[Spatial pattern analysis and associations of Quercus aquifolioides population at different growth stages in Southeast Tibet, China].

This article analyzed the spatial pattern and its correlation of Quercus aquifolioides, Southeast Tibet at different growing stages by using Ripley' s L function in the method of point pattern, analysis. The results showed the diameter structure of Q. aquifolioides population in Southeast Tibet followed a 'single peak' shape and the saplings and medium trees predominated in number in the whole population. The population had a high regeneration rate and was of increase type. In the growth process of Q. aquifolioides from saplings to large trees, saplings and medium trees showed aggregation distribution at.small scale, while large trees showed basically random distribution at whole scale. There was significant correlation between saplings with medium or large trees at small scale, however, there was no correlation between medium and large trees. In the growth process of Q. aquifolioides population from saplings, medium trees to large trees, its spatial pattern developed from aggregative distribution to random distribution. The natural regeneration of Q. aquifolioides population was affected not only by interspecific competition, but also by intraspecific competition. In the similar natural environment, the most important factors affecting the spatial pattern of Q. aquifoioides population were its own biological and ecological characteristics.

[Ecological footprint of farmers and herdsmen in Tibet Autonomous Region, China].

Based on relevant statistical yearbook and with an integrated method, the ecological footprint and ecological carrying capacity of farmers and herdsmen during the period from 2000 to 2012 in Tibet Autonomous Region, China were studied. The results showed that the ecological status of farmers and herdsmen were in a surplus state during the study period, but the surplus amount exhibited a decreasing tendency. The ecological capacity decreased from 7.49 hm2 in 2000 to 6.35 hm2 in 2012, with a decrease of 15.3%, while the ecological footprint increased gradually from 1.03 hm2 in 2000 to 1.26 hm2 in 2012.

[Biomass and yield of Betula platyphylla population in Mila Mount of Tibet].

Mila Mount in Southeast Tibet is the west boundary of the horizontal distribution of Betula platyphylla. It is also the highest altitude area in China and the world, where Betula platyphylla is distributed. Based on the investigation of regional sample plots and the analysis of analytic trees, this paper compared the biomass and yield of Betula platyphylla population at different slope orientation and different altitude. The results showed that the growth of Betula platyphylla was greatly interfered by human activities. The yearly productivity of Betula platyphylla grown in Mila Mount was 363.1-2,072.94 kg x hm(-2), and the biomass was 7,625.00-33,167.00 kg x hm(-2), indicating that the biomass of Betula platyphylla was quite different for different population. The productivity and biomass of Betula platyphylla coppice after cutting were lower than those of seedling forest, and there existed youth broken-down in the coppice. The zonal changes of water resources had no significant effect on the water allocation and the biomass of Betula platyphylla.