Europe has a history rich in examples of successful and problematic introductions of trees with a native origin outside of Europe (non-native trees, NNT). Many international legal frameworks such as treaties and conventions and also the European Union have responded to the global concern about potential negative impacts of NNT that may become invasive in natural ecosystems. It is, however, national and regional legislation in particular that affects current and future management decisions in the forest sector and shapes the landscapes of Europe. We identified all relevant legal instruments regulating NNT, the different legal approaches and the regulatory intensity in 40 European countries (no microstates). Information on hard and effective soft law instruments were collected by means of a targeted questionnaire and consultation of international and national legislation information systems and databases. In total, 335 relevant legal instruments were in place in June/July 2019 to regulate the use of NNT in the investigated 116 geopolitical legal units (countries as well as sub-national regions with their own legislation). Countries and regions were empirically categorized according to ad hoc-defined legislation indicators. These indicators pay respect to the general bans on the introduction of non-native species, the generally allowed and prohibited NNT, approval mechanisms and specific areas or cases where NNT are restricted or prohibited. Our study revealed a very diverse landscape of legal frameworks across Europe, with a large variety of approaches to regulating NNT being pursued and the intensity of restriction ranging from very few restrictions on species choice and plantation surface area to the complete banning of NNT from forests. The main conclusion is that there is a clear need for more co-ordinated, science-based policies both at the local and international levels to enhance the advantages of NNT and mitigate potential negative effects.

中文翻译：

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绘制欧洲非本地树种的不完整立法景观图

欧洲拥有丰富的成功实例，介绍了欧洲以外的原生树种（非原生树种，NNT）的成功案例。许多国际法律框架，例如条约和公约，以及欧洲联盟，已经对全球对NNT的潜在负面影响的反应作出了回应，NNT可能会在自然生态系统中受到侵害。但是，尤其是国家和地区立法会影响森林部门当前和未来的管理决策并影响欧洲的景观。我们确定了监管NNT的所有相关法律文书，不同的法律方法以及40个欧洲国家（无微观国家）的监管强度。通过有针对性的调查表并与国际和国家立法信息系统和数据库进行协商，收集了关于硬法和有效软法文书的信息。总共有335项相关法律文书于2019年6月/ 7月制定，以规范NNT在被调查的116个地缘政治法律单位（国家以及拥有自己法律的次国家地区）中的使用。国家和地区根据经验进行了分类临时定义的立法指标。这些指标尊重关于引入非本地物种的一般禁令，普遍允许和禁止的NNT，批准机制以及限制或禁止NNT的特定领域或案例。我们的研究揭示了整个欧洲法律框架的情况非常多样化，正在采用多种方法来规范NNT，并且限制的强度从对物种选择和人工林表面积的极少限制到完全禁止森林中的NNT。主要结论是，显然需要在地方和国际层面上采取更加协调，基于科学的政策，以增强NNT的优势并减轻潜在的负面影响。