NI: Lightning in African tropical forests: from tree mortality to carbon dynamics

树木在生长过程中从大气中吸收碳，但这些碳最终会在它们死亡时释放出来。热带森林中树木的绝对数量意味着这些生长和死亡速度的微小变化，以及由此导致的碳吸收或释放平衡的变化，可以对气候产生重大影响。虽然许多研究都集中在温度和降雨的变化如何影响热带森林树木的生长和死亡上，但闪电的潜在影响在很大程度上被忽视了。一项追踪巴拿马雷击的研究发现，雷击造成了一半以上的大树死亡，尽管巴拿马是世界上研究最深入的森林之一，但这一影响此前没有记录在案。这个项目将为评估闪电的强烈影响是否会成为一种更普遍的现象提供重要的步骤。与其他热带地区相比，非洲森林的特点是大树占主导地位，因此根据巴拿马的研究结果，预计非洲森林更容易受到闪电的袭击。或者，非洲的高频率闪电可能选择了能够更好地承受其影响的树木。了解闪电是否在各大洲具有一致的影响，对于确定未来的工作是否应该集中于了解闪电影响变化的原因，还是可以探索这些影响的更广泛的影响，是很重要的。新的国际合作者埃文·戈拉（Evan Gora）开发了一种通过无人机调查和后续徒步调查来检测闪电损害的方法，可以对大片森林进行调查。我们将这四家网站在一个戏剧性的梯度闪电的频率在艾伯丁裂谷(在刚果民主共和国的边界,卢旺达和乌干达)(1)测试是否在非洲的树木在不同网站或多或少容易被闪电比在巴拿马,(2)确定森林结构随闪电频率和(3)使用这些观测评估潜在的闪电对碳储量和动力学的影响。项目团队将在整个项目期间定期举行在线会议，所有人都将在卢旺达会面，接受戈拉的培训，学习如何检测闪电损害，团队的一部分人也将在实地工作后在英国会面。总的来说，随着项目的发展，这些会议提供了相当大的空间来分享想法，最终形成未来合作的五年计划。我们将通过定期举办一系列研讨会和圆桌讨论，寻求科学家和利益攸关方提供更广泛的意见，并将举办在线培训讲习班，以建立监测闪电对热带森林影响的能力。

Trees take in carbon from the atmosphere as they grow, but this is eventually released when they die. The sheer number of trees in tropical forests means that small changes in these rates of growth and death, and the resulting change in the balance of carbon taken in or released, can have a big effect on the climate. While a lot of research has focused on how changes in temperature and rainfall affects the growth and death of tropical forest trees, the potential effects of lightning have been largely neglected. A study tracking lightning strikes in Panama found that they caused more than half of all deaths of large trees, a previously undocumented effect despite being in one of the most intensively studied forests in the world. This project will provide important steps towards assessing whether this strong impact of lightning is a more widespread phenomenon. Forests in Africa are characterised by a greater dominance of large trees than elsewhere in the tropics, so based on results from Panama they would be expected to be more vulnerable to lightning. Alternatively, the high frequency of lightning in Africa may have selected for trees that are better able to withstand its effects. Knowing whether or not lightning has a consistent effect across continents is important for determining whether future work should focus on understanding the causes of variation in the impact of lightning, or can instead explore the wider implications these effects.The new international collaborator (Evan Gora) has developed an approach for detecting lightning damage from drone surveys and follow-up investigation on foot that allows large areas of forest to be surveyed. We will apply this at four sites along a dramatic gradient of lightning frequency in the Albertine Rift (on the boundary of the Democratic Republic of the Congo, Rwanda and Uganda) to (1) test whether trees at different sites in Africa are more or less vulnerable to being killed by lightning than those in Panama, (2) determine how forest structure varies with lightning frequency and (3) use these observations to assess the potential effect of lightning on carbon stocks and dynamics.The project team will have regular online meetings throughout the project, will all meet in Rwanda to receive training from Gora in how to detect lightning damage, and a subset of the team will also meet in the UK after fieldwork. Collectively, these meetings provide considerable space to share ideas as the project develops, culminating in a five-year plan for future collaboration. We will seek wider input from scientist and stakeholders through a regular series of seminars and roundtable discussions, and will hold online training workshops to build capacity in monitoring the effects of lightning on tropical forests.