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/hm
2, 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/hm
2, 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/hm
2, 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.