Southern Forests: a Journal of Forest Science最新文献_第10页

An analysis of South African sawmilling competitiveness 南非锯木厂竞争力分析

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2020.1813646

S. Grobbelaar, J. Visser

{"title":"An analysis of South African sawmilling competitiveness","authors":"S. Grobbelaar, J. Visser","doi":"10.2989/20702620.2020.1813646","DOIUrl":"https://doi.org/10.2989/20702620.2020.1813646","url":null,"abstract":"The South African sawn timber market supply and demand are in equilibrium and significantly associated with the local residential construction market. During the great financial crisis (GFC), the local residential construction market contracted. This caused a reduction in sawn timber demand, price and margin. Subsequently, the competition between sawmillers increased and led to the closure of 41 mills. This study included a sawmilling competitiveness analysis for South African sawmills taking part in the Crickmay Intermill comparison from 2004 to 2017. The Crickmay Intermill comparison assumes that nett margin is the measurement for competitiveness. Spearman correlation tests were used to compare performance measurements with nett margin. This and other studies found significant associations between the implementation of value-adding strategies and competitiveness. Sawmills that effectively create more value from the raw material tend to be more competitive. In contrast with other studies, our research determined that people costs are significantly associated with competitiveness. However, like other studies, it was confirmed that labour productivity is not associated with competitiveness. This study argues that South African sawmillers can increase competitiveness by implementing value-adding strategies, implementing competitive remuneration policies and increasing the sawn timber usage intensity in South Africa.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"54 1","pages":"28 - 37"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74561463","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}

引用次数: 1

Natural regeneration status and soil seed bank composition in IITA Forest Reserve, Ibadan, Oyo State, Nigeria 尼日利亚奥约州伊巴丹IITA森林保护区自然更新状况及土壤种子库组成

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2020.1759293

Bright Danso Appiagyei, A. O. Adejoke

{"title":"Natural regeneration status and soil seed bank composition in IITA Forest Reserve, Ibadan, Oyo State, Nigeria","authors":"Bright Danso Appiagyei, A. O. Adejoke","doi":"10.2989/20702620.2020.1759293","DOIUrl":"https://doi.org/10.2989/20702620.2020.1759293","url":null,"abstract":"The International Institute of Tropical Agriculture (IITA) Forest Reserve is a secondary rainforest that has been protected since 1965. It serves as a refuge for many species that were once common but have declined, due to urbanisation and population pressure. The study was conducted to assess the natural regeneration status and soil seed bank composition of the Forest Reserve. Two transects of 500 m were laid out using systematic line transect sampling technique. Ten sample plots of 25 m × 25 m (625 m2) on each line transect were used to identify tree species. Subplots of 5 m × 5 m for shrub and climber species, as well as 1 m × 1 m for herb species were demarcated at the corners and centre of the main plots for identification. Quadrats (15 × 15 cm) were laid out at the corners of the plots and at the centre for soil collection at depths of 0–5 cm, 5–10 cm and 10–15 cm. The regeneration status of species was determined based on sample size of seedlings, saplings and mature trees. Floristic compositions in the Forest Reserve included 58 tree, 26 shrub, 19 climber and 6 herb species. The natural regeneration status of the Forest Reserve was good with high numbers of seedlings (465/ha; 37.05%) and saplings (431/ha; 34.34%) compared with mature trees (359/ha; 28.61%). The families observed to be most abundant in the regeneration were Malvaceae, Moraceae and Apocynaceae. A total of 21 species was recorded using the seedling emergence technique. There were 11 herbs, six climbers, one shrub and three tree species. Similarity between standing vegetation and seed bank was low (0.067). The study revealed a poor soil seed bank composition, suggesting that regeneration of woody species from the persistent seed bank would be hampered if the standing vegetation is degraded.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"90 1","pages":"1 - 9"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84302458","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}

引用次数: 1

Residual fertiliser and liming impacts in a long-term Acacia mearnsii trial 长期金合欢试验中残余肥料和石灰的影响

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2020.1820917

L. Titshall

引用次数: 1

Models for predicting slenderness coefficient from stump diameter for Tectona grandis stands in south-western Nigeria 用树桩直径预测尼日利亚西南部大构造林长细系数的模型

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2020.1814108

Onyekachi Chukwu

{"title":"Models for predicting slenderness coefficient from stump diameter for Tectona grandis stands in south-western Nigeria","authors":"Onyekachi Chukwu","doi":"10.2989/20702620.2020.1814108","DOIUrl":"https://doi.org/10.2989/20702620.2020.1814108","url":null,"abstract":"Illegal logging has continued to be a major cause of depletion of the tropical forests in developing countries. However, empirical means of estimating the growth characteristics of a removed tree, which will facilitate the conviction of illegal loggers in judicial proceedings, are lacking. This study aimed at developing a model that can predict individual tree slenderness coefficients (SC) from stump diameter (Ds) for Tectona grandis stands in Omo Forest Reserve, Nigeria, for timber valuation in case of illegal felling. Diameter at breast height (DBH; cm), Ds (cm) and total height Ht (m) were measured from all T. grandis stands with a DBH ≥ 5.0 cm, within 35 temporary sample plots (TSPs) randomly laid out in 6 age series (26, 23, 22, 16, 14 and 12 years). The least squares regression method was used to model tree SC from Ds. Six SC-Ds models were fitted and evaluated. The relationship was best described by the single logarithmic function which gave best-fit values for the adjusted coefficient of determination, the Furnival’s index and the standard error of the estimate. This study showed that tree SC estimations were possible even when the only information available was the Ds. The single logarithmic model was validated using independent data and was found to be suitable for estimating the SC of T. grandis stands in Omo Forest Reserve, south-western Nigeria. Future studies should consider developing models for predicting other tree growth variables from Ds.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"4 1","pages":"38 - 42"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88784453","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}

引用次数: 1

Perspectives and drivers of modernisation of silviculture re-establishment in South Africa 南非造林重建现代化的前景和驱动因素

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2020.1819152

M. Ramantswana, M. Brink, K. Little, R. Spinelli, P. Chirwa

{"title":"Perspectives and drivers of modernisation of silviculture re-establishment in South Africa","authors":"M. Ramantswana, M. Brink, K. Little, R. Spinelli, P. Chirwa","doi":"10.2989/20702620.2020.1819152","DOIUrl":"https://doi.org/10.2989/20702620.2020.1819152","url":null,"abstract":"Efficient and cost-effective re-establishment practices are important parts of any sustainable forest re-establishment programme. Re-establishment activities include residue management (post-harvest slash), preparation of a planting position, planting, fertilisation and vegetation management. In South Africa, these activities are largely labour intensive, time-consuming and relatively costly. Although mechanisation of site preparation during afforestation was achieved in the mid to late 1990s, plantation re-establishment operations in South Africa have remained manually oriented. However, there have been notable technology developments over the past decade. Semi-structured interviews were conducted with 66 experts (grower company specialists, foresters, contractors and machine manufacturers) to get their perspectives on modernisation of re-establishment activities in South Africa. Frequency distribution and chi-square test analysis found that two-thirds of the experts believed that re-establishment activities had progressed in terms of technology over the past decade. This development was reported as primarily due to the need to improve health and safety (91%), increase production whilst reducing costs (89%), improve stand productivity (quality) (86%), mitigate social (mainly labour) risks (80%) and reduce prevalent negative environmental impacts (50%). Key barriers to modernisation were identified as the capital cost of equipment (65%), reduction in employment opportunities (44%) and low utilisation of equipment due to seasonality of silviculture work (18%). Experts indicated that the efficiency of mechanised re-establishment equipment can be affected negatively by residues, high stumps and compaction of the site after harvesting. The results of this study will assist forestry stakeholders to make informed decisions when planning and implementing modernised silviculture operations.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"74 1","pages":"79 - 87"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85881423","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}

引用次数: 1

Developing a satellite-based frost risk model for the Southern African commercial forestry landscape 为南部非洲商业林业景观开发基于卫星的霜冻风险模型

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2020.1759304

R. Ismail, J. Crous, Giovanni Sale, Andrew Morris, K. Peerbhay

引用次数: 3

Miombo woodlands in a changing environment: securing the resilience and sustainability of people and woodlands 环境变化中的Miombo林地:确保人类和林地的恢复力和可持续性

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2021.1884031

A. Sitoe

引用次数: 1

Tier 2 above-ground biomass expansion functions for South African plantation forests 南非人工林的第2层地上生物量扩展功能

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2020.1819151

S. Dovey, B. du Toit, J. Crous

{"title":"Tier 2 above-ground biomass expansion functions for South African plantation forests","authors":"S. Dovey, B. du Toit, J. Crous","doi":"10.2989/20702620.2020.1819151","DOIUrl":"https://doi.org/10.2989/20702620.2020.1819151","url":null,"abstract":"Carbon stocks estimated for greenhouse gas emission reporting in South African plantation forests require improvement for local relevance. We developed biomass expansion and conversion factor (BECF) models to convert enumeration data to above-ground biomass (AGB) for major genera. Local biomass data and allometric models were aggregated across major taxa and scaled to utilisable stem and non-utilisable (bark, branch, foliar) biomass on 1 735 permanent sample plots. Models were developed for each genus to estimate BECF from utilisable volume to overcome bracket stepping in the Intergovernmental Panel on Climate Change (IPCC) lookup tables. To enable more accurate biomass estimates for growers who record tree volume and bone-dry wood density, an alternative calculation was developed that capitalises on stem-wood comprising 70% to 90% of AGB at rotation age. AGB is the sum of utilisable stem and non-utilisable components. Stem mass can be calculated as the product of volume and wood density. Models to estimate non-utilisable biomass from utilisable volume were developed for each genus. Local models estimated lower hardwood biomass and marginally lower softwood biomass than IPCC estimates. Use of local estimates compared to default values result in lower carbon stock estimates and reduced fluxes using the stock change method. Developing further allometric models and BECFs at the species or hybrid level will have little value due to rapidly changing genetic deployment and current work has indicated non-significant differences between genotypes within each genus. Further work should focus on improved tree volume and wood density estimates as well as on below-ground biomass estimates.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"84 1","pages":"69 - 78"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82664051","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}

引用次数: 0

Solid wood property variations in early-age Acacia plantation trees grown in southern Vietnam 越南南部生长的早期金合欢人工林的实木特性变化

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2020.1813645

D. Blackburn, Vu Dinh Huong, N. D. Thanh, D. Mendham

{"title":"Solid wood property variations in early-age Acacia plantation trees grown in southern Vietnam","authors":"D. Blackburn, Vu Dinh Huong, N. D. Thanh, D. Mendham","doi":"10.2989/20702620.2020.1813645","DOIUrl":"https://doi.org/10.2989/20702620.2020.1813645","url":null,"abstract":"A high demand for woodchips has encouraged smallholder farmers in Vietnam to invest in short-rotation Acacia plantations to produce pulpwood that has a relatively quick, though often low, income return. Because of an expanding export furniture industry, the Vietnam Government has sought to increase sawlog production and, at the same time, improve returns to smallholder farmers. However, currently the quality and therefore market value of the timber from acacias under differing management strategies has not been well quantified. Acacia auriculiformis, both in its pure form and its hybrid with A. mangium (Acacia hybrid) are grown in plantations in Vietnam to produce merchantable timber, though the inferior mechanical properties of juvenile wood at an early age has impeded access to higher-value product markets. However, with thinning, there may be improvements in wood properties that could enhance sawlog values. This study examined how the wood properties of plantation grown Acacia hybrid change with stand age, explored differences in wood properties between Acacia hybrid and A. auriculiformis following different thinning treatments, and determined which of the two species is the most favourable for solid wood products. The potential to supply logs to produce sliced veneer for the furniture industry was also investigated. Logs from A. hybrid trees aged eight years could be processed to manufacture structural products, and at age five years for manufacturing utility furniture. Acacia auriculiformis thinned to 833 stems per hectare at age 4 years had mechanical wood properties indicating a potential for durable flooring products that can command a high value in the market. Because of dead knots, most sliced veneer samples were not acceptable for face veneer, though visual assessments indicated that with pruning, an attractive high-value product could potentially be produced. Tree species rather than age or thinning treatment had the most influence on wood properties.","PeriodicalId":21939,"journal":{"name":"Southern Forests: a Journal of Forest Science","volume":"1 1","pages":"19 - 27"},"PeriodicalIF":0.0,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89649178","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}

引用次数: 2

Analysing species site-specific tree growth, mortality and in-growth for miombo woodlands in Tanzania 分析坦桑尼亚miombo林地树种特定地点的树木生长、死亡率和生长量

Southern Forests: a Journal of Forest Science Pub Date : 2021-01-02 DOI: 10.2989/20702620.2020.1814113

E. Njoghomi, S. Valkonen, K. Karlsson

引用次数: 2