Stem respiration constitutes a substantial proportion of autotrophic respiration in forested ecosystems, but its drivers across different spatial scales and land-use gradients remain poorly understood. This study quantifies and examines the impact of logging disturbance on stem CO2 efflux (EA) in Malaysian Borneo. EA was quantified at tree- and stand-level in nine 1-ha plots over a logging gradient from heavily logged to old-growth using the static chamber method.<br /> Tree-level results showed higher EA per unit stem area in logged vs old-growth plots (37.0 +/- 1.1 vs 26.92 +/- 1.14 g C m(-2) month(-1)). However, at stand-level, there was no difference in EA between logged and old-growth plots (6.7 +/- 1.1 vs 6.0 +/- 0.7 Mg C ha(-1) yr(-1)) due to greater stem surface area in old-growth plots. Allocation to growth respiration and carbon use efficiency was significantly higher in logged plots. Variation in EA at both tree- and stand-level was driven by tree size, growth and differences in investment strategies between the forest types.<br /> These results reflect different resource allocation strategies and priorities, with a priority for growth in response to increased light availability in logged plots, while old-growth plots prioritise maintenance and cell structure
