To understand the magnitudes of temporal variation in soil respiration (
Rs) and its spatial heterogeneity, and the effect of abiotic and biotic factors to cause the variation in a young plantation recovering after the clear-cutting of a mature forest, we analyzed 8 year
Rs, microclimate, and vegetation data obtained in a young hybrid larch plantation with dense undergrowth of dwarf bamboo
Sasa in northern Japan during snow-free periods from 2004 to 2014.
Rs was measured by a multichannel automated chamber system and was resolved into two components, temperature sensitivity of respiration,
Q10, and temperature-normalized basal respiration at 10°C,
R10. Volumetric soil water content affects both seasonal and inter-annual variation of
Rs by suppressing
R10, whereas soil temperature affects only its seasonal variation. Vegetation recovery had significant effect on both temporal variation and spatial heterogeneity in
Rs, although the tree and undergrowth
Sasa had different contribution to these variations. Increase in the undergrowth
Sasa PAI (plant area index) recovering after clear-cutting increased the
Rs through the increase in
Q10, whereas the spatial heterogeneity in
Rs was increased by the increase in the tree PAI through the increase in
R10. These results reveal that the soil water and vegetation has strong effect on the inter-annual variation of
Rs and its spatial heterogeneity in the recovering young plantation, in spite of the strong exponential relationship of
Rs with
Ts in their seasonal variation. Although our results were obtained under the limited range in the inter-annual variation in seasonal mean
Ts ( < 2°C), this may not be the unique case only in our study site and gives us a caution when predicting
Rs in future warmer environment.
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