林冠间隙和相关的生物量损失——结合无人机图像和亚马逊中部森林的野外数据

IF 3.9 2区 地球科学 Q1 ECOLOGY Biogeosciences Pub Date : 2023-09-13 DOI:10.5194/bg-20-3651-2023
Adriana Simonetti, Raquel Fernandes Araujo, Carlos Henrique Souza Celes, Flávia Ranara da Silva e Silva, Joaquim dos Santos, Niro Higuchi, Susan Trumbore, Daniel Magnabosco Marra
{"title":"林冠间隙和相关的生物量损失——结合无人机图像和亚马逊中部森林的野外数据","authors":"Adriana Simonetti, Raquel Fernandes Araujo, Carlos Henrique Souza Celes, Flávia Ranara da Silva e Silva, Joaquim dos Santos, Niro Higuchi, Susan Trumbore, Daniel Magnabosco Marra","doi":"10.5194/bg-20-3651-2023","DOIUrl":null,"url":null,"abstract":"Abstract. Understanding mechanisms of tree mortality and the dynamics of associated canopy gaps is relevant for robust estimates of carbon balance in forests. We combined monthly RGB images acquired from an unoccupied aerial vehicle with field surveys to identify gaps in an 18 ha plot installed in an old-growth central Amazon forest. We measured the size and shape of gaps and analyzed their temporal variation and correlation with rainfall over a period of 28 months. We further described associated modes of tree mortality (i.e., snapping, uprooting and standing dead) and branch fall and quantified associated losses of biomass. In total, we detected 32 gaps either in the images or field ranging in area from 9 to 835 m2. Relatively small gaps (< 39 m2) opened by branch fall were the most frequent (11 gaps). Out of 18 gaps for which both field and image data were available, three could not be detected remotely. Gaps observed in the field but not captured on the imagery were relatively small and mainly formed by the fall of branches from live and standing dead trees. Our data show that ∼ 17 % of the tree-mortality and branch-fall events only affected the lower canopy and the understory of the forest and are likely neglected by top-of-the-canopy assessments. Regardless of the detection method, the size distribution was best described by a lognormal function for gaps starting from the smallest detected size (9 and 10 m2 for field and imagery data, respectively), and the Weibull and Power functions for gaps larger than 25 m2. Properly assessing associated confidence intervals requires larger sample sizes. Repeated field measurements reveal that gap area does not differ significantly among modes of tree mortality or branch fall in central Amazon forests, with the last contributing the least to biomass loss. Predicting mechanisms of gap formation based on associated area and biomass loss remains challenging, which highlights the need for larger datasets. The rate of gap area formation was positively correlated with the frequency of extreme rainfall events, which may be related to a higher frequency of storms propagating extreme rain and wind gusts. While remote sensing has proven to be an accurate and precise method for mapping gaps compared to field data (i.e., ground truth), it is important to note that our sample size was relatively small. Therefore, the extrapolation of these results beyond our study region and landscape shall be made cautiously. Apart from improving landscape assessments of carbon balance, regional information on gap dynamics and associated mechanisms of formation are fundamental to address forest responses to altered disturbance regimes resulting from climate change.","PeriodicalId":8899,"journal":{"name":"Biogeosciences","volume":"26 1","pages":"0"},"PeriodicalIF":3.9000,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Canopy gaps and associated losses of biomass – combining UAV imagery and field data in a central Amazon forest\",\"authors\":\"Adriana Simonetti, Raquel Fernandes Araujo, Carlos Henrique Souza Celes, Flávia Ranara da Silva e Silva, Joaquim dos Santos, Niro Higuchi, Susan Trumbore, Daniel Magnabosco Marra\",\"doi\":\"10.5194/bg-20-3651-2023\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Abstract. Understanding mechanisms of tree mortality and the dynamics of associated canopy gaps is relevant for robust estimates of carbon balance in forests. We combined monthly RGB images acquired from an unoccupied aerial vehicle with field surveys to identify gaps in an 18 ha plot installed in an old-growth central Amazon forest. We measured the size and shape of gaps and analyzed their temporal variation and correlation with rainfall over a period of 28 months. We further described associated modes of tree mortality (i.e., snapping, uprooting and standing dead) and branch fall and quantified associated losses of biomass. In total, we detected 32 gaps either in the images or field ranging in area from 9 to 835 m2. Relatively small gaps (< 39 m2) opened by branch fall were the most frequent (11 gaps). Out of 18 gaps for which both field and image data were available, three could not be detected remotely. Gaps observed in the field but not captured on the imagery were relatively small and mainly formed by the fall of branches from live and standing dead trees. Our data show that ∼ 17 % of the tree-mortality and branch-fall events only affected the lower canopy and the understory of the forest and are likely neglected by top-of-the-canopy assessments. Regardless of the detection method, the size distribution was best described by a lognormal function for gaps starting from the smallest detected size (9 and 10 m2 for field and imagery data, respectively), and the Weibull and Power functions for gaps larger than 25 m2. Properly assessing associated confidence intervals requires larger sample sizes. Repeated field measurements reveal that gap area does not differ significantly among modes of tree mortality or branch fall in central Amazon forests, with the last contributing the least to biomass loss. Predicting mechanisms of gap formation based on associated area and biomass loss remains challenging, which highlights the need for larger datasets. The rate of gap area formation was positively correlated with the frequency of extreme rainfall events, which may be related to a higher frequency of storms propagating extreme rain and wind gusts. While remote sensing has proven to be an accurate and precise method for mapping gaps compared to field data (i.e., ground truth), it is important to note that our sample size was relatively small. Therefore, the extrapolation of these results beyond our study region and landscape shall be made cautiously. Apart from improving landscape assessments of carbon balance, regional information on gap dynamics and associated mechanisms of formation are fundamental to address forest responses to altered disturbance regimes resulting from climate change.\",\"PeriodicalId\":8899,\"journal\":{\"name\":\"Biogeosciences\",\"volume\":\"26 1\",\"pages\":\"0\"},\"PeriodicalIF\":3.9000,\"publicationDate\":\"2023-09-13\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Biogeosciences\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.5194/bg-20-3651-2023\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ECOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biogeosciences","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.5194/bg-20-3651-2023","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 0

摘要

摘要了解树木死亡的机制和相关林冠间隙的动态变化对森林碳平衡的可靠估计具有重要意义。我们将从无人飞行器获得的每月RGB图像与实地调查相结合,以确定位于亚马逊中部原始森林的18公顷地块的缝隙。我们测量了裂缝的大小和形状,并分析了它们在28个月期间的时间变化及其与降雨量的相关性。我们进一步描述了树木死亡的相关模式(即折断、连根拔起和枯死)和树枝脱落,并量化了相关的生物量损失。我们总共在图像或野外检测到32个缺口,面积从9到835 m2不等。相对较小的间隙(<39 m2)被枝落打开最多(11个)。在现场和图像数据都可用的18个缺口中,有3个无法远程检测到。在野外观测到但未被图像捕捉到的裂缝相对较小,主要是由活树和站立的死树的树枝掉落形成的。我们的数据显示,约17%的树木死亡和树枝倒下事件仅影响森林的下层冠层和林下植被,可能被冠层顶部评估所忽略。无论采用何种检测方法,对于从最小检测尺寸(野外和图像数据分别为9和10 m2)开始的间隙,用对数正态函数描述尺寸分布是最好的,对于大于25 m2的间隙,用Weibull和Power函数描述。正确评估相关的置信区间需要更大的样本量。重复的野外测量表明,在亚马逊中部森林中,树木死亡或树枝脱落的模式之间的间隙面积没有显着差异,最后一种对生物量损失的贡献最小。基于相关面积和生物量损失预测林隙形成机制仍然具有挑战性,这突出了对更大数据集的需求。间隙区形成速率与极端降雨事件发生频率呈正相关,这可能与暴雨传播极端降雨和阵风的频率较高有关。虽然与实地数据(即地面真实值)相比,遥感已被证明是一种准确而精确的测绘缺口方法,但重要的是要注意,我们的样本量相对较小。因此,将这些结果外推到我们的研究区域和景观之外,需要谨慎。除了改善碳平衡的景观评估外,关于林隙动态和相关形成机制的区域信息对于解决森林对气候变化引起的干扰制度改变的反应至关重要。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
查看原文
分享 分享
微信好友 朋友圈 QQ好友 复制链接
本刊更多论文
Canopy gaps and associated losses of biomass – combining UAV imagery and field data in a central Amazon forest
Abstract. Understanding mechanisms of tree mortality and the dynamics of associated canopy gaps is relevant for robust estimates of carbon balance in forests. We combined monthly RGB images acquired from an unoccupied aerial vehicle with field surveys to identify gaps in an 18 ha plot installed in an old-growth central Amazon forest. We measured the size and shape of gaps and analyzed their temporal variation and correlation with rainfall over a period of 28 months. We further described associated modes of tree mortality (i.e., snapping, uprooting and standing dead) and branch fall and quantified associated losses of biomass. In total, we detected 32 gaps either in the images or field ranging in area from 9 to 835 m2. Relatively small gaps (< 39 m2) opened by branch fall were the most frequent (11 gaps). Out of 18 gaps for which both field and image data were available, three could not be detected remotely. Gaps observed in the field but not captured on the imagery were relatively small and mainly formed by the fall of branches from live and standing dead trees. Our data show that ∼ 17 % of the tree-mortality and branch-fall events only affected the lower canopy and the understory of the forest and are likely neglected by top-of-the-canopy assessments. Regardless of the detection method, the size distribution was best described by a lognormal function for gaps starting from the smallest detected size (9 and 10 m2 for field and imagery data, respectively), and the Weibull and Power functions for gaps larger than 25 m2. Properly assessing associated confidence intervals requires larger sample sizes. Repeated field measurements reveal that gap area does not differ significantly among modes of tree mortality or branch fall in central Amazon forests, with the last contributing the least to biomass loss. Predicting mechanisms of gap formation based on associated area and biomass loss remains challenging, which highlights the need for larger datasets. The rate of gap area formation was positively correlated with the frequency of extreme rainfall events, which may be related to a higher frequency of storms propagating extreme rain and wind gusts. While remote sensing has proven to be an accurate and precise method for mapping gaps compared to field data (i.e., ground truth), it is important to note that our sample size was relatively small. Therefore, the extrapolation of these results beyond our study region and landscape shall be made cautiously. Apart from improving landscape assessments of carbon balance, regional information on gap dynamics and associated mechanisms of formation are fundamental to address forest responses to altered disturbance regimes resulting from climate change.
求助全文
通过发布文献求助,成功后即可免费获取论文全文。 去求助
来源期刊
Biogeosciences
Biogeosciences 环境科学-地球科学综合
CiteScore
8.60
自引率
8.20%
发文量
258
审稿时长
4.2 months
期刊介绍: Biogeosciences (BG) is an international scientific journal dedicated to the publication and discussion of research articles, short communications and review papers on all aspects of the interactions between the biological, chemical and physical processes in terrestrial or extraterrestrial life with the geosphere, hydrosphere and atmosphere. The objective of the journal is to cut across the boundaries of established sciences and achieve an interdisciplinary view of these interactions. Experimental, conceptual and modelling approaches are welcome.
期刊最新文献
Spatial and seasonal variability in volatile organic sulfur compounds in seawater and the overlying atmosphere of the Bohai and Yellow seas Root distributions predict shrub–steppe responses to precipitation intensity Geographically divergent trends in snow disappearance timing and fire ignitions across boreal North America Driving and limiting factors of CH4 and CO2 emissions from coastal brackish-water wetlands in temperate regions Temporary stratification promotes large greenhouse gas emissions in a shallow eutrophic lake
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
已复制链接
已复制链接
快去分享给好友吧!
我知道了
×
扫码分享
扫码分享
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1