云南松林林窗下小尺度空间的天然更新模式

为了解云南松天然更新密度和幼树保存率的动态变化及保留幼树空间分布格局,在云南昆明宜良禄丰村林场尖山林区约4.0 km2范围的50余年林龄云南松人工林内,设置17块具有典型代表性的5 m×5 m固定样地,开展连续4 a的天然更新及其保存调查。结果表明,2012—2015年,样地的年度更新密度分别为0~211 600株·hm-2,最高年份的更新密度为12 000~211 600株·hm-2。2012—2014年,更新的苗木在1年生时保存率仅为初始更新时密度的13.8%~22.0%,更新后的第1年,保存率急剧降低。3年生更新的幼树保存率趋于相对稳定,保存率仅约为初始更新密度的5%。云南松天然更新保留幼树在小尺度空间范围呈不均匀的小群丛状分布。

Natural regeneration model of the small-scale space under the gap in the Pinus yunnanensis forest

In order to understand dynamic densities, treelet survival percents, with the spatial distribution patterns of the survival seedlings and saplings of Pinus yunnanensis natural regeneration, the fixed 17 sampling plots of the 5 m×5 m area were set to conduct investigation of natural regeneration and its survival for 4 consecutive years at 4.0 km2 region in Jianshan Forest Zone of Lufengcun Forestry Farm, Yiliang County, Kunming, Yunnan for an about 50-year-old plantation.The results showed that annual seedling regeneration densities of the individual sampling plots were 0~211 600 tree·hm-2 , respectively, with the highest year of which 12 000~211 600 tree·hm-2 in the 2012-2015.The survival rate for 1-year-old seedings were only the 13.8%~22.0% compared to original regenerated seedlings in 2012-2014, with the survival rate decreased dramatically at the first year of natural regeneration.After 3 years of the natural regeneration, the treelet survival percents tended to be relatively stable with only the 5% compared to original regeneration densities.The survival treelets of P.yunnanensis natural regeneration presented a model of uneven clusters distribution in a small-scale spatial area.