Respiration of downed logs in pine and oak forests in the Qinling Mountains, China

This study presents a full year time series of Rlog measurements for 30 logs (3 replicate logs × 5 decay classes × 2 tree species). The Rlog measurements were repeated 468 times for each log from May 2014 to April 2015. The log temperature (Tlog), air temperature (TA), soil temperature (TS) at a depth of 10 cm, and log water content (Wlog) were measured simultaneously with Rlog. Moreover, the log density (Dlog) and chemical composition (C, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)) were determined. Our results showed significant seasonal variation in Rlog for both species, which corresponded to variations in Tlog during the study period. The annual mean Rlog of Q. aliena var. acuteserrata (1.69 ± 1.60 μmol m−2·s-1) was higher than that of P. armandi (1.55 ± 1.43 μmol m−2·s−1), but the difference was not significant (P = 0.61). The decay classes, Tlog, Wlog, and the N, P, Ca, and Mg concentrations were positively correlated with Rlog. Moreover, the K concentration was negatively correlated with Rlog, and the C concentration in logs was not correlated with Rlog. The total annual Rlog flux did not differ significantly between the P. armandi (67.25 ± 7.28 g C·m−2·y−1) and Q. aliena var. acuteserrata (74.69 ± 9.31 g C·m−2·y−1) forests (P = 0.26). These results provide insight into the factors responsible for seasonal changes in Rlog and can improve estimates of the ann...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research