Effects of timber harvest on carbon pools in Ozark forests

Abstract

We quantified and compared carbon (C) pools at a Missouri Ozark experimental forest 8 years after different harvest treatments. Total C pools were 182, 170, and 130 Mg C·ha–1for the control (no-harvest management; NHM), single-tree, uneven-age management (UAM), and clearcut even-age management (EAM) stands, respectively. Harvesting reduced the live tree C pool by 31% in the UAM, 93% in EAM stands, and increased the coarse woody debris (CWD) C pool by 50% in UAM and 176% for EAM, compared with NHM stands. UAM significantly (p = 0.02) increased the mineral soil C pool by 14%, whereas EAM had no effect. More interestingly, the distribution of C among various components (i.e., live, dead wood, CWD, litter, and soil) ranged from 0.7% to 29% on NHM stands and from 0.1% to 43% on EAM stands. Soil nitrogen (N) (%) was significantly correlated with soil C (%) in the UAM stands, whereas soil temperature was negatively related to live tree C. Soil N (%) and canopy cover were significantly correlated with live tree and soil C (%) pools at EAM stands. Our results revealed that the largest C pool in these forests was living trees. The soil and CWD C pool sizes suggest the importance of dynamics of decaying harvest debris, which influences N retention.