水杉原生母树种群研究

Study on the Population of the Primary Metasequoia glyptostroboides Mother Trees

通过野外调查,采用样方数据进行方差均值比的方法分析水杉原生母树空间分布格局,结果呈明显的集群分布.以10m为步长,对水杉原生母树进行树高分级,分析树高结构.参考树体生长势,结合对当地村民的走访,对水杉原生母树年龄作了估测.现存水杉原生母树种群径级结构呈瓮型金字塔,为衰退种群.胸径在40~99cm的母树个体数多,有5 221株.胸径在60~99cm时,胸径生长速率最大;胸径在40cm以下时,树高生长速率最大;而胸径在80~99cm时,是其旺盛生长期.胸径在120cm以上的母树,仍然处于良好的生长状态.

By making a field study on 5746 primary Metasequoia glyptostroboides mother trees growing in Hubei＇s Lichuan City,this paper gathers statistics about the pattern of Metasequoia glyptostroboides mother trees,studies the size structure of the population and the height structure in different plots.The results show that the pattern of the primary Metasequoia glyptostroboides mother trees population is contagious distribution.The diameter structure of the mother trees is like an urn-shaped pyramid and the mother trees are declining population.The rejuvenescence of the population is difficult because most of them belong to the middle age class.There are 5 221 individual trees with the diameter at breast height（DBH） between 40 and 99 centimeters.The growth rate of DBH will be the maximum when it is 60 to 99 centimeters.While DBH is less 40 centimeters,the growth rate of height will be the maximum.The fast increase of the tree will appear when DBH is within 80 to 90 centimeters.The primary Metasequoia glyptostroboides mother trees still grow well after DBH reaches 120 centimeters.