秦岭南坡不同生境条件下栓皮栎伐桩萌芽特性

Sprouting and Growth Characteristics of Quercus variabilis Stump after Cutting in Different Habitats of the Southern Slope of the Qinling Mountains

以陕西省佛坪县的栓皮栎伐桩为研究对象,分析2种生境条件下栓皮栎伐桩直径和高度与萌苗数量、萌苗生长的关系,并通过2年跟踪观测研究伐桩的萌发能力。结果表明:1)阳坡伐桩上的萌苗数量多于阴坡,但阴坡的萌苗生长量(基径、高度和冠幅)优于阳坡;2)萌苗数量随伐桩直径增大先增加后减少,直径在15～25cm间的伐桩萌苗数量最多,萌苗生长量随伐桩直径增加先减小后增加;3)伐桩高度与萌苗数量的关系不明显,随着伐桩高度增加,萌苗生长量增加;4)萌苗基径随萌苗数量增多而减小,萌苗高度与之相反,阳坡萌苗数量与萌苗生长量的关系比阴坡密切;5)砍伐2年后,伐桩萌发能力和萌苗生长量均出现降低趋势。栓皮栎伐桩的萌苗数量不仅受到光照条件的影响,也受到伐桩直径和砍伐后时间长度的影响,但萌苗的生长则受到环境条件、伐桩直径、伐桩高度以及萌苗数量的共同影响。因此,择伐栓皮栎次生林中基径为15～25cm的个体最有利于林地快速恢复,在随后的经营管理中控制伐桩的萌苗数量并疏伐过密的萌苗丛有利于萌苗生长。

Most of natural Quercus variabilis forests in China have degenerated to be secondary forests after overexploitation and continuously cutting. Stump sprouting is the most significant asexual reproduction type in this kind of forests. In this study, 192 Q. variabilis stumps located in sunny slope and shady slope of Foping, Shaanxi Province, China, were investigated in order to understand the stump sprouting capability, sprout growth characteristics and the relationship between sprouting and stump. All stumps formed after small scale clear cutting conducted in 2007 winter. The results showed： 1）The sprout number per stump was more in sunny slope than that in shady slope, in contrast sprout growth amount（base diameter, height and crown width）were all greater in shady slope than those in sunny slope; sprout number had a negative relation with growth amount at similar environment conditions. 2）Sprout number per stump increased at first and then decreased slightly along with the increasing of stump diameter, and the stumps with their base diameter of 15-25 cm had the strongest sprouting capacity; and sprout growth amount increased with increasing stump diameter. 3）There was no relationship between stump height and sprout number, however, there was a positive relationship between stump height and sprout growth amount. 4）Base diameter of sprout declined along with the growing of sprout number per stump, sprout height showed an almost opposite tendency; sprout growth amount was influenced by sprout number more heavily in sunny slope than in shady slope. 5）The percentage of sprouting stump and sprout growth amount in both habitats all declined significantly after two years of cutting, moreover, sprouts in sunny slope had lower annual growth compared with those in shady slope. All the results implied that sprouting capacity was influenced by habitats condition especially irradiation, stump diameter and stump age（years after cutting）; sprout growth were influenced not only by the factors described above, but also by stump height and sprout number per stump. Therefore, selective cutting the individuals which are 15-25 cm in base diameter and leaving the stump height more than 30 cm are propitious to forestland recovering in short time. Meanwhile, controlling stump sprouting after two years of cutting and thinning overstocked sprouts have positive influence on sprout growth.