不同林分枯落物层的水文生态功能

Ecohydrological Functions of Litter on Different Forest Stands

分析了八达岭林场4种林分枯落物层的蓄积量、持水能力、阻滞径流速度和减流减沙的效应。结果表明:①油松的总蓄积量为29 20t/hm2,最大持水量为61 36t/hm2,有效拦蓄量为19 38t/hm2;侧柏总蓄积量为4 62t/hm2,最大持水量为57 84t/hm2,有效拦蓄量为16 58t/hm2;元宝枫总蓄积量为17 76t/hm2,最大持水量为30 92t/hm2,有效拦蓄量为71 73t/hm2;刺槐总蓄积量为10 26t/hm2,最大持水量为43 12t/hm2,有效拦蓄量为24 63t/hm2;在这4种林分枯落物中,元宝枫的有效拦蓄量为最大,相当于7 17mm的降雨。②4种枯落物未分解层和半分解层持水量与浸水时间的关系为:W=Aln(t)+B,未分解层持水量均大于半分解层持水量,吸水速度同浸水时间的关系式为V=ktn,在0～2h之间,枯落物未分解层和半分解层吸水速率较快,在4～6h后下降速率逐渐减缓。③随坡度增加,枯落物阻滞径流速率、减沙减流的效果更加明显,元宝枫在此效应中表现最佳。

The ecohydrological functions were studied which include litter storage, the water capacity, retarding effect on runoff and reducing effect on the sediment and runoff yield. The result shows:①The total storage capacity of the Pinus tabulae formis stands is 29.20t/hm^2, the maximum water capacity is 61.36 t/hm^2, the modified interception amount is 19. 38 t/hm^2; The total storage capacity of the Platycladus orientalis is 4.62 t/hm^2, the maximum water capacity is 57.84 t/hm^2, the modified interception amount is 16.58 t/hm^2; The total storage capacity of Acer truncutum is 17.76 t/hm^2, the largest water-holding capacity is 30.92 t/hm^2, the modified interception amount is 71.73 t/hm^2; The storage capacity of the Robinia pseudoacacia is 10.26 t/hm^2, the largest water-holding capacity is 43.12 t/hm^2, the modified interception amount is 24.63 t/hm^2; in these four kinds of forest stands, the modified interception amount of the Acer truncutum is for being biggest, equivalent to the rainfall of 7.17mm. ②The relationship of four undecomposed litter and half-decomposed litter of water-holding capacity and immersion time is: W=A ln (t)+B, undecomposed is greater than half-decomposed of water-holding capacity, relational expression of the absorption rate and immersion time is: V=kt^n, between 0～2 h, undecomposed and half-decomposed litter absorb water speed very fast, drop the speed to slow down gradually after 4～6 h. ③With the increase of the slope, it is more obvious to retard effect on runoff and reduce effect on the sediment and runoff yield,it is the best that the Acer truncutum in this effect.