间伐对库区生态公益林养分流失的影响

以福建永安安砂库区生态公益林为研究对象,通过设置径流小区法,分别在坡度25°和32°的林地中,设计不间伐、间伐强度20%、40%、60%4种处理,研究不同间伐强度对安砂库区生态公益林养分流失的影响。结果表明:林地坡度25°情况下,在养分月流失量及流失总量上,间伐强度60%、40%均明显大于不间伐处理,而间伐强度20%与不间伐处理间差异并不明显,且流失量较少。林地坡度32°条件下,养分的月流失量及流失总量总体上随着间伐强度的加大而增加。此外,同一间伐强度下,养分流失总量随着坡度的增加而增加。可见,对库区生态公益林进行抚育间伐时,选择坡度较缓的林地进行低强度间伐(间伐强度20%)较为合理,能够在很好地发挥生态公益林的生态效益的同时获得一定的经济效益,进而实现库区生态公益林的可持续经营。

Effect of Intermediate Cutting on the Nutrient Elements Loss in Ecological Public Welfare Forest around Reservoir

Taking the ecological public welfare forest around Ansha Reservoir which was in Yong'an,Fujian as the research object.Thinning intensities with four different treatments of 20%(Ⅰ),40%(Ⅱ),60%(Ⅲ)and CK(Ⅳ)on the undergrowth were carried out on the gradient 25° and 32° respectively through setting runoff plots,and the loss amount of nutrient elements in the plots were investigated and compared.The results showed that on the gradient 25° of the ecological public welfare forestland,the monthly and total amount of nutrient elements loss of thinning intensities with 60% and 40% were obviously higher than those with non-thinning.There was no obvious difference between thinning intensity with 20% and non-thinning,and the loss was few.However,the monthly and total amount of nutrient elements loss increased with the increase of the thinning intensity on the gradient 32°.In addition,the total nutrient elements loss of different thinning intensities increased with the increase of slope.So it was proposed that the optimum method of tending and intermediate cutting in ecological public welfare forest around reservoir was the thinning intensity 20%on the low slope,it would achieve apparent ecological benefit,and certain economic benefits at the same time.So that it would ensure sustainable development of ecological public welfare forest.