1. The importance of wood decay for global carbon and nutrient cycles is widely recognized. However, relatively little is known about bark decay dynamics, even though bark represents up to 25% of stem dry mass. Moreover, bark presence versus absence can significantly alter wood decay rates. Therefore, it really matters for the fate of carbon whether variation in bark and wood decay rates is coordinated across tree species.
2. Answering this question requires advances in methodology to measure both bark and wood mass loss accurately. Decay rates of large logs in the field are often quantified as loss in tissue density, in which case volume depletions of bark and wood can yield large underestimations.
3. To quantify the real decay rates, we assessed bark mass loss per stem surface area and wood mass loss based on volume‐corrected density loss. We further defined the range of actual bark mass loss by considering bark cover loss. Then, we tested the correlation between bark and wood mass loss across 20 temperate tree species during 4 years of decomposition.
4. The area‐based method generally showed more than 3‐fold higher bark mass loss than the density‐based method (even higher if considering bark cover loss), and volume‐corrected wood mass losses were 1.08–1.12 times higher than density‐based mass loss. The deviation of bark mass loss between the two methods was higher for tree species with thicker inner bark. Bark generally decomposed twice as fast as wood across species, and faster decaying bark came with faster decaying wood (R² = 0.26, p = 0.006).
5. We strongly suggest using corrected volume when assessing wood mass loss especially for the species with faster decomposable sapwood and all the wood at advanced decay stages. Further studies of coarse stem decomposition should consider trait ‘afterlife’ effects of inner bark and estimate fraction of stem bark cover to obtain more accurate decay rates.
6. Our new method should benefit our understanding of the in situ dynamics of woody debris decay and monitoring research in different forest ecosystems world‐wide, and should aid meta‐analyses across diverse studies.

中文翻译：

---

方法学对于比较树木物种的粗木和树皮腐烂率很重要

1. 木材腐烂对于全球碳和养分循环的重要性已得到广泛认可。然而，即使树皮占茎干质量的25％，对树皮衰变动力学的了解还很少。此外，树皮的存在与不存在可以显着改变木材的腐烂率。因此，对于碳的命运而言，树皮间树皮和木材腐烂率的变化是否协调是至关重要的。
2. 要回答这个问题，就需要先进的方法来准确测量树皮和木材的质量损失。野外大型原木的腐烂率通常被量化为组织密度的损失，在这种情况下，树皮和木材的体积枯竭可能会导致大大的低估。
3. 为了量化实际的腐烂率，我们根据体积校正的密度损失评估了每茎表面积的树皮质量损失和木材质量损失。通过考虑树皮覆盖率损失，我们进一步定义了实际的树皮质量损失范围。然后，我们测试了4年分解过程中20种温带树种的树皮与木材质量损失之间的相关性。
4. 基于面积的方法通常显示出比基于密度的方法高出三倍以上的树皮质量损失（如果考虑到树皮覆盖率损失，则更高），而体积校正的木材质量损失是基于密度的质量的1.08-1.12倍失利。对于内部树皮较厚的树种，两种方法之间的树皮质量损失偏差较高。通常，树皮的腐烂速度是整个物种的两倍，而腐烂的树皮伴随着腐烂的木材也更快（R ²  = 0.26，p  = 0.006）。
5. 我们强烈建议在评估木材质量损失时使用校正后的体积，尤其是对于具有更快可分解边材的树种以及所有处于晚期腐烂阶段的木材。对粗茎分解的进一步研究应考虑内树皮的性状“来世”效应，并估计茎皮的覆盖率，以获得更准确的衰减率。
6. 我们的新方法应该有益于我们了解木质碎片腐烂的原位动力学，并监测全球不同森林生态系统中的研究，并且应该有助于跨各种研究的荟萃分析。