy with which the FRS extension reproduces several key characteristics of existing road networks in two managed regions in Quebec, Canada: road density, road position, and fragmentation of the landscape. The FRS extension is easy to parameterize, proposing many options for researchers to simulate forest road networks at a strategic level in managed landscapes. It can tackle new research questions investigating the effects of forest roads within management strategies, such as the cost of road construction and habitat fragmentation, across large management units and long planning horizons.
{"title":"A LANDIS-II extension for simulating forest road networks","authors":"C. Hardy, C. Messier, O. Valeria, É. Filotas","doi":"10.1139/cjfr-2022-0306","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0306","url":null,"abstract":"Forest roads are an important part of forest management, both in terms of cost and impact on surrounding ecosystems. Existing tools to simulate the construction of forest roads have been designed for tactical or operational planning purposes, for relatively small areas (<10 000 ha) and small-scale topographic information. Hence, no forest road simulation tool properly exists to assist forest landscape ecology and management research. Here, we present the Forest Roads Simulation (FRS) extension for the LANDIS-II model—a spatially explicit landscape simulation model of forest succession and disturbances. The FRS extension simulates forest road networks via a least-cost path algorithm accounting for landscape structure, decision inputs, and forest road types. We demonstrate the accuracy with which the FRS extension reproduces several key characteristics of existing road networks in two managed regions in Quebec, Canada: road density, road position, and fragmentation of the landscape. The FRS extension is easy to parameterize, proposing many options for researchers to simulate forest road networks at a strategic level in managed landscapes. It can tackle new research questions investigating the effects of forest roads within management strategies, such as the cost of road construction and habitat fragmentation, across large management units and long planning horizons.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48877236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yan Boulanger, Jesus Pascual Puigdevall, Annie Claude Bélisle, Y. Bergeron, Marie‐Hélène Brice, Dominic Cyr, L. De Grandpré, D. Fortin, S. Gauthier, P. Grondin, Guillemette Labadie, Mathieu Leblond, Maryse Marchand, T. B. Splawinski, Martin‐Hugues St‐Laurent, É. Thiffault, J. Tremblay, S. Yamasaki
Regional analyses assessing the vulnerabilities of forest ecosystems and the forest sector to climate change are key to consider the heterogeneity of climate change impacts but also the fact that risks, opportunities and adaptation capacities might differ regionally. Here we provide the Regional Integrated Assessment of climate change on Quebec’s forests, a work that involved several research teams and that focused on climate change impacts on Quebec’s commercial forests and on potential adaptation solutions. Our work showed that climate change will alter several ecological processes within Quebec’s forests. These changes will result in important modifications in forest landscapes. Harvest will cumulate with climate change effects to further alter future forest landscapes which will also have consequences on wildlife habitat (including woodland caribou habitat), avian biodiversity, carbon budget and a variety of forest landscape values for Indigenous peoples. The adaptation of the forest sector, will be crucial to mitigate the impacts of climate change on forest ecosystem goods and services and improve their resilience. Moving forward, a broad range of adaptation measures, notably through reducing harvest levels, should be explored to help strike a balance among social, ecological and economic values. We conclude that without climate adaptation strong negative economical and ecological impacts will likely affect Quebec’s forests.
{"title":"A regional integrated assessment of the impacts of climate change and of the potential adaptation avenues for Quebec’s forests","authors":"Yan Boulanger, Jesus Pascual Puigdevall, Annie Claude Bélisle, Y. Bergeron, Marie‐Hélène Brice, Dominic Cyr, L. De Grandpré, D. Fortin, S. Gauthier, P. Grondin, Guillemette Labadie, Mathieu Leblond, Maryse Marchand, T. B. Splawinski, Martin‐Hugues St‐Laurent, É. Thiffault, J. Tremblay, S. Yamasaki","doi":"10.1139/cjfr-2022-0282","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0282","url":null,"abstract":"Regional analyses assessing the vulnerabilities of forest ecosystems and the forest sector to climate change are key to consider the heterogeneity of climate change impacts but also the fact that risks, opportunities and adaptation capacities might differ regionally. Here we provide the Regional Integrated Assessment of climate change on Quebec’s forests, a work that involved several research teams and that focused on climate change impacts on Quebec’s commercial forests and on potential adaptation solutions. Our work showed that climate change will alter several ecological processes within Quebec’s forests. These changes will result in important modifications in forest landscapes. Harvest will cumulate with climate change effects to further alter future forest landscapes which will also have consequences on wildlife habitat (including woodland caribou habitat), avian biodiversity, carbon budget and a variety of forest landscape values for Indigenous peoples. The adaptation of the forest sector, will be crucial to mitigate the impacts of climate change on forest ecosystem goods and services and improve their resilience. Moving forward, a broad range of adaptation measures, notably through reducing harvest levels, should be explored to help strike a balance among social, ecological and economic values. We conclude that without climate adaptation strong negative economical and ecological impacts will likely affect Quebec’s forests.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49283319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Deforestation causes forest fragmentation and associated edge effects. The boreal forest of Alberta, Canada has undergone substantial fragmentation via the creation of seismic lines, roads, and wellpads for resource exploration and extraction, but their associated edge effects have not been fully assessed, particularly for the latter two footprint types. We examined how these disturbances influence forest composition and structure along anthropogenic forest edges in the oil sands region of northeastern Alberta. We then used generalized linear models to test distance to edge responses in tree and shrub density given treatment (disturbance) type and forest canopy composition. Our results indicate the presence of edge effects, even along narrow seismic lines. Tree and shrub density and tree basal area were greater at the forest edge, being two times greater 1 m from the forest edge relative to intermediate interior forest distances (~30 m). Variation in tree basal area, tree density, and shrub and sapling density were best explained by interactions between disturbance type, distance from the forest edge, and percent conifer composition. This study demonstrates that anthropogenic disturbances from energy exploration in the boreal forests causes change in tree and shrub density (structure) and this effect is most pronounced in deciduous-dominated forests.
{"title":"Effects of oil sands disturbances on shrub and tree structure along forest edges in Alberta's boreal forest","authors":"Rykkar S. Jackson, J. Dennett, S. Nielsen","doi":"10.1139/cjfr-2023-0005","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0005","url":null,"abstract":"Deforestation causes forest fragmentation and associated edge effects. The boreal forest of Alberta, Canada has undergone substantial fragmentation via the creation of seismic lines, roads, and wellpads for resource exploration and extraction, but their associated edge effects have not been fully assessed, particularly for the latter two footprint types. We examined how these disturbances influence forest composition and structure along anthropogenic forest edges in the oil sands region of northeastern Alberta. We then used generalized linear models to test distance to edge responses in tree and shrub density given treatment (disturbance) type and forest canopy composition. Our results indicate the presence of edge effects, even along narrow seismic lines. Tree and shrub density and tree basal area were greater at the forest edge, being two times greater 1 m from the forest edge relative to intermediate interior forest distances (~30 m). Variation in tree basal area, tree density, and shrub and sapling density were best explained by interactions between disturbance type, distance from the forest edge, and percent conifer composition. This study demonstrates that anthropogenic disturbances from energy exploration in the boreal forests causes change in tree and shrub density (structure) and this effect is most pronounced in deciduous-dominated forests.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44370997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Fleming, P. Uhlig, D. Morris, M. Kwiaton, K. Baldwin, P. Hazlett, K. Webster, K. Chapman
Soil Nutrient Regimes (SNRs) are often incorporated in ecosystem classifications. Evaluation of actual nutrient levels associated with these SNRs and development of complimentary Soil Chemistry Regimes (SCRs) could broaden their utility. Using data from 618 forest stands in northwestern Ontario, we developed five-category SCRs using K-means clustering, and examined relationships among individual nutrients, SCRs, and the SNRs of the Canadian National Vegetation Classification Associations and the Ontario Ecological Land Classification Ecosites. F, A and B horizon samples were analyzed for organic C (OrgC), total N (TotN), C:N ratio (C:N), cation exchange capacity (CEC), exchangeable bases, base saturation (BaSat) and pH. CEC, pH and BaSat showed good correspondence across horizons, and together with C:N accounted for much of the variation in chemical properties. There was broad agreement between Association and Ecosite SNRs and B horizon (BHorz) and All horizon (AllHorz) SCRs. C:N decreased while pH and cation metrics increased with increasing SNR and SCR richness. User’s accuracies (SNRs vs. SCRs) for the classifications ranged from 31-39% but increased to 80-86% for SNR values within +/- one SCR class. Classification trees identified pH class, soil texture and overstory composition as the principal field-measured factors related to BHorzSCRs.
{"title":"A Quantitative Approach to Defining Soil Nutrient Regimes within Ecosystem Classifications for Northwestern Ontario","authors":"R. Fleming, P. Uhlig, D. Morris, M. Kwiaton, K. Baldwin, P. Hazlett, K. Webster, K. Chapman","doi":"10.1139/cjfr-2022-0296","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0296","url":null,"abstract":"Soil Nutrient Regimes (SNRs) are often incorporated in ecosystem classifications. Evaluation of actual nutrient levels associated with these SNRs and development of complimentary Soil Chemistry Regimes (SCRs) could broaden their utility. Using data from 618 forest stands in northwestern Ontario, we developed five-category SCRs using K-means clustering, and examined relationships among individual nutrients, SCRs, and the SNRs of the Canadian National Vegetation Classification Associations and the Ontario Ecological Land Classification Ecosites. F, A and B horizon samples were analyzed for organic C (OrgC), total N (TotN), C:N ratio (C:N), cation exchange capacity (CEC), exchangeable bases, base saturation (BaSat) and pH. CEC, pH and BaSat showed good correspondence across horizons, and together with C:N accounted for much of the variation in chemical properties. There was broad agreement between Association and Ecosite SNRs and B horizon (BHorz) and All horizon (AllHorz) SCRs. C:N decreased while pH and cation metrics increased with increasing SNR and SCR richness. User’s accuracies (SNRs vs. SCRs) for the classifications ranged from 31-39% but increased to 80-86% for SNR values within +/- one SCR class. Classification trees identified pH class, soil texture and overstory composition as the principal field-measured factors related to BHorzSCRs.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48026800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Climate projections predict more frequent and severe drought in coastal Pseudotsuga menziesii forests of western North America, raising concerns over how to promote drought adaptation. Thinning often increases drought resistance (the ability to maintain growth during a drought) and resilience (the ability to recover growth after a drought), but these effects vary with thinning intensity, shift over time, and may have tradeoffs with fiber production. We collected tree cores from a long-term thinning study with four residual density levels replicated across both uniform thinning and thinning with gaps, and used annual growth data to investigate responses to droughts occurring 8 and 21 years after thinning. For the first drought, resistance and resilience were higher in treatments with lower residual densities. For the second drought, there were no differences in drought response between the lowest and highest residual density treatments, and all treatments had lower drought resistance and resilience than for the first drought. Spatial arrangement had little impact on drought resistance or resilience and residual density level had a significant effect on the periodic annual volume increment – drought resistance tradeoff. Our results suggest that thinning can promote drought adaptation in Pseudotsuga menziesii forests, but these effects dissipate over time.
{"title":"Effects of Thinning on Tradeoffs Between Drought Resistance, Drought Resilience, and Wood Production in mature Douglas-fir in Western OR, USA","authors":"L. M. Elfstrom, M. Powers","doi":"10.1139/cjfr-2022-0235","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0235","url":null,"abstract":"Climate projections predict more frequent and severe drought in coastal Pseudotsuga menziesii forests of western North America, raising concerns over how to promote drought adaptation. Thinning often increases drought resistance (the ability to maintain growth during a drought) and resilience (the ability to recover growth after a drought), but these effects vary with thinning intensity, shift over time, and may have tradeoffs with fiber production. We collected tree cores from a long-term thinning study with four residual density levels replicated across both uniform thinning and thinning with gaps, and used annual growth data to investigate responses to droughts occurring 8 and 21 years after thinning. For the first drought, resistance and resilience were higher in treatments with lower residual densities. For the second drought, there were no differences in drought response between the lowest and highest residual density treatments, and all treatments had lower drought resistance and resilience than for the first drought. Spatial arrangement had little impact on drought resistance or resilience and residual density level had a significant effect on the periodic annual volume increment – drought resistance tradeoff. Our results suggest that thinning can promote drought adaptation in Pseudotsuga menziesii forests, but these effects dissipate over time.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42507409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vesa-Pekka Parkatti, O. Tahvonen, T. Viskari, J. Liski
We integrate a carbon net sink and stand-level wood production to analyze their simultaneous optimization as an economic problem. Carbon is included in living trees, wood products, and forest soil. Forestry is specified by a size-structured model for optimizing thinning timing and intensity, rotation period, and the optimal choice of rotation versus continuous cover forestry. The optimal inclusion of a carbon net sink increases the carbon pool mainly in living trees and forest soil, while the effect on the product carbon pool remains minor. With a 3% interest rate, increasing the CO2 price to €40 per tCO2 increases the total steady-state carbon pool by 131% and the soil carbon accounts for ca. 60% of the increased carbon storage. Omitting soil carbon, as in previous studies, leads to underestimates of the carbon sink, significantly decreasing the optimal total CO2 net sink and achievable economic net gain from joint wood production and carbon management. The inclusion of soil carbon suggests that, in contrast to previous results, a higher CO2 price does not necessarily favor continuous cover forestry.
{"title":"Including soil alters the optimization of forestry with carbon sinks","authors":"Vesa-Pekka Parkatti, O. Tahvonen, T. Viskari, J. Liski","doi":"10.1139/cjfr-2022-0226","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0226","url":null,"abstract":"We integrate a carbon net sink and stand-level wood production to analyze their simultaneous optimization as an economic problem. Carbon is included in living trees, wood products, and forest soil. Forestry is specified by a size-structured model for optimizing thinning timing and intensity, rotation period, and the optimal choice of rotation versus continuous cover forestry. The optimal inclusion of a carbon net sink increases the carbon pool mainly in living trees and forest soil, while the effect on the product carbon pool remains minor. With a 3% interest rate, increasing the CO2 price to €40 per tCO2 increases the total steady-state carbon pool by 131% and the soil carbon accounts for ca. 60% of the increased carbon storage. Omitting soil carbon, as in previous studies, leads to underestimates of the carbon sink, significantly decreasing the optimal total CO2 net sink and achievable economic net gain from joint wood production and carbon management. The inclusion of soil carbon suggests that, in contrast to previous results, a higher CO2 price does not necessarily favor continuous cover forestry.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42476645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Retraction: Examination of two new technologies to assess the diet of woodland caribou: video recorders attached to collars and DNA barcoding","authors":"","doi":"10.1139/cjfr-2023-0042","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0042","url":null,"abstract":"","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45928640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-13eCollection Date: 2023-01-01DOI: 10.3897/BDJ.11.e99650
Jean-Yves Meunier, Benoît Geslin, Mehdi Issertes, Gilles Mahé, Frédéric Vyghen, Harold Labrique, Yves Dutour, Vincent Poncet, Jérémy Migliore, Gabriel Nève
Background: Many insect species have shown dramatic declines over the last decades, as a result of man-related environmental changes. Many species which were formerly widespread are now rare. To document this trend with evidence, old records of collected specimens are vital.
New information: We provide here the data on 9752 bee (Hymenoptera: Apoidea) specimens hosted in several museums of south-east France: Musée des Confluences in Lyon, Muséum d'Histoire Naturelle de Marseille, Muséum d'Aix-en-Provence and the Muséum Départemental du Var in Toulon. Most of the specimens (9256) come from France and include data on 552 named species. For most of these specimens, the geographical location, including geographical coordinates, is based on the locality (town or village) where they were collected. The specimens were captured from the beginning of the nineteenth century to 2018. The identifications of 1377 specimens, mainly belonging to the genus Bombus, are considered reliable, as these were performed or been checked since 2009. All the other reported identifications are the original ones given by the original collectors.
{"title":"Apoidea of the collections of Lyon, Aix-en-Provence, Marseille and Toulon Museums of Natural History (France).","authors":"Jean-Yves Meunier, Benoît Geslin, Mehdi Issertes, Gilles Mahé, Frédéric Vyghen, Harold Labrique, Yves Dutour, Vincent Poncet, Jérémy Migliore, Gabriel Nève","doi":"10.3897/BDJ.11.e99650","DOIUrl":"10.3897/BDJ.11.e99650","url":null,"abstract":"<p><strong>Background: </strong>Many insect species have shown dramatic declines over the last decades, as a result of man-related environmental changes. Many species which were formerly widespread are now rare. To document this trend with evidence, old records of collected specimens are vital.</p><p><strong>New information: </strong>We provide here the data on 9752 bee (Hymenoptera: Apoidea) specimens hosted in several museums of south-east France: Musée des Confluences in Lyon, Muséum d'Histoire Naturelle de Marseille, Muséum d'Aix-en-Provence and the Muséum Départemental du Var in Toulon. Most of the specimens (9256) come from France and include data on 552 named species. For most of these specimens, the geographical location, including geographical coordinates, is based on the locality (town or village) where they were collected. The specimens were captured from the beginning of the nineteenth century to 2018. The identifications of 1377 specimens, mainly belonging to the genus <i>Bombus</i>, are considered reliable, as these were performed or been checked since 2009. All the other reported identifications are the original ones given by the original collectors.</p>","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"24 1","pages":"e99650"},"PeriodicalIF":1.3,"publicationDate":"2023-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10848718/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85920802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Dagley, Judson Fisher, J. Teraoka, Scott L. Powell, J. Berrill
Forest restoration thinning has the potential to enhance structural complexity and accelerate development of large trees important to wildlife, aesthetics, and wildfire resistance. These are key objectives for restoration of even-aged secondary forests within Redwood National Park in Humboldt County, California, USA. We evaluated tree growth and stand structure 10 years after two thinning methods were applied at two intensities in a 40-year-old mixed redwood (Sequoia sempervirens (Lamb. ex D. Don) Endl.))/Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) stand. Heavy thinning enhanced diameter growth of redwood and Douglas-fir trees more than light thinning. Crown thinning generally enhanced structural diversity more than low thinning, and structural diversity increased progressively over the 10 years following thinning. Understory plant richness fluctuated between measurement years. Heavy thinning enhanced understory shrub cover. The fastest-growing trees in heavily-thinned stands were much more likely to sustain bear damage, especially redwood trees. Overall, different thinning methods and intensities induced a different suite of outcomes, yet none restored redwood dominance, but all treatments enhanced some other ecosystem values important for old-growth restoration such as large overstory trees, understory plant and shrubs, and elements of structural complexity including tree-size variability, snags, down logs, and trees exhibiting stem or top damage.
{"title":"Heavy crown thinning in redwood/Douglas-fir gave superior forest restoration outcomes after 10 years","authors":"C. Dagley, Judson Fisher, J. Teraoka, Scott L. Powell, J. Berrill","doi":"10.1139/cjfr-2022-0214","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0214","url":null,"abstract":"Forest restoration thinning has the potential to enhance structural complexity and accelerate development of large trees important to wildlife, aesthetics, and wildfire resistance. These are key objectives for restoration of even-aged secondary forests within Redwood National Park in Humboldt County, California, USA. We evaluated tree growth and stand structure 10 years after two thinning methods were applied at two intensities in a 40-year-old mixed redwood (Sequoia sempervirens (Lamb. ex D. Don) Endl.))/Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) stand. Heavy thinning enhanced diameter growth of redwood and Douglas-fir trees more than light thinning. Crown thinning generally enhanced structural diversity more than low thinning, and structural diversity increased progressively over the 10 years following thinning. Understory plant richness fluctuated between measurement years. Heavy thinning enhanced understory shrub cover. The fastest-growing trees in heavily-thinned stands were much more likely to sustain bear damage, especially redwood trees. Overall, different thinning methods and intensities induced a different suite of outcomes, yet none restored redwood dominance, but all treatments enhanced some other ecosystem values important for old-growth restoration such as large overstory trees, understory plant and shrubs, and elements of structural complexity including tree-size variability, snags, down logs, and trees exhibiting stem or top damage.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46317544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aaron Knauer, Tiffany L. Betras, A. Royo, T. Diggins, W. Carson
White-tailed deer ( Odocoileus virginianus) have been overabundant in eastern North America for more than five decades, resulting in depauperate understories and ricocheting effects on higher trophic levels. Even after deer populations are reduced, understory plant communities may fail to recover for an unknown length of time due to persistent legacy effects. We surveyed understory plant communities in six deer exclosures and paired reference plots in northwestern Pennsylvania to determine the degree to which 19 years of deer exclusion was sufficient for recovery of species richness, diversity, percent cover, and understory structural complexity. We observed a 2.3-fold increase in tree cover and a 60% reduction in fern cover in the ground layer, as well as a 114-fold increase in foliage density between 80 and 200 cm above ground level, in exclosures compared to reference plots. However, the exclosures did not permanently support higher overall percent cover, species richness, or diversity in the ground layer, nor did we detect any meaningful divergence in community composition between exclosures and reference plots. We conclude that 19 years of release from chronic over-browsing are sufficient to restore understory structural complexity, but recovery of diversity in the ground layer will require more time or direct intervention.
{"title":"Understory plant communities fail to recover species diversity after excluding deer for nearly 20 years","authors":"Aaron Knauer, Tiffany L. Betras, A. Royo, T. Diggins, W. Carson","doi":"10.1139/cjfr-2022-0234","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0234","url":null,"abstract":"White-tailed deer ( Odocoileus virginianus) have been overabundant in eastern North America for more than five decades, resulting in depauperate understories and ricocheting effects on higher trophic levels. Even after deer populations are reduced, understory plant communities may fail to recover for an unknown length of time due to persistent legacy effects. We surveyed understory plant communities in six deer exclosures and paired reference plots in northwestern Pennsylvania to determine the degree to which 19 years of deer exclusion was sufficient for recovery of species richness, diversity, percent cover, and understory structural complexity. We observed a 2.3-fold increase in tree cover and a 60% reduction in fern cover in the ground layer, as well as a 114-fold increase in foliage density between 80 and 200 cm above ground level, in exclosures compared to reference plots. However, the exclosures did not permanently support higher overall percent cover, species richness, or diversity in the ground layer, nor did we detect any meaningful divergence in community composition between exclosures and reference plots. We conclude that 19 years of release from chronic over-browsing are sufficient to restore understory structural complexity, but recovery of diversity in the ground layer will require more time or direct intervention.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44981032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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