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841.
选择8个乡土阔叶树种,取粗度相近的截成13cm的短木段,进行栽培灵芝试验。结果表明,所选8个树种栽培灵芝,皆能发菌出菇,树种间栽培灵芝的产量差异显著。单位体积木段的灵芝产量,千金榆、白牛槭最高,白桦、蒙古栎、紫椴次之,核桃楸、色木槭、青楷槭最低。  相似文献   
842.
杨云 《林业调查规划》2003,28(4):104-107
西双版纳有着丰富的乡土植物资源,当地居民有着采集野生林产品及种植四旁树的悠久历史,没有大面积种植乡土树种的习惯。中德技术合作西双版纳热带林保护与恢复项目通过示范和资助开展了乡土树种的育苗和种植活动,取得了一定的成果,并对今后工作提出了建议。  相似文献   
843.
阳春市野生珍稀濒危植物和国家重点保护野生植物   总被引:1,自引:2,他引:1  
阳春市植物资源丰富,东北部有百涌省级自然保护区,西南部有正在申报省级的鹅凰嶂自然保护区。据调查和现有资料统计,阳春市自然分布的珍稀濒危植物34种,国家重点保护野生植物19种。为保护好这批珍贵的植物资源,作者提出了具体的保护建议。  相似文献   
844.
树种枝叶微观结构对树种燃烧性的影响研究   总被引:3,自引:1,他引:3  
选择具有不同抗火能力的亚热带树种来研究树叶和树枝的微观组织结构与燃烧性的关系,分别测定木荷、茶树、油茶、苦槠、女贞、石楠、日本珊瑚树、枇杷、杉木和马尾松等10个树种叶片、叶脉和树枝的组织比,并利用锥形量热仪测定样品的阻火性。结果发现,树叶构造对燃烧性有影响,阔叶树种的树叶结构有利于水分的传输与蒸散,叶脉中木质部比重越大,越有利于水分的传输;海绵组织,栅栏组织与火发生指数之间存在显著的回归关系,茶树、木荷的海绵组织,栅栏组织比值高,抗火能力强。树枝的燃烧性与其结构密切相关。特别是树枝的抗火性与其导管所占比例正相关,木荷、日本珊瑚树的导管比重大,传输水分的能力强,抗火烧能力强。  相似文献   
845.
贵州省竹产业发展的现状与展望   总被引:2,自引:0,他引:2  
从竹种资源、竹林资源和竹产品3个方面,系统总结了贵州省近30年竹产业的动态,阐述了竹资源分布与发展的区域性,分析了竹产品的结构动态.在现有竹产业布局基础上提出了修订竹产业规划、优化竹资源结构、宏扬竹文化、加速竹产品升级换代和建设品牌企业5大举措,以提高竹业产值及在贵州省林业与国民经济总产值中的比例.  相似文献   
846.
The coastal forest of Gabon abounds in monospecific secondary Aucoumea klaineana stands derived from natural regeneration after shifting cultivation. This paper aims to describe the changes in the structure and dynamics of these stands with age. It then assesses the impact of selective thinning in the upper storey on both structural and dynamic parameters.

The experiment consisted of 34 Permanent Plots in stands from establishment to more mature stages (ca. 50 years old). Thirteen plots (17–45 years old) were thinned. More than 80% of the removal came from supernumerary dominant A. klaineana.

A. klaineana represented 60% of the total density in stands ca. 15 years old but >90% of the dominant trees in older stands. The changes with age in the floristic composition of the unthinned stands showed three successional stages during which pioneer species associated with A. klaineana (from establishment to ca. 15 years) were progressively replaced by mature forest species.

Basal area increased and density decreased with age before reaching stable values at ca. 40–45 years. Mortality was very high in young stands but decreased in the older ones. Mortality generally affected small diameter individuals in the dominated storey. Diameter and basal area increments showed that the stand growth resulted from the growth of dominant A. klaineana. Diameter increments of A. klaineana were elevated during the first years of colonisation (1.9 cm/year) and were still ca. 0.7 cm/year for 50-year-old dominant trees.

Thinning did not increase the mortality of the dominant population. It favoured the individual growth of A. klaineana. The gain was substantial for dominated trees and small dominant trees (from 60 to 100%) but was lower for large dominant trees (ca. 25–30%). Therefore, stimulation of individual growth did not compensate for the loss of basal area at the stand level.  相似文献   

847.
The process of decline of an endangered tree species,Pinus armandii var.amamiana, was monitored on the southern slope of Mt. Hasa-dake in Yaku-shima Island from 1994 to 1998. There are 163 trees ofP. armandii var.amamiana over 1.3 m in height. They are distributed on steep ridges and rocks with a thin soil layer mostly consisting of friable granite. During the monitoring period, 21 trees ofP. armandii var.amamiana died and the mortality rate was 12.9%. Dead trees were categorized into three types: standing, uprooted and landslide. The uprooted- and landslide-typed dead trees were found only after a severe typhoon struck Yaku-shima Island. This suggests that the combination of fragile site conditions and severe typhoons play an important role in the process of decline ofP. armandii var.amamiana. The standing-typed dead trees were presumed to have been killed by pine wilt disease, accounting for 71.4% of the dead trees. However,Bursaphelenchus xylophilus, the cause of pine wilt disease, was not detected from any of the wood chips or branch samples from the standing-typed dead trees ofP. armandii var.amamiana. This might indicate that some factor(s) other than pine wilt disease could be responsible for the standing-typed death ofP. armandii var.amamiana in natural habitats. A part of this paper was presented at the 109th Meeting of the Japanese Forestry Society.  相似文献   
848.
In order to precisely assess the role of agroforestry for the conservation of (agro-)biological diversity there is a need to adjust sampling methods used in plant sociology. This study is on the contribution of agroforestry land use to the in-situ conservation of indigenous trees within a typical East-African smallholder farming system in Western Kenya. A modified approach to measuring species richness and abundance is presented. The selection of tree-rich structures was done according to management patterns rather than considering syntaxonomic classifications from the vegetation science point of view. This approach, which is better suited to the strongly human-influenced vegetation of agroecosystems, employs between-management unit diversity measures to help evaluate abundance and constancy of species in particular management units. The predominant off-farm vegetation patterns are riverine forests, rocky hillsides, hedgerows, wooded grassland relicts, woodlands or colline forest relicts and tree groves whereas the noticeable tree-rich on-farm management units are homegardens, homesteads, life fences, coffee- and banana-groves and annual cropping fields. 98% out of all indigenous tree species known from Bungoma, occur in off-farm lands. 53% of the indigenous tree species occur in tree rich on-farm management units while 47% of the indigenous trees are dependent on the maintenance of off-farm lands. Hedgerows embody the most promising secondary vegetation structure that shows ample potential to accommodate a wide range of indigenous perennial species outside the natural vegetation formations. The pattern of distribution of various vegetation structures, and the mixture with diverse tree-based on-farm plots are interesting features in regard to floristic and eco-diversity on a landscape level. In this respect, three areas that show different population densities and distinct agro-historical conditions were compared. In regions of particular high population density the degree of association of various functional land use forms and woodland structures – each characterised by its own floristic make-up – is comparatively high. In contrast, in regions with less population but that were settled at a later date, one encounters fewer stands of woody plants with lower numbers of species. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
849.
分析种草在退耕还林工程中的重要地位和作用,提出退耕种草的草种选择和种植模式,并探讨发展草产业的途径和方向。  相似文献   
850.
高速公路坡面防护草种选择和应用技术研究   总被引:8,自引:1,他引:8  
根据试验及调查结果,分析研究了护坡草皮生长及水土保持效果的评价指标,分析评价了不同草种,选用不同的种植方法,在不同季节种植的生长状况和水土保持效果,并根据防护效果和不同的工程造价,确立适宜于我省或相近气候区域内公路坡面防护的优良草种及其种植方法。  相似文献   
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