权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

DECOMPOSITION OF DEADWOOD DEBRIS LEFT OVER FROM TROPICAL RAINFOREST LOGGING OPERATIONS

热带雨林伐木作业留下的死木碎片的分解

基本信息

批准号：
NE/P002218/1
负责人：
Robert Ewers
金额：
$ 82.14万
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FP002218%2F1
关键词：
DECOMPOSITION DEADWOOD DEBRIS LEFT OVER

项目摘要

The widespread and rapid logging of tropical forests may mean their global carbon emissions have been underestimated because they do not fully account for the dead wood left behind. Living trees take in carbon dioxide whereas dead and decaying ones release it. It is the balance between these two processes that determines whether a large area of forest is a source of carbon dioxide, or a 'sink' that helps to absorb carbon dioxide from the atmosphere. Partially-logged tropical rainforests are probably emitting more carbon than assumed because they contain a high proportion of dead wood. Loggers will typically leave around one quarter of all the trees they cut, or that get damaged during logging operations, to rot in the forest. This dead wood can make up almost two third of the biomass, the biological material found above ground, in logged forests. Compare that proportion to untouched forests, where dead wood is created through natural processes, and where it makes up around 20 per cent of the total aboveground biomass. Around one third of all tropical forests have been logged and that proportion is increasing rapidly, meaning tropical forests contain much larger amounts of dead wood than previously thought. Learning how rapidly that dead wood will decompose is a key ingredient for calculating the carbon balance of tropical forests. And the carbon balance of forest could, in turn, hold the key to combating climate change.We don't know if dead wood in a logged forest will take longer to decompose than dead wood in an untouched forest, and getting that answer is a complicated business. Not only do we need to know how fast the dead wood left behind by the loggers will decompose, we also need to know how fast new pieces of dead wood are created. And logged forest creates a lot because the trees left behind in logged forests live and die faster than the trees the loggers take away, and when they die they turn into dead wood. One of the reasons these trees live and die so fast is that they have low wood density - their wood is relatively soft meaning it is fast to grow - and soft wood decomposes faster than hard wood so at first glance we would expect the dead wood in logged forests to decompose rapidly. But it's not so clear cut. One of the most important animal groups in tropical rainforests are termites, many of which are specialist dead wood eaters, and the amount of wood these millions of small animals munch their way through is one of the key reasons why decomposition happens so fast. Termites have very soft bodies and don't respond well to logging. Logging removes a lot of the forest canopy, opening it up to the sun and making the forest floor a hotter and drier place. Because of that, logged forests only have about one third the number of termites that you find in untouched forest and that, in turn, means dead wood might decompose much slower.This new research sets out to discover whether the high speed life and death of trees in logged forests counterbalances the loss of termites, or if one of these forces is stronger and outweighs the other. The answer is important. Protecting tropical forests is one of the most cost-effective ways for taking carbon dioxide out of the atmosphere. But by leaving behind large piles of dead wood, and potentially slowing the rate at which that dead wood decomposes, logging of those forests has the potential to render this key mechanism for combating climate change ineffective.

热带森林的广泛和快速砍伐可能意味着它们的全球碳排放量被低估了，因为它们没有完全考虑到留下的枯木。活着的树木吸收二氧化碳，而死亡和腐烂的树木释放二氧化碳。正是这两个过程之间的平衡决定了大片森林是二氧化碳的来源，还是帮助吸收大气中二氧化碳的“汇”。部分砍伐的热带雨林可能会排放比想象中更多的碳，因为它们含有很高比例的枯木。伐木者通常会留下大约四分之一的他们砍伐的树木，或者在伐木操作中受损的树木，让它们腐烂在森林中。这些枯木几乎占到了伐木森林中生物量的三分之二，生物量是在地面上发现的生物材料。将这一比例与未开发的森林进行比较，在原始森林中，枯木是通过自然过程产生的，占地上总生物量的20%左右。大约三分之一的热带森林被砍伐，而且这一比例正在迅速增加，这意味着热带森林中的枯木数量比之前想象的要大得多。了解枯木分解的速度是计算热带森林碳平衡的关键因素。反过来，森林的碳平衡可能是应对气候变化的关键。我们不知道伐木森林中的枯木是否会比未被破坏的森林中的枯木需要更长的时间才能分解，而要找到答案是一件复杂的事情。我们不仅需要知道伐木者留下的枯木分解的速度有多快，我们还需要知道新的枯木产生的速度有多快。而被砍伐的森林创造了很多东西，因为留在被砍伐森林中的树木比伐木者砍伐的树木活得更快，死亡的速度更快，当它们死亡时，它们就变成了枯木。这些树木生死如此之快的原因之一是它们的木材密度较低--它们的木材相对较软，这意味着它生长得很快--软木比硬木分解得更快，所以乍一看，我们预计伐木森林中的枯木会迅速分解。但这并不是那么明确。热带雨林中最重要的动物群体之一是白蚁，其中许多是专门吃死木材的动物，而这些数百万小动物咀嚼的木材数量是分解如此之快的关键原因之一。白蚁的身体非常柔软，对伐木反应不好。伐木去除了大量的森林树冠，使其暴露在阳光下，使森林地面变得更加炎热和干燥。正因为如此，被砍伐的森林中白蚁的数量只有你在未被破坏的森林中发现的大约三分之一，这反过来意味着枯死的木材可能会分解得更慢。这项新的研究旨在发现，被砍伐的森林中树木的高速生死是否抵消了白蚁的损失，或者是其中一种力量更强，而且比另一种力量更大。答案很重要。保护热带森林是将二氧化碳从大气中清除出去的最具成本效益的方法之一。但是，由于留下了大量的枯木，并有可能减缓枯木的分解速度，对这些森林的砍伐有可能使应对气候变化的这一关键机制失效。

项目成果

期刊论文数量（8）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Radial and vertical variation of wood nutrients in Bornean tropical forest trees

婆罗洲热带森林树木木材养分的径向和垂直变化

DOI：
10.1111/btp.13250
发表时间：
2023
期刊：
Biotropica
影响因子：
2.1
作者：
Inagawa T
通讯作者：
Inagawa T

Tropical forests post-logging are a persistent net carbon source to the atmosphere.

DOI：
10.1073/pnas.2214462120
发表时间：
2023-01-17
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
影响因子：
11.1
作者：
Mills, Maria B.;Malhi, Yadvinder;Ewers, Robert M.;Kho, Lip Khoon;Teh, Yit Arn;Both, Sabine;Burslem, David F. R. P.;Majalap, Noreen;Nilus, Reuben;Huasco, Walter Huaraca;Cruz, Rudi;Pillco, Milenka M.;Turner, Edgar C.;Reynolds, Glen;Riutta, Terhi
通讯作者：
Riutta, Terhi

Recovery of logged forest fragments in a human-modified tropical landscape during the 2015-16 El Niño.

DOI：
10.1038/s41467-020-20811-y
发表时间：
2021-03-09
期刊：
Nature communications
影响因子：
16.6
作者：
Nunes MH;Jucker T;Riutta T;Svátek M;Kvasnica J;Rejžek M;Matula R;Majalap N;Ewers RM;Swinfield T;Valbuena R;Vaughn NR;Asner GP;Coomes DA
通讯作者：
Coomes DA

The impact of logging on vertical canopy structure across a gradient of tropical forest degradation intensity in Borneo

婆罗洲热带森林退化强度梯度伐木对垂直冠层结构的影响