Alicia Azpeleta Tarancón, P. Fulé, Abel García Arévalo
In the aftermath of a high-intensity wildfire in La Michilia Biosphere Reserve, Mexico, an initial study suggested a shift from an oak-pine forest to a grass-savanna ecosystem. We conducted repeated measurements on sixty permanent plots 1, 5, 10, and 20 years after the original wildfire at paired burned and unburned study sites to capture spatial and temporal dynamics in forest composition and structure. We found that the burned site regained most pre-wildfire characteristics two decades after the wildfire. The ongoing regeneration in the burned site suggests that despite the remaining differences, the site is approaching a complete recovery, with forest characteristics analogous to the unburned site. Our findings indicate that the combination of seeders' wildfire resistance and resprouters' post-wildfire sprouting strategies in mixed-species forests provide high resilience to high-intensity wildfire. Moreover, protecting La Michilía as a biosphere reserve and heightened public awareness of the natural environment likely played an indispensable role in facilitating the recovery of the post-wildfire ecosystem.
{"title":"Mexican mixed-species forest shows resilience to high-intensity fire","authors":"Alicia Azpeleta Tarancón, P. Fulé, Abel García Arévalo","doi":"10.1139/cjfr-2023-0185","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0185","url":null,"abstract":"In the aftermath of a high-intensity wildfire in La Michilia Biosphere Reserve, Mexico, an initial study suggested a shift from an oak-pine forest to a grass-savanna ecosystem. We conducted repeated measurements on sixty permanent plots 1, 5, 10, and 20 years after the original wildfire at paired burned and unburned study sites to capture spatial and temporal dynamics in forest composition and structure. We found that the burned site regained most pre-wildfire characteristics two decades after the wildfire. The ongoing regeneration in the burned site suggests that despite the remaining differences, the site is approaching a complete recovery, with forest characteristics analogous to the unburned site. Our findings indicate that the combination of seeders' wildfire resistance and resprouters' post-wildfire sprouting strategies in mixed-species forests provide high resilience to high-intensity wildfire. Moreover, protecting La Michilía as a biosphere reserve and heightened public awareness of the natural environment likely played an indispensable role in facilitating the recovery of the post-wildfire ecosystem.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"320 2","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139250659","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}
S. B. Acquah, Peter L. Marshall, B. Eskelson, Ian S Moss, Ignacio Barbeito
We assessed the impacts of three approaches to thinning from below with varying spatial patterns on several stand and individual tree variables for interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), interior spruce (Picea glauca [Moench] Voss × Picea engelmannii Engelm.), and lodgepole pine (Pinus contorta Dougl. Ex Loud. var. latifolia Englem.) in central British Columbia, Canada. The three thinning treatments were two experimental “clumped” treatments (3 m Clumped and 5 m Clumped) and the Standard (more uniform spacing) thinning treatment that was employed operationally at that time. We used long-term data from 24 plots measured five times over 21 years. Thinning increased stand basal area increment, with the plots that received the 5 m Clumped treatment having significantly higher periodic annual relative basal area increment than the unthinned Control plots. The responses for the two clumped treatments were not any lower than the Standard. The 3 m Clumped treatment was best if one is concerned about fast recovery of the growing space; however, the 5 m Clumped spacing treatment may be preferable if higher individual tree vigour is needed for resistance and resilience to fire, insects, and disease.
{"title":"Growth responses to thinning from below in uneven-aged interior Douglas-fir dominated stands.","authors":"S. B. Acquah, Peter L. Marshall, B. Eskelson, Ian S Moss, Ignacio Barbeito","doi":"10.1139/cjfr-2023-0154","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0154","url":null,"abstract":"We assessed the impacts of three approaches to thinning from below with varying spatial patterns on several stand and individual tree variables for interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), interior spruce (Picea glauca [Moench] Voss × Picea engelmannii Engelm.), and lodgepole pine (Pinus contorta Dougl. Ex Loud. var. latifolia Englem.) in central British Columbia, Canada. The three thinning treatments were two experimental “clumped” treatments (3 m Clumped and 5 m Clumped) and the Standard (more uniform spacing) thinning treatment that was employed operationally at that time. We used long-term data from 24 plots measured five times over 21 years. Thinning increased stand basal area increment, with the plots that received the 5 m Clumped treatment having significantly higher periodic annual relative basal area increment than the unthinned Control plots. The responses for the two clumped treatments were not any lower than the Standard. The 3 m Clumped treatment was best if one is concerned about fast recovery of the growing space; however, the 5 m Clumped spacing treatment may be preferable if higher individual tree vigour is needed for resistance and resilience to fire, insects, and disease.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"97 5","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139254279","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}
Cleide Beatriz Bourscheid, Roger E. Hernandez, Claudia Cáceres, Carl Blais
The effects of cutting speed (CS), feed per knife (FK), and temperature condition on energy requirements for processing black spruce logs by a chipper-canter were assessed. Nine groups of fifteen logs were tested at three CS (20, 25, and 30 m/s) and three FK (19, 25, and 32 mm). Each log was processed under frozen (-13°C) and unfrozen (19°C) conditions. Mean power increased as CS and FK increased. This behaviour is explained by the mechanical relationships between the parameters and the rotation and feed speeds, as well as by the increase in the volume of wood cut. The energy consumption and the specific energy consumption increased as CS increased and FK decreased. For the three electrical criteria, more energy was consumed when processing frozen logs, which is due to the greater mechanical properties of wood. A positive relationship was identified between sapwood and heartwood moisture content, basic density, grain angle, and wood volume transformed into chips, as covariates, and the three energy criteria. These results give useful information on energy requirements to adjust cutting parameters of chipper-canters for a better energy management in sawmills.
{"title":"EFFECTS OF CUTTING SPEED AND FEED PER KNIFE ON ENERGY REQUIREMENTS FOR PROCESSING BLACK SPRUCE LOGS WITH A CHIPPER-CANTER","authors":"Cleide Beatriz Bourscheid, Roger E. Hernandez, Claudia Cáceres, Carl Blais","doi":"10.1139/cjfr-2023-0167","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0167","url":null,"abstract":"The effects of cutting speed (CS), feed per knife (FK), and temperature condition on energy requirements for processing black spruce logs by a chipper-canter were assessed. Nine groups of fifteen logs were tested at three CS (20, 25, and 30 m/s) and three FK (19, 25, and 32 mm). Each log was processed under frozen (-13°C) and unfrozen (19°C) conditions. Mean power increased as CS and FK increased. This behaviour is explained by the mechanical relationships between the parameters and the rotation and feed speeds, as well as by the increase in the volume of wood cut. The energy consumption and the specific energy consumption increased as CS increased and FK decreased. For the three electrical criteria, more energy was consumed when processing frozen logs, which is due to the greater mechanical properties of wood. A positive relationship was identified between sapwood and heartwood moisture content, basic density, grain angle, and wood volume transformed into chips, as covariates, and the three energy criteria. These results give useful information on energy requirements to adjust cutting parameters of chipper-canters for a better energy management in sawmills.
","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"32 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134957565","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}
Artis Becs, Dan Bergström, Gustaf Egnell, Arne Pommerening
Forest biomass has become a viable alternative energy source for replacing fossil fuels, particularly after the European Union acknowledged its sustainability status. In order to reach zero net greenhouse gas emissions by 2045 in Sweden, new efficient methods of biomass extraction, such as geometrical biomass thinnings, are being explored and tested. These machine-based methods involve the extraction of above-ground biomass in narrow 1-2 m-wide strips between extraction racks. While evidence-based optimization of biomass extraction mostly focuses on time- and cost-efficiency and on stand growth, criteria such as tree diversity are often overlooked. However, with ongoing climate change tree diversity is crucial to strengthening the resilience and productivity of future forests, which also enhance the provision of ecosystem services, and overall biological diversity. Therefore, we studied the effects of different biomass thinning strategies on spatial tree diversity in Southern Sweden using nearest-neighbour summary statistics. We found scientific evidence that different geometrical designs of biomass thinning, especially in 1 or 2 m-wide strips, resulted in higher spatial tree diversity compared to conventional biomass thinning. Hence, in mixed conifer-broadleaved forests, biomass thinning in 1 or 2 m-wide strips is recommended for maintaining spatial tree diversity.
{"title":"How do different thinning methods influence spatial tree diversity in mixed forest stands of planted Norway spruce (Picea abies L.) and naturally regenerated birch (Betula spp.) in Southern Sweden?","authors":"Artis Becs, Dan Bergström, Gustaf Egnell, Arne Pommerening","doi":"10.1139/cjfr-2023-0146","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0146","url":null,"abstract":"Forest biomass has become a viable alternative energy source for replacing fossil fuels, particularly after the European Union acknowledged its sustainability status. In order to reach zero net greenhouse gas emissions by 2045 in Sweden, new efficient methods of biomass extraction, such as geometrical biomass thinnings, are being explored and tested. These machine-based methods involve the extraction of above-ground biomass in narrow 1-2 m-wide strips between extraction racks. While evidence-based optimization of biomass extraction mostly focuses on time- and cost-efficiency and on stand growth, criteria such as tree diversity are often overlooked. However, with ongoing climate change tree diversity is crucial to strengthening the resilience and productivity of future forests, which also enhance the provision of ecosystem services, and overall biological diversity. Therefore, we studied the effects of different biomass thinning strategies on spatial tree diversity in Southern Sweden using nearest-neighbour summary statistics. We found scientific evidence that different geometrical designs of biomass thinning, especially in 1 or 2 m-wide strips, resulted in higher spatial tree diversity compared to conventional biomass thinning. Hence, in mixed conifer-broadleaved forests, biomass thinning in 1 or 2 m-wide strips is recommended for maintaining spatial tree diversity.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" 14","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135340960","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}
Shawn Fraver, Colby Bosely-Smith, Camilla Seirup, Christopher H. Guiterman, Thomas Schmeelk, Aaron Teets, Ruth Van Kampen, Laura S. Kenefic
Abstract: Although northern white-cedar (Thuja occidentalis; henceforth cedar) is thought to have few insect pests, arborvitae leafminers (primarily Argyresthia thuiella) have been known to cause leaf necrosis. Yet historical evidence for leafminer outbreaks is limited. We combined leafminer larval surveys conducted between 1950 and 1992 with tree-ring analyses from eight cedar stands to reconstruct a history of leafminer outbreaks in Maine, USA. Our tree-ring data show distinctive two- to three-year growth reductions that we attribute to leafminers. Several such growth reductions correspond to peak leafminer larval abundances, providing evidence that the reductions are reliable indicators of leafminer activity. Outbreak severity within a site was unrelated to cedar abundance. Outbreak periods thus identified (beginning ca. 1919, 1937, 1950, 1962, mid-1970s, but not at all sites) suggest that leafminer damage may have been more prevalent (albeit patchy) than previously thought. This historical information is relevant given current outbreaks in Maine and elsewhere.
{"title":"Dendrochronological reconstruction of arborvitae leafminer (Argyresthia spp.) outbreaks on northern white-cedar (Thuja occidentalis) in Maine, USA","authors":"Shawn Fraver, Colby Bosely-Smith, Camilla Seirup, Christopher H. Guiterman, Thomas Schmeelk, Aaron Teets, Ruth Van Kampen, Laura S. Kenefic","doi":"10.1139/cjfr-2023-0193","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0193","url":null,"abstract":"Abstract: Although northern white-cedar (Thuja occidentalis; henceforth cedar) is thought to have few insect pests, arborvitae leafminers (primarily Argyresthia thuiella) have been known to cause leaf necrosis. Yet historical evidence for leafminer outbreaks is limited. We combined leafminer larval surveys conducted between 1950 and 1992 with tree-ring analyses from eight cedar stands to reconstruct a history of leafminer outbreaks in Maine, USA. Our tree-ring data show distinctive two- to three-year growth reductions that we attribute to leafminers. Several such growth reductions correspond to peak leafminer larval abundances, providing evidence that the reductions are reliable indicators of leafminer activity. Outbreak severity within a site was unrelated to cedar abundance. Outbreak periods thus identified (beginning ca. 1919, 1937, 1950, 1962, mid-1970s, but not at all sites) suggest that leafminer damage may have been more prevalent (albeit patchy) than previously thought. This historical information is relevant given current outbreaks in Maine and elsewhere.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" 47","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135340804","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":"Overview of the 2022 North American Forest Ecology Workshop (NAFEW): Turning Ecological Answers into Forest Management Actions","authors":"Lisa Venier, Dave Morris, Timothy Work","doi":"10.1139/cjfr-2023-0217","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0217","url":null,"abstract":"","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"30 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135373282","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}
Rapid establishment of closed canopy cover is a key goal in land reclamation. While re-establishment of understory vegetation is likely to positively contribute to this goal, native herbaceous species are not typically planted on reclaimed sites though it is an alternative to reliance on natural regeneration. The objective of the present study was to test the principle of hitchhiker production of a tree species with native herbaceous species on recently reclaimed industrial sites with the aim of (1) understanding growth tradeoffs when mixing these species in the same container and (2) if hitchhiking had negative growth and survival outcomes for white spruce ( Picea glauca) seedlings compared with singly grown white spruce seedlings. White spruce seeds were sown in nursery containers of contrasting cavity sizes, followed by sowing a forb species ( Eurybia conspicua or Chamerion angustifolium) at different time intervals or grown singly. Larger cavities and earlier sow dates were associated with higher persistence and growth of the forbs, while later sow dates were associated with larger white spruce seedlings. We observed no evidence to suggest that hitchhiked seedlings were at a competitive disadvantage in terms of growth or survival compared with singly grown seedlings that were initially similar in size.
{"title":"Hitchhiker planting: mixed-species container stock planting as a novel tool to increase plant diversity on industrially disturbed sites","authors":"A.L. Schoonmaker, A. Mathison, M.D. Mackenzie","doi":"10.1139/cjfr-2023-0094","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0094","url":null,"abstract":"Rapid establishment of closed canopy cover is a key goal in land reclamation. While re-establishment of understory vegetation is likely to positively contribute to this goal, native herbaceous species are not typically planted on reclaimed sites though it is an alternative to reliance on natural regeneration. The objective of the present study was to test the principle of hitchhiker production of a tree species with native herbaceous species on recently reclaimed industrial sites with the aim of (1) understanding growth tradeoffs when mixing these species in the same container and (2) if hitchhiking had negative growth and survival outcomes for white spruce ( Picea glauca) seedlings compared with singly grown white spruce seedlings. White spruce seeds were sown in nursery containers of contrasting cavity sizes, followed by sowing a forb species ( Eurybia conspicua or Chamerion angustifolium) at different time intervals or grown singly. Larger cavities and earlier sow dates were associated with higher persistence and growth of the forbs, while later sow dates were associated with larger white spruce seedlings. We observed no evidence to suggest that hitchhiked seedlings were at a competitive disadvantage in terms of growth or survival compared with singly grown seedlings that were initially similar in size.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"236 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136103050","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}
Moose are an iconic symbol of northern forests. In many jurisdictions, the management of moose has focused on regulating harvest with less emphasis on understanding moose-habitat relationships. We reviewed the literature and summarised the effects of forest harvest and management on the ecology of moose. Greater than 40 years of scientific studies document both positive and negative effects of forest harvest and associated activities such as silviculture and road building. Moose require spatially adjacent patches of younger plant communities for forage and older forests for thermal and security cover. Extensive and rapid forest harvest can result in the prevalence of young forest with a corresponding reduction in the fitness of moose populations. A warming climate likely will exacerbate the negative effects associated with the broad-scale removal of forest cover. Resource roads can create edge habitat that may serve as forage, but those features result in increased hunting and collisions with vehicles and facilitate the movement of predators. Post-harvest silviculture, including the application of herbicides, can create stand conditions that provide very little or low-quality forage. The ecological and societal benefits of moose are dependent on forest management that provides a mix of old and young forest, employs silviculture that retains adequate cover and forage plants, and minimises the development of roads.
{"title":"Response of Moose to Forest Harvest and Management: A Literature Review","authors":"C. Johnson, Roy Rea","doi":"10.1139/cjfr-2023-0158","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0158","url":null,"abstract":"Moose are an iconic symbol of northern forests. In many jurisdictions, the management of moose has focused on regulating harvest with less emphasis on understanding moose-habitat relationships. We reviewed the literature and summarised the effects of forest harvest and management on the ecology of moose. Greater than 40 years of scientific studies document both positive and negative effects of forest harvest and associated activities such as silviculture and road building. Moose require spatially adjacent patches of younger plant communities for forage and older forests for thermal and security cover. Extensive and rapid forest harvest can result in the prevalence of young forest with a corresponding reduction in the fitness of moose populations. A warming climate likely will exacerbate the negative effects associated with the broad-scale removal of forest cover. Resource roads can create edge habitat that may serve as forage, but those features result in increased hunting and collisions with vehicles and facilitate the movement of predators. Post-harvest silviculture, including the application of herbicides, can create stand conditions that provide very little or low-quality forage. The ecological and societal benefits of moose are dependent on forest management that provides a mix of old and young forest, employs silviculture that retains adequate cover and forage plants, and minimises the development of roads.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135808261","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}
Joseph M Nash, Matthew Vadeboncoeur, Gregory G. McGee, Christopher W. Woodall, Ruth D. Yanai
Successional, second-growth forests dominate much of eastern North America, thus patterns of biomass accumulation in standing trees and downed wood are of great interest for forest management and carbon accounting. The timing and magnitude of biomass accumulation in later stages of forest development are not fully understood. We applied a “chronosequence with resampling” approach to characterize live and dead biomass accumulation in sixteen northern hardwood stands in the White Mountains of New Hampshire. Live aboveground biomass increased rapidly and leveled off at about 350 Mg/ha by 145 years. Downed wood biomass fluctuated between 10 and 35 Mg/ha depending on disturbances. The species composition of downed wood varied predictably with overstory succession, and total mass of downed wood increased with stand age and the concomitant production of larger material. Fine woody debris peaked at 30-50 years during the self-thinning of early-successional species, notably pin cherry. Our data support a model of northern hardwood forest development wherein live tree biomass accumulates asymptotically and begins to level off at ~140-150 years. Still, 145-year-old second-growth stands differed from old-growth forests in their live (p = 0.09) and downed tree diameter distributions (p = 0.06). These patterns of forest biomass accumulation would be difficult to detect without a time series of repeated measurements of stands of different ages.
{"title":"Biomass accumulation in trees and downed wood in northern hardwood forests: repeated measures of a successional chronosequence in New Hampshire, USA
 
","authors":"Joseph M Nash, Matthew Vadeboncoeur, Gregory G. McGee, Christopher W. Woodall, Ruth D. Yanai","doi":"10.1139/cjfr-2023-0060","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0060","url":null,"abstract":"Successional, second-growth forests dominate much of eastern North America, thus patterns of biomass accumulation in standing trees and downed wood are of great interest for forest management and carbon accounting. The timing and magnitude of biomass accumulation in later stages of forest development are not fully understood. We applied a “chronosequence with resampling” approach to characterize live and dead biomass accumulation in sixteen northern hardwood stands in the White Mountains of New Hampshire. Live aboveground biomass increased rapidly and leveled off at about 350 Mg/ha by 145 years. Downed wood biomass fluctuated between 10 and 35 Mg/ha depending on disturbances. The species composition of downed wood varied predictably with overstory succession, and total mass of downed wood increased with stand age and the concomitant production of larger material. Fine woody debris peaked at 30-50 years during the self-thinning of early-successional species, notably pin cherry. Our data support a model of northern hardwood forest development wherein live tree biomass accumulates asymptotically and begins to level off at ~140-150 years. Still, 145-year-old second-growth stands differed from old-growth forests in their live (p = 0.09) and downed tree diameter distributions (p = 0.06). These patterns of forest biomass accumulation would be difficult to detect without a time series of repeated measurements of stands of different ages.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"20 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134906803","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}
Seedling establishment is crucial for the development of self-regenerating tree populations. Determinants of tree establishment vary widely and may compound in their effects. Using a factorial experiment, we manipulated invasive shrubs, downed woody debris (DWD), and rodent access to evaluate factors limiting the establishment of six woody species (five native trees, one invasive shrub). Our results suggest these factors independently contribute to tree seedling establishment. Exclusion of rodents increased establishment three-fold. Invasive shrub removal (Elaeagnus umbellate; Lonicera maackii) and the presence of DWD promoted establishment of two native trees (Pinus strobus; Sassafras albidum). Notably, the presence of DWD halved L. maackii establishment. In identifying rodents as drivers of seed limitation, our results support findings that seed additions will likely promote woody seedling establishment when rodents are not abundant (e.g., low populations) or when seeds are physically or chemically protected (e.g., via taste deterrents). Management plans vary in DWD retention; results from our experimental cohort indicate retaining or introducing DWD promotes native tree recruitment and limits invasive shrub establishment. Future studies exploring the species-specific effects of invasive shrub removal and DWD amendments across multiple cohorts will help determine which woody species benefit most from these management practices.
{"title":"Rodent-mediated seed limitation affects woody seedling establishment more than invasive shrubs and downed woody debris","authors":"Brian Connolly, Chad Zirbel, John L. Orrock","doi":"10.1139/cjfr-2023-0131","DOIUrl":"https://doi.org/10.1139/cjfr-2023-0131","url":null,"abstract":"Seedling establishment is crucial for the development of self-regenerating tree populations. Determinants of tree establishment vary widely and may compound in their effects. Using a factorial experiment, we manipulated invasive shrubs, downed woody debris (DWD), and rodent access to evaluate factors limiting the establishment of six woody species (five native trees, one invasive shrub). Our results suggest these factors independently contribute to tree seedling establishment. Exclusion of rodents increased establishment three-fold. Invasive shrub removal (Elaeagnus umbellate; Lonicera maackii) and the presence of DWD promoted establishment of two native trees (Pinus strobus; Sassafras albidum). Notably, the presence of DWD halved L. maackii establishment. In identifying rodents as drivers of seed limitation, our results support findings that seed additions will likely promote woody seedling establishment when rodents are not abundant (e.g., low populations) or when seeds are physically or chemically protected (e.g., via taste deterrents). Management plans vary in DWD retention; results from our experimental cohort indicate retaining or introducing DWD promotes native tree recruitment and limits invasive shrub establishment. Future studies exploring the species-specific effects of invasive shrub removal and DWD amendments across multiple cohorts will help determine which woody species benefit most from these management practices.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":"27 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135567526","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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