| Quercus aliena var. acuterrata forest is one of the major forest types in Huoditang of Qinling Mountain. It plays an important role in construction and maintenance of forest ecosystems, and have the function of water conservation. Because of humans disturbance in long time, the forest structure has been damaged. The aims of this paper is to evaluate the health situation of Q.s aliena var. forest and find the influencing factors.The results was as follow:(1)The Q. aliena var. forest Health Assessment Indicator System was been established by the sensitivity analysis method. The weight of each index was determined by AHP method. 30 samples were been evaluated by comprehensive evaluation.The results showed that: 16 samples of 30 samples were unhealthy which average health index is 0.316; 11 samples of 30 samples were sub-healthy which average health index is 0.469; 4 samples of 30 samples, which were samples 4, 11,14, 24 and 25, were healthy, the average health index is 0.577; in a word, the Q. aliena var. forest in Huoditang region is being in sub-healthy state, the mean health index is 0.407.(2) The health condition of different forest types in Q. aliena var. forest showed that: the Q. aliena var. mixed pinus forest, which mean healthy index is 0.475, was healthier than pure Q. aliena var. forest (mean healthy index,0.369) and Broad-leaved mixed forest(mean healthy index, 0.442). According to health level, the pure Q. aliena var. forest is in an unhealthy state, the Q. aliena var. mixed pinus forest and broad-leaved forest in sub-health state.(3) The results of the main influencing factors on Q.aliena var. forest health showed that: these factors, which were stand volume, biomass of herb layer, Shannon-Wiener index of tree layer, tree richness, mixed proportion of tree, leaf area index, solid carbon and oxygen release can promote the healthy growth of natural Q. aliena var. forest; No significantly correlation between the existing litter and healthy index indicated that the increasing of existing litter can inhibit the healthy growth of Q. aliena var. . The analysis of healthy state in different Q. aliena var. forest types indicated that the stand type and human disturbance also affected the health of Q. aliena var. forest in some extent.(4) This research established an indicator system for Q. aliena var. forest health evaluation in subcompartment level by target method. This system based on the principle of representativeness and maneuverability. The rule hierarchy includes characteristic of vegetation and soil. The indicator layer includes stand volume, average DBH of dominant tree species, average height of dominant tree species, canopy density, composition of tree species, height of regeneration species, thickness of soil, texture of soil and soil humidity. The system was tested by the field sample data in different subcompartment. The results showed that: the difference for evaluation results on the community and subcompartment level was significant. The evaluation result on community level appeared a significant linear regression correlation with the result on subcompartment level. The regression equation was Y = 0.838 X? 0.079( F=44.954,R = 0.785, P <0.0001). Therefore it is possible to assess community by using the indicator system for health evaluation in subcompartment level .(5) Through analysis of healthy state of Q. aliena var. forest at different time point (1958, 1987, 2004)。The results showed that: Q. aliena var. forest in 1958 was most healthy, the healthy and subhealthy subcompartment took up 86.7% of total; the fellow one was the forest in 1987, the healthy and subhealthy subcompartment took up 36.4% of total; the oak forest in 2004 had less healthy and subhealthy subcompartment which took up 26.4% of total. |
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