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| Water holding characteristics of litters in three types of forest in the
upper reaches of Banchengzi Basin |
| Jia Jianbo1, Liu Wenna, Yu Xinxiao1, Xun Zhiqiang |
| 1.Key Lab. of Soil & Water Conservation and Desertification Combating of the Ministry of Education, Beijing Forestry University, 100083,Beijing, China; 2.Forestry Bureau of Fengning County, 068350, Fengning, Hebei, China
Beijing, China; 2.Forestry Bureau of Fengning County, 068350, Fengning, Hebei, China |
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Abstract In order to explore the water holding capacity of forest litter in rocky mountain regions of northern China, we selected litters in three types of pure forest, i.e.,Pinus tabulaeformis,Robinia pseudoacacia and Platycladus orientalis in Banchengzi Basin, Beijing, as research objects. The litters were dried in oven and soaked in water in July 2014. At the same time, we analyzed the litter water holding capacity and compared the litter reserves, water holding features and intercept water change inthese forests. The results showed that: 1) the total amount of litters in three types of forest followed the order of Pinus tabulaeformis(24.40 t/hm2)>Robinia pseudoacacia(19.68t/hm2)>Platycladusorientalis(9.58 t/hm2). The total thickness of litter in Pinus tabulaeformis forest (3.57cm) was the highest, followed by Robinia pseudoacacia forest (3.30cm), and the least was in Platycladus orientalis forest (1cm). 2) The maximum water holding amount of broad leaved forest was higher than that of coniferous forest, ranked as Robinia pseudoacacia forest (48.77 t/hm2)>Pinus tabulaeformis forest(40.27 t/hm2)>Platycladus orientalis forest (15.81t/hm2); the difference was not significant between Robinia pseudoacacia forest and Pinus tabulaeformis forest, but was significant between Platycladus orientalis forest and the other two types of forest. The maximum water holding rate followed the order of Robinia seudoacacia forest (388.15%)>Pinus tabulaeformis forest (276.49%)>Platycladus orientalisforest(211.40%), with significant differences among them. The maximum water holding amount and rate of Pinus tabulaeformis forest were all lower than the national average level. 3) The relationship between water absorption, water absorption rate and immersion time conformed to logarithmic function and exponential function, respectively. In the first half hour of water absorption, water absorption rate increased rapidly, and then tended to be stable over time after 4 to 5 hours. The water absorption and water absorption rate of Robinia pseudoacacia forest was the largest, thus we can conclude that the water storage capacity of broad leaved forest is stronger under concentrated rainfall conditions.The rule of intercept water amount followed the order ofRobinia pseudoacacia forest (46.80 t/hm2) >Pinus tabulaeformisforest (38.72 t/hm2) >Platycladus orientalis forest (14.19 t/hm2). We can judge the litter characteristics at the Banchengzi Basin from the calculation of total litter amount, maximum water holding amount and rate, and intercept water amount. It shows that the total litter amount of coniferous forest is larger, but the hydrological effect is lower. The broad leaved forest is just opposite: it has higher hydrological effect but fewer total litter amount. Thus, when we select tree species, we could take into account the litter hydrological effect, and optimize the spatial structure of tree species. This study would provide some theoretical basis and reference for tree species selection and assessment of water conservation ecological service in local forest development.
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Received: 27 October 2015
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