Separation of soil respiration into CO₂ emission sources using ¹³C natural abundance in a deciduous broad-leaved forest in Japan

Figures & data

Figure 1  Seasonal fluctuations in (a) air temperature, (b) precipitation, (c) soil temperature and soil moisture content at 5 cm depth and (d) CO2 emission rates from forest floor (RS) and litter (RL). Error bars represent the standard error.

Table 1 Masses and stable carbon isotope ratios of soil, litter and roots

	Dry weight (kg m^−2)	Carbon content (kg kg^−3)	δ^13C value (‰)
Litter	0.440 ± 0.083	0.485 ± 0.009	30.1 ± 0.1
Fine roots†	0.306 ± 0.096‡ 0.247 ± 0.049‡	0.435 ± 0.004	28.9 ± 0.1
Soil†	71.4 ± 3.86	0.104 ± 0.002	24.3 ± 0.5
†Samples were collected from a depth of 0–20 cm.
^‡The upper and lower data were sampled in July 2001 and December 2001, respectively.

Figure 2  Seasonal fluctuations in the carbon isotope ratio of CO2 emitted by soil respiration. Error bars represent the standard error.

Figure 3  Seasonal fluctuations of CO2 emissions and the contribution ratios from roots (RRHI), soil organic matter (RSOM) and litter (RL). Error bars represent the standard error. N.E., values that were not able to be estimated.