Promoting resilience of UK tree species to novel pests and pathogens: ecological and evolutionary solutions

灰树枯萎病等例子清楚地表明，我们的树木面临着来自新病虫害的严重威胁。由于树木无处不在，是我们风景中备受喜爱的部分，是我们经济的重要组成部分，也是我们生物多样性的重要组成部分，它们的丧失会带来严重的后果。然而，应对每一个新的威胁都是困难、昂贵的，而且可能是徒劳的，因为威胁的演变速度可能比它们的树宿主快得多。此外，树木健康不仅关乎单一的病虫害，还关乎在正确的地方种植树木，关乎保持种群规模，关乎确保树苗有机会生长，关乎允许森林随着环境变化而改变。因此，为了找到保持树木健康的可持续的长期战略，我们需要考虑树木面临的一系列现实和潜在的威胁，并试图共同应对这些威胁。与此同时，我们需要问一问，改变我们种植树木的方式可能是什么：我们现在如何利用树木，未来我们希望从我们的树木中得到什么，我们愿意接受多少变化？通过找到一个中间地带，将最好的生物学知识与对可能的适应方式的清楚了解结合在一起，我们可以给我们的树木提供尽可能好的机会来抵御新的威胁。找到一种方法来做到这一点的最重要的部分是将许多不同的人群和不同类型的知识聚集在一起。关于我们的许多树木，人们已经知道了很多，但通常这些知识来自不相关的独立研究，很少有一项研究的结果能告诉我们另一项研究的情况，即使是同一树种。需要更好的协调。为了说明如何做到这一点，我们打算以苏格兰松为例，这是一种重要的本土树种。对于苏格兰松树，我们知道有几个严重的威胁，要么就在这里，要么可能很快到达英国。剩下的原生苏格兰松林很小，而且分散，但我们知道它们适应了当地的环境：所以来自这个国家一个地区的松树生长的方式与另一个地区的不同。在英国的许多地方都有大型的苏格兰松园--种植的数量是当地森林遗骸的十倍--而且这些松园的密度往往比自然中发现的要高得多，而且往往与来自世界其他地区的松树种植园并驾齐驱。该物种也有很强的文化依恋；在许多地方，松树被重新种植，它经常被用作花园或市容树。我们的项目旨在衡量对苏格兰松树的威胁有多大的可变性和适应性，测试树种对这些威胁的抵抗力有多大，并找到方法让人们参与到更健康的松林中来。通过这样做，我们的目的也是为了展示如何为任何其他树种做同样的事情，并为完成这一任务提供工具。我们将重点关注对苏格兰松树的三个重要威胁--Dothistroma针叶枯萎病、松树细长蛾和松树沥青溃烂病。我们将召集一群科学家--生态学、树木遗传学、森林病理学、植物生物化学、真菌生态和进化以及社会科学的专家--他们将共同研究同样精心挑选的松树。这项工作将告诉我们，英国苏格兰松树的种群数量有多大的变化，它可以在一代又一代之间变化多少；威胁的种群是如何增长和变化的；以及可以做些什么来使我们的松林更具弹性。我们将从作物农业中吸取经验教训，几代人都面临着类似的问题，并将这些经验用于寿命更长的树木和森林。最后，通过与与树木打交道和使用树木的人以及普通公众交谈，我们将找到利用这些信息的方法，使情况发生改变。

It has been made clear by examples such as Ash Dieback, that our trees face a serious threat from new diseases and pests. As trees are everywhere and are well-loved parts of our landscape, an important part of our economy and an essential part of our biodiversity, their loss has serious consequences. However, dealing with each new threat as it comes along is difficult, expensive and potentially futile as threats can evolve so much faster than their tree hosts. Also, tree health is not just about a single pest or disease, but about growing trees in the right place, about keeping population sizes up, about ensuring seedlings get a chance to grow and about allowing forests to change as the environment changes. So, in order to find a sustainable long-term strategy for keeping our trees healthy, we need to consider the range of real and potential threats that trees face and try to deal with these together. At the same time, we need to ask what is possible for changing the way we grow trees: how do we use trees now, what do we want from our trees in the future, and how much change are we willing to accept? By finding a middle ground, that brings together the best biological knowledge with a clear understanding of the possible ways to adapt, we can give our trees the best possible chance of withstanding new threats.The most important part of finding a way to do this is bringing together many different groups of people, and different types of knowledge. A lot is known about many of our trees already, but usually this knowledge comes from unlinked, independent studies and rarely do results from one study tell us something about another, even for the same tree species. Much better coordination is needed. To show how this can be done, we aim to use the example of Scots pine, an important native tree species. For Scots pine, we know of several serious threats that are either here or are likely to reach the UK soon. The remaining native Scots pine forests are small and fragmented, but we know that they are adapted to their local environments: so pine trees from one part of the country grow differently than those from another. There are large plantations of Scots pine in many parts of the UK - there is ten times as much planted as remains in the native forests - and these are often at much higher densities than are found in nature, and often alongside plantations of pines from other parts of the world. There is also a strong cultural attachment to the species; in many places pinewoods are being replanted and it is often used as a garden or amenity tree. Our project aims to measure how variable and adaptable are the threats to Scots pine, to test how much variation there is in the tree species in resistance to these threats, and to find ways to get people involved in making healthier pine forests. By doing this we also aim to show how the same thing can be done for any other tree species, and to put in place the tools for getting it done. We will focus on three important threats to Scots pine - Dothistroma needle blight, the pinetree Lappet moth and pine pitch canker. We will bring together a group of scientists - specialists in ecology, tree genetics, forest pathology, plant biochemistry, fungal ecology and evolution and social science - who will work together on the same, carefully chosen pine trees. This work will tell us how much the UK Scots pine population varies and how much it can change from generation to generation; how populations of the threats grow and change; and what can be done to make the pine forests we have more resilient. We will bring in lessons from crop agriculture, where similar problems have been faced for generations, and adapt these for trees and forests, that have much longer lifespans. Finally, by talking to people who work with and use trees, and the general public, we will find ways to use this information to make things change on the ground.