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Changes in Catchments Runoff Due to Forest Vegetation Variety in Xiaoxing’an Mountains

Author: CuiXueQing
Tutor: CaiTiJiu
School: Northeast Forestry University
Course: Ecology
Keywords: Deforestation Small Watershed Runoff Xiaoxing'anling
CLC: S715
Type: Master's thesis
Year: 2010
Downloads: 123
Quote: 1
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Abstract


Changes in forest cover, including forest harvesting on watershed runoff and forest restoration on runoff in two small runoff. Different mode of operation of the harvesting of Plantation forest runoff are also differences. Forest Xiaoxing'anling vast, rich in water resources, but due to over-harvesting in the region once appeared serious soil erosion, floods, riverbed and ecological crisis. To the new forest ditch and silviculture ditch, two located in the region of Xiaoxing'anling contrast small basin, basin 1970-2005 meteorological, hydrological and forest survey data, sample surveys and combination of statistics and analysis of the deforestation Plantation vegetation changes on small runoff. The results show that: the new forest ditch forest between 1970 to 2005 take selective cutting of forest management, forest type has been mainly broadleaved Korean pine, complex stand structure, forest coverage rate of between 70% to 80% long-term stability. Large area of ??clear-cutting and silviculture ditch after year after year afforestation, changes in forest coverage rate rose from 28% to 79% in three stages, the inflection point for 1980 and 1990. Afforestation species for artificial larch forest than a single structure. Original forest soil compaction size lt; choose the deforestation lt; clearcutting forest turn increase especially clearcutting compaction, moisture buffering effect of artificial larch and blocking force is less than the original surface runoff broad and natural secondary forest, thus changing the runoff. New the forest ditch uneven coefficient of linear regression slope of 0.0013 or slightly increased, while the silviculture ditch uneven coefficient linear regression slope of -0.0058, slightly downward trend. Runoff degree of uneven distribution of silviculture ditch during the year than the new forest ditch. According to the Mann-Kendall test, new forest ditch, silviculture ditch precipitation trend, the increasing trend of runoff; silviculture ditch snowmelt runoff increasing trend is not significant, a larger increase in annual runoff and flood peak in the early, which from 1981 began to increase significantly, while the new forest ditch the snowmelt runoff, runoff and flood peak increase in value were not through 0.05 significant test on silviculture ditch forest vegetation changes on small watershed runoff changes, annual runoff and flood peak diameter flow and snowmelt diameter The flows have had an impact. Annual runoff of forest vegetation change on forest runoff, peak runoff, snowmelt runoff, three factors have an impact. The silviculture ditch larch forest after forest harvesting to create annual runoff depth - the annual precipitation, snowmelt runoff - last year the snowfall and peak runoff of rainfall in 24 hours dual cumulative line exhibited decreased, and 2 inflection point ( p lt; 0.05); forest coverage rate is stable at the extent of 80%, close to the two small watershed factor, but due to the rejection of artificial larch rain and the blockade of litter and soil layer on the surface runoff than The original broad and natural secondary forest, the silviculture ditch cumulative line slope is still larger than the new forest ditch. Able the small watershed Xiaoxing'anling deforestation blocking force to reduce the retention capacity of the soil and litter precipitation and surface runoff, thereby the forest runoff increased during the year runoff uneven degree of, annual runoff, snowmelt runoff, peak runoff . With the continuous growth larch forest canopy forest of the ability to regulate the enhancement of forest hydrological cycle, annual runoff, snowmelt runoff, the reduction in force of the flood peak runoff correspondingly enhanced. The gradual recovery of artificial larch ability to regulate runoff in a certain period of time is difficult to restore to its original level.

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CLC: > Agricultural Sciences > Forestry > Forestry basic science > Forest Hydrology
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