首页|Monitoring tree-crown scale autumn leaf phenology in a temperate forest with an integration of PlanetScope and drone remote sensing observations

Monitoring tree-crown scale autumn leaf phenology in a temperate forest with an integration of PlanetScope and drone remote sensing observations

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  • NETL
  • NSTL
  • Elsevier
In temperate forests, autumn leaf phenology signals the end of leaf growing season and shows large variability across tree-crowns, which importantly mediates photosynthetic seasonality, hydrological regulation, and nutrient cycling of forest ecosystems. However, critical challenges remain with the monitoring of autumn leaf phenology at the tree-crown scale due to the lack of spatially explicit information for individual tree-crowns and high (spatial and temporal) resolution observations with nadir view. Recent availability of the PlanetScope constellation with a 3 m spatial resolution and near-daily nadir view coverage might help address these observational challenges, but remains underexplored. Here we developed an integration of PlanetScope with drone observations for improved monitoring of crown-scale autumn leaf phenology in a temperate forest in Northeast China. This integration includes: 1) visual identification of individual tree-crowns (and species) from drone observations; 2) extraction of time series of PlanetScope vegetation indices (VIs) for each identified tree-crown; 3) derivation of three metrics of autumn leaf phenology from the extracted VI time series, including the start of fall (SOF), middle of fall (MOF), and end of fall (EOF); and 4) accuracy assessments of the PlanetScope-derived phenology metrics with reference from local phenocams. Our results show that (1) the PlanetScopedrone integration captures large inter-crown phenological variations, with a range of 28 days, 25 days, and 30 days for SOF, MOF, and EOF, respectively, (2) the extracted crown-level phenology metrics strongly agree with those derived from local phenocams, with a root-mean-square-error (RMSE) of 4.1 days, 3.0 days and 5.4 days for SOF, MOF, and EOF, respectively, and (3) PlanetScope maps large variations in autumn leaf phenology over the entire forest landscape with spatially explicit information. These results demonstrate the ability of our proposed method in monitoring the large spatial heterogeneity of crown-scale autumn leaf phenology in the temperate forest, suggesting the potential of using high-resolution satellites to advance crown-scale phenology studies over large geographical areas.

Multi-scale remote sensingPhenocamHigh-resolution satelliteMODISIndividual tree-crownLeaf phenology

Wu, Shengbiao、Wang, Jing、Yan, Zhengbing、Song, Guangqin、Chen, Yang、Ma, Qin、Deng, Meifeng、Wu, Yuntao、Zhao, Yingyi、Guo, Zhengfei、Yuan, Zuoqiang、Dai, Guanhua、Xu, Xiangtao、Yang, Xi、Su, Yanjun、Liu, Lingli、Wu, Jin

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Univ Hong Kong, Sch Biol Sci, Pokfulam, Hong Kong, Peoples R China

Chinese Acad Sci, Inst Bot, State Key Lab Vegetat & Environm Change, Beijing, Peoples R China

Chinese Acad Sci, Inst Appl Ecol, Key Lab Forest Ecol & Management, Shenyang 110164, Peoples R China

Cornell Univ, Dept Ecol & Evolutionary Biol, Ithaca, NY USA

Univ Virginia, Dept Environm Sci, 291 McCormick Rd, Charlottesville, VA USA

Chinese Acad Sci, Inst Bot, State Key Lab Vegetat & Environm Change, Beijing, Peoples R China|Univ Chinese Acad Sci, Yuquan Rd, Beijing, Peoples R China

Univ Hong Kong, Sch Biol Sci, Pokfulam, Hong Kong, Peoples R China|Chinese Univ Hong Kong, State Key Lab Agrobiotechnol, Hong Kong, Peoples R China

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2021

10.1016/j.isprsjprs.2020.10.017

ISPRS journal of photogrammetry and remote sensing

ISPRS journal of photogrammetry and remote sensing

EISCI
ISSN：0924-2716
年,卷(期)：2021.171(Jan.)
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