Purpose of Review

Non-native tree species (NNT) raise a range of different associations and emotions—to many citizens they are just an exotic curiosity in parks, to many conservationists they are an evil to native ecosystems that should be eradicated, to a rising group of foresters they are part of the solution to climate change and an increasing timber demand, and to others they are already daily forestry business. In this review, where we also summarise the findings of the recent COST Action FP1403 (NNEXT) ‘Non-native tree species for European forests: experiences, risks and opportunities’, we highlight opportunities and challenges in the light of climate change, ecological risks and legislative limits of growing non-native tree species in Europe.

Recent Findings

Few NNT in Europe show invasive behaviour and are listed as prohibited species or as species to be monitored. A larger number of NNT is utilised in productive forestry and forest restoration due to their superior growth, valuable timber properties and good performance under harsh growing conditions. Current species distribution, experiences with success and failures and environmental concerns differ profoundly across Europe, with Western Europe overall revealing higher shares in NNT and showing a stronger interest of forestry related stakeholder groups to continue planting NNT.

Summary

Many more NNT are already used in forestry than previously thought, but relatively few species have major importance in terms of area, mainly in western European countries. Diversification, mixing and avoidance of invasion in relation to NNT are necessities that are relatively new on the agenda. In contrast, provenance research of major NNT has been going on for many decades and now provides important information for climate change adaptation. Despite the limitations to the use of NNT either through legal restrictions or forest certification that differ considerably across Europe, the careful integration of a range of tested NNT also into future forest management planning shows a high potential for climate change adaptation and mitigation.

中文翻译：

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在欧洲森林中种植非本地树木带来好处和机遇，但也有其风险和局限性

审查目的

非本地树种（NNT）引发了一系列不同的联想和情感-对许多公民来说，它们只是公园里的一种奇特的好奇心，对许多保护主义者而言，它们对应该被铲除的原生生态系统是一种恶魔，对于不断上升的森林人群体它们是应对气候变化和木材需求增长的解决方案的一部分，而对于其他公司来说，它们已经是日常的林业业务。在这篇评论中，我们还总结了最近的COST行动FP1403（NNEXT）“欧洲森林的非本地树种：经验，风险和机遇”的发现，我们着眼于气候变化，生态风险强调了机遇与挑战以及欧洲非本地树种的立法限制。

最近的发现

欧洲很少有NNT表现出入侵行为，并被列为禁用物种或需要监测的物种。由于NNT具有卓越的生长，宝贵的木材特性以及在恶劣的生长条件下的良好性能，因此在生产性林业和森林恢复中使用了大量的NNT。在欧洲，当前物种的分布，成功与失败的经历以及对环境的关注差异很大，西欧总体上显示NNT的份额更高，并且与林业相关的利益相关者团体对继续种植NNT的兴趣更大。

概要

在林业中已使用的NNT数量比以前想象的要多，但相对而言，只有极少数物种在面积方面具有重要意义，主要是在西欧国家。与NNT有关的多样化，混合和避免入侵是日程上相对较新的必需品。相反，主要NNT的来源研究已经进行了数十年，现在为适应气候变化提供了重要信息。尽管通过法律限制或森林认证在整个欧洲使用NNT的限制存在很大差异，但将一系列经过测试的NNT仔细整合到未来的森林管理规划中，仍然显示出适应和缓解气候变化的巨大潜力。