The study was a repeated measures with monthly sampling for up to 12 month after prescribed burning in a subtropical native forest.

Overall, there were positive correlations among soil (0-5 cm) water soluble C and N, hot water soluble C and N and litterfall δ13C. These variables were all negatively correlated with litterfall total C and litterfall δ15N. No significant correlation was observed among the mentioned variables and monthly rainfall and temperature.

My suggested scenario is:

The negative correlation between litterfall TC and litterfall δ13C may reflect the stomatal closure resulted in reducing C fixation and using the 13C trapped due to the closure. This might be resulted in a reduction in N uptake due to the reduced evapotranspiration and therefore reduced water potential. Hence, plant could uptake the lighter 14N.

Questions:

1- If the scenario is correct, why there is no correlation between litterfall δ13C and rainfall and temperature as a reason for stomatal closure ? and what are the other possible scenarios?

2- If the scenario is correct, how can we explain the positive correlation among litterfal δ13C and soil labile C and N? and the negative correlation between litterfall total C and soil labile C and N?

Thanks