Data from: Does biomass growth increase in the largest trees? Flaws, fallacies and alternative analyses

The long-standing view that biomass growth in trees typically follows a rise-and-fall unimodal pattern has been challenged by studies concluding that biomass growth increases with size even among the largest stems in both closed forests and in open competition-free environments. We highlight challenges and pitfalls that influence such interpretations.
The ability to observe and calibrate biomass change in large stems requires adequate data regarding these specific stems.
Data checking and control procedures can bias estimates of biomass growth and generate false increases with stem size.
It is important to distinguish aggregate and individual-level trends: a failure to do so results in flawed interpretations.
Our assessment of biomass growth in 706 tropical forest stems indicates that individual biomass growth patterns often plateau for extended periods, with no significant difference in the number of stems indicating positive and negative trends in all but one of the 14 species. Nonetheless, when comparing aggregate growth during the most recent five years, 13 out of our 14 species indicate that biomass growth increases with size even among the largest sizes. Thus, individual and aggregate patterns of biomass growth with size are distinct.
Claims concerning general biomass growth patterns for large trees remain unconvincing. We suggest how future studies can improve our knowledge of growth patterns in and among large trees.

长期以来的主流观点认为，林木的生物量增长（biomass growth）通常遵循先升后降的单峰模式（unimodal pattern），但近期研究对此提出了挑战——这些研究指出，无论在封闭森林还是无竞争开放环境中，即便对于最大尺寸的茎干，其生物量增长仍随个体尺寸增大而提升。本研究着重探讨了影响此类解读的各类挑战与潜在陷阱。
对大型茎干的生物量变化进行观测与校准，需要针对这些特定茎干的充足观测数据。
数据核查与管控流程可能会对生物量增长的估算产生偏倚，进而得出茎干尺寸越大生物量增长越高的虚假结论。
区分总体与个体水平的增长趋势至关重要：若未能做到这一点，将导致解读出现偏差。
我们对706株热带林木茎干的生物量增长评估结果显示，个体生物量增长模式往往会长期趋于平稳；在14个树种中，除1个树种外，其余所有树种呈现正向增长趋势与负向增长趋势的茎干数量均无显著差异。不过，若对比最近五年的总体增长情况，14个树种中有13个树种的生物量增长仍随尺寸增大而提升，即便对于最大尺寸的茎干亦是如此。由此可见，生物量增长随尺寸变化的个体模式与总体模式存在显著差异。
有关大型林木通用生物量增长模式的相关论断仍缺乏说服力。本研究提出了未来研究可如何深化我们对大型林木自身及林木间增长模式的认知的可行路径。