RAINFALL INTERCEPTION BY GRASS

Forestry and forest industry in the Republic of South Africa are compared first with other primary and secondary industries in the country with regard to capital invested, value of output, number of employees, salaries and wages paid out, and export earnings.

Secondly, South Africa is compared with other countries with regard to forest area, growth and timber output, and per caput consumption of forest products.     

长白山落叶松人工林天然化空间格局变化

用点格局分布、混交度和胸径大小比数3个林分空间结构参数,分析了1985与2005年长白山落叶松人工林与天然林木混交林分的空间结构变化。结果表明:在空间分布上,入侵的天然树种空间分布由随机分布向聚集分布转变,落叶松由轻微聚集分布向均匀分布和随机分布转变。整体林分格局变化不大,但出现了小范围的聚集分布现象。整体林分的混交度出现了小幅下降,但依然保持了强度混交。林分主要树种落叶松的混交度上升,但是天然树种均呈现了不同幅度的下降。树木之间的胸径差异正在扩大。落叶松在其结构单元中优势增大,天然树种云杉、椴树、红松、冷杉呈优势下降趋势,水曲柳、榆树和杂木类呈优势上升趋势。