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高山松是藏东南针叶林的主要建群种之一,高山松林是雅鲁藏布江中下游、尼洋河、帕隆藏布等流域的重要水源涵养林。采用样地样方调查、野外定位监测、室内试验分析等方法对藏东南高山松天然林的高山松种子雨、土壤种子库、高山松种子萌发及天然更新特征进行了研究。结果表明,高山松种子雨强度平均为249.30±78.42粒/m~2,其中饱满种子为168.09±56.36粒/m~2、虫蛀种子为41.11±20.25粒/m~2、空种子为40.10±21.04粒/m~2,种子雨强度随时间表现出先增加后减少的单峰型趋势。整个落种过程和不同落种时间的种子空间分布格局均表现为聚集分布,在一定范围内随着与母树距离的增加,种子雨扩散强度减弱,表现为近似正态分布。高山松土壤种子库高山松种子平均密度为231粒/m~2,其中62.77%的种子分布在枯落物层中、37.23%的种子分布在土壤层中,种子雨到土壤种子库过程中有近8%的种子损失。野外实地播种观测发现,高山种子累积萌发率与萌发天数的关系符合Logistics方程y=91.404/(1+e~(6.619-0.449t))。高山松幼苗和幼树的高度结构、基径结构和年龄结构均呈反“J”型,表明高山松天然更新良好,保护好现有的环境状况,种群将呈稳定增长型。研究结果为高山松资源的有效保护和可持续利用提供了科学依据,同时进一步丰富了西藏高原国家生态安全屏障评价内容。
Alpine pine is one of the main constructive species of the coniferous forest in the southeastern Tibet. Alpine pine forest is an important water conservation forest in the middle and lower reaches of the Brahmaputra, the Niyang River and Palong Zangbu. The characteristics of seed germination and natural renewal of Pinus densata seed rain, soil seed bank and Pinus densata were studied by using plots of quadrats, field survey and indoor test. The results showed that the average intensity of seed rain of Pinus densata was 249.30 ± 78.42 seeds / m ~ 2, including 168.09 ± 56.36 seeds / m ~ 2 for full seed, 41.11 ± 20.25 seeds / m ~ 2 for worm moth, 40.10 ± 21.04 seeds / m ~ 2, the intensity of seed rain showed a unimodal trend that firstly increased and then decreased with time. The spatial pattern of seed distribution during the whole seed-setting process and the different seed-setting time showed aggregation distribution. Within a certain range, with the increase of the distance from the parent tree, the seed rain diffusion intensity weakened and showed an approximately normal distribution. The average density of alpine pine seed seed banks was 231 grains / m ~ 2, of which 62.77% seeds were distributed in the litter layer, 37.23% of the seeds were distributed in the soil layer, Nearly 8% of the seeds lost. Field field sowing observation found that the relationship between the cumulative germination rate of alpine seed and germination days was in accordance with the Logistics equation y = 91.404 / (1 + e ~ (6.619-0.449t)). Alpine pine seedlings and young saplings showed a high level of structure, base structure and age structure of the “J” type, indicating a good natural regeneration of Pinus, to protect the existing state of the environment, the population will show a steady growth. The results provide a scientific basis for effective protection and sustainable use of Alpine pine resources, and at the same time further enrich the national eco-safety barrier assessment in the Tibetan Plateau.