Pub Date : 2022-12-20DOI: 10.2989/20702620.2022.2155090
S. K. Bhandari, E. Veneklaas, L. McCaw, R. Mazanec, M. Renton
Karri (Eucalyptus diversicolor F. Muell.) forest is an endemic forest type of southwest Western Australia (SWWA), noted for having the tallest trees in the region, and providing commercial, ecological and conservation value. To inform management aimed at optimising these values, a thinning trial was commenced in 1992. The aim of this study was to evaluate the effects of thinning on individual tree growth, stand level growth and allometry of karri trees in even-aged stands. Mixed effect models were used to compare the effect of different levels of thinning on individual tree growth and stand level growth of karri. We developed allometric equations modelling the relationship between diameter at breast height (DBH) and height, and tested whether thinning affected this allometric relationship. Thinning enhanced DBH, height and crown width (CW) growth of individual trees by up to 149%, 56% and 108% respectively in heavily thinned stands, with stand basal area growth optimised at retained basal areas of 13 m2 ha−1. Thinning had a significant effect on allometry of DBH with height, height-DBH ratio (HDR) and CW. Reduction in stand density through thinning from below increased diameter growth of individual trees. Stand level basal area growth is optimised at an intermediate level of thinning. Thinning can be a good management tool for even-aged karri forest because it may promote the diameter and thereby basal area growth, good health of individual trees, and potential ecological benefits including accelerated development of larger tree crowns typical of mature forest.
Karri (Eucalyptus diversicolor F. Muell.)森林是西澳大利亚西南部(SWWA)的一种特有森林类型，以该地区最高的树木而闻名，具有商业、生态和保护价值。为了向旨在优化这些值的管理部门提供信息，1992年开始了一项减薄试验。本研究的目的是评价间伐对均匀龄林分上karri树单株生长、林分生长和异速生长的影响。采用混合效应模型比较了不同间伐程度对柠条单株生长和林分生长的影响。我们建立了模拟胸高直径(DBH)和身高之间关系的异速生长方程，并测试了变薄是否会影响这种异速生长关系。间伐可使林分单株胸径、高度和冠宽(CW)分别提高149%、56%和108%，其中林分基片面积保持在13 m2 ha−1时生长最优。间伐对胸径与高度、高胸径比(HDR)和连续波(CW)的异速生长有显著影响。通过从下面疏伐增加单株直径来降低林分密度。林分水平基底面积生长在间伐的中间水平得到优化。间伐可以作为一种良好的管理工具，因为它可以促进直径，从而促进基底面积的生长，良好的单株健康，以及潜在的生态效益，包括加速成熟森林典型的更大树冠的发育。
{"title":"Effect of thinning on growth and allometry of Eucalyptus diversicolor","authors":"S. K. Bhandari, E. Veneklaas, L. McCaw, R. Mazanec, M. Renton","doi":"10.2989/20702620.2022.2155090","DOIUrl":"https://doi.org/10.2989/20702620.2022.2155090","url":null,"abstract":"Karri (Eucalyptus diversicolor F. Muell.) forest is an endemic forest type of southwest Western Australia (SWWA), noted for having the tallest trees in the region, and providing commercial, ecological and conservation value. To inform management aimed at optimising these values, a thinning trial was commenced in 1992. The aim of this study was to evaluate the effects of thinning on individual tree growth, stand level growth and allometry of karri trees in even-aged stands. Mixed effect models were used to compare the effect of different levels of thinning on individual tree growth and stand level growth of karri. We developed allometric equations modelling the relationship between diameter at breast height (DBH) and height, and tested whether thinning affected this allometric relationship. Thinning enhanced DBH, height and crown width (CW) growth of individual trees by up to 149%, 56% and 108% respectively in heavily thinned stands, with stand basal area growth optimised at retained basal areas of 13 m2 ha−1. Thinning had a significant effect on allometry of DBH with height, height-DBH ratio (HDR) and CW. Reduction in stand density through thinning from below increased diameter growth of individual trees. Stand level basal area growth is optimised at an intermediate level of thinning. Thinning can be a good management tool for even-aged karri forest because it may promote the diameter and thereby basal area growth, good health of individual trees, and potential ecological benefits including accelerated development of larger tree crowns typical of mature forest.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"49 1","pages":"298 - 310"},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87539716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-20DOI: 10.2989/20702620.2022.2149364
Hakan Can, K. Enez, Ender Buğday
The most significant steps in the management of forests is to identify the management strategies of existing forest roads, which are basic infrastructure facilities. In the present study, managerial strategies were put forward by evaluating the strengths, weaknesses, opportunities, and threats of forest road management. To create a strategy in forest road management, sub-factors were identified for the SWOT analysis and five strategy criteria were developed by using expert opinions obtained through questionnaires. As SWOT analysis is a qualitative analysis and decision-making method, the strategy criteria were then modelled using the Buckley and Chang approaches, both of which are widely used in the fuzzy analytical hierarchy process (FAHP), to quantify the factors used to reach an analytical result in determining the effects and significance levels of the factors. A total of five strategy criteria along with 22 sub-factors that were prepared for SWOT analysis were modelled by making 170 pairwise comparisons and quantifying them with FAHP. The most significant factor identified, which was among the opportunity factors according to both approaches, was ‘Assisting in controlling forest fires’. According to the Buckley and Chang approaches, it was identified that the strategy that had the highest significance was ‘Protecting forest/forest resources, and improving physical infrastructure’. It was found that the sub-factor group that had the highest degree of significance was ‘weaknesses’, while the lowest sub-factor group was the ‘opportunity’ factor. The study concluded that modelling qualitative analyses in the decision-making process after quantification results in more rational solutions because it allows a comparison of the factors.
{"title":"Evaluation of strategic management using SWOT-FAHP approaches in forest roads management","authors":"Hakan Can, K. Enez, Ender Buğday","doi":"10.2989/20702620.2022.2149364","DOIUrl":"https://doi.org/10.2989/20702620.2022.2149364","url":null,"abstract":"The most significant steps in the management of forests is to identify the management strategies of existing forest roads, which are basic infrastructure facilities. In the present study, managerial strategies were put forward by evaluating the strengths, weaknesses, opportunities, and threats of forest road management. To create a strategy in forest road management, sub-factors were identified for the SWOT analysis and five strategy criteria were developed by using expert opinions obtained through questionnaires. As SWOT analysis is a qualitative analysis and decision-making method, the strategy criteria were then modelled using the Buckley and Chang approaches, both of which are widely used in the fuzzy analytical hierarchy process (FAHP), to quantify the factors used to reach an analytical result in determining the effects and significance levels of the factors. A total of five strategy criteria along with 22 sub-factors that were prepared for SWOT analysis were modelled by making 170 pairwise comparisons and quantifying them with FAHP. The most significant factor identified, which was among the opportunity factors according to both approaches, was ‘Assisting in controlling forest fires’. According to the Buckley and Chang approaches, it was identified that the strategy that had the highest significance was ‘Protecting forest/forest resources, and improving physical infrastructure’. It was found that the sub-factor group that had the highest degree of significance was ‘weaknesses’, while the lowest sub-factor group was the ‘opportunity’ factor. The study concluded that modelling qualitative analyses in the decision-making process after quantification results in more rational solutions because it allows a comparison of the factors.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"43 1","pages":"283 - 297"},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83505285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.2989/20702620.2022.2045881
René Oum Lissouck, Rachel Raïssa Ngono Mvondo, François René Ateba, R. Pommier
The development of glulam may give complementary, added-value to an important part of the timber production in the Congo Basin. Nevertheless, the high humidity in which these timbers operate may cause problems such as cracks and severe deformations if they are not suitably bonded. Moreover, there is a lack of knowledge concerning the refined design of the bondlines of glulam assembling from the Congo Basin hardwoods. We investigated the durability, mechanical strength, and variability features of the bondlines, manufactured under higher moisture conditions. Eight hardwood species with very different properties were selected. A one-component polyurethane adhesive was used. Industrial gluing parameters were kept constant. Delamination, shear tests and analysis of bondlines thickness were carried out. Multivariate analysis and a goodness-of-fit test of the strength variability of the bondlines were performed. Optimum bondlines thicknesses were obtained. Their durability exhibited satisfactory trends up to a density of 750 kg/m3. The behaviour of the bondlines can operate in three homogeneous groups. In each of them, the variability of the shear strength can be properly modelled using a 3-parameter Weibull probability. Wood failure trends were in accordance with several international requirements. The density value of 750 kg/m3 appeared as critical for the compatibility between the shear strength, the durability and the bondlines thickness. The overall results showed the ability of several tropical timber species to be valorised in green-glulam applications. Moreover, the findings unlock new trends concerning a reliable and safe design of tropical glulam as a structural wood-based product.
{"title":"Investigation of green-glued laminated timber from the Congo Basin: durability, mechanical strength and variability trends of the bondlines","authors":"René Oum Lissouck, Rachel Raïssa Ngono Mvondo, François René Ateba, R. Pommier","doi":"10.2989/20702620.2022.2045881","DOIUrl":"https://doi.org/10.2989/20702620.2022.2045881","url":null,"abstract":"The development of glulam may give complementary, added-value to an important part of the timber production in the Congo Basin. Nevertheless, the high humidity in which these timbers operate may cause problems such as cracks and severe deformations if they are not suitably bonded. Moreover, there is a lack of knowledge concerning the refined design of the bondlines of glulam assembling from the Congo Basin hardwoods. We investigated the durability, mechanical strength, and variability features of the bondlines, manufactured under higher moisture conditions. Eight hardwood species with very different properties were selected. A one-component polyurethane adhesive was used. Industrial gluing parameters were kept constant. Delamination, shear tests and analysis of bondlines thickness were carried out. Multivariate analysis and a goodness-of-fit test of the strength variability of the bondlines were performed. Optimum bondlines thicknesses were obtained. Their durability exhibited satisfactory trends up to a density of 750 kg/m3. The behaviour of the bondlines can operate in three homogeneous groups. In each of them, the variability of the shear strength can be properly modelled using a 3-parameter Weibull probability. Wood failure trends were in accordance with several international requirements. The density value of 750 kg/m3 appeared as critical for the compatibility between the shear strength, the durability and the bondlines thickness. The overall results showed the ability of several tropical timber species to be valorised in green-glulam applications. Moreover, the findings unlock new trends concerning a reliable and safe design of tropical glulam as a structural wood-based product.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"1 1","pages":"225 - 241"},"PeriodicalIF":0.0,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90528319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.2989/20702620.2022.2138624
Gabriel Soares Lopes Gomes, S. N. O. Neto, H. Leite, Márcio Lopes da Silva, L. S. D. S. Lopes, Bruno Leão Said Schettini
Tree cultivation spacing can influence productivity and wood quality, with silvicultural, technological and economic implications. This study aimed to estimate the production and provide an economic analysis of Eucalyptus urophylla × Eucalyptus grandis stands as a function of planting spacing in a small rural property. The study was carried out in the Zona da Mata of Minas Gerais state, with the hybrid clone (GG100) established in 2 × 1 m, 2 × 2 m, 3 × 2 m and 3 × 3 m spacing. Inventories were carried out at 14, 54 and 84 months in four plots from each spacing, with 24 plants. Diameter at breast height (DBH), total height and survival rate were evaluated. The study evaluated the logistic model of growth and yield for the different spacings and analysed production costs, characterising the expenditure elements related to inputs and labour. For the economic analysis, we considered a discount rate of 8% p.a. and the valuation methods of net present value (NPV), annual equivalent value (AEV), average production cost (APC), and cost–benefit ratio (CBR). Spacing influenced diameter distribution, tree height and productivity. The optimal harvest age showed a tendency to decrease in smaller spacing. The increase in plant density (smaller spacing) did not promote a proportional increase in volumetric production. Our results indicated economic viability from 60 months onwards for all spacing, except for 2 × 1 m.
{"title":"Relationships between spacing, productivity and profitability of eucalypt plantations in a small rural property in south-eastern Brazil","authors":"Gabriel Soares Lopes Gomes, S. N. O. Neto, H. Leite, Márcio Lopes da Silva, L. S. D. S. Lopes, Bruno Leão Said Schettini","doi":"10.2989/20702620.2022.2138624","DOIUrl":"https://doi.org/10.2989/20702620.2022.2138624","url":null,"abstract":"Tree cultivation spacing can influence productivity and wood quality, with silvicultural, technological and economic implications. This study aimed to estimate the production and provide an economic analysis of Eucalyptus urophylla × Eucalyptus grandis stands as a function of planting spacing in a small rural property. The study was carried out in the Zona da Mata of Minas Gerais state, with the hybrid clone (GG100) established in 2 × 1 m, 2 × 2 m, 3 × 2 m and 3 × 3 m spacing. Inventories were carried out at 14, 54 and 84 months in four plots from each spacing, with 24 plants. Diameter at breast height (DBH), total height and survival rate were evaluated. The study evaluated the logistic model of growth and yield for the different spacings and analysed production costs, characterising the expenditure elements related to inputs and labour. For the economic analysis, we considered a discount rate of 8% p.a. and the valuation methods of net present value (NPV), annual equivalent value (AEV), average production cost (APC), and cost–benefit ratio (CBR). Spacing influenced diameter distribution, tree height and productivity. The optimal harvest age showed a tendency to decrease in smaller spacing. The increase in plant density (smaller spacing) did not promote a proportional increase in volumetric production. Our results indicated economic viability from 60 months onwards for all spacing, except for 2 × 1 m.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"24 1","pages":"206 - 214"},"PeriodicalIF":0.0,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90181305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.2989/20702620.2022.2147874
Ullrich Hechter, K. Little, Julian Chan, J. Crous, Dean da Costa
A review was conducted to highlight the most important factors contributing to increased mortality and decreased growth in eucalypt plantations during re-establishment (0–12 months). Citations were ranked in terms of credibility, with the importance ratings (derived from the literature sources) applied to the different factors affecting survival and growth during eucalypt re-establishment. Of the various factors impacting early eucalypt mortality, water stress and planting stock quality were considered highly important. Other factors that negatively influence survival and early growth, albeit to a lesser degree than water stress and planting stock quality were the manner and quality of site preparation (soil and slash); planting practices (planting depth included); timing of planting (during dry, hot periods); various post-planting operations (incorrect fertiliser placement or herbicide drift) and insect pests and diseases. In South African forestry, soil water availability is a major contributor of re-establishment success and, as a water scarce country, research indicates the negative impacts this can have on survival and growth. Plant stock quality was also considered important, especially in terms of matching planting stock size (as influenced by age in container, species, season raised, etc.) to container type/size, as the planting of over- or under-prime planting stock will result in higher mortality. These factors cannot be considered in isolation due to the complex interactions that exist among them and determining the primary causes of mortality can be elusive, especially as their impacts tend to be additive by nature. Despite all the research implemented under controlled and field conditions, high mortality (and subsequently below optimal final yield) is still problematic. Most commercial forestry companies target a survival of at least 90% three months after planting, but it is not clear where this threshold level originates and it may be purely anecdotal. This raises key questions pertaining to the economic implications of various mitigation practices, including blanking, replanting and planting at higher densities that can ensure optimum stocking at rotation-end. The factors need to be looked at in greater detail to quantify the relative importance of each. The degree of interrelatedness among the factors should also be further researched.
{"title":"Factors affecting eucalypt survival in South African plantation forestry","authors":"Ullrich Hechter, K. Little, Julian Chan, J. Crous, Dean da Costa","doi":"10.2989/20702620.2022.2147874","DOIUrl":"https://doi.org/10.2989/20702620.2022.2147874","url":null,"abstract":"A review was conducted to highlight the most important factors contributing to increased mortality and decreased growth in eucalypt plantations during re-establishment (0–12 months). Citations were ranked in terms of credibility, with the importance ratings (derived from the literature sources) applied to the different factors affecting survival and growth during eucalypt re-establishment. Of the various factors impacting early eucalypt mortality, water stress and planting stock quality were considered highly important. Other factors that negatively influence survival and early growth, albeit to a lesser degree than water stress and planting stock quality were the manner and quality of site preparation (soil and slash); planting practices (planting depth included); timing of planting (during dry, hot periods); various post-planting operations (incorrect fertiliser placement or herbicide drift) and insect pests and diseases. In South African forestry, soil water availability is a major contributor of re-establishment success and, as a water scarce country, research indicates the negative impacts this can have on survival and growth. Plant stock quality was also considered important, especially in terms of matching planting stock size (as influenced by age in container, species, season raised, etc.) to container type/size, as the planting of over- or under-prime planting stock will result in higher mortality. These factors cannot be considered in isolation due to the complex interactions that exist among them and determining the primary causes of mortality can be elusive, especially as their impacts tend to be additive by nature. Despite all the research implemented under controlled and field conditions, high mortality (and subsequently below optimal final yield) is still problematic. Most commercial forestry companies target a survival of at least 90% three months after planting, but it is not clear where this threshold level originates and it may be purely anecdotal. This raises key questions pertaining to the economic implications of various mitigation practices, including blanking, replanting and planting at higher densities that can ensure optimum stocking at rotation-end. The factors need to be looked at in greater detail to quantify the relative importance of each. The degree of interrelatedness among the factors should also be further researched.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"34 1","pages":"253 - 270"},"PeriodicalIF":0.0,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73109685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.2989/20702620.2022.2128931
T. X. Hung, P. Q. Thu, N. Chi, L. Binh, B. Dell
There are over two million hectares of Acacia plantations in Vietnam and loss from infestations of ambrosia beetles is of increasing concern. In this study, we first determined the key taxa and the extent of damage, and then identified effective trap and lure combinations for trapping adult beetles, and finally quantified the seasonality of flight of Euwallacea for informing pest management decisions. Based on analysis of the mitochondrial cytochrome c oxidase subunit I gene, the greatest threats were confirmed as Euwallacea fornicatus and E. similis (Coleoptera: Curculionidae), which are native to Southeast Asia but known as invasive species in South Africa and elsewhere. The damage incidence of Euwallacea ranged from 16.7% to 34.9% in Acacia plantations throughout Vietnam. There were no significant differences in the numbers of beetles captured between the three trap types (plastic bottles, funnels and panels). Ethanol and quercivorol were more effective as lures than cubeb oil, α-pinene or a distilled water control. Trapping from June 2020 to May 2021 revealed a bimodal frequency of E. fornicatus and E. similis in A. mangium and Acacia hybrid plantations, with captures peaking in April (spring) and October (autumn). These findings can be applied to develop early detection and trapping control programmes for Euwallacea in Acacia plantations in Vietnam and elsewhere.
{"title":"Impacts and trapping of ambrosia beetles Euwallacea fornicatus and E. similis in Acacia plantations in Vietnam","authors":"T. X. Hung, P. Q. Thu, N. Chi, L. Binh, B. Dell","doi":"10.2989/20702620.2022.2128931","DOIUrl":"https://doi.org/10.2989/20702620.2022.2128931","url":null,"abstract":"There are over two million hectares of Acacia plantations in Vietnam and loss from infestations of ambrosia beetles is of increasing concern. In this study, we first determined the key taxa and the extent of damage, and then identified effective trap and lure combinations for trapping adult beetles, and finally quantified the seasonality of flight of Euwallacea for informing pest management decisions. Based on analysis of the mitochondrial cytochrome c oxidase subunit I gene, the greatest threats were confirmed as Euwallacea fornicatus and E. similis (Coleoptera: Curculionidae), which are native to Southeast Asia but known as invasive species in South Africa and elsewhere. The damage incidence of Euwallacea ranged from 16.7% to 34.9% in Acacia plantations throughout Vietnam. There were no significant differences in the numbers of beetles captured between the three trap types (plastic bottles, funnels and panels). Ethanol and quercivorol were more effective as lures than cubeb oil, α-pinene or a distilled water control. Trapping from June 2020 to May 2021 revealed a bimodal frequency of E. fornicatus and E. similis in A. mangium and Acacia hybrid plantations, with captures peaking in April (spring) and October (autumn). These findings can be applied to develop early detection and trapping control programmes for Euwallacea in Acacia plantations in Vietnam and elsewhere.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"15 1","pages":"242 - 252"},"PeriodicalIF":0.0,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91136419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.2989/20702620.2022.2147873
V. Cysneiros, S. Machado, A. Pelissari, E. Urbano
Assessing variations in tree allometry is useful for understanding height growth strategies in relation to life-history trajectories, light competition and environmental restrictions. Scaling exponent and asymptotic heights obtained from height–diameter (HD) models may elucidate how trees optimise growth strategies and the potential drivers that influence tree height. Our main objective was to explore how the HD relationship in Bracatinga (Mimosa scabrella) varies along stands chronosequence and life history. The study was carried out in discontinuous stands located across the metropolitan region of Curitiba, southern Brazil. We used HD data from 300 temporary plots in chronosequences dating from a disturbance, which represented stand development after intervention, covering the life history of the species. Power and exponential models were fitted to data to describe the HD relationship over time. Mixed-effects models were applied to explain the height variations by stand characteristics. We found that tree height and allometry were influenced by stand development phase and tree life stage along the chronosequence. Changes in tree height were also driven by light competition related to certain stand characteristics, such as basal area, stem density and species diversity. We concluded that growth strategies are conditioned by interactions between light requirements along a tree’s life history and successional stand evolution. The results revealed that gradual changes in tree development might be recognised by stationary data along chronosequences. Quantifying changes in HD allometry has ecological and practical applications for explaining the strategies and drivers underpinning tree growth and providing useful knowledge for improving growing stock predictions and stand management.
{"title":"Height growth strategies of Mimosa scabrella along a chronosequence","authors":"V. Cysneiros, S. Machado, A. Pelissari, E. Urbano","doi":"10.2989/20702620.2022.2147873","DOIUrl":"https://doi.org/10.2989/20702620.2022.2147873","url":null,"abstract":"Assessing variations in tree allometry is useful for understanding height growth strategies in relation to life-history trajectories, light competition and environmental restrictions. Scaling exponent and asymptotic heights obtained from height–diameter (HD) models may elucidate how trees optimise growth strategies and the potential drivers that influence tree height. Our main objective was to explore how the HD relationship in Bracatinga (Mimosa scabrella) varies along stands chronosequence and life history. The study was carried out in discontinuous stands located across the metropolitan region of Curitiba, southern Brazil. We used HD data from 300 temporary plots in chronosequences dating from a disturbance, which represented stand development after intervention, covering the life history of the species. Power and exponential models were fitted to data to describe the HD relationship over time. Mixed-effects models were applied to explain the height variations by stand characteristics. We found that tree height and allometry were influenced by stand development phase and tree life stage along the chronosequence. Changes in tree height were also driven by light competition related to certain stand characteristics, such as basal area, stem density and species diversity. We concluded that growth strategies are conditioned by interactions between light requirements along a tree’s life history and successional stand evolution. The results revealed that gradual changes in tree development might be recognised by stationary data along chronosequences. Quantifying changes in HD allometry has ecological and practical applications for explaining the strategies and drivers underpinning tree growth and providing useful knowledge for improving growing stock predictions and stand management.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"101 1","pages":"215 - 224"},"PeriodicalIF":0.0,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78094702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.2989/20702620.2022.2110538
A. Morris
South Africa has 1.2 million hectares of plantations developed progressively through the 20th century. These occur from 23° to 34°S, from near sea level to 2 000 m above sea level and in both Mediterranean winter rainfall and summer subtropical rainfall climates. Plantations supply pulp mills, sawmills, treated pole and mining timber production, and wattle tannin production. The diversity of sites and markets requires planting of a range of taxa of pine, eucalypt and wattle. A survey of planted area by taxa in South African forest plantations is reported and compared to statistics available from national annual reporting on the commercial timber resources in the country. The survey found a similar number of taxa are currently planted (15) as in the 1950s but only 6 of the earlier options remain in use. Changes have occurred in the last 30 years, with 40% of planted area in 2019 using options not available before 1990. From the 1990s, Eucalyptus grandis has been extensively replaced by eucalypt hybrids and E. dunnii and Pinus elliottii × P. caribaea var. hondurensis has become an important pine planting option. Over the past decade, E. nitens replacement with other existing frost tolerant eucalypt planting options has occurred, use of P. radiata has reduced and P. patula has been replaced on a significant scale with P. patula hybrids. Many of these changes have been to mitigate the impact of new pests and pathogens and, on lower productivity sites, periodic severe droughts. However, the new planting options also provide increased yields and have wood properties acceptable to the intended markets. Meeting all three criteria is likely to remain a requirement for successful introduction of future new planting options. The survey indicates a need to revise current national reporting requirements to better reflect use of species and hybrids in South African plantations.
南非有120万公顷的种植园在20世纪逐步发展起来。这些气候发生在23°至34°S，从接近海平面到海拔2000米，地中海冬季降雨和夏季亚热带降雨气候。种植园供应纸浆厂，锯木厂，处理杆和采矿木材生产，和金合欢单宁生产。场地和市场的多样性需要种植一系列松树、桉树和金合欢的分类群。报告了对南非森林人工林按分类群划分的种植面积的调查，并将其与关于该国商业木材资源的国家年度报告提供的统计数据进行了比较。调查发现，目前种植的分类群数量与20世纪50年代相似(15种)，但只有6种较早的选择仍在使用。过去30年发生了变化，2019年40%的种植面积采用了1990年之前没有的选择。20世纪90年代以来，大桉树已被桉树杂交种所广泛取代，杜尼松(E. dunnii)和油松(Pinus elliottii × P. caribaea var hondurensis)已成为重要的松树种植选择。在过去的十年中，已经出现了用其他现有的耐霜桉树种植方案替代nitens的情况，辐射桉树的使用减少了，而patula已被patula杂交品种大规模取代。其中许多变化是为了减轻新的害虫和病原体的影响，以及在生产力较低的地区，周期性的严重干旱。然而，新的种植选择也增加了产量，并具有预期市场可接受的木材性能。满足所有三个标准可能仍然是成功引进未来新的种植方案的必要条件。调查表明，需要修订目前的国家报告要求，以更好地反映南非种植园中物种和杂交品种的使用情况。
{"title":"Changing use of species and hybrids in South African forest plantations","authors":"A. Morris","doi":"10.2989/20702620.2022.2110538","DOIUrl":"https://doi.org/10.2989/20702620.2022.2110538","url":null,"abstract":"South Africa has 1.2 million hectares of plantations developed progressively through the 20th century. These occur from 23° to 34°S, from near sea level to 2 000 m above sea level and in both Mediterranean winter rainfall and summer subtropical rainfall climates. Plantations supply pulp mills, sawmills, treated pole and mining timber production, and wattle tannin production. The diversity of sites and markets requires planting of a range of taxa of pine, eucalypt and wattle. A survey of planted area by taxa in South African forest plantations is reported and compared to statistics available from national annual reporting on the commercial timber resources in the country. The survey found a similar number of taxa are currently planted (15) as in the 1950s but only 6 of the earlier options remain in use. Changes have occurred in the last 30 years, with 40% of planted area in 2019 using options not available before 1990. From the 1990s, Eucalyptus grandis has been extensively replaced by eucalypt hybrids and E. dunnii and Pinus elliottii × P. caribaea var. hondurensis has become an important pine planting option. Over the past decade, E. nitens replacement with other existing frost tolerant eucalypt planting options has occurred, use of P. radiata has reduced and P. patula has been replaced on a significant scale with P. patula hybrids. Many of these changes have been to mitigate the impact of new pests and pathogens and, on lower productivity sites, periodic severe droughts. However, the new planting options also provide increased yields and have wood properties acceptable to the intended markets. Meeting all three criteria is likely to remain a requirement for successful introduction of future new planting options. The survey indicates a need to revise current national reporting requirements to better reflect use of species and hybrids in South African plantations.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"34 1","pages":"193 - 205"},"PeriodicalIF":0.0,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83114913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-03DOI: 10.2989/20702620.2022.2045880
F. Santos, F. Balieiro, Danilo Henrique dos Santos Ataíde, Pedro Vaz da Rocha, Bruno JR Alves, G. Chaer
We hypothesised that N inputs to the soil from residues of adult trees of Acacia mangium Willd. increase soil nitrate availability and consequently induce higher nitrous oxide (N2O) fluxes, irrespective of being in pure or mixed stands with Eucalyptus. A randomised block-design experiment was set up on Haplic Planosol in Brazil to study the impact of monospecific stands of Eucalyptus urograndis (Eucalyptus urophylla S. T. Blake × Eucalyptus grandis W. Hill ex Maiden) fertilised with 120 kg N ha−1 (E100+N) and A. mangium (A100), along with the mixture of both species (E50A50) on soil N mineralisation and its relationship with soil N2O emissions. In situ monitoring of N mineralisation, N2O emissions and the soil N stocks was carried out between five- and six-year-old plantations. The total soil net mineralisation of N that was accumulated in plantations A100 and E50A50 was on average 3.5- and 2.5-times greater than in the E100+N plantation. The NO3 − produced throughout the year by the plantations was proportional to the total net mineralisation, according to the following order of production scale: A100 > E50A50 > E100+N. Furthermore, N2O emissions in the plantations that included A. mangium (A100 and E50A50) were significantly higher in some periods of the year, as compared with in the E100+N plantation. This pattern caused a more pronounced curve of accumulated N2O emissions under A. mangium plantations (pure and mixed) as compared with the monospecific Eucalyptus plantation (E100+N). However, the magnitude of N accumulation emissions suggests that mixed plantations could increase the nutritional status of sandy soils.
我们假设mangium野生金合欢成年树残体对土壤的氮输入。增加土壤硝酸盐的有效性，从而诱导更高的一氧化二氮(N2O)通量，无论在纯桉树林中还是混合桉树林中。在巴西的Haplic Planosol上建立了一个随机区组设计试验，研究了在120 kg N ha - 1 (E100+N)和A. mangium (A100)以及这两种物种的混合物(E50A50)施肥后，尾巨桉(Eucalyptus urophylla s.t. Blake × Eucalyptus grandis W. Hill ex Maiden)单种林分对土壤N矿化的影响及其与土壤N2O排放的关系。在5年至6年的人工林之间进行了N矿化、N2O排放和土壤N储量的现场监测。A100和E50A50人工林累积的土壤净矿化总氮平均是E100+N人工林的3.5倍和2.5倍。各人工林全年NO3−产生量与净矿化总量成正比，生产规模顺序为:A100 > E50A50 > E100+N。此外，与E100+N人工林相比，在一年中的某些时期，mangium人工林(A100和E50A50)的N2O排放量显著高于E100+N人工林。这种模式导致mangium人工林(纯和混合)的N2O累积排放曲线比单一桉树人工林(E100+N)更明显。然而，氮积累排放的大小表明，混合人工林可以改善沙质土壤的营养状况。
{"title":"Nitrogen mineralisation and N2O emissions in pure and mixed-species plantations of Eucalyptus urograndis and Acacia mangium","authors":"F. Santos, F. Balieiro, Danilo Henrique dos Santos Ataíde, Pedro Vaz da Rocha, Bruno JR Alves, G. Chaer","doi":"10.2989/20702620.2022.2045880","DOIUrl":"https://doi.org/10.2989/20702620.2022.2045880","url":null,"abstract":"We hypothesised that N inputs to the soil from residues of adult trees of Acacia mangium Willd. increase soil nitrate availability and consequently induce higher nitrous oxide (N2O) fluxes, irrespective of being in pure or mixed stands with Eucalyptus. A randomised block-design experiment was set up on Haplic Planosol in Brazil to study the impact of monospecific stands of Eucalyptus urograndis (Eucalyptus urophylla S. T. Blake × Eucalyptus grandis W. Hill ex Maiden) fertilised with 120 kg N ha−1 (E100+N) and A. mangium (A100), along with the mixture of both species (E50A50) on soil N mineralisation and its relationship with soil N2O emissions. In situ monitoring of N mineralisation, N2O emissions and the soil N stocks was carried out between five- and six-year-old plantations. The total soil net mineralisation of N that was accumulated in plantations A100 and E50A50 was on average 3.5- and 2.5-times greater than in the E100+N plantation. The NO3 − produced throughout the year by the plantations was proportional to the total net mineralisation, according to the following order of production scale: A100 > E50A50 > E100+N. Furthermore, N2O emissions in the plantations that included A. mangium (A100 and E50A50) were significantly higher in some periods of the year, as compared with in the E100+N plantation. This pattern caused a more pronounced curve of accumulated N2O emissions under A. mangium plantations (pure and mixed) as compared with the monospecific Eucalyptus plantation (E100+N). However, the magnitude of N accumulation emissions suggests that mixed plantations could increase the nutritional status of sandy soils.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"56 1","pages":"113 - 122"},"PeriodicalIF":0.0,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85641080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-03DOI: 10.2989/20702620.2022.2102453
M. Cheek, J.R.U. Wilson, DM Richardson, Ş. Procheş
Collections of living trees (hereafter arboreta) are important for conservation, research on species selection for forestry, and as sentinel sites for monitoring pests and diseases. Arboreta can also be the source of propagules for biological invasions. Between 2012 and 2022 a survey was undertaken to assess the status of arboreta in South Africa and the taxa present in such sites, the first such assessment since 1986. At least 172 arboreta have existed in South Africa, but 51 of these are no longer present, with the total number of arboreta peaking around 1980 and declining thereafter. Arboreta have been lost mostly because of conversion of sites to other land-uses, but in some cases because the specimens were felled or burnt down and not replaced. Most of the remaining 121 arboreta are on municipal or forestry land. The biggest challenge facing the extant arboreta is the financial burden of maintaining the collections. The extant arboreta house 2 309 taxa from 158 plant families; of these, 128 taxa (occurring variously in 88 arboreta) are listed as Vulnerable, Endangered, Critically Endangered or Extinct in the Wild under the 2020 IUCN Red List, and 400 taxa (occurring variously in 113 arboreta) have been listed as invasive somewhere in the world. Biogeographic regions that are relatively well represented include the East African Steppe, Sino-Japanese Region, West African Rainforest, North-Eastern Australia, and the Caribbean, making the arboreta valuable sources of germplasm for taxa from these regions. Arboreta are an important resource for South Africa, but a resource that appears to be shrinking. If the value of current arboreta for conservation, education, and research is to be fulfilled, they need to be formally catalogued, their species lists regularly updated, and measures put in place to ensure their sustainability.
{"title":"The status of arboreta in South Africa and the taxa they contain","authors":"M. Cheek, J.R.U. Wilson, DM Richardson, Ş. Procheş","doi":"10.2989/20702620.2022.2102453","DOIUrl":"https://doi.org/10.2989/20702620.2022.2102453","url":null,"abstract":"Collections of living trees (hereafter arboreta) are important for conservation, research on species selection for forestry, and as sentinel sites for monitoring pests and diseases. Arboreta can also be the source of propagules for biological invasions. Between 2012 and 2022 a survey was undertaken to assess the status of arboreta in South Africa and the taxa present in such sites, the first such assessment since 1986. At least 172 arboreta have existed in South Africa, but 51 of these are no longer present, with the total number of arboreta peaking around 1980 and declining thereafter. Arboreta have been lost mostly because of conversion of sites to other land-uses, but in some cases because the specimens were felled or burnt down and not replaced. Most of the remaining 121 arboreta are on municipal or forestry land. The biggest challenge facing the extant arboreta is the financial burden of maintaining the collections. The extant arboreta house 2 309 taxa from 158 plant families; of these, 128 taxa (occurring variously in 88 arboreta) are listed as Vulnerable, Endangered, Critically Endangered or Extinct in the Wild under the 2020 IUCN Red List, and 400 taxa (occurring variously in 113 arboreta) have been listed as invasive somewhere in the world. Biogeographic regions that are relatively well represented include the East African Steppe, Sino-Japanese Region, West African Rainforest, North-Eastern Australia, and the Caribbean, making the arboreta valuable sources of germplasm for taxa from these regions. Arboreta are an important resource for South Africa, but a resource that appears to be shrinking. If the value of current arboreta for conservation, education, and research is to be fulfilled, they need to be formally catalogued, their species lists regularly updated, and measures put in place to ensure their sustainability.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"13 1","pages":"174 - 191"},"PeriodicalIF":0.0,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87259283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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