Characteristics of Plant Life-form of Degraded Vegetations in Sub-alpine of Northwest Yunnan
Abstract
Five forest communities of extreme degraded forest,heavy degraded forest,medium degraded forest,light degraded forest and none degradation in sub-alpine of Northwest Yunnan were selected to set up study plots.Sample method was adopted to carry out comparative study on characteristics of plant life-form in the five degraded forests communities.The results showed that there were 7 life-forms in degraded forests,including meso-phanerophytes,micro-phanerophytes,nanophanerophytes,chamaephytes,hemicryptophytes,geophytes and annuals,and hemicryptophytes were the dominate,the proportions of annuals,meso-phanerophytes and geophytes were the lowest,megaphanerophyte over 30 m was not found.With the reduction of degradation gradient in five sample forest communities,the species richness showed the tendency of first increase and then decrease in none degradation,the percentage of meso-phanerophytes and micro-phanerophytes significantly increased.With the aggravation of degradation,the proportion of hemicryptophyte obviously increased and became the dominant species of plant life-form composition.