| Carbon storage and its influencing factors were researched in pure forests of Pinustabulaeformis, Quercus aliena var. acuteserrata, and Pinus armandi, as well as mixed forestsbetween Q. aliena var. acuteserrata and P. tabulaeformis, Q. aliena var. acuteserrata and P.armandi at Huoditang forest region in the Qinling Mountains. The results are as follows:1. The carbon storage in arbor layers of the pure forest of P. tabulaeformis, Q. aliena var.acuteserrata, and P. armandi, as well as mixed forest between Q. aliena var. acuteserrata andP. tabulaeformis, Q. aliena var. acuteserrata and P. armandi were105.653t·hm-2,107.741t·hm-2,95.157t·hm-2,89.632t·hm-2, and97.659t·hm-2respectively; for shrub layers,1.551t·hm-2,1.912t·hm-2,1.446t·hm-2,1.202t·hm-2, and1.328t·hm-2respectively; and for herblayers0.255t·hm-2,0.220t·hm-2,0.143t·hm-2,0.184t·hm-2, and0.182t·hm-2respectively.There were significant differences among the carbon storage of different forests. For the arborand shrub layers, the carbon storage of pure forest was higher than that of the mixed forest.The carbon storage of shrub layers was a very important component of the whole forestcarbon storage.2. The spatial distribution patterns of the soil physicochemical properties in the fiveforest types were: the pH value was5.20～6.21, soil bulk density0.808～1.297g·cm-3,content of soil available nitrogen76.883～207.492mg·kg-1, nitrate nitrogen1.290～10.183mg·kg-1, ammonium nitrogen12.477～21.297mg·kg-1, organic matter22.722～60.586g·kg-1, available phosphorus3.437～37.554mg·kg-1, available potassium50.002～226.667mg·kg-1. The properties had some regularity and differences along with the changesof the forest types and sampling depth. The pH had a significant difference among the fiveforest types. The soil bulk density had a significant difference except of the pure forest of P.tabulaeformis and the mixed forest between Q. aliena var. acuteserrata and P. armandi.There were higher contents of available nitrogen, nitrate nitrogen and ammonium nitrogen inthe surface layer of the soil depth. With the increase of section depth of soil samples indifferent forests, the content of soil available nitrogen decreased gradually. The organicmatter had no significant difference in the pure forest of Q. aliena var. acuteserrata and themixed forest between Q. aliena var. acuteserrata and P. tabulaeformis. The availablephosphorus and potassium had significant differences in the five forest types. With the changes of the forest types, the available phosphorus and potassium had differentcharacteristics.3. There was a positive significant correlation between the carbon storage of the arborlayer and that of the shrub one, however, no significant correlation with the herb layer couldbe found. The carbon storage of all the three layers had a significant negative correlation withthe forest types. The forest species composition had a significant impact on the carbonstorage of different layers. The carbon storage of arbor and shrub layers had no significantcorrelations with the soil physicochemical properties in shallow soil. With the increase of soildepth, the carbon storage of arbor layers had significant correlations with the contents ofnitrate nitrogen and available phosphorus. The pH, nitrogen, phosphorus and organic matterall had significant correlations with the shrub carbon storage as the increase of soil depth. Thefactors having significant correlations with the carbon storage of herb could be found in allthe soil depths.4. The main factors affecting the carbon storage changed from forest types, altitude, andaspect to the factors of the soil itself, such as pH and phosphorus with the increase of soildepth. Forest types, altitude and the content of soil nitrogen and phosphorus were the mainfactors influencing the arbor carbon storage. However, the main factors affecting the shrubcarbon storage were forest types, altitude, pH, nitrogen, phosphorus and organic matter.Aspect and soil phosphorus were the main impact factors of the herb carbon storage. |
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