中山市防火林带树种组成与冠层结构

防火林带的树种组成与冠层结构可影响林带的防火功能。为评价中山市防火林带的树种组成 和冠层结构，对中山市防火林带树种进行了调查，并在防火林带中选取了9 个典型林带类型，建立标准 地，对其树种组成与冠层结构进行了对比研究。结果表明：中山市13 个镇区的生物防火林带共应用了31 个树种，隶属17 科24 属，豆科、山茶科和樟科树种最多，数量最多的有荷木Schima superba、马尾松 Pinus massoniana、台湾相思Acacia confusa、柠檬桉Eucalyptus citriodora、米老排Mytilaria laosensis；以 针叶树为主的针叶林林冠开度最大，达38.07%，林下植物相对茂盛，分别以米老排和杨梅Myrica rubra 为主的阔叶混交林林冠开度最小，分别为12.36% 和13.88%。米老排与杨梅为主要树种的阔叶林林冠开 度比以马尾松为主的针叶林的林冠开度要小，阔叶林的冠层郁闭度较高；自然保护区核心区针阔混交林 的叶面积指数最大，达2.64，显著高于马尾松纯林和马占相思Acacia mangium、荷木和藜蒴Castanopsis fissa 等阔叶混交林，为0.99 和1.65；山脚的荷木林地、荷木与马尾松的混交林和以米老排为主的阔叶混 交林的林下光照较弱，林下植被稀少，冠层结构较为疏散，是较好的防火林带。对现有防火林带的林分 改造，如增加经济林木、果树等阔叶树种，可进一步提高防火林带的防火作用。

Tree Species Composition and Canopy Structure of Fire-resistant Forest Belt in Zhongshan City

Fire prevention forest tree species composition and canopy structure can affect the forest fire prevention function. To evaluate the Zhongshan city fire prevention forest tree species composition and canopy structure, the tree species were surveyed, and nine typical types were establish as standard plots, for floristic composition and canopy structure comparative study. The results showed that 31 species were used in the biofireproof forest belts of 13 towns in Zhongshan city, belonging to 17 families and 24 genera, with the largest number of species of Legume, Camellidae and Camphaceae, and the largest number of species were Schima superba, Pinus massoniana, Acacia confusa, Eucalyptus citriodora, Mytilaria laosensis. Coniferous forests, coniferous trees mainly, had the largest canopy opening, reaching up to 38.07%, and the undergrowth plants were relatively flourishing. The broad-leaved mixed forests, mainly composed of Mytilaria laosensis and Myrica rubra, had the smallest canopy opening, which was 12.36% and 13.88%, respectively. The canopy opening of broadleaved forest was smaller than that of coniferous forest dominated by Pinus massoniana, and the canopy density of broad-leaved forest was higher. The leaf area index of mixed coniferous and broad-leaved forest in the core area of nature reserve was the largest, reaching 2.64, significantly higher than that of pure forest of Pinus massoniana and mixed forest of broad-leaved Acacia mangium, Schima superba, Pinus massoniana and Castanopsis fissa, which were 0.99 and 1.65. At the foot of the mountain, the S. superba woodland, the mixed forest of S. superba and Pinus massoniana, and broad-leaved mixed forest dominated by Mytilaria laosensis are appriopriate fireresistant forest belt because of the weak light, sparse understory vegetation and the relatively evacuated canopy structure. The fire prevention effect of the fire-resistant forest belt can be further improved by reforming the existing forest distribution of the fire-resistant forest belt, such as increasing the economic tree, fruit tree and other broad-leaved tree species.