Gray Correlation Analysis On The Ecological Benefit Of The Typical Vegetation Types In Dahei Mountain Watershed In The Western Part Of Liaoning Province

The plant community’s species richness, diversity and evenness all have beensignificantly improved and the plant community’s structure also has been stabilized afterecological rehabilitation. The species diversity of the secondary forest plant community waslarger than that of the other plant community; the species diversity of mixed forest communityin both secondary forest and artificial forest were better than that of the pure forest; afterafforestation by using replantation and wasteland, both the two species diversity of whichhave been improved. Hence, enclosure and management measures should be strengthened tothe existing second forest in ecological rehabilitation. According to the principle “if there isbetter for arbor, then arbor, or if there is better for shrub, then shrub”, it was better tointroduce the suitable tree species to mix in the pure forest to promote biodiversity’srestoration and enhancement by artificial work.The structure and water status of soil have been improved significantly and the porosityalso has been increased in the ecological restoration. From the perspective of soil particle sizedistribution characteristics, the soil non-uniform coefficient of the secondary forest was20.41%higher than that of the artificial forest, while the mixed forest was13.91%higher thanthe pure forest, and the secondary forest was2.48%higher than the plantation forest, whilemixed forest was2.20%higher than the pure forest, after afforestation by using replantation,the mixed forest such as Chinese pine plus prunus armeniaca has been improved4.77%morethan the single Chinese pine, while the mixed forest such as Chinese pine plus sea buckthornhas been improved4.77%more than the wasteland. From the perspective of soil bulk density,the Secondary forest (1.19g/cm~3) was less than the artificial forest (1.27g/cm~3), and the mixedforest in both secondary forest and the artificial forest were slightly smaller than the pureforests, while after replantation and afforestation respectively, the mixed forest such asChinese pine plus prunus armeniaca and Chinese pine plus sea buckthorn have beendecreased by22.49%and24.36%respectively. From the perspective of soil porosity, the soiltotal porosity, capillary porosity, non-capillary porosity of the secondary forest wererespectively10.87%,5.62%and4.37%higher than that of the artificial forest, that was to say,the secondary forest precedes the artificial forest under the soil porosity condition, meanwhile, the soil total porosity, capillary porosity of mixed forest in both the secondary forest andartificial forest(mean value were51.16%and42.38%respectively) were better than that of thepure forest(mean value were47.19%and41.35%respectively), then after replantation andafforestation respectively, the soil total porosity, capillary porosity of mixed forest such asChinese pine plus prunus armeniaca and Chinese pine plus sea buckthorn were respectively22.49%,18.83%and24.36%,6.58%higher than before ecological rehabilitation. The resultshowed that the soil structural parameters such as soil particle size distribution characteristics,fractal dimension, bulk density and porosity were all better than before ecologicalrehabilitation, which namely that after ecological rehabilitation, the soil particle sizeheterogeneity, aggregate structure, capacity and permeability were better than that of beforeecological rehabilitation, and the soil parameters such as soil structural property and porosityof the mixed forest in both secondary forest and artificial forest were better than the pureforests. So if more attention would be paid to the combination of various tree species, it wouldbe more beneficial to the improvement of the forest stand soil structure.The soil ability to store and conserve water in ecological restoration area has beenobviously increased. From the perspective of soil water storage capacity under saturationcondition, the secondary forest was averagely10.87%higher than the artificial forest, and themixed forest was averagely10.87%higher than the pure forest, while after replantation andafforestation respectively, the mixed forest such as Chinese pine plus prunus armeniaca andChinese pine plus sea buckthorn were respectively11.66%and18.83%higher than beforeecological rehabilitation. From the perspective of soil steady infiltration rate in average, thesecondary forest (10.34mm/min) was higher than the artificial forest (8.03mm/min), and themixed forest (9.93mm/min) in both the second forest and artificial forest was better than thepure forest (8.161mm/min), after afforestation by using replantation, the mixed forest such asChinese pine plus prunus armeniaca has been improved2.78mm/min more than the singleChinese pine, while the mixed forest such as Chinese pine plus sea buckthorn has beenimproved2.97mm/min more than the wasteland. The result showed that the mixed forest hadthe best effect on soil structure and permeability improvement. Therefore, it should be done tostrengthen the existing forest management based on the secondary forest enclosure measure toprevent damage from human and livestock and to increase the soil water storage capacity offorest land. For the wasteland under good site conditions, artificial afforestation measureshould be done to form the structure of combination arbor, shrub and grass to increase thetotal water storage capacity of forest land.The negative air ions concentration increased by ecological restoration. The negative air ions evaluation index(FCI) of the secondary forest in descending order were Quercusmongolica forest (1.57), Black birch plus aspens mixed forest (1.15), Mongolia oak pluslinden mixed forest (1.06), secondary miscellaneous shrub forest (0.90), and the negative airions evaluation index(FCI) of the artificial forest in descending order were pure pine forest(1.19), wild apricot plus elm mixed forest (1.10), while the FCI value of the secondary forestwas2.0%higher than that of the artificial forest. After afforestation by using replantation, theFCI of the mixed forest (0.85) such as Chinese pine plus prunus armeniaca was more than thatof the single Chinese pine (0.78), while the FCI of the mixed forest (0.54) such as Chinesepine plus sea buckthorn was more than that of the wasteland (0.50), which were respectively56.51%,57.26%higher than before ecological rehabilitation.The highest gray relational degree value and comprehensive evaluation value in alltypical vegetation types is the mixed forest of Mongolia oak plus tilia (0.8569,0.8810), thelowest were pure Chinese pine forest (0.6005,0.6230), which showed that the secondaryforest was better than the artificial forest, and the mixed forest was better than the pure forestwhen comparing the ecological restoration effect; meanwhile, after replantation andafforestation respectively, the gray relational degree value and comprehensive evaluationvalue of the mixed forest such as Chinese pine plus prunus armeniaca and Chinese pine plussea buckthorn both were better than before ecological rehabilitation and also the effect wasobvious. So in the process of ecological rehabilitation of soil and water conservation andvegetation recovery, the secondary forest should be enclosed and protected, and meanwhilethe efforts of implementation on artificial forest, replantation and afforestation and wastelandafforestation should be enhanced, the attention should be paid to suitably mix the tree specieswith diverse biomass features when do afforestation to promote the recovery andimprovement of ecological rehabilitation benefit.