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991.
Traditional agroforestry systems in the communal areas of Zimbabwe are described. There are systems centered on main fields, on home gardens, on homesites and on grazing areas. In the main fields, the major tree-related management practice is the conservation of preferred indigenous fruit trees. Fruit trees are also the focus of forestry activities around the gardens and the homesite; but here it is the planting of exotic species. In a localized area of Zimbabwe Acacia albida is important in fields. There is almost no use of tree fallows in Zimbabwe. Trees in grazing areas have numerous roles, but at present there is little knowledge about traditional management practices in these areas. In the development of agroforestry systems in Zimbabwe it is suggested that those systems designed to improve fodder production will make a significant contribution to farm productivity because of the importance of cattle in the farming system and the present fodder shortage. Interventions involving the planting of fruit trees are likely to be very successful, as there is much interest in such planting. Another area that needs to be developed is that of tree plantings to improve soil fertility. 相似文献
992.
993.
XIEFu-ju XIAODu-ning LIXiu-zhen WANGXu-gao SHIBao-dong 《林业研究》2005,16(2):125-131
The restoration of forest landscape has drawn much attention since the catastrophic fire took place on the northern slope of Great Xing‘an Mountains in 1987. Forest canopy density, which has close relation to forest productivity, was selected as a key factor to find how much the forest quality was changed 13 years after fire, and how fire severity, regeneration way and terrain factors influenced the restoration of forest canopy density, based on forest inventory data in China, and using Kendall Bivariate Correlation Analysis, and Distances Correlation Analysis. The results showed that fire severity which was inversely correlated with forest canopy density grade was an initial factor among all that selected. Regeneration way which did not remarkably affect forest canopy density restoration in short period, may shorten the cycle of forest succession and promote the forest productivity of conophorium in the future, Among the three terrain factors, the effect of slope was the strongest, the position on slope was the second and the aspect was the last. 相似文献
994.
Md.DaneshMiah MohammadMoshiurRahman 《林业研究》2004,15(1):55-60
2002年1月至6月对孟加拉涝原地区两个不同的宗教部落(印度教和穆斯林教)的传统家园森林进行了探索性研究,包括印度教和穆斯林教社团对树种(乔木和灌木)的偏爱度、类似性、造林材料及来源、植树地点和间距。研究发现Mangifera indica作为乔木树种,Ocimum sanctum作为灌木树种为印度教社团最喜爱的树种;Artocarpus heterophyllus和Lawsonia inermis分别为穆斯林社团最喜爱乔木树种和灌木树种。两中不同宗教社团选择乔木数种的相同性为86.57%,灌木树种为78.48%。两个宗教部落使用种子和苗木作为造林材料最多。乔木树种的造林材料主要来自家园(39%)灌木树种主要来自自然界(40%)。表3参27。 相似文献
995.
连云港云台山风景区有竹类植物7属20种,1变种和11变型,5个栽培变型。其中,短穗竹属1种,箬竹属2种,竹属2种3变型,刚竹属8种,1变种和9个变型,2个栽培变型,青篱竹属5种2变型,矢竹属1种,支竹属1变型。这些竹种中,属云台山乡土竹种有3属8种,1变种5变型2栽培变型。其中金条竹为国内首次发现并命名的新变型。经长期观察,刚竹属大部分竹种能适应云台山的生态环境,并在自然状态下生存繁衍。20世纪90年代后引进的观赏竹种也表现出较强的生命力。连云港云台山地区是我国黄河—长江竹区长江以北重要的竹种资源地,同时也是南竹北移理想的驯化场所。 相似文献
996.
本文对长江流域防护林主要构建树种的生物学特性及资源分布、主要林副产品及其用途、开发利用现状等进行了综述,旨在说明长江流域防护林的柏木、马尾松、杜仲、银杏、喜树和香樟等树种的林副产品综合开发利用有着广阔的前景和深远的意义。 相似文献
997.
998.
ZHAO Fengjun SHU Lifu WANG Mingyu LIU Xiaodong 《中国林业科技(英文版)》2007,6(4):62-66
Forest fires occurrence is influenced by many factors, such as inter-annual weather variations and regional fuel distributions. Fires occurrence in different forest region has distinct spatial and temporal characteristics. The paper studied the natural forest fire environment in Northeastern China, as well as forest fires occurrence, burned area and fire seasons in Northeastern Forest Region. The result shows that more than 50% of annual burned area occurred in Northeast China Forest Region. Main fire seasons in the region are spring and autumn. Fires occurrence in spring is larger than that in autumn. There are few fires in summer. The authors' suggestions for fire management department are to emphasize the fuel management, improve the roads conditions, and enhance the fires control ability. 相似文献
999.
1000.
Stephen Adu-Bredu Taketo Yokota Kazuharu Ogawa Akio Hagihara 《Journal of Forest Research》1997,2(1):31-37
The study was carried out in a 9-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.), stand over a span of three years from July 1992 to June 1995, primarily to predict litter production
from exteral tree dimensions by combining open-top clothtrap and clipping methods. Litter production was virtually concentrated
in October and November. Stem cross-sectional area at the crown base was proved to be the reliable predictor of litter production,
and that single regression model was evolved irrespective of year. The regression model had proportional constants of 2.696
× 10−2 and 3.540 × 10−2 kg cm−2 year−1 for leaf litter and total litter production, respectively. Utilizing the model, leaf litter production of the stand was assessed
to be 5.04, 5.12, and 4.99, and total litter production to be 6.48, 6.58, and 6.40 Mg ha−1 year−1 for the first, second and third year, respectively. Biomass increment was 6.67, 7.80, and 7.70, tree mortality was 0.15,
0.13, and 0.41, and insect grazing was 0.09, 0.05, and 0.002 Mg ha−1 year−1 for the first, second and third year, respectively. Above-groud net production was therefore 13.39, 14.55, and 14.51, Mg
ha−1 year−1, and biomass accumulation ratio (biomass/net production) was 1.86, 2.21, and 2.76 year for the first, second and third year,
respectively. Considering data from earlier studies and the results of this study, biomass accumulation ratio,BAR (year), of hinoki stands was best related to above-ground biomass,y (Mg ha−1), using the power function:BAR=0.112y
0.936. Excluding seedling stands, leaf efficiency (above-ground net production per unit leaf mass) of hinoki stands was 0.91±0.02
(SE) Mg Mg−1 year−1, irrespective of stand biomass or age. 相似文献