杉阔异龄混交模式的初步研究

A Preliminary Study on Uneven-Aged Mixing Patterns of Cunninghamia lanceolata and Broad-Leaved Trees

为了研究不同杉阔异龄混交方式对珍贵阔叶树种生长情况的影响,通过带状混交、均匀混交和纯林3种造林方式,在国有七坡林场杉木成熟林中混交香合欢(Albiziaodoratissima)、红椿(Toonaciliata)、交趾黄檀(Dalbergia cochinchinensis Pierre)、红锥(Castanopsis hystrix)、楠木(Phoebe bournei)、金丝李(Garcinia paucinervis Chun et How)等珍贵阔叶树种,以混交后2.5年生珍贵树种的树高、胸径和单株材积为评价指标,开展杉木异龄混交珍贵树种不同模式的对比试验。结果显示:纯林模式的珍贵树种单株材积大于混交模式,其中香合欢的生长速度最快;混交模式中交趾黄檀的生长速度最快;2种混交模式中以带状混交的珍贵树种单株材积为最大,带状混交、均匀混交分别以15 m带宽、80%间伐强度的珍贵树种长势为最好。综上所述,树种选择和混交方式是影响林下复合经营短期成效的关键,短期来看,杉木林复层改造的优良树种和优良模式分别是交趾黄檀和带状混交;另外,香合欢的生长速度虽非常快,但不适合林下种植。

To study the effects of different age mixing modes of Cunninghamia lanceolata and broad-leaved trees on the growth of broad-leaved trees, we mixed precious broad-leaved tree species such as Albizia odoratissima, Toona ciliata, Dalbergia cochinchinensis, Castanopsis hystrix, Phoebe bournei, and Garcinia paucinervis in the mature Cunninghamia lanceolata forest of the Guangxi Region State-Owned Qipo Forest Farm by four afforestation methods, namely mixed by strip, mixed by uniform and pure forest. The tree height, DBH, and volume per tree of the studied tree species after 2.5 years of mixing were used as evaluation indices. Comparative tests of different patterns of C. lanceolata mixed with other tree species were carried out. The results showed that the volume of individual precious tree species in the pure forest pattern was higher than in the mixed forest pattern. The growth rate of D. cochinchinensis was the fastest in mixed modes and that of A. odoratissima in pure forest mode. Among the three mixed forest patterns, the volume of individual precious tree species in the pattern of mixed by strip was the largest. The best growth rate of the pattern mixed by strip and mixed by uniform was a 15 m wide planting belt and 80% thinning intensity. In conclusion, tree species selection and mixing mode are the key to the short-term effect of understory combined management. In the short term, D. cochinchinensis is the best interplanting species for the C. lanceolata forest, and the pattern of mixed by strip is the best mixing method. A. odoratissima grows very fast but is not suitable for understory planting.