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柚木基因资源的特点和我国柚木遗传改良途径 总被引:1,自引:0,他引:1
本文论述世界柚木基因资源的特点及其在我国的发展前途和遗传改良途径。柚木基因资源分成三个互不连续的天然分布区,生态背景十分复杂。种内包括种源间的变异多种多样。印度被视为世界柚木的“多变异中心”而受人重视。我国目前拥有的柚木种源,与辽阔的宜林地很不相称,是发展柚木人工林的障碍之一。世界柚木的基因库,可为我国柚木人工林的发展提供丰富的基因资源。为此柚木遗传改良途径应在地理种源试验或类型划分的基础上,进行混合与单株并行选择,并与无性系育种结合起来。 相似文献
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介绍国内外柚木遗传改良工作的基本情况,分析了柚木原产地及云南引进的柚木种源特点。对红河州引进保存的来自世界柚木分布区8个引种国家126个种源的试验情况进行了评价。依据柚木的生态学特性、发展前景及红河州的自然特点,提出了柚木的改良目标、方向、策略、途径及程序,提出柚木应适地、适树、适种源,因地制宜地加以集约栽培,柚木人工林的经济效益才会最大,才能在适宜栽培范围内得到发展。 相似文献
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柚木是一种名贵高档的木材,以色泽美、纹理细、经久耐用而著称。世界上天然生长柚木的国家只有印度、缅甸、老挝和泰国。在印尼爪畦现也可能到天然生长的柚木,但一般认为它们是400~600年前从国外引种的。目前柚木不仅在亚洲热带国家有人工林,同时在非洲如尼日利亚、塞拉利昂、坦桑尼亚等国、拉丁美洲和加勒比海地区也在人工林发展。柚木还被引种到太平洋一些岛屿上,澳大利亚北部地区也在开展种植试验。 相似文献
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2008年新年初,由于许多买家对天然柚木比人工林生产的柚木更为热衷,国际木材市场上对缅甸柚木的需求继续坚挺。2007年12月份,为欧盟、美国和日本所热追的高档柚木价格继续强劲,而其他买家喜欢购买的较低档的柚木木材价格下降。 相似文献
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In this study soil samples were taken from the O/A and B horizons of undisturbed forest, active pasture, and 8- to 12-year-old teak and mixed native plantations. Samples were analyzed for K, Ca, Mg, soil organic carbon, pH, exchangeable acidity, bulk density, and compared with a fertility equation. Bulk density was significantly lower in the undisturbed forest than other land uses, suggesting that after approximately 10 years of growth neither plantation lowered bulk density significantly from that of the active pasture. Teak plantations had significantly higher Mg and K (B horizon) and Ca (O/A horizon) concentrations than the undisturbed forest. This trend suggests that exchangeable base concentrations increase when land use changes from undisturbed forest to pasture, then pasture to plantation, with the most pronounced effect of this in teak plantations exhibiting more high fertility plots than other land uses. Soil organic carbon concentration was similar for all land uses except for a significantly lower concentration in teak plantations than in active pasture (O/A horizons). These results suggest that teak plantations may be advantageous for increasing soil fertility but, with respect to restoration of undisturbed forest conditions, present significant deviations in soil chemistry. Options for improved plantations soil management are discussed. 相似文献
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Teak plantations date back to 1871 in Bangladesh.This study was designed to assess how teak monoculture has impacted the soil properties in Bangladesh.Multiple linear regression and correlation matrices were estimated to evaluate these impacts.The means of soil physicochemical properties were compared across various attributes of the plantations.Older plantations accumulated more organic carbon in the soils than the younger plantations.Excessive removal of litter from the forest floor resulted in reduced levels of N, P, K, and other nutrients in the soils.Since bulk density was continuously decreasing deeper into the soil, the penetration of mineral nutrients into the soil was low.Furthermore, moisture content in the topsoil was significantly lower than that in the bottom layers due to the exposed and dry condition of the forest floor under teak plantations.For improving depleted teak plantation soils, teak could be planted with other tree species rather than just in monocultures.In addition, the forest floor could be enriched with leguminous herbs and shrubs to improve soil health in these plantations. 相似文献
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Determination of site quality is a basic tool for proper selection of locations and species, in management of forest plantations.Throughout the Caribbean studies of site quality are few and are hampered by statistical limitations, inappropriate growth models, and limited data. We fitted growth curves for dominant height to evaluate and classify site quality of teak (Tectona grandis) plantations by using data from 44 permanent sample plots established since 1990 in 3 22 years old teak plantations in the Colombian Caribbean region. We used Korf’s and von Bertalanffy’s models to fit curves as nonlinear effects models. Both models, with a single random parameter, were considered as adequate for dominant height growth modelling, but Korf’s model was superior. There sulting curves were anamorphic and closely reflected high variability insite quality. Five site classes were clarified: at a base age of 12 years old,teak reached a mean dominant height of 24.8 m on the best sites, 9.8 m inthe worst sites, and in the averages sites, 15.8-18.8 m. Using this model,we identified the best and the worst sites for teak plantations in the Caribbean region. This model proved a useful tool, not only for site quality evaluation, but also for improved teak plantation planning and management. 相似文献
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Coppicing is an alternative reforestation tool for teak in the tropics, substantially reducing regeneration time/costs and associated demands for labor and seed when available. Growth rates of coppiced material are rapid in most situations, but stem/wood quality is a frequent concern. We compared coppiced teak plantations to paired seed-origin plantations, at ages 3, 8, and 13 years, on Forest State Corporation managed land located in Java, Indonesia. Teak trees were evaluated for height, diameter, lower-bole straightness, and presence of disease in both plantation types and at three ages. Mean height and diameter of trees in coppiced plantations were both significantly greater than that in their paired seed-origin plantations at all three ages. Furthermore, heights and diameters in coppiced plantations were higher than expected based on established growth tables for Java. Coppiced plantations were less symptomatic of disease than seed-origin plantations, which promises better wood production and quality. Lower-bole stems in coppiced plantations developed less straight than those in seed-origin plantations, but these deviations faded with time and will likely become insignificant within a 60-year rotation. Based on these results from existing coppiced plantations in Java, coppiced plantations can make a major contribution to teak production in Indonesia. 相似文献
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Exploring the Socio-Economic Situation of Plantation Villagers: A Case Study in Myanmar Bago Yoma 总被引:1,自引:1,他引:0
Since the early 1980s, Myanmar Forest Department has been recruiting shifting cultivators, establishing plantation villages
and applying the taungya method in establishing teak plantations. From the beginning, there has been an argument about whether
the program is creating ‘forest protective groups’ or ‘forest destructive groups’. A key determinant to that question from
the research viewpoint is the socio-economic situation; knowing the present situation of the plantation villagers can help
to understand their forest management practices. Interview surveys were carried out in three villages in Bago Yoma, the main
region of the special teak plantation program, to examine the current economic benefits to plantation villagers. Questions
were designed mainly to explore the incentives for people participation and the socio-economic situations of the plantation
villagers. Principal component analysis was used to group landholder types. It was found that local people are willing to
participate in the initial establishment of plantations. However, all the incentives relating to plantation projects are temporary,
with no long-term consideration for taungya farmers, which jeopardizes the plan to create forest protective groups. It is
concluded that the time has come for the Myanmar Forest Department to change its main aim of earning foreign exchange from
establishment of teak plantations through the taungya method to redressing deforestation through people participation based
on rural socio-economic development.
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Tin Min MaungEmail: |
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Teak (Tectona grandis L. f) has been introduced to reforestation programs in many tropical countries for timber production. The use of teak plantations has changed the supply from large-diameter logs to small-diameter logs featuring a higher proportion of juvenile wood and more knots. Generally, the teak from fast-growth plantation is harvested after 15–30 years of growth, with logs ranging from 12 to 30 cm in diameter. The goal of this work was to review the factors that influence the heartwood formation, variation, quality, color, and durability in teak and to understand which factors should be controlled in fast-growth plantations. Important factors in the heartwood properties of teak trees from fast-growth plantations are as follows: the tree age, longitudinal variation, geographic location, environmental conditions, and silvicultural activities. These factors influence heartwood extractive content, color variation, and durability. 相似文献
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Puangpaka Kaewkrom Jiragorn Gajaseni Carl F. Jordan Nantana Gajaseni 《Forest Ecology and Management》2005,210(1-3):351-361
Teak is the most important timber species in northern Thailand, and as such, large areas of teak forest have been disturbed or become highly degraded. Teak plantations have been established on this highly degraded land, where the rate of natural recovery is relatively slow. At the study site, five mixed or pure teak plantation types have been established to ameliorate limiting soil properties in order that long-term productivity is maintained. Observations within these plantations in northern Thailand have suggested that native species become established naturally under the shade of a “nurse” plantation, one that shades out early successional species. The objective of this study was to investigate the influence of the number of species in nurse plantations on the diversity and number of seedlings representative of mature native forests that become established within the plantations. Five types of plantations were investigated: (1) Tectona grandis L.f. (T); (2) T.grandis and Tamarindus indica L. (TT); (3) T.grandis and Gmelina arborea Roxb. (TG); (4) T.grandis, T. indica and G. arborea (TTG); (5) T.grandis, T.indica and Anacardium occidentale L. (TTA). These plantations were established primarily for the production of T.grandis (teak), with the other species introduced as economic trees. The plantations were surrounded by native stands of species representative of late successional and mature teak forests. In each of the plantations studies measurements were made on species density, species diversity, and evenness of plants regenerating in the understorey. Results showed that plantations consisting of several species in the overstorey had a higher diversity of native forest species in the understorey than the single-species plantation. Mixed plantation types were also found to reduce the density of the grass Imperata cylindrica (L.) P. Beauv. Consideration of the establishment of woody species found that TG and TTA had high densities of trees and shrubs. This suggested that if the goal of management was to regenerate forest with a high diversity of tree species similar to that found in native mature forests, multiple-species plantations, especially TG and TTA, would be more effective nurse communities than the single-species plantation in providing an environment into which seeds of native species could disperse and germinate. In addition, several climax species, such as Xylia xylocarpa (Roxb.) Taub. var. kerrii (Craib & Hutch) I.C. Nielsen, Pterocarpus macrocarpus Kurz, Largerstroemia sp., Afzelia xylocarpa (Kurz) Craib, Lannea coromandelica (Houtt) Merr., Spondias pinnata (L.f.) Kurz, Garuya pinnata Roxb., Terminalia mucronata Craib & Hutchison, Diospyoros mollis Griff., Irvingia malayana Oliv. ex Benn., Milletia leucantha Kurz, Dalbergia oliviri Gamble ex Prain, Chukrasia tabularis A. Juss and Schleichera oleosa (Lour.) Oken, were found in the early stages of succession, thus indicating that some may be suitable for planting in future restoration processes in order to accelerate natural succession and provide economic returns to managers. 相似文献
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This paper investigates the profitability of cloned teak seedlings among small-scale farmers in the Canton of Hojancha in Costa Rica. A survey was conducted among small-scale farmers to explore their opinions regarding tree breeding. Most respondents considered that the use of improved seedling material is profitable and their willingness to plant clones in the future was high. The net present value of teak plantations at a 5% discount rate was estimated to be USD 12,330, USD 12,814, USD 14,284 and USD 14,308 per hectare for four non-genetically modified seedling plantations. According to a sensitivity analysis, the profitability of a teak plantation based on non-genetically modified seedlings is more sensitive to changes in timber prices than to changes in silvicultural costs. Investment in clone planting appears potentially highly profitable. With interest rates of 5 and 3%, it was profitable to plant clones if only 1% of genetic gain in volume was achieved and if the price of the clones was not greater than 50% of non-genetically modified seedlings. 相似文献
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Dawa Mndez‐lvarez Arantxa Rodríguez Yorleny Badilla‐Valverde Olman Murillo‐Gamboa 《Forest Pathology》2019,49(3)
Teak plantation productivity and economic value have risen significantly since 2000; however, teak dieback syndrome in commercial plantations is becoming worse every year. We isolated, characterized and identified the causal agents of teak dieback, based on morphological characteristics in culture and DNA sequencing. The pathogenicity of Lasiodiplodia theobromae and Fusarium proliferatum (separate and together) was confirmed in inoculations of teak elite genotypes, fulfilling Koch's postulates. To our knowledge, this is the first report of L. theobromae and F. proliferatumcausing teak dieback syndrome in Costa Rica. 相似文献