Rebecca Anne Riggs, Jasmine Arora, Agni Klintuni Boedhihartono, Chris Gaston, Adinda Rizky Herdianti, James Douglas Langston, Erin Robinson, Jeffrey Sayer, Emilio Valeri
Forestry is becoming more complex as a result of diverging societal demands. Indigenous Peoples’ reconciliation and the challenges of climate change call for research that embraces transdisciplinarity, reciprocity, and problem-focused learning at the landscape scale. Both globally and in Canada, forestry and forest research are struggling to keep pace with this growing complexity. Place-based collaborative research and learning initiatives, described here as “learning landscapes,” offer an under-explored approach to meeting diversifying goals for forest landscapes. We describe recent progress in Quesnel, British Columbia, where researchers and local institutions are engaging to strengthen resilience and innovation in the forest sector. We first define the concept of learning landscape in the context of transdisciplinary sustainability science, and then illustrate this approach using the case study of Quesnel. We describe a process of systems diagnosis, including asset mapping and analysis of potential forestry pathways through a “best bets” framework. We propose a Theory of Change as a way forward, outlining opportunities for government, industry, and communities in developing regional capacity for integrated management and high-value forest products. We reflect on the contributions of learning landscapes to knowledge generation, experiential learning, and institutional development, and discuss implications for steering decision-making in locally driven sustainability transitions.
{"title":"Transdisciplinary science for strengthening forest systems in British Columbia: Quesnel as a learning landscape","authors":"Rebecca Anne Riggs, Jasmine Arora, Agni Klintuni Boedhihartono, Chris Gaston, Adinda Rizky Herdianti, James Douglas Langston, Erin Robinson, Jeffrey Sayer, Emilio Valeri","doi":"10.1139/cjfr-2023-0057","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0057","url":null,"abstract":"Forestry is becoming more complex as a result of diverging societal demands. Indigenous Peoples’ reconciliation and the challenges of climate change call for research that embraces transdisciplinarity, reciprocity, and problem-focused learning at the landscape scale. Both globally and in Canada, forestry and forest research are struggling to keep pace with this growing complexity. Place-based collaborative research and learning initiatives, described here as “learning landscapes,” offer an under-explored approach to meeting diversifying goals for forest landscapes. We describe recent progress in Quesnel, British Columbia, where researchers and local institutions are engaging to strengthen resilience and innovation in the forest sector. We first define the concept of learning landscape in the context of transdisciplinary sustainability science, and then illustrate this approach using the case study of Quesnel. We describe a process of systems diagnosis, including asset mapping and analysis of potential forestry pathways through a “best bets” framework. We propose a Theory of Change as a way forward, outlining opportunities for government, industry, and communities in developing regional capacity for integrated management and high-value forest products. We reflect on the contributions of learning landscapes to knowledge generation, experiential learning, and institutional development, and discuss implications for steering decision-making in locally driven sustainability transitions.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135607612","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}
In boreal old-growth forests, advance regeneration typically attains canopy dominance through growth release events following partial disturbances. We sampled competing Picea mariana (Mill.) and Abies balsamea (L.) in disturbed old-growth stands in Quebec, Canada, to understand the intra- and interspecific size hierarchy development. We reconstructed tree size development and examined the role of initial size difference, time between germination and a disturbance, and the strength of response to the disturbance in determining tree size hierarchies. Trees that regenerated first generally dominated their intraspecific competitors also following a disturbance event. However, prolonged time between germination and disturbance resulted in a less deterministic outcome. Tree size difference prior to disturbance also influenced the development of size hierarchies. In interspecific competition between individuals of the same diameter, A. balsamea had a 61% probability of gaining dominance over P. mariana, the probability being 50% if P. mariana was 5 mm larger than A. balsamea. Dominant trees generally had the strongest response to the disturbance, reinforcing the existing size hierarchies. The largest trees typically gain dominance after a partial disturbance. However, interspecific competition is less predictable than intraspecific competition, small initial size difference, and prolonged time in suppression potentially changing tree size hierarchies.
{"title":"Race to the canopy: the development of tree size hierarchies following a partial disturbance in a boreal old-growth forest","authors":"Niko Kulha, A. Ahokas, S. Gauthier, T. Aakala","doi":"10.1139/cjfr-2022-0224","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0224","url":null,"abstract":"In boreal old-growth forests, advance regeneration typically attains canopy dominance through growth release events following partial disturbances. We sampled competing Picea mariana (Mill.) and Abies balsamea (L.) in disturbed old-growth stands in Quebec, Canada, to understand the intra- and interspecific size hierarchy development. We reconstructed tree size development and examined the role of initial size difference, time between germination and a disturbance, and the strength of response to the disturbance in determining tree size hierarchies. Trees that regenerated first generally dominated their intraspecific competitors also following a disturbance event. However, prolonged time between germination and disturbance resulted in a less deterministic outcome. Tree size difference prior to disturbance also influenced the development of size hierarchies. In interspecific competition between individuals of the same diameter, A. balsamea had a 61% probability of gaining dominance over P. mariana, the probability being 50% if P. mariana was 5 mm larger than A. balsamea. Dominant trees generally had the strongest response to the disturbance, reinforcing the existing size hierarchies. The largest trees typically gain dominance after a partial disturbance. However, interspecific competition is less predictable than intraspecific competition, small initial size difference, and prolonged time in suppression potentially changing tree size hierarchies.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44617426","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}
Using multi-scale trembling aspen tree-ring width data from Alberta, we show that scaling has a profound influence on dendroecological inferencing. At all scales of sampling there is a significant climatological signal whose strength is nevertheless superseded by the pervasive effect of insect herbivory. At the smallest spatial scale, 20km x 20km, we demonstrate a quasi-periodic pattern of sharp growth reductions, and the existence of negative spatial correlations amongst successive outbreaks. At the intermediate spatial scale of 20km x 80 km, we show that the period 1930-1963 was marked by extremely low correlations in aspen ring widths, with much higher correlations occurring both before and after, despite high variance in precipitation that might have caused ring widths to correlate under moisture limitation. At the largest spatial scale of the entire province, aspen ring widths in the boreal forest became de-correlated abruptly in 1916, after cycling synchronously for the previous 80 years. This occurred despite a warming climate that heightened moisture-limitation. Something in the environment prevents some outbreak cycles from rising to maximum intensity and from spreading to maximum extent. This appears to be the key to better predictability and management of forest insects and forests at short and long time scales.
利用阿尔伯塔省的多尺度颤抖白杨树年轮宽度数据，我们发现尺度对树木生态学推断有着深远的影响。在所有采样尺度上，都有一个重要的气候信号，其强度被昆虫食草动物的普遍影响所取代。在20公里x 20公里的最小空间尺度上，我们证明了生长急剧减少的准周期性模式，并且连续爆发之间存在负空间相关性。在20km x 80km的中等空间尺度上，我们发现1930-1963年期间白杨环宽度的相关性极低，前后的相关性要高得多，尽管降水量的高度变化可能导致环宽度在湿度限制下相互关联。在全省最大的空间尺度上，北方森林中的白杨环宽度在经历了80年的同步循环后，于1916年突然脱钩。尽管气候变暖加剧了水分限制，但还是发生了这种情况。环境中的某些东西阻止了一些疫情周期上升到最大强度并传播到最大程度。这似乎是在短时间和长时间尺度上更好地预测和管理森林昆虫和森林的关键。
{"title":"Variable synchrony in insect outbreak cycling across a forest landscape gradient: multi-scale evidence from trembling aspen in Alberta","authors":"B. Cooke, J. Roland","doi":"10.1139/cjfr-2022-0246","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0246","url":null,"abstract":"Using multi-scale trembling aspen tree-ring width data from Alberta, we show that scaling has a profound influence on dendroecological inferencing. At all scales of sampling there is a significant climatological signal whose strength is nevertheless superseded by the pervasive effect of insect herbivory. At the smallest spatial scale, 20km x 20km, we demonstrate a quasi-periodic pattern of sharp growth reductions, and the existence of negative spatial correlations amongst successive outbreaks. At the intermediate spatial scale of 20km x 80 km, we show that the period 1930-1963 was marked by extremely low correlations in aspen ring widths, with much higher correlations occurring both before and after, despite high variance in precipitation that might have caused ring widths to correlate under moisture limitation. At the largest spatial scale of the entire province, aspen ring widths in the boreal forest became de-correlated abruptly in 1916, after cycling synchronously for the previous 80 years. This occurred despite a warming climate that heightened moisture-limitation. Something in the environment prevents some outbreak cycles from rising to maximum intensity and from spreading to maximum extent. This appears to be the key to better predictability and management of forest insects and forests at short and long time scales.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46094223","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}
Gissella Betzavel Quiroga, Allison B Simler-Williams, Kerri M Frangioso, Susan Frankel, David M. Rizzo, Richard Cobb
Many coastal forests stretching from central California to southwest Oregon are threatened or have been impacted by the invasive forest pathogen Phytophthora ramorum, the cause of sudden oak death. We analyzed a set of stand-level forest treatments aimed at preventing or mitigating disease impacts on stand composition, biomass, and fuels using a before–after-control-intervention experiment with a re-evaluation after 5 years. We compared the effects of restorative management for invaded stands and preventative treatments for uninvaded forests with two stand-level experiments. The restorative treatments contrasted two approaches to mastication, hand-crew thinning, and thinning with pile burning with untreated controls replicated at three distinct sites ( N = 30), while the preventative treatments were limited to hand-crew thinning ( N = 10) conducted at a single site. Half of the restoration treatments had basal sprouts removed 2 and 4 years after treatment. All treatments significantly reduced stand density and increased average tree size without significantly decreasing total basal area, both immediately and 5 years after treatments. Preventative treatments did not reduce the basal area or density of timber species not susceptible to P. ramorum, suggesting the relative dominance of these species increased in accordance with host removal. Follow-up basal sprout removal in the restoration experiment appears to maintain treatment benefits for average tree size and may be associated with small decreases in stand density 5 years after initial treatment. Our study demonstrates that for at least 5 years, a range of common stand management practices can improve forest conditions threatened or impacted by sudden oak death.
{"title":"An experimental comparison of stand management approaches to sudden oak death: prevention vs. restoration","authors":"Gissella Betzavel Quiroga, Allison B Simler-Williams, Kerri M Frangioso, Susan Frankel, David M. Rizzo, Richard Cobb","doi":"10.1139/cjfr-2022-0328","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0328","url":null,"abstract":"Many coastal forests stretching from central California to southwest Oregon are threatened or have been impacted by the invasive forest pathogen Phytophthora ramorum, the cause of sudden oak death. We analyzed a set of stand-level forest treatments aimed at preventing or mitigating disease impacts on stand composition, biomass, and fuels using a before–after-control-intervention experiment with a re-evaluation after 5 years. We compared the effects of restorative management for invaded stands and preventative treatments for uninvaded forests with two stand-level experiments. The restorative treatments contrasted two approaches to mastication, hand-crew thinning, and thinning with pile burning with untreated controls replicated at three distinct sites ( N = 30), while the preventative treatments were limited to hand-crew thinning ( N = 10) conducted at a single site. Half of the restoration treatments had basal sprouts removed 2 and 4 years after treatment. All treatments significantly reduced stand density and increased average tree size without significantly decreasing total basal area, both immediately and 5 years after treatments. Preventative treatments did not reduce the basal area or density of timber species not susceptible to P. ramorum, suggesting the relative dominance of these species increased in accordance with host removal. Follow-up basal sprout removal in the restoration experiment appears to maintain treatment benefits for average tree size and may be associated with small decreases in stand density 5 years after initial treatment. Our study demonstrates that for at least 5 years, a range of common stand management practices can improve forest conditions threatened or impacted by sudden oak death.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135643036","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}
Baburam Rijal, Hugues Power, Isabelle Auger, Emmanuel Duchateau, Robert Schneider, Steve Bedard, François Guillemette
Saplings (tree species whose diameter at breast height ranges from 1.1 to 9.0 cm) are important in forest growth and development. Their abundance and density can lead to specific forest successional trajectories and ecosystem characteristics. Yet, the consideration of saplings in forest management planning is a relatively new topic and is still rarely included in forest growth models. We developed sapling density models for 10 species groups with the objective of providing forest managers with additional tools to support the development of more precise prediction systems. We used dendrometric and environmental variables to model sapling density and species-wise density ratios. We evaluated Poisson and gamma regressions for the modelling of sapling density and zero-inflated logistic regressions to model species ratios. We used repeated measurements (from 1982 to 2019) from permanent sample plots located in hardwood forests in northeastern North America. Our results show that the gamma regression was superior to the Poisson regression. The cross-validated mean bias using gamma regression was 55 stems·ha −1 with a relative percentage error of 2.5% and an R 2 of 0.43. The species-wise sapling density ratio model had an overall R 2 of 0.93, and the species-wise mean R 2 ranged between 0.90 and 0.96. Among the examined model covariates, stem density of merchantable-sized trees and latitude were significant in both models. We believe that the models we developed can be useful for forest management planning and sustainable merchantable production.
{"title":"Modelling sapling density for sugar maple-dominated mixed stands of eastern Canada","authors":"Baburam Rijal, Hugues Power, Isabelle Auger, Emmanuel Duchateau, Robert Schneider, Steve Bedard, François Guillemette","doi":"10.1139/cjfr-2023-0062","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0062","url":null,"abstract":"Saplings (tree species whose diameter at breast height ranges from 1.1 to 9.0 cm) are important in forest growth and development. Their abundance and density can lead to specific forest successional trajectories and ecosystem characteristics. Yet, the consideration of saplings in forest management planning is a relatively new topic and is still rarely included in forest growth models. We developed sapling density models for 10 species groups with the objective of providing forest managers with additional tools to support the development of more precise prediction systems. We used dendrometric and environmental variables to model sapling density and species-wise density ratios. We evaluated Poisson and gamma regressions for the modelling of sapling density and zero-inflated logistic regressions to model species ratios. We used repeated measurements (from 1982 to 2019) from permanent sample plots located in hardwood forests in northeastern North America. Our results show that the gamma regression was superior to the Poisson regression. The cross-validated mean bias using gamma regression was 55 stems·ha −1 with a relative percentage error of 2.5% and an R 2 of 0.43. The species-wise sapling density ratio model had an overall R 2 of 0.93, and the species-wise mean R 2 ranged between 0.90 and 0.96. Among the examined model covariates, stem density of merchantable-sized trees and latitude were significant in both models. We believe that the models we developed can be useful for forest management planning and sustainable merchantable production.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135643034","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}
As forest managers increasingly seek to implement partial harvest silviculture systems in complex forests, more data are required on the potential development of the residual stand following treatment. In this study, we present 25-year data from a long-term silvicultural study of tree- and stand-level responses to differing levels of basal area following partial harvest in a complex spruce-fir forest in central British Columbia, Canada. Reducing stand basal area elicited stronger basal area increment response in fir than spruce, however, spruce productivity was overall higher than fir across all treatments. Smaller trees increased their size proportionally more than larger trees, and thinning resulted in increased recruitment of smaller trees into larger diameter classes. At the stand-level, basal area reductions to well below 20m2/ha resulted in higher volume and basal area growth over the length of this study, and suggests that optimum stand –level growth may be achieved at lower basal areas than suggested in prior literature. We also found a positive relationship between stand-level residual basal area and mortality. In central British Columbia, stand structure, species composition and growth rates in complex spruce-fir forests can be maintained through partial harvest silviculture treatments.
{"title":"Stand- and tree-level responses to a range of initial basal area densities following partial harvest of complex spruce-fir stands in central British Columbia: 25-year results of a long-term field experiment","authors":"M. Jull, Hardy Griesbauer","doi":"10.1139/cjfr-2023-0017","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0017","url":null,"abstract":"As forest managers increasingly seek to implement partial harvest silviculture systems in complex forests, more data are required on the potential development of the residual stand following treatment. In this study, we present 25-year data from a long-term silvicultural study of tree- and stand-level responses to differing levels of basal area following partial harvest in a complex spruce-fir forest in central British Columbia, Canada. Reducing stand basal area elicited stronger basal area increment response in fir than spruce, however, spruce productivity was overall higher than fir across all treatments. Smaller trees increased their size proportionally more than larger trees, and thinning resulted in increased recruitment of smaller trees into larger diameter classes. At the stand-level, basal area reductions to well below 20m2/ha resulted in higher volume and basal area growth over the length of this study, and suggests that optimum stand –level growth may be achieved at lower basal areas than suggested in prior literature. We also found a positive relationship between stand-level residual basal area and mortality. In central British Columbia, stand structure, species composition and growth rates in complex spruce-fir forests can be maintained through partial harvest silviculture treatments.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43672178","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}
As one of the most widely used dwarf bamboos, Pleioblastus viridistriatus has well-developed rhizome and root systems, which can rapidly expand into forest stands. However, little is known about the influence of P. viridistriatus expansion on the undergrowth diversity in subtropical forests of China, and its association with the diversity of soil bacterial microbiota. The species diversity and soil bacterial community structure were investigated in a forest where P. viridistriatus was expanding into coniferous and broad-leaved mixed forest. We found that P. viridistriatus expansion reduced species diversity in the shrub and herbaceous layers and had significant effects on major soil physicochemical properties. In addition, the Alpha diversity indexes were significantly increased, the abundance of Actinobacteria and Candidatus Saccharibact increased, while the abundance of Nitrospirae and Deinococcus Thermus decreased with the increasing expansion. At the genus level, a total of 25 genera of soil bacteria showed significant difference in abundance. Overall, expansion of P. viridistriatus reduced forest species diversity, while increased soil nutrient accumulation and specific bacterial abundance to improve nutrient acquisition. Our results can provide guidance for controlling dwarf bamboo expansion, and help the sustainable forest management.
{"title":"Effects of Pleioblastus viridistriatus expansion on species diversity of understory vegetation and soil bacterial community in subtropical forests","authors":"Lu Qiu, Gang Lei, Z. Yan, Bo Deng","doi":"10.1139/cjfr-2022-0261","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0261","url":null,"abstract":"As one of the most widely used dwarf bamboos, Pleioblastus viridistriatus has well-developed rhizome and root systems, which can rapidly expand into forest stands. However, little is known about the influence of P. viridistriatus expansion on the undergrowth diversity in subtropical forests of China, and its association with the diversity of soil bacterial microbiota. The species diversity and soil bacterial community structure were investigated in a forest where P. viridistriatus was expanding into coniferous and broad-leaved mixed forest. We found that P. viridistriatus expansion reduced species diversity in the shrub and herbaceous layers and had significant effects on major soil physicochemical properties. In addition, the Alpha diversity indexes were significantly increased, the abundance of Actinobacteria and Candidatus Saccharibact increased, while the abundance of Nitrospirae and Deinococcus Thermus decreased with the increasing expansion. At the genus level, a total of 25 genera of soil bacteria showed significant difference in abundance. Overall, expansion of P. viridistriatus reduced forest species diversity, while increased soil nutrient accumulation and specific bacterial abundance to improve nutrient acquisition. Our results can provide guidance for controlling dwarf bamboo expansion, and help the sustainable forest management.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45087130","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}
T. Work, D. Morris, Sarah Loboda, Jan Klimasweski, K. Wainio-Keizer, L. Venier
Forest biomass harvest has the potential to provide feedstocks for energy production to offset fossil fuel consumption. However, concerns have been raised regarding the ecological sustainability of removing additional biomass from forests, in particular the impacts on biodiversity. In this paper we used a suite of ground-dwelling arthropod taxa (ground beetles, spiders, and rove beetles) to measure community compositional changes along a gradient of biomass removal treatments 7 years post-harvest, and compared against reference. Based on multivariate regression trees, changes in species composition reflected the intensity gradient of the biomass removal treatments or stand attributes associated with the level of forest floor disturbance across all arthropod groups. For each arthropod group, changes in composition were defined primarily by reductions or loss of abundant forest associated species and increases in the number and abundance of species associated with more xeric conditions and increased disturbance intensity. There were no differences between full-tree and tree-length treatments. Overall, results indicated a strong arthropod response to the removal of overstory, forest floor disturbance and reductions in understory cover mostly resulting from the glyphosate applications. Arthropod recovery would benefit from overstory retention, reduction in forest floor disturbance and judicial use of glyphosate.
{"title":"Cumulative effects of biomass harvesting and herbicide application on litter-dwelling arthropod communities in jack pine-dominated forests: 7th year post-harvest assessment.","authors":"T. Work, D. Morris, Sarah Loboda, Jan Klimasweski, K. Wainio-Keizer, L. Venier","doi":"10.1139/cjfr-2023-0018","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0018","url":null,"abstract":"Forest biomass harvest has the potential to provide feedstocks for energy production to offset fossil fuel consumption. However, concerns have been raised regarding the ecological sustainability of removing additional biomass from forests, in particular the impacts on biodiversity. In this paper we used a suite of ground-dwelling arthropod taxa (ground beetles, spiders, and rove beetles) to measure community compositional changes along a gradient of biomass removal treatments 7 years post-harvest, and compared against reference. Based on multivariate regression trees, changes in species composition reflected the intensity gradient of the biomass removal treatments or stand attributes associated with the level of forest floor disturbance across all arthropod groups. For each arthropod group, changes in composition were defined primarily by reductions or loss of abundant forest associated species and increases in the number and abundance of species associated with more xeric conditions and increased disturbance intensity. There were no differences between full-tree and tree-length treatments. Overall, results indicated a strong arthropod response to the removal of overstory, forest floor disturbance and reductions in understory cover mostly resulting from the glyphosate applications. Arthropod recovery would benefit from overstory retention, reduction in forest floor disturbance and judicial use of glyphosate.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45108238","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}
Decades of acidic deposition and timber harvesting have depleted calcium (Ca) stocks in soils. One approach to tracking Ca sources from soil is by using Ca/Sr ratios, while 87Sr/86Sr ratios have been used to estimate mineral weathering rates. To evaluate the uses of Ca/Sr ratios and Sr isotopes in identifying Ca sources in sugar maple (Acer saccharum Marsh) trees, three base-poor sites on the Canadian Shield and three limestone sites in southern Ontario were sampled. Higher Ca/Sr ratios in soil extracts and sugar maple tissues at base rich sites reflect different minerology among regions, while the Ca/Sr discrimination factor between roots and foliage indicated that internal cycling exerts a major control on Ca/Sr ratios in sugar maple. At the three off-shield sites, 87Sr/86Sr ratios in soil and tree tissues were higher than precipitation but were indistinguishable for off-shield sites. Mixing models using a 1.0 M HCl soil extract as the weathering endmember indicated that a lower proportion of weathering-Ca compared with other geochemical approaches. One potential explanation is that the extraction method dissolves more recalcitrant minerals to a greater extent than under field conditions, leading to a higher weathering rate endmember value used in the mixing model.
几十年的酸性沉积和木材采伐已经耗尽了土壤中的钙(Ca)储量。从土壤中追踪Ca来源的一种方法是使用Ca/Sr比率，而87Sr/86Sr比率已用于估计矿物风化速率。为了评估Ca/Sr比值和Sr同位素在鉴别糖枫(Acer saccharum Marsh)树Ca来源中的应用，我们对加拿大地盾上的三个碱基贫乏的地点和安大略省南部的三个石灰岩地点进行了采样。富碱区土壤抽提物和糖枫组织Ca/Sr比值较高反映了不同地区矿物学特征的差异，根系和叶片Ca/Sr判别因子表明糖枫体内循环对Ca/Sr比值起主要控制作用。在3个非屏蔽站点，土壤和树木组织87Sr/86Sr比值高于降水，但在非屏蔽站点无法区分。以1.0 M HCl土壤萃取物为风化端元的混合模型表明，与其他地球化学方法相比，风化钙的比例较低。一种可能的解释是，萃取方法比现场条件下溶解了更多的难溶性矿物，导致混合模型中使用的风化速率端元值更高。
{"title":"Evaluating the use of Ca/Sr and 87Sr/86Sr ratios to track Ca sources in sugar maple in Ontario","authors":"Thu Hang Nguyen, S. Watmough, D. H. Dang","doi":"10.1139/cjfr-2022-0326","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0326","url":null,"abstract":"Decades of acidic deposition and timber harvesting have depleted calcium (Ca) stocks in soils. One approach to tracking Ca sources from soil is by using Ca/Sr ratios, while 87Sr/86Sr ratios have been used to estimate mineral weathering rates. To evaluate the uses of Ca/Sr ratios and Sr isotopes in identifying Ca sources in sugar maple (Acer saccharum Marsh) trees, three base-poor sites on the Canadian Shield and three limestone sites in southern Ontario were sampled. Higher Ca/Sr ratios in soil extracts and sugar maple tissues at base rich sites reflect different minerology among regions, while the Ca/Sr discrimination factor between roots and foliage indicated that internal cycling exerts a major control on Ca/Sr ratios in sugar maple. At the three off-shield sites, 87Sr/86Sr ratios in soil and tree tissues were higher than precipitation but were indistinguishable for off-shield sites. Mixing models using a 1.0 M HCl soil extract as the weathering endmember indicated that a lower proportion of weathering-Ca compared with other geochemical approaches. One potential explanation is that the extraction method dissolves more recalcitrant minerals to a greater extent than under field conditions, leading to a higher weathering rate endmember value used in the mixing model.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44317293","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}
J. D. León‐Peláez, J. C. Villegas, Jorge Alejandro Amador-Pérez, D. Suescún
Understanding ecohydrological dynamics that result from land-use conversions is fundamental in managing ecosystem services. One common forest transformation in the tropics is the establishment of monospecific plantations with exotic species for timber exploitation, replacing highly diverse natural forests. The impacts of establishing forest plantations in hydrological processes and biogeochemical dynamics, have been highly controversial, with functions from structurally homogeneous plantations being sometimes assumed to be comparable to natural forests. To assess the effects of planting exotic conifer species versus natural forests on hydrological and biogeochemical functions, we measured incoming precipitation, throughfall and stemflow. To compare between forest types, we propose the use of basal area for standardization of hydrochemical fluxes. While net precipitation was similar among forest types, the transmission of water to the forest floor per basal area unit was significantly higher in native forests. Yet, nutrient concentrations were similar among them. However, greater nutrient enrichment per unit basal area was observed for the native species. This more efficient nutrient cycling could be related to native forests being better adapted to oligotrophic soils. The re-establishment of native species rather than with exotic species can result in more efficient hydrochemical regulation, improving the capacity of these ecosystems to produce services.
{"title":"Hydrological and nutrient regulation per occupation unit differ between structurally contrasting native and planted forests in the Northern Andes","authors":"J. D. León‐Peláez, J. C. Villegas, Jorge Alejandro Amador-Pérez, D. Suescún","doi":"10.1139/cjfr-2022-0263","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0263","url":null,"abstract":"Understanding ecohydrological dynamics that result from land-use conversions is fundamental in managing ecosystem services. One common forest transformation in the tropics is the establishment of monospecific plantations with exotic species for timber exploitation, replacing highly diverse natural forests. The impacts of establishing forest plantations in hydrological processes and biogeochemical dynamics, have been highly controversial, with functions from structurally homogeneous plantations being sometimes assumed to be comparable to natural forests. To assess the effects of planting exotic conifer species versus natural forests on hydrological and biogeochemical functions, we measured incoming precipitation, throughfall and stemflow. To compare between forest types, we propose the use of basal area for standardization of hydrochemical fluxes. While net precipitation was similar among forest types, the transmission of water to the forest floor per basal area unit was significantly higher in native forests. Yet, nutrient concentrations were similar among them. However, greater nutrient enrichment per unit basal area was observed for the native species. This more efficient nutrient cycling could be related to native forests being better adapted to oligotrophic soils. The re-establishment of native species rather than with exotic species can result in more efficient hydrochemical regulation, improving the capacity of these ecosystems to produce services.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43184335","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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