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Lars Eklundh

Professor

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Development of a method for monitoring of insect induced forest defoliation – limitation of MODIS data in Fennoscandian forest landscapes

Author

  • Per-Ola Olsson
  • Tuula Kantola
  • Päivi Lyytikäinen-Saarenmaa
  • Anna Maria Jönsson
  • Lars Eklundh

Summary, in English

We investigated if coarse-resolution satellite data from the MODIS sensor can be used for

regional monitoring of insect disturbances in Fennoscandia. A damage detection method based on

z-scores of seasonal maximums of the 2-band Enhanced Vegetation Index (EVI2) was developed.

Time-series smoothing was applied and Receiver Operating Characteristics graphs were used for

optimisation. The method was developed in fragmented and heavily managed forests in eastern

Finland dominated by Scots pine (Pinus sylvestris L.) (pinaceae) and with defoliation of European

pine sawfly (Neodiprion sertifer Geoffr.) (Hymenoptera: Diprionidae) and common pine sawfly

(Diprion pini L.) (Hymenoptera: Diprionidae). The method was also applied to subalpine mountain

birch (Betula pubescens ssp. Czerepanovii N.I. Orlova) forests in northern Sweden, infested by

autumnal moth (Epirrita autumnata Borkhausen) and winter moth (Operophtera brumata L.).

In Finland, detection accuracies were fairly low with 50% of the damaged stands detected, and

a misclassification of healthy stands of 22%. In areas with long outbreak histories the method

resulted in extensive misclassification. In northern Sweden accuracies were higher, with 75% of

the damage detected and a misclassification of healthy samples of 19%. Our results indicate that

MODIS data may fail to detect damage in fragmented forests, particularly when the damage history

is long. Therefore, regional studies based on these data may underestimate defoliation. However,

the method yielded accurate results in homogeneous forest ecosystems and when long-enough

periods without damage could be identified. Furthermore, the method is likely to be useful for

insect disturbance detection using future medium-resolution data, e.g. from Sentinel‑2.

Department/s

  • Dept of Physical Geography and Ecosystem Science
  • MERGE - ModElling the Regional and Global Earth system
  • BECC - Biodiversity and Ecosystem services in a Changing Climate

Publishing year

2016

Language

English

Publication/Series

Silva Fennica

Volume

50

Issue

2

Document type

Journal article

Publisher

Helsinki : Suomen metsätieteellinen seura, 1926-

Topic

  • Physical Geography

Status

Published

ISBN/ISSN/Other

  • ISSN: 2242-4075