Kelly French, M. Vadeboncoeur, H. Asbjornsen, S. Fraver, L. Kenefic, David Moore, J. Wason
Silvicultural thinning can lead to rapid microclimatic changes for residual trees. Despite the benefits of decreased competition, thinning may induce “thinning shock” – temporary negative physiological responses as trees acclimate to new conditions. We examined the impact of thinning on the microclimate and physiology of residual, previously shaded red spruce (Picea rubens Sarg.) trees relative to non-thinned controls. Both daily maximum temperature and vapor pressure deficit increased post thinning, with larger increases observed on hotter and drier days. In response to these environmental changes, we found clear evidence of physiological declines. At 1.7 weeks post thinning, we found a 0.59-MPa reduction in average midday water potential relative to control trees, which lasted for an additional 1.4 weeks. Thus, the trees in the thinning treatment were at or beyond published estimates of needle turgor loss. Thinning decreased photosynthetic efficiency of current-year needles 3.8% after two weeks, and it declined by 1.3% per week for the remainder of the growing season. These results suggest that thinning shock occurs in red spruce, a shade-adapted, climate-sensitive species. Thinning shock may contribute to the lagged growth responses commonly observed post thinning, and these effects may be more extreme in novel future climates.
{"title":"Temporary thinning shock in previously shaded red spruce","authors":"Kelly French, M. Vadeboncoeur, H. Asbjornsen, S. Fraver, L. Kenefic, David Moore, J. Wason","doi":"10.1139/cjfr-2022-0227","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0227","url":null,"abstract":"Silvicultural thinning can lead to rapid microclimatic changes for residual trees. Despite the benefits of decreased competition, thinning may induce “thinning shock” – temporary negative physiological responses as trees acclimate to new conditions. We examined the impact of thinning on the microclimate and physiology of residual, previously shaded red spruce (Picea rubens Sarg.) trees relative to non-thinned controls. Both daily maximum temperature and vapor pressure deficit increased post thinning, with larger increases observed on hotter and drier days. In response to these environmental changes, we found clear evidence of physiological declines. At 1.7 weeks post thinning, we found a 0.59-MPa reduction in average midday water potential relative to control trees, which lasted for an additional 1.4 weeks. Thus, the trees in the thinning treatment were at or beyond published estimates of needle turgor loss. Thinning decreased photosynthetic efficiency of current-year needles 3.8% after two weeks, and it declined by 1.3% per week for the remainder of the growing season. These results suggest that thinning shock occurs in red spruce, a shade-adapted, climate-sensitive species. Thinning shock may contribute to the lagged growth responses commonly observed post thinning, and these effects may be more extreme in novel future climates.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46202424","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}
Wagner Squizani, Betania Vahl de Paula, L. Stefanello, D. Rozane, Elias Frank de Araújo, W. Natale, G. Brunetto
Genus Eucalyptus can be grown in different soils worldwide, although it is not always ready to fulfill plants’ nutrient demands. Whenever such nutrient shortage happens, it is necessary applying the nutrients missing, which can be established based on the critical levels and sufficiency ranges (SRs) of nutrients in leaves or by multivariate mathematical models, such as the composition nutrient diagnosis (CND). This study aimed to investigate the nutritional status of Eucalyptus plantations in Brazil, based on the CND method. A total of 119 12-month-old Eucalyptus saligna (E. saligna) plantations were sampled in the Rio Grande do Sul State (RS), Southern Brazil. Nutrient concentration in leaves and the diameter at breast height (DBH) was measured. The E. saligna nutritional status was calculated through the CND method. High- and low-yield populations were set based on DBH of 4.2 cm. The SRs proposed by the CND method were narrower than the ones proposed by official recommendations for Eucalyptus, especially for magnesium (Mg), boron (B), and iron (Fe). The CND-r2 index recorded for each nutrient generated a limitation order for nutrients. The greater accuracy of the recommendations proposed by the CND method, compared with univariate and bivariate methods, contribute to reducing the use of fertilizers.
{"title":"Assessing the nutritional status of Southern Brazilian Eucalyptus plantations by the CND method","authors":"Wagner Squizani, Betania Vahl de Paula, L. Stefanello, D. Rozane, Elias Frank de Araújo, W. Natale, G. Brunetto","doi":"10.1139/cjfr-2022-0210","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0210","url":null,"abstract":"Genus Eucalyptus can be grown in different soils worldwide, although it is not always ready to fulfill plants’ nutrient demands. Whenever such nutrient shortage happens, it is necessary applying the nutrients missing, which can be established based on the critical levels and sufficiency ranges (SRs) of nutrients in leaves or by multivariate mathematical models, such as the composition nutrient diagnosis (CND). This study aimed to investigate the nutritional status of Eucalyptus plantations in Brazil, based on the CND method. A total of 119 12-month-old Eucalyptus saligna (E. saligna) plantations were sampled in the Rio Grande do Sul State (RS), Southern Brazil. Nutrient concentration in leaves and the diameter at breast height (DBH) was measured. The E. saligna nutritional status was calculated through the CND method. High- and low-yield populations were set based on DBH of 4.2 cm. The SRs proposed by the CND method were narrower than the ones proposed by official recommendations for Eucalyptus, especially for magnesium (Mg), boron (B), and iron (Fe). The CND-r2 index recorded for each nutrient generated a limitation order for nutrients. The greater accuracy of the recommendations proposed by the CND method, compared with univariate and bivariate methods, contribute to reducing the use of fertilizers.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45936237","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}
Saba Gazran, T. Boukherroub, M. Rönnqvist, M. Paquet
The Fourth Industrial Revolution offers new opportunities for improving the efficiency and agility of supply chain operations such as transportation. This study explores the impact of integrating truck platooning technology in forestry products supply networks. Companies need to know how and where to use truck platooning in transportation networks to get optimum benefits from truck platooning in supply chains. To this end, a Mixed-Integer Linear Programming (MILP) model was developed. Decisions to be made include the selection of the potential terminal locations, the number of ordinary and platooning trucks needed in the transportation network, the origin and destination of products, and their flow in direct and backhaul routes. The objective is to minimize the overall transportation cost including terminal location costs, fixed costs for ordinary and platoon trucks, fuel, and driver costs. The results show that the potential savings of combining the two types of trucks are in the range of 1%–12% in the scenarios in which truck platooning transportation is allowed only between terminal and mill nodes. This savings could reach more than 20% when the truck platoons are allowed to visit forest areas, depending on how many forest areas are visited. The number of drivers can be reduced by 3% to more than 30%. In addition, using truck platooning and backhauling together could reduce fuel consumption by 15.6% on average.
{"title":"Optimizing truck platooning transportation planning: an application to forestry products supply chains","authors":"Saba Gazran, T. Boukherroub, M. Rönnqvist, M. Paquet","doi":"10.1139/cjfr-2022-0209","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0209","url":null,"abstract":"The Fourth Industrial Revolution offers new opportunities for improving the efficiency and agility of supply chain operations such as transportation. This study explores the impact of integrating truck platooning technology in forestry products supply networks. Companies need to know how and where to use truck platooning in transportation networks to get optimum benefits from truck platooning in supply chains. To this end, a Mixed-Integer Linear Programming (MILP) model was developed. Decisions to be made include the selection of the potential terminal locations, the number of ordinary and platooning trucks needed in the transportation network, the origin and destination of products, and their flow in direct and backhaul routes. The objective is to minimize the overall transportation cost including terminal location costs, fixed costs for ordinary and platoon trucks, fuel, and driver costs. The results show that the potential savings of combining the two types of trucks are in the range of 1%–12% in the scenarios in which truck platooning transportation is allowed only between terminal and mill nodes. This savings could reach more than 20% when the truck platoons are allowed to visit forest areas, depending on how many forest areas are visited. The number of drivers can be reduced by 3% to more than 30%. In addition, using truck platooning and backhauling together could reduce fuel consumption by 15.6% on average.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41476276","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}
V. Lieffers, B. Pinno, A. Johnson, K. Hossain, T. Gooding
We modelled the potential impact of intensification of plantation management and thinning, on timber supply of an ~500,000 ha forest in Alberta, Canada over a 200-year planning horizon. Pre-commercial and commercial thinning were applied to a portion of the better sites, which allowed shortening of the time to merchantability and earlier harvest than unthinned stands; less than 25% of the forest was thinned over the course of the plan. The sustainable harvest rate, represented here as the annual allowable cut (AAC), increased by ~14% above baseline, when thinning was applied. Similarly, there was a 20.7% increase in AAC projected with the relaxation of even flow rules if thinning was also applied. Finally, thinning offset the expected decline in AAC after a 20-year surge in cutting of mature pine, designed to slow an epidemic of mountain pine beetle. In terms of wood supply, the volume extracted at thinning was <2% of annual supply but volume from final harvest from thinned stands, at times, surpassed that of unthinned stands of the forest. Individual tree size from thinned stands was ~twice that from unthinned areas in the second part of the planning period, offsetting the expected decline in piece size after the era of harvest of natural forests.
{"title":"Intensive management increases flexibility in managing wood supply","authors":"V. Lieffers, B. Pinno, A. Johnson, K. Hossain, T. Gooding","doi":"10.1139/cjfr-2022-0317","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0317","url":null,"abstract":"We modelled the potential impact of intensification of plantation management and thinning, on timber supply of an ~500,000 ha forest in Alberta, Canada over a 200-year planning horizon. Pre-commercial and commercial thinning were applied to a portion of the better sites, which allowed shortening of the time to merchantability and earlier harvest than unthinned stands; less than 25% of the forest was thinned over the course of the plan. The sustainable harvest rate, represented here as the annual allowable cut (AAC), increased by ~14% above baseline, when thinning was applied. Similarly, there was a 20.7% increase in AAC projected with the relaxation of even flow rules if thinning was also applied. Finally, thinning offset the expected decline in AAC after a 20-year surge in cutting of mature pine, designed to slow an epidemic of mountain pine beetle. In terms of wood supply, the volume extracted at thinning was <2% of annual supply but volume from final harvest from thinned stands, at times, surpassed that of unthinned stands of the forest. Individual tree size from thinned stands was ~twice that from unthinned areas in the second part of the planning period, offsetting the expected decline in piece size after the era of harvest of natural forests.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49536616","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}
The current context of ecological transition and the fight against climate change have revived interest in short-rotation coppiced (SCR) of woody crops for bioenergy or bioproduct purposes. In order to determine the growth and yield potential of different willow cultivars, plantations were established in five regions of Quebec (Canada) across a wide climatic gradient. The present study compares results obtained after six years of cultivation at two coppicing frequencies (two and three years). Although annual yields approaching 20 tons per hectare have been recorded at several of the study sites, little difference in the productivity of the tested cultivars was found, except for S. viminalis ‘5027’, which was generally less productive. Overall productivity was weakest at La Morandière, the northernmost site. Neither frequency of coppicing lead to a difference in yields. At La Pocatière, one of the coldest regions in this study, yields of cultivars were comparable to those recorded at the southern-most sites. Moreover, the highest cumulative yield after six years was recorded at that site with the cultivar ‘SV1’. The fact that yields at most sites remain high after several years is indicative of the production potential of willow crops in SRC for Eastern Canada.
{"title":"Comparing biomass yields of various willow cultivars in short rotation coppice over six growing seasons across a broad climatic gradient in eastern Canada","authors":"M. Labrecque, S. Daigle, S. Olishevska","doi":"10.1139/cjfr-2022-0205","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0205","url":null,"abstract":"The current context of ecological transition and the fight against climate change have revived interest in short-rotation coppiced (SCR) of woody crops for bioenergy or bioproduct purposes. In order to determine the growth and yield potential of different willow cultivars, plantations were established in five regions of Quebec (Canada) across a wide climatic gradient. The present study compares results obtained after six years of cultivation at two coppicing frequencies (two and three years). Although annual yields approaching 20 tons per hectare have been recorded at several of the study sites, little difference in the productivity of the tested cultivars was found, except for S. viminalis ‘5027’, which was generally less productive. Overall productivity was weakest at La Morandière, the northernmost site. Neither frequency of coppicing lead to a difference in yields. At La Pocatière, one of the coldest regions in this study, yields of cultivars were comparable to those recorded at the southern-most sites. Moreover, the highest cumulative yield after six years was recorded at that site with the cultivar ‘SV1’. The fact that yields at most sites remain high after several years is indicative of the production potential of willow crops in SRC for Eastern Canada.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42405850","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}
The issue of forest trees biologically designed to withstand wind and slope stresses for improving tree anchorage and stability has been of interest to many forest ecologists for over 200 years. Asymmetry in architecture and function is a typical effect of biomechanical design. This review tried to find the architectural connectivity between belowground and aboveground organs of a tree based on a summary of observations of the asymmetric growth of crown, trunk, and root system. The asymmetrical aboveground growth is influenced by a complex interaction of tree species, age, neighborhood competition, wind, lighting, slope, and elevation. The asymmetrical belowground development is dependent on tree species, age, trunk leaning, wind, soil, and slope. Uneven water conduction, nutrient allocation, hormone content, and photosynthesis rate can influence the relationship of architectural mechanisms between the belowground and aboveground organs. The contradictory observations on the directional deformations of the root system (buttresses) reveal the particular prominence of combined effects of multiple factors. Future research should focus on the comprehensive understanding of the belowground and aboveground architectural relationships of different tree species. Our review provides novel insights into the connotations of root–shoot balance in biomass distribution of the individual plant organs.
{"title":"Asymmetric growth of belowground and aboveground tree organs and their architectural relationships: a review","authors":"Hongbing Wang, J. Qin, Yonghong Hu, Chenbing Guo","doi":"10.1139/cjfr-2022-0216","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0216","url":null,"abstract":"The issue of forest trees biologically designed to withstand wind and slope stresses for improving tree anchorage and stability has been of interest to many forest ecologists for over 200 years. Asymmetry in architecture and function is a typical effect of biomechanical design. This review tried to find the architectural connectivity between belowground and aboveground organs of a tree based on a summary of observations of the asymmetric growth of crown, trunk, and root system. The asymmetrical aboveground growth is influenced by a complex interaction of tree species, age, neighborhood competition, wind, lighting, slope, and elevation. The asymmetrical belowground development is dependent on tree species, age, trunk leaning, wind, soil, and slope. Uneven water conduction, nutrient allocation, hormone content, and photosynthesis rate can influence the relationship of architectural mechanisms between the belowground and aboveground organs. The contradictory observations on the directional deformations of the root system (buttresses) reveal the particular prominence of combined effects of multiple factors. Future research should focus on the comprehensive understanding of the belowground and aboveground architectural relationships of different tree species. Our review provides novel insights into the connotations of root–shoot balance in biomass distribution of the individual plant organs.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45424296","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}
K. Eyvindson, S. Launiainen, Kersti Leppä, Anna Repo, A. Salmivaara, A. Lehtonen
In Finland, the widespread drainage of boreal peatlands has led to increased forest productivity. The cost is a dramatic increase in soil greenhouse gas emissions. Empirical research of drained peatlands has found a correlation between greenhouse gas emissions and the ground water table. This suggests an opportunity to mitigate greenhouse gas emissions through forest management. We explore this opportunity at the landscape level through a simulation and optimization framework. We explore how forest management actions can impact the ground water table and the related greenhouse gas emissions. There are various economic and societal constraints for a set of forested peatland landscapes in Finland. Firstly, we link forest simulations with hydrological and statistical models to predict CO2, CH4, and N2O emissions from the drained peatlands. We present the range of landscape level solutions that prioritize between minimizing the net ecosystem greenhouse gas emissions, the economic timber value and the even flow of timber income over time. Our results highlight the impact integrating peatland soil greenhouse gas emissions will have on the planning process. This promotes the use of management options that benefit both biomass growth and reduced peatland soil greenhouse gas emissions.
{"title":"Trade-offs between greenhouse gas mitigation and economic objectives with drained peatlands in Finnish landscapes.","authors":"K. Eyvindson, S. Launiainen, Kersti Leppä, Anna Repo, A. Salmivaara, A. Lehtonen","doi":"10.1139/cjfr-2022-0101","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0101","url":null,"abstract":"In Finland, the widespread drainage of boreal peatlands has led to increased forest productivity. The cost is a dramatic increase in soil greenhouse gas emissions. Empirical research of drained peatlands has found a correlation between greenhouse gas emissions and the ground water table. This suggests an opportunity to mitigate greenhouse gas emissions through forest management. We explore this opportunity at the landscape level through a simulation and optimization framework. We explore how forest management actions can impact the ground water table and the related greenhouse gas emissions. There are various economic and societal constraints for a set of forested peatland landscapes in Finland. Firstly, we link forest simulations with hydrological and statistical models to predict CO2, CH4, and N2O emissions from the drained peatlands. We present the range of landscape level solutions that prioritize between minimizing the net ecosystem greenhouse gas emissions, the economic timber value and the even flow of timber income over time. Our results highlight the impact integrating peatland soil greenhouse gas emissions will have on the planning process. This promotes the use of management options that benefit both biomass growth and reduced peatland soil greenhouse gas emissions.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43056278","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}
Marion Noualhaguet, T. Work, Maxence Soubeyrand, N. Fenton
The Natural Disturbance Based Management (NDBM) aims to maintain specific structural and compositional attributes of natural forests in managed stands. Operationally, NDBM relies on diversifying and adapting silvicultural practices, including partial harvesting (PC), to expand the range of options beyond that of simply clearcuts (CC). Established in 1998, the SAFE (Sylviculture et Aménagement Forestier Écosystémique) project evaluates this potential in hardwood, mixedwood and coniferous stands in northwestern Québec, Canada. Our results confirmed a part of the NDBM objectives i.e., PC allowed the maintenance of stands with mixed structure and composition, constituting an interesting complement to CC, which reset stand regeneration. However, PC did not accelerate the stands transition to later stages with less intensive harvesting or to earlier stages with more intensive harvesting. We essentially had an initial impact, delaying or stopping the stands evolution which dissipates over time and more quickly with less intensive harvesting. Furthermore, our results did not support the ability of PC to enhance the development of old-growth attributes like deadwood. Despite the 20-year horizon of this study further field surveys will be required in the future to better understand the impact of different silvicultural treatments on forest productivity and biodiversity preservation throughout a forest rotation.
{"title":"Twenty-year recovery of managed stand, in structure and composition, in boreal mixedwood stands of northwestern Quebec","authors":"Marion Noualhaguet, T. Work, Maxence Soubeyrand, N. Fenton","doi":"10.1139/cjfr-2022-0309","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0309","url":null,"abstract":"The Natural Disturbance Based Management (NDBM) aims to maintain specific structural and compositional attributes of natural forests in managed stands. Operationally, NDBM relies on diversifying and adapting silvicultural practices, including partial harvesting (PC), to expand the range of options beyond that of simply clearcuts (CC). Established in 1998, the SAFE (Sylviculture et Aménagement Forestier Écosystémique) project evaluates this potential in hardwood, mixedwood and coniferous stands in northwestern Québec, Canada. Our results confirmed a part of the NDBM objectives i.e., PC allowed the maintenance of stands with mixed structure and composition, constituting an interesting complement to CC, which reset stand regeneration. However, PC did not accelerate the stands transition to later stages with less intensive harvesting or to earlier stages with more intensive harvesting. We essentially had an initial impact, delaying or stopping the stands evolution which dissipates over time and more quickly with less intensive harvesting. Furthermore, our results did not support the ability of PC to enhance the development of old-growth attributes like deadwood. Despite the 20-year horizon of this study further field surveys will be required in the future to better understand the impact of different silvicultural treatments on forest productivity and biodiversity preservation throughout a forest rotation.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42657996","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}
There is increasing interest in mixed conifer-broadleaf stands as a way to increase the diversity and productivity of managed forests. This study examined the impacts of varying densities of planted broadleaf trees on conifer performance, total stand productivity, and understory plant cover 20 years after stand establishment. The study took place in the Malcolm Knapp Research Forest in Maple Ridge, British Columbia. It used a randomized complete block design to compare treatments containing low, moderate, or high broadleaf densities added to a constant conifer density. Each block contained a conifer-only plot as a control. Conifers were comprised of equal amounts of western hemlock, western redcedar, and Douglas-fir. Broadleaves were comprised of either red alder or paper birch. We found that conifer volume was significantly lower in most broadleaf treatments relative to the control, due to lower hemlock and redcedar volumes. Douglas-fir, on the other hand, had a higher volume—albeit not significant—in the broadleaf treatments. There were no significant differences in total stand volume between any of the treatments and the control. Shrub cover was significantly higher in the low and high alder treatments relative to the control, but there were no differences in shrub cover between birch treatments and the control. We suggest that low alder density provides a good balance of conifer yield and understory development.
{"title":"Conifer performance, stand productivity, and understory cover in varying densities of mixed conifer-broadleaf stands in southwestern British Columbia","authors":"Yudel L. Huberman, B. Eskelson","doi":"10.1139/cjfr-2022-0211","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0211","url":null,"abstract":"There is increasing interest in mixed conifer-broadleaf stands as a way to increase the diversity and productivity of managed forests. This study examined the impacts of varying densities of planted broadleaf trees on conifer performance, total stand productivity, and understory plant cover 20 years after stand establishment. The study took place in the Malcolm Knapp Research Forest in Maple Ridge, British Columbia. It used a randomized complete block design to compare treatments containing low, moderate, or high broadleaf densities added to a constant conifer density. Each block contained a conifer-only plot as a control. Conifers were comprised of equal amounts of western hemlock, western redcedar, and Douglas-fir. Broadleaves were comprised of either red alder or paper birch. We found that conifer volume was significantly lower in most broadleaf treatments relative to the control, due to lower hemlock and redcedar volumes. Douglas-fir, on the other hand, had a higher volume—albeit not significant—in the broadleaf treatments. There were no significant differences in total stand volume between any of the treatments and the control. Shrub cover was significantly higher in the low and high alder treatments relative to the control, but there were no differences in shrub cover between birch treatments and the control. We suggest that low alder density provides a good balance of conifer yield and understory development.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46234090","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}
The development of stand survival models can provide an important basis for the sustainable management of forest resources. In a new approach developed in this study, parameters of four survival quantile regression models were predicted from a quantile associated with a current stand density. The curves from these quantile regression models were then used to project future stand density for that stand. A three-fold cross-validation revealed that the quantile regression approach outperformed the least squares method based on three evaluation statistics, especially for longer projection lengths. These results were consistent for all four survival models evaluated. The best survival model is Clutter–Jones model, without constraints, but its ln( N)–ln( Dq) trajectories ( N = stand density and Dq = quadratic mean diameter) from the quantile regression showed the linear self-thinning trend.
{"title":"A quantile regression approach to model stand survival in Chinese fir plantations","authors":"Hanyue Chen, Q. V. Cao, Yihang Jiang, Jianguo Zhang, Xiongqing Zhang","doi":"10.1139/cjfr-2022-0196","DOIUrl":"https://doi.org/10.1139/cjfr-2022-0196","url":null,"abstract":"The development of stand survival models can provide an important basis for the sustainable management of forest resources. In a new approach developed in this study, parameters of four survival quantile regression models were predicted from a quantile associated with a current stand density. The curves from these quantile regression models were then used to project future stand density for that stand. A three-fold cross-validation revealed that the quantile regression approach outperformed the least squares method based on three evaluation statistics, especially for longer projection lengths. These results were consistent for all four survival models evaluated. The best survival model is Clutter–Jones model, without constraints, but its ln( N)–ln( Dq) trajectories ( N = stand density and Dq = quadratic mean diameter) from the quantile regression showed the linear self-thinning trend.","PeriodicalId":9483,"journal":{"name":"Canadian Journal of Forest Research","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48951313","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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