Mixed Forest plantations for climate Change mitigation and adaptation

森林景观恢复和植树造林作为减缓气候变化(CC)的一个重要机会，最近受到了国际社会的广泛关注。因此，它在欧盟绿色协议和波恩挑战等许多政治倡议中占据突出地位。然而，由CC推动的生物和非生物压力的持续增加将森林置于威胁之下。面对碳汇，森林的适应和缓解最终是联系在一起的，因为森林长期固定碳(C)的能力取决于树木应对多重压力的能力。越来越多的证据表明，混交林种植园，即几个树种混合的种植园，在固定碳方面更有效，同时更好地应对与CC相关的压力。因此，混合种植园为缓解和适应CC提供了一个重要的基于自然的解决方案的机会。然而，单一栽培仍然主导着世界上的森林种植园。需要在未来的森林政策中查明和解决土地所有者和利益攸关方明显抵制混合种植园的原因，以促进更具CC复原力的混交林种植园的大规模扩张。可能阻碍混合种植园大规模扩张的可能因素之一是从业人员和政策制定者的科学证据不足。利用全球森林生物多样性实验网络(TreeDivNet)，我们将以双赢的方式提供关于树木多样性、物种特性和管理(间伐和施肥)如何影响混交林人工林缓解(碳固存)和适应(干旱和草食)CC的潜力的机械性理解。此外，我们将把这些知识转化为可被从业者和政策制定者广泛采用的指导方针。TreeDivNet网络包括分布在全球的26个实验，种植了大约120万棵树。所有这些实验都基于一种常见的、统计上合理的设计，该设计允许检测树木多样性、管理和森林生态系统功能之间的因果关系(包括。C自动减支)。MixForChange的功能和机制重点以及网络中嵌入的对比环境背景将使我们能够扩大我们的发现，超越案例研究，为广泛环境中的混合种植园管理提供循证指导。此外，MixForChange将在一个共同的框架内以前所未有的规模分析混合种植园的CC缓解和适应潜力与实现利益攸关方目标之间的协同作用和权衡。MixForChange的社会影响将通过高度重视各级管理和治理中的知识转让和能力建设来确保。MixForChange将为推动混交林种植园成为对抗CC的自然解决方案做出重要贡献。

Forest landscape restoration and afforestation have recently received much international attention as a crucial opportunity for mitigating climate change (CC). Therefore, it features prominently in many political initiatives such as the EU Green Deal and the Bonn Challenge. Yet, the ongoing increase in biotic and abiotic stress driven by CC puts forests under threat. In the face of CC, adaptation and mitigation by forests are ultimately linked, because the ability of forests to sequester carbon (C) in the long run depends on the ability of trees to cope with multiple stresses. A growing body of evidence suggests that mixed forest plantations, i.e., plantations where several tree species are mixed, are more efficient in sequestrating C, while better coping with CC-related stress. Mixed plantations thus represent an opportunity for an important nature-based solution for CC mitigation and adaptation. However, monocultures still dominate the world’s forest plantations. The reasons for the apparent resistance to mixed plantations among landowners and stakeholders need to be identified and addressed in future forest policies to promote the large-scale expansion of more CC-resilient mixed forest plantations. One of the possible factors that may have prevented the expansion of mixed plantations at large scales is insufficient scientific evidence for practitioners and policy-makers. Using a global network of forest biodiversity experiments (TreeDivNet), we will provide a mechanistic understanding of how tree diversity, species identities and management (thinning and fertilization) influence both the potential of mixed forest plantations to mitigate (C sequestration) and adapt (drought and herbivory resilience) to CC, in a win-win approach. In addition, we will translate this knowledge into guidelines that can be widely adopted by practitioners and policy-makers. The TreeDivNet network comprises 26 experiments spread across the globe, with ca. 1.2M planted trees. All these experiments were based on a common, statistically sound design that allows detection of causal relationships between tree diversity, management and forest ecosystem functioning (incl. C sequestration). The functional and mechanistic focus of MixForChange and the contrasting environmental contexts embedded in the network will allow us to scale-up our findings beyond case studies to provide evidence-based guidelines for mixed plantation management in a broad range of environments. Moreover, MixForChange will analyse in a common framework, and at unprecedented scale, synergies and trade-offs between the CC mitigation and adaptation potential of mixed plantations and the fulfilment of stakeholders’ objectives. The societal impact of MixForChange will be ensured by a strong focus on knowledge transfer and capacity-building at all levels of management and governance. MixForChange will make an important contribution to promoting mixed forest plantations as nature-based solutions to fight CC.