A global increase in tree cover extends the growing season length as observed from satellite records

Zhongxiang Fang, Martin Brandt, Lanhui Wang*, Rasmus Fensholt

*Corresponding author for this work

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    3 Citations (Scopus)
    49 Downloads (Pure)

    Abstract

    Plant phenology provides information on the seasonal dynamics of plants, and changes herein are important for understanding the impact of climate change and human management on the biosphere. Land surface phenology is the study of plant phenology across large spatial scales estimated by satellite observations. However, satellite observations (pixels) are often composed of a mixture of vegetation types, like woody vegetation and herbaceous vegetation, having different phenological characteristics. Therefore, any changes in tree cover presumably impact land surface phenology, as trees usually have a different seasonal cycle compared to herbaceous vegetation. On the other hand, changes in land surface phenology are often interpreted as a result of climate change-induced impacts on the photosynthetic activity of vegetation. Therefore, it is important to better understand the role of changes in vegetation cover (here, the proportion between tree and short vegetation cover) in satellite-derived land surface phenology analysis. We studied the impact of changes in tree cover on satellite observed land surface phenology at a global scale over the past three decades. We found an extension of the growing season length in 36.6% of the areas where tree cover increased, whereas only 20.1% of the areas where tree cover decreased showed an increase in growing season length. Furthermore, the ratio between tree cover and short vegetation cover was found to affect changes in the length of the growing season, with the denser tree cover showing a more pronounced extension of the growing season length (especially in boreal forests). These results highlight the importance of changes in tree cover when analyzing the impact of climate change on vegetation phenology. Our study thereby addresses a critical knowledge gap for an improved understanding of changes in land surface phenology during recent decades in the context of climate and human-induced global land cover change.

    Original languageEnglish
    Article number151205
    JournalScience of the Total Environment
    Volume806
    Issue numberPart 3
    Number of pages9
    ISSN0048-9697
    DOIs
    Publication statusPublished - 2022

    Bibliographical note

    Publisher Copyright:
    © 2021 The Authors

    Keywords

    • Global change
    • Land cover change
    • Land surface phenology
    • Length of season
    • Time series analysis
    • Vegetation composition

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