Spatial Distribution And Stoichiometric Characteristics Of Carbon,Nitrogen And Phosphorus For Forest Ecosystem In Liaoning Province

As the main part of terrestrial ecosystem,forest ecosystem plays an important role in maintaining element balance and mitigating climate change of global.Forest plants sequester carbon by photosynthesis,and the coupling of nitrogen and phosphorus with carbon cycle is an important research direction for carbon cycle.Therefore,the storage of carbon,nitrogen and phosphorus in forest ecosystem has become the basic parameter in studying the carbon,nitrogen and phosphorus exchange between forest and atmosphere.The forest ecosystem in Liaoning Province is the important part of the forest ecosystem in Northeast China,and the present situation of carbon,nitrogen and phosphorus storage and its stoichiometric characteristics play an important role in the nutrient cycling of the northeast forest ecosystem.The carbon,nitrogen,phosphorus density,storage,spatial distribution and ecological stoichiometric characteristics of forest ecosystem in Liaoning Province were studied by the results of sample land survey and the survey of forest resource in Liaoning Province in 2010(the second class investigation).The main results were as follows:(1)The average density of carbon,nitrogen and phosphorus for arbor layer of forest ecosystem in Liaoning Province were 24.752,0.580 and 0.056Mg/ha respectively,1.078,0.076 and 0.007 Mg/ha for shrub-grass layer.The litter layer were 2.223,0.075 and 0.001 Mg/ha.The soil layer were 133.016,19.467 and 10.026 Mg/ha,respectively.The average carbon and phosphorus density in different forest types increased with the increase of forest age,while nitrogen density increased firstly,and then decreased with the increase of forest age.The young and middle age forest are the main parts in Liaoning Province at present,which has great potential for carbon,nitrogen,phosphorus and other nutrients.The density of carbon,nitrogen and phosphorus for forest ecosystem in east of Liaoning Province were higher than that in other areas.(2)The storage of carbon,nitrogen and phosphorus in arbor layer were 114.966 Tg C,2.693 Tg N and 0.261 Tg P.The shrub-grass layer were 5.008 Tg C,0.352 Tg N and0.031 Tg P,the litter layer were 10.324 Tg C,0.349 Tg N and 0.032 Tg P,and the soil layer were 617.819 Tg C,90.420 Tg N and 46.566 Tg P,respectively.The order of carbon,nitrogen,phosphorus storage was soil layer > arbor layer > litter layer >shrub-grass layer.Soil was the main part of carbon,nitrogen and phosphorus storage in forest ecosystem of Liaoning Province.Under the influence of forest area,there were differences in carbon,nitrogen and phosphorus storage among different forest types and ages.The storage of carbon,nitrogen and phosphorus in Quercus mongolica forest,Larix gemellini plantation and Pinus tabulaeformis forest were higher than others.And the storage of carbon,nitrogen and phosphorus in young and middle age forests accounted for 68.820%,72.870% and 58.320% of the total storage,respectively,which were major contributors to carbon,nitrogen and phosphorus storage in Liaoning Province.The spatial distribution characteristics of carbon,nitrogen and phosphorus storage in forest ecosystem of Liaoning Province were the highest in the northeast and the second in the southwest,it was the lowest in the central plain.(3)C,N,P contents in leaves of different forest types were higher than those in litter and soil,because the photosynthesis of plant leaves provided nutrients for themselves.Forest vegetation was restricted by N in Liaoning Province,in which N:P was 12.010 in the leaves in east and 8.990 in the west.So,the forest vegetation was even more deficient in N,because of the soil type and environment.The nutrient content and stoichiometric ratio were correlated among leaves,litter and soil in different forest types,and it was necessary to study the influence mechanism in the nutrient content and stoichiometric characteristics between plant and soil in the future.