Purpose of the Review

Improved forest management is a promising avenue for climate change mitigation. However, we lack synthetic understanding of how different management actions impact aboveground carbon stocks, particularly at scales relevant for designing and implementing forest-based climate solutions. Here, we quantitatively assess and review the impacts of three common practices—application of inorganic NPK fertilizer, interplanting with N-fixing species, and thinning—on aboveground carbon stocks in plantation forests.

Recent Findings

Site-level empirical studies show both positive and negative effects of inorganic fertilization, interplanting, and thinning on aboveground carbon stocks in plantation forests. Recent findings and the results of our analysis suggest that these effects are heavily moderated by factors such as species selection, precipitation, time since practice, soil moisture regime, and previous land use. Interplanting of N-fixing crops initially has no effect on carbon storage in main tree crops, but the effect becomes positive in older stands. Conversely, the application of NPK fertilizers increases aboveground carbon stocks, though the effect lessens with time. Moreover, increases in aboveground carbon stocks may be partially or completely offset by emissions from the application of inorganic fertilizer. Thinning results in a strong reduction of aboveground carbon stocks, though the effect lessens with time.

Summary

Management practices tend to have strong directional effects on aboveground carbon stocks in plantation forests but are moderated by site-specific management, climatic, and edaphic factors. The effect sizes quantified in our meta-analysis can serve as benchmarks for the design and scoping of improved forest management projects as forest-based climate solutions. Overall, management actions can enhance the climate mitigation potential of plantation forests, if performed with sufficient attention to the nuances of local conditions.

中文翻译：

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量化管理行动对人工林地上碳储量的影响大小

审查的目的

改善森林管理是减缓气候变化的一个有前途的途径。然而，我们缺乏对不同管理行动如何影响地上碳储量的综合理解，特别是在与设计和实施基于森林的气候解决方案相关的规模上。在这里，我们定量评估和回顾了三种常见做法——施用无机氮磷钾肥、套种固氮物种和间伐——对人工林地上碳储量的影响。

最近的发现

实地实证研究表明，无机施肥、套种和间伐对人工林地上碳储量既有积极影响，也有消极影响。最近的发现和我们的分析结果表明，这些影响在很大程度上受到物种选择、降水、实践后时间、土壤湿度状况和以前的土地利用等因素的影响。套种固氮作物最初对主要木本作物的碳储存没有影响，但对老林的影响变得积极。相反，施用 NPK 肥料会增加地上碳储量，但效果会随着时间的推移而减弱。此外，地上碳储量的增加可能会部分或完全被无机肥料施用的排放所抵消。间伐导致地上碳储量大幅减少，但效果会随着时间的推移而减弱。

概括

管理实践往往对人工林地上碳储量具有强烈的方向性影响，但会受到特定地点管理、气候和土壤因素的调节。我们的荟萃分析中量化的效应大小可以作为改进森林管理项目作为基于森林的气候解决方案的设计和范围界定的基准。总体而言，如果充分关注当地条件的细微差别，管理行动可以增强人工林减缓气候变化的潜力。