Carbon Storage In Manchurian Ash And Dahurian Larch Plantations With Different Stand Structures

Manchurian ash(Fraxinus mandshurica) and dahurian larch (Larix olgensis) are the main afforestation species in Northeast China. The objective of this study was to determine the impact of stand structure on the carbon storage of manchurian ash and dahurian larch plantations. The carbon storage of manchurian ash stand with different densities, and the carbon storage of manchurian ash pure stand, dahurian larch pure stand, manchurian ash and dahurian larch mixed stand were estimated in Maoershan Experimental Forest Farm of Northeast Forestry University. The results showed:1. In the four different density stands (1325、214、2766、4125plant·hm-2), with stand density increasing, the carbon storage of tree, litter and soil layer were increased, but the carbon storage of understory vegetation was decreased. The carbon storage of soil accounting for a large proportion of the total carbon storage of the stand, were79.6%～82.4%. The carbon storage of tree accounting for14.1%～17.0%. The carbon storage of litter accounting for3.2%～3.3%. The carbon storage of understory vegetation was the least, which accounting for0.1%～0.2%. The spatial distribution of carbon storage in the four different density stands was soil> tree> litter> understory vegetation.2. The total carbon storage and the annual carbon accumulation of tree in the four stands were increased with stand density increasing. The total carbon storage from low density to high density were139.90～175.42t·hm-2. The annual carbon accumulation of tree from low density to high density were2.62-3.73t·hm-2·a-1, converted into the amount of CO2were9.61～13.68t·hm-2·a-1. In manchurian ash young plantations, higher density with larger carbon storage.3. The carbon storage of tree and soil layer in the mixed stand was higher than the pure stands. The carbon storage of understory vegetation was manchurian ash pure stand> mixed stand> dahurian larch pure stand, the carbon storage of litter was dahurian larch pure stand> mixed stand> manchurian ash pure stand. The carbon storage of soil accounting for a large proportion of the total carbon storage of the stand, were71.6%～80.1%. The carbon storage of tree accounting for17.3%～24.5%. The carbon storage of litter accounting for2.3%～4.3%. The carbon storage of understory vegetation was the least, which accounting for0.1%～0.3%. The spatial distribution of carbon storage was soil> tree> litter> understory vegetation.4. The carbon storage of stand and the annual carbon accumulation of tree in the mixed stand was higher than the pure stands. The total carbon storage of stand from high to low were manchurian ash and dahurian larch mixed stand (246.15t·hm-2)> dahurian larch pure stand (232.01t·hm-2)> manchurian ash pure stand (211.86t·hm-2). The annual carbon accumulation of tree from high to low were manchurian ash and dahurian larch mixed stand (3.88t·hm-2a-1) > dahurian larch pure stand (2.92t·hm-2·a-1)> manchurian ash pure stand (2.87t·hm-2·a-1)..Establishment of manchurian ash and dahurian larch mixed stand could be beneficial to increase the carbon storage of the stand.