海南木麻黄无性系生长过程研究

目的]为了研究海南地区木麻黄无性系的生长过程,并确定其数量成熟龄和合理轮伐期。方法]本研究利用海南岛3个试验点4个相同无性系10 a的生长数据分析了木麻黄无性系的树高、胸径和材积的生长规律。结果]表明:木麻黄无性系树高和胸径的生长均呈"先快后慢"的生长模式,造林后1~6 a为快速生长期,6 a后进入缓慢生长期;材积生长则呈"慢—快—慢"的S型生长模式,造林后1~3 a为慢速生长期,4~7 a为快速生长期,8 a后进入缓速生长期。根据材积年平均生长量和连年生长量曲线的相交点,各无性系材积生长的数量成熟龄处于6~9a。利用3个试验点4个无性系获得的材积生长平均值,拟合了木麻黄无性系材积生长曲线的Richards模型,并得出材积快速增长的起始期t_1=4.9 a,终止期t_2=8.4 a,最大相对生长速率期t_m=6.9 a,最大材积增长速率25.8m~3·hm~(-2)。结论]综合上述结果,建议海南地区将木麻黄无性系的轮伐期定为6~9 a。

Studies on Growth Processes of Casuarina Clones in Hainan Island

Objective] To study the growth patterns and determine their quantitative maturity and appropriate rotation age of casuarina clones in Hainan island. Methods] The field test data of ten years'' growth data of height, diameter at breast height (DBH), and volume of 4 casuarina clones at 3 trial sites of Hainan Island were collected to analyze the growth processes of different casuarina clones. Results] Both the height and DBH growth of casuarina clones presented a "fast-slow" growth pattern. The fast-growing phase appeared 1-6 years after planting, and then the slow-growing phase appeared. The volume growth presented a "slow-fast-slow" pattern. The slow-growing phase appeared from the first year to the third year after planting, and fast-growing phase appeared in the 4th to 7th year after planting, then slow-growing phase appeared again. Based on the volume curve intersection point of mean annual increment and current annual increment, the quantitative maturity of casuarina clones was in the 6th to 8th year after planting. Based on the volume mean value of 4 casuarina clones in 3 trial sites, Richards curve of volume growth of casuarina clone in Hainan Island was fitted. The characteristic values obtained from Richards curve are as follows: the initial phase of fast-growing of volume growth t₁ = 4.9 years after planting, the termination phase t₂ = 8.4 years, the period of maximum relative growth rate t_m = 6.9 years, and the maximum volume growth rate V_m = 25.8 m³·hm^-2. Conclusion] Based on the aforementioned results, the rotation of casuarina clone in Hainan Island are recommended as 6-9 years after planting.