Wood debris is an important component of forest ecosystems, because it influences nutrient cycling, humus formation, carbon storage, fire frequency and water cycles. Its CO₂ return to the atmosphere is comparable to that from fossil-fuel combustion. Dr.Douglas Schaefer  and his students of Xishuangbanna Tropical Botanical Garden (XTBG) measured environmental factors and wood debris decay by CO₂ release rates to investigate variations through time.

   The study was conducted in a subtropical moist forest located at an elevation of 2476 m, about 2 km north of the Ailao Field Station for Forest Ecosystem Studies (24°32′ N, 101°01′ E).At the study site, most wood debris came from Lithocarpus chintungensis, Lithocarpus xylocarpus, or Schima noronhae, so the researchers limited the study to those three species. They examined decay rates of the three dominant tree species six times during two years. Three decay classes were defined for each of those species, yielding nine groups.

The objectives of the study were: (1) to quantify wood debris decay rates and their variability, (2) to identify environmental and other variables linked with wood debris decay, and (3) to explore decay-rate variability unrelated to those factors.

Their study found that average decay rates of individual pieces varied by a factor of almost 18. Their results supported previous studies on the importance of environmental factors in determining wood debris decomposition, but with only half of the variation explained. Their study also suggested that community structure of fungal decomposers probably affected wood-decay rates.

The researchers got financial support from the Asia-Pacific Network for Global Change Research (ARCP 2009-18MY), the National Science Foundation of China (30970535 and 41271278), and the Chinese Academy of Sciences 135 program (XTBG-T01).

The study entitled “What controls the variability of wood-decay rates?” has been published online in Forest Ecology and Management.