四川理县杂谷脑干旱河谷岷江柏造林恢复效果评价

在岷江干旱河谷杂古脑河流域,选择岷江柏(Cupressus chengiana)5个不同年份的造林地,调查了岷江柏的生长情况、植物群落特征与土壤理化性质,总体评价干旱河谷乡土树种的造林成效及造林后的生态效果。结果表明:不同年份造林地岷江柏幼树生长状况良好,2003年造林地生长最好,基径、树高和冠径分别达到4.39cm、4.17m和1.01m,当年生长量超过43cm;2001年和2005年造林地次之,基径为4.19cm和4.52cm,冠径为0.55m和0.61m,当年生长量37cm左右,树高为2.50和2.17m;2007年和2009年造林地由于幼树生长时间较短,其基径、树高和冠径都较小,但当年生长量也都超过20cm。不同年份造林地的植被覆盖度变化相对复杂,除2001年造林地外,灌木层盖度随造林时间的增加而逐渐降低;草本层盖度变化较小,2005造林地最高,其他年份造林地没有显著差异。同时,不同年份造林地的群落结构都比较单一,随造林时间的增长,群落物种数量反而降低。在5个不同年份造林地,土壤pH、有机质和养分含量差异相对较小,土壤含水量尽管存在较大差异,但没有明显的变化趋势。综合分析认为,在杂谷脑干旱河谷中山区岷江柏作为造林树种具有一定的生长优势,但造林地的植被和土壤并没有得到改善,需要更加长期的观测评估。

Assessing effects of Cupressus chengiana plantations in the dry valley of Zagunao River, Li county of Sichuan Province

In the arid valley of the Zagunao River, five plantation plots of Cupressus chengiana with different years were chosen, and the growth of C. chengiana young trees (including tree height, basal diameter, crown diameter, and growth of height), plant community characteristics (vegetation coverage and species composition) and soil properties (soil pH, water content, soil nutrient content) were examined to assess the ecological effects of plantation using native tree species. The growth of all young trees with different planting years was well, young trees planted in 2003 were the best, the basal diameter, tree height and crown diameter respectively was 4.39cm, 4.17m and 1.01m, the increment of height was more than 43cm; young trees planted in 2001 and 2005 were relatively good, the base diameters were 4.19cm and 4.52cm, tree heights were 2.50m and 2.17m, the crown diameters were 0.55m and 0.61m, the increments of height approximately 37cm. Due to the shorter growth time of young trees planted in 2007 and 2009, their base diameters, tree heights and crown diameters were smaller, but their increments of height were more than 20cm. The changes of vegetation coverage in the plantations with different years were relatively complex, except the plantation of 2001, the shrub layer coverage decreased gradually with increase of plantation time, while the changes of herb layer coverage were small, the herb layer coverage of plantation of 2005 was the highest, and there were no significant differences among other plantations. Community structure of the plantations was simple, and plant species numbers reduced with the plantation time except the plantation of 2001. In addition, the changes of soil pH, organic matter and nutrient contents were also small among different plantations. Although the differences of soil water content among them were significant, there was no obvious trend. The results indicates that C. chengiana is a suitable tree species for plantation in the Zagunao river basin of arid valley of the upper Minjiang River, but the ecological effects of vegetation restoration and soil improvement are not fully reflected. Long-term observations need to be conducted for rational assessment of their ecological effects.