| In recent years,under the promotion of national"Natural Forest Protection"project,the forest community in Huoditang forest region of Qinling Mountains of Shaanxi province has gradually recovered,and the vegetation resources are increasingly rich and the species diversity is increasing.In this study,six main stands of Huoditang Forest in the Qinling Mountains were selected:Picea wilsonii(PW),Betula albosinensis(B),Tsuga chinensis(T),Pinus armandii(PA),Pinus tabuliformis(PT),Quercus aliena var.acutiserrata(Q)were studied by field sampling and indoor nutrient composition determination.In order to provide scientific data for the national ecosystem research network,the community characteristics,litter layer inventory,nutrient elements content and their influencing factors of different stands were clarified.The main results are as follows:1.The species of PA forest were 32 species,29 genera,25 families,23 species,22genera,19 families in PT forest,22 species,22 genera,18 families in B,17 species,17genera,16 species,15 families in T,and 7 species,6 genera,6 families in Q.Simpson index,Shannon-Wiener index and Pielou index ranged from 0 to 0.607,0 to 1.177 and 0 to 0.657,respectively.The Simpson index,Shannon-Wiener index and Pielou index of shrub layer ranged from 0.122 to 0.861,0.261 to 2.169 and 0.189 to 0.873.In herb layer,Simpson index ranged from 0.008 to 0.707,Shannon-Wiener index ranged from 0.026 to 1.577,Pielou index ranged from 0.037 to 0.817.2.The average arbor layer biomass was 160.87t/hm~2 in PW>155.89t/hm~2 in Q>142.33t/hm~2 in PA>131.35t/hm~2 in PT>87.51t/hm~2 in B>34.17t/hm~2 in T.The biomass of shrub and herb layer was 0.8073t/hm~2 in Q>0.3772t/hm~2 in PW>0.3266t/hm~2 in PA>0.3244t/hm~2 in PT>0.2727t/hm~2 in T>0.1878t/hm~2 in B.The shrub layer was 0.2710t/hm~2in Q>0.2224t/hm~2 in PW>0.2140t/hm~2 in PA>0.1219t/hm~2 in T>0.1082t/hm~2 in PT>0.1080t/hm~2 in B.The biomass of herbactic layer was 0.2710t/hm~2 in Q>0.2162t/hm~2 in PT>0.1548t/hm~2 in PW>0.1508t/hm~2 in T>0.1126t/hm~2 in PA>0.0797t/hm~2 in B.The biomass of shrubbery layer was significantly different.3.The order of organic carbon(TOC)content in arbor layer was:PT 513.37g/kg>PA503.47g/kg>PW 487.72 g/kg>T 483.01 g/kg>B 469.43 g/kg>Q 432.27g/kg,and the order of total nitrogen(TN)content was Q 4.75g/kg>PT 4.53 g/kg>PA 4.48g/kg>B 4.25 g/kg>PW 3.66 g/kg>T 2.79g/kg,total phosphorus(TP)content order:B 0.6938g/kg>PA0.6871g/kg>PT 0.66 g/kg>Q 0.61g/kg>PW 0.55 g/kg>T 0.42g/kg,and the order of total potassium(TK)content was 2.23g/kg in Q>PA 2.13g/kg>PT 2.01 g/kg>PW 1.83 g/kg>T1.25 g/kg>B 1.19g/kg.4.The forest litter stock of PW,PT,PA,Q,B and T was 7.4858t/hm~2>7.0409t/hm~2>6.9071t/hm~2>6.1792t/hm~2>6.0760t/hm~2>6.0520t/hm~2.The content of organic carbon(TOC)in litter was 465.96g/kg in T>456.78g/kg in B>456.34g/kg in PT>450.99g/kg in PW>448.39g/kg in Q>446.84g/kg in PA.The Total nitrogen(TN)content was 17.48g/kg in B>12.49g/kg in PA>9.02g/kg in PT>7.17g/kg in Q>6.20g/kg in T>4.93g/kg in PW.The total phosphorus(TP)content was 1.59g/kg in B>1.06g/kg in PA>0.67g/kg in PT>0.65g/kg in Q>0.51g/kg in T>0.50g/kg in PW.Total potassium(TK)content was 4.54g/kg in PA>2.00g/kg in B>1.35g/kg in PT>0.90g/kg in Q>0.85g/kg in T>0.80g/kg in PW.There were significant differences in total nitrogen(TN),total phosphorus(TP)and total potassium(TK)contents of litter among different stand types,but no significant differences in organic carbon (TOC) contents. |
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