This research was carried out to quantify the variation of biomass carbon density and distribution patterns of Larix priucipis-rupprechtii plantation at different forest ages in Yanshan Mountainous area. The results can provide a scientific foundation of service function of carbon sequestration. According to three forest ages of L. priucipis-rupprechtii Plantation of Xinfeng Experimental Forest Farm of the Mulan State-owned Forest Farm Bureauin Hebei Province，basing on the data of 9 pieces of sample plots survey and 27 larch wood of different forest age

size order

we obtained larch biomass carbon density of different forest ages by using regression analysis

the method of quadrat harvest

soil profile sampling method and potassium dichromate oxidation-external heating method

and analyzed the characteristics and change tendency. The results showed that the performance of total ecosystem carbon density of different forest age of L. priucipis-rupprechtii plantation were 32 years (97.29 t/hm2) >21 years (90.56 t/hm2) >11 years (44.57 t/hm2)

the arbor layer and soil layer were the main carbon pools

the proportion of the sum of these two was as high as 52.59%～71.51%; the carbon accumulation ability of the arbor layer increased with the increase of stand-age

the tree layer carbon density of L. priucipis-rupprechtii plantation at the forest ages of 11

21

32 years were 14.27

38.57和42.37 t/hm2

and the difference reached the significant level; the carbon density of every organ of three forest ages of L. priucipis-rupprechtii were trunk >branch >root >bark >leaf

the difference of contribution rate between each organ had reached the extremely significant level. Among them

the contribution of trunk was the largest

with the increase of forest age

the proportion of carbon density of trunk increased

the proportion of carbon density of branch

leaf

bark declined

and the distribution ratio of root system was relatively stable. The tread of carbon density of the understory cover were litter layer > herb layer > shrub layer

and it increased with the increase of forest age; the carbon density of 0—60 cm soil layer showed that the carbon density decreased with the deepening of soil layer

the surface organic carbon content was the highest

and it increased with the increase of forest age

difference among different forest ages reached significant level; it was better to choose two factors of DBH and tree height to construct the model of predicting the carbon density of the tree layer with two elements. The change of carbon storage in L. priucipis-rupprechtii plantation was mainly affected by its own growth and development

at the same time

it was also affected by the density change caused by artificial tending.