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991.
在试验、研究、实践的基础上,针对高寒漫甸区不同的立地条件,探索出了几种治理模式和相应的技术措施。并通过对比分析,科学客观地总结了该地区农田草场防护林体系建设的成功经验,从而为同一立地类型防护林建设提供了技术支持。 相似文献
992.
Many expert-designed agroforestry projects enunciated in 1970s around the world, particularly in the developing countries,
had uneven success due to inadequate adoption or abandonment after adoption. There are many empirical studies on factors affecting
on-farm tree cultivation mainly where expert-designed agroforestry programmes were introduced but lacking in case of traditional
agroforestry. Moreover, the concern to identify key factors influencing on-farm tree growing is gaining importance. The present
study identifies key factors in on-farm tree growing based on investigation of traditional agroforestry using logistic regression
approach. The study is based on household survey of 401 households located in Indian Western Himalaya. The factors affecting
on-farm tree growing were grouped into: biophysical (included land use and infrastructural aspects) and social. Models predicting
on-farm tree growing for each category were developed and key factors affecting on-farm tree growing in the respective category
were identified. A composite model was also developed by combining biophysical and social factors. In the present study, farm
size, agroclimatic zone, soil fertility, mobility and importance of tree for future generations respectively were the key
factors which influenced tree growing. In contrast to many previous studies which considered either biophysical or social
factors, the composite model in the present study reveals that both biophysical and social factors are simultaneously important
in motivating the farmers to grow trees on their farms in traditional agroforestry. Moreover, the present study open vistas
for using farmers’ experience and knowledge of adoption of agroforestry to stimulate on-farm tree growing. The wider implication
of the study is that biophysical as well as social variables should be considered together in designing suitable agroforestry
systems in various parts of the world. 相似文献
993.
994.
在对河西绿洲农田防护林调查研究的基础上,列出了12种防护林模式,并对各种模式的适宜条件、技术措施、存在问题进行了分析和评价。 相似文献
995.
应用帽儿山天然次生林区不同林分条件下选设的20块椴树(Tilia amurensis)固定样地的解析木调查资料,分析多个单木竞争指标与对象木胸高断面积定期生长量的相关关系,在椴树单木胸高断面积生长模型中引入林木自身大小、单木竞争指标和立地因子,应用回归分析法建立帽儿山地区天然次生椴树单木胸高断面积生长模型。研究表明:天然次生林下椴树的胸高断面积定期生长量与对象木相对直径(RD)和竞争压力指数(SCI)等指标存在比较明显的相关关系。应用主分量线性组合的方法构造的综合竞争指标(MCI)包含了各竞争指标与胸高断面积生长量之间的绝大部分的相关信息,可以作为竞争指标应用于单木胸高断面积生长模型。 相似文献
996.
基于工作流技术的森工企业信息系统模型的构建 总被引:1,自引:0,他引:1
针对黑龙江省森工企业信息化建设的现状和存在的问题,介绍工作流技术的原理,给出基于工作流技术的森工企业管理信息系统的结构框架。根据工作流管理系统参考模型的规范,构建森工企业管理信息系统模型。提出工作流在森工企业信息化建设中应用的优势。 相似文献
997.
998.
Many boreal tree stands are neither clearly even-aged nor clearly uneven-aged. The stands may undergo a series of stages, during which an even-aged stand is transformed into two-storied mixed stand, and finally to multistoried or uneven-aged stand structure. The species composition often changes during the succession of stand stages. This study developed models for stand dynamics that can be used in different stand structures and species compositions. The model set consists of species-specific individual-tree diameter increment and survival models, and models for ingrowth. Separate models were developed for Scots pine, Norway spruce, and hardwood species. The models were used in a growth simulator, to give illustrative examples on species influences and stand dynamics. Methods to simulate residual variation around diameter increment and ingrowth models are also presented. The results suggest that mixed stands are more productive than one-species stands. Spruce in particular benefits from an admixture of other species. Mixed species improve diameter increment, decrease mortality, and increase ingrowth. Pine is a more beneficial admixture than birch. Simulations showed that uneven-aged management of spruce forests is sustainable and productive, and even-aged conifer stands growing on medium sites can be converted into uneven-aged mixed stands by a series of strong high thinnings. 相似文献
999.
1000.
Litter Decomposition in Three Plantation Species in Semi-Arid and Sub-Humid Regions of Central India
《Journal of Sustainable Forestry》2013,32(1):47-62
Abstract The forest floor litter decomposition rate followed in the order: Tectona grandis(teak) > Madhuka indica (mahua) > Butea monosperma (palas). Higher decomposition rates were observed during rainy season and lowest during winter. The decay rate was significantly correlated with rainfall and soil moisture, and with population densities of earthworms. The lumbricid distribution under three plantations of semi-arid and sub-humid regions of central India in relation to several environmental factors including climate, soil moisture and litter quality was studied. Native species of earthworms and their densities were not abundant in this forest due to less moisture content in soil and accidental forest fires. Eight earthworms were identified and three of them were epigeic earthworms, viz., Eisenia fetida (Savigny), Perionyx excavatus (Perrier) and Dichogaster bolaui (Michaelsen), which were predominant throughout the year. 相似文献