Carbon balance in an interplanting Pinus massoniana stand in subtropical eroded red soil region, China.

Abstract

We measured the annual net biomass growth, carbon content of each component and soil heterotrophic respiration in four low-efficiency interplanting patterns, i.e., Pinus massoniana stands interplanting Myrica rubra, Sapindus mukurossi, Camellia oleifera and Gardenia jasminoides in Changting County, Fujian Province, with the aim to analyze the effects of interplanting patterns on carbon storage pattern and carbon balance of low-efficiency P. massoniana stand. The ranges of carbon content in different organs of M. rubra, S. mukurossi, C. oleifera, G. jasminoides and P. massoniana were 41.1%-50.1%, 42.2%-50.6%, 45.1%-48.9%, 44.7%-49.6% and 46.1%-51.9%, respectively. Carbon content of the same organ significantly differed among tree species. The pattern of P. massoniana interplanting M. rubra and S. mukurossi had the highest carbon stock and annual net carbon increase reserves, with values of 67.62-68.42 t·hm-2 and 9.21-9.45 t·hm-2·a-1, respectively. Followed by the lower pattern of C. oleifera, G. jasminoides, with values of 31.96-36.24 t·hm-2 and 4.09-4.16 t·hm-2·a-1, respectively. The P. massoniana pure forest was the lowest, with values of 17.01 t·hm-2 and 2.00 t·hm-2·a-1, respectively. Annual flux of soil heterotrophic respiration was following the order of P. massoniana interplanting M. rubra pattern (7.41 t·hm-2·a-1) > P. massoniana interplanting C. oleifera pattern (5.89 t·hm-2·a-1)> P. massoniana interplanting S. mukurossi pattern (5.86 t·hm-2·a-1) > P. massoniana interplanting G. jasminoides pattern (4.95 t·hm-2·a-1) > P. massoniana pure forest (2.45 t·hm-2·a-1). Annual net ecosystem carbon balance of P. massoniana interplanting M. rubra and S. mukurossi patterns were 2.04 and 3.27 t C·hm-2·a-1, showing a "carbon sink" pattern. The net carbon balance in the patterns of P. massoniana interplanting C. oleifera and G. jasminoides along with P. massoniana pure forest were -1.80, -0.80 and -0.45 t C·hm-2·a-1, which expressed a "carbon source" pattern. In the short-term, interplanting with M. rubra or S. mukurossi could improve the carbon income of the low-efficiency P. massoniana stand ecosystem.