抚育管理对三峡库区不同类型马尾松林枯落物层持水特性的影响

Effects of Tending and Management on Water Retention Characteristics of Litter Layers in Different Types of Pinus Massoniana Forest Within the Three Gorges Reservoir Area

  • 摘要: 以三峡库区不同类型马尾松林为研究对象,综合考虑树种组成差异和抚育管理等因素,选择抚育型马尾松 + 杉木混交林 (Ⅰ)、抚育型马尾松 + 油茶混交林 (Ⅱ)、未管理型马尾松纯林 (Ⅲ)、未管理型马尾松 + 杉木混交林 (Ⅳ) 4种马尾松林分,采用野外调查和室内浸泡法,比较分析不同类型马尾松林枯落物层持水特性和持水能力。结果表明:4种类型马尾松林分枯落物储量变化范围为16.45~24.67 t/hm2,枯落物储量由大到小排序为 Ⅳ > Ⅱ > Ⅲ > Ⅰ,且半分解层枯落物储量均高于未分解层储量。枯落物最大持水量变化范围为48.59~85.18 t/hm2,最大持水率为301.68%~360.08%;枯落物有效拦蓄量为31.49~52.18 t/hm2,有效拦蓄率为173.74%~227.77%,枯落物有效拦蓄量由大到小排序为 Ⅱ > Ⅳ > Ⅲ > Ⅰ,有效拦蓄率为 Ⅱ > Ⅰ > Ⅳ > Ⅲ。除未管理型马尾松 + 杉木混交林外,其余3种林分类型的枯落物最大持水率和有效拦蓄率均表现为半分解层 > 未分解层。枯落物持水量与浸泡时间呈对数函数关系:W= alnt + b,吸水速率与浸泡时间呈幂函数关系:V = atb。可见,4种类型马尾松林以抚育型马尾松 + 油茶混交林的枯落物持水效果最好,加强抚育管理的马尾松针阔混交林能更有效地发挥枯落物层水源涵养功能。

     

    Abstract: Taking different types of ponytail pine forests in the Three Gorges Reservoir area as the research object, and taking into account the differences in species composition and nursery management, 4 stand types of nurtured Pinus massoniana + Cunninghamia lanceolata mixed forest(Ⅰ), nurtured P. massoniana + Camellia oleifera mixed forest(Ⅱ), unmanaged P. massoniana pure forest(Ⅲ) and unmanaged P. massoniana + C.lanceolata mixed forest(Ⅳ) were selected as the research subjects by field investigation and indoor soaking method, the water-holding characteristics and water-holding capacity of litter layers of the different stand types were compared and analyzed. The results showed that the variation of litter storage in the 4 types of P. massoniana forest stands ranged from 16.45 to 24.67 t/hm2, and the litter storage was in the order of Ⅳ > Ⅱ > Ⅲ > Ⅰ, and the storage in the semi-decomposed layer of litter was higher than the storage in the undecomposed layer. The maximum water-holding capacity of litter varied from 48.59 to 85.18 t/hm2, and the maximum water-holding rate varied from 301.68% to 360.08%. The effective storage capacity of litter varied from 31.49 to 52.18 t/hm2, and the effective storage rate varied from 173.74% to 227.77%. The effective storage capacity showed the order of Ⅱ > Ⅳ > Ⅲ > Ⅰ from large to small, and the effective storage rate of litter was ranked as Ⅱ > Ⅰ > Ⅳ > Ⅲ. Except for unmanaged P. massoniana + C.lanceolata mixed forest, the maximum water retention rate and effective storage rate of litter in the semi-decomposed layer were higher than those in the non-decomposed layer. The water holding capacity of dead wood was logarithmically related to the soaking time: W = alnt + b, and the water absorption rate was power-functional to the soaking time: V = atb. In conclusion, among the 4 types of P. massoniana forest, the care-type nurtured P. massoniana + Camellia oleifera mixed forest has the best water retention effect in litter layer, and the P. massoniana needle-width mixed forests with strengthened nursery management could play the function of the deadfall layer in water conservation more effectively.

     

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