Scattered tree death contributes to substantial forest loss in California

Yan Cheng, Stefan Oehmcke, Martin Stefan Brandt, Lisa Rosenthal, Adrian Das, Anton Vrieling, Sassan Saatchi, Fabien Wagner, Maurice Mugabowindekwe, Wim Verbruggen, Claus Beier, Stéphanie Horion

Research output: Contribution to journalJournal articleResearchpeer-review

3 Citations (Scopus)
39 Downloads (Pure)

Abstract

In recent years, large-scale tree mortality events linked to global change have occurred around the world. Current forest monitoring methods are crucial for identifying mortality hotspots, but systematic assessments of isolated or scattered dead trees over large areas are needed to reduce uncertainty on the actual extent of tree mortality. Here, we mapped individual dead trees in California using sub-meter resolution aerial photographs from 2020 and deep learning-based dead tree detection. We identified 91.4 million dead trees over 27.8 million hectares of vegetated areas (16.7-24.7% underestimation bias when compared to field data). Among these, a total of 19.5 million dead trees appeared isolated, and 60% of all dead trees occurred in small groups ( ≤ 3 dead trees within a 30 × 30 m grid), which is largely undetected by other state-level monitoring methods. The widespread mortality of individual trees impacts the carbon budget and sequestration capacity of California forests and can be considered a threat to forest health and a fuel source for future wildfires.
Original languageEnglish
Article number641
JournalNature Communications
Volume15
Issue number1
Pages (from-to)1-13
ISSN2041-1723
DOIs
Publication statusPublished - 2024

Bibliographical note

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Keywords

  • Faculty of Science
  • tree mortality
  • droughts
  • deep learning
  • earth observations
  • climate extremes
  • carbon
  • California
  • USGS

    Yan Cheng (Visiting researcher)

    Jul 2023

    Activity: Visiting an external institution typesVisiting an external academic institution

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