皆伐对青藏高原东部银露梅种群生长与繁殖的影响

调查了青藏高原东部川西云杉原始林下优势灌木银露梅及其在皆伐7 a后迹地上的种群结构、生长与繁殖状况,并进行了对比研究.发现(1)皆伐迹地生境中的银露梅灌丛年龄结构、萌生株年龄结构、萌生株数大小结构和冠幅结构与原始林下相比均存在着较大的差异;(2)在皆伐生境中,与林下同龄的银露梅丛冠幅、基径总和以及株高总和均显著增加,皆伐显著促进了银露梅的无性萌生能力和结实数量的增加.综合分析表明,银露梅能有效适应迹地退化形成的阳性生境,因此可作为高海拔地区皆伐迹地植被恢复中先锋灌木种.图2表1参21

Effects of Clear Cutting on Growth and Reproduction of Potentilla glabra Population in the Eastern Qinghai-Tibetan Plateau

The population structure, growth and reproduction of Potentilla glabra shrubs under primary Picea balfouriana forest and on nearby 7-year-old cutover were investigated to explore how clear cutting affected the understory shrub population developement in the eastern Qinghai -Tibetan Plateau. It was found that significant differences in clump age structure, coverage and ramet number of P. glabra population existed between under the primary forest and on the cutover. The same aged P. glabra displayed greater values in coverage, ramet diameter and height summation on the cutover compared to those in the primary forest, but no significant differences in both average ramet diameter and height were found. About 82% ramets/sprouts were less than 7 years old, indicating that 82% P. glabra individuals were re-sprouted after clear cutting. P. glabra population also bore more fruits on the cutover than under the forest. The clear cutting obviously improved the population enlargement owing to rapid sprouting and newly recruited growth after the forest canopy was removed. It was suggested that P. glabra was well adapted to the environment of the cutover in the eastern Qinghai - Tibetan Plateau and probably was a pioneer shrub to promote cutover restoration in the high-elevation region. Fig 2, Tab 1, Ref 21