杉木观光木混交林生物产量结构特征

Biomass Allocation in Mixed Forest of Cunninghamia lanceolata and Tsoongiodendron odorum

通过对中亚热带杉木观光木混交林和杉木纯林产量分配结构特征的研究,结果表明,混交林林分生物量是杉木纯林的1.29倍,乔木层生物量所占比例较纯林的高,而林下植被层所占的比例则比纯林的低.混交林中杉木有效冠高与观光木有所交叉,但比观光木的高.混交林阳冠厚度比纯林的厚4m,阳冠的活枝和叶生物量所占比例比纯林的大,表明混交林乔木层具有更高的光能利用率.混交林中杉木和纯林杉木的粗根垂直分布均呈单峰型,细根则分别呈梯形或单峰型;观光木粗根和细根则均呈双峰型.杉木和观光木粗根呈明显垂直镶嵌分布,而细根均在表层土壤富集,而在较深层土壤分布具分层性;与混交林杉木相比,纯林杉木粗根量最大层次上移,而细根量最大层次则下移.

The biomass and its allocation in mixed forest of Cunninghamia lanceolata and Tsoongiodendron odorum and pure forest of Cunninghamia lanceolata in midsubtropic were studied The stand biomass in mixedforest is 129 times of that in pure forest, and the proportion of stratum layer in stand biomass of mixed stand were higher, and that of undergrowth were lower, than that of pure stand In mixed forest, the height of functional crown of Cunninghamia lanceolata was higher than that of Tsoongiodendron odorum, though they intercrossed each other Compared to pure forest, the functional crown of mixed forest was 4 m thicker and the proportion of live branches and leaves were higher, which manifested that mixed forest had higher efficiency in utilization of radial energy In either mixed or pure forest, the vertical distribution for coarse roots of Cunninghamia lanceolata showed single apex, and the fine roots presented a trapezium or singleapex type; for Tsoongiodendron odorum, the distribution of coarse and fine roots both had two apices In mixedforest, coarse roots of both Cunninghamia lanceolata and Tsoongiodendron odorum were enchased each other, while both fine roots were concentrated at surface soil and were isolated from each other at deep soilCompared to mixed forest, the layer with maximum coarse roots was higher, and that with maximum fine roots was lower, for Cunninghamia lanceolata in pure forest