Douglas firs with severe needle reddening symptoms (Photo: S. Blaser, WSL)
Douglas firs with severe needle reddening symptoms (Photo: S. Blaser, WSL) The Douglas firs in Switzerland had a bad year: starting in mid-April 2023, foresters noticed conspicuously red-coloured needles. Investigations show that this is probably frost damage. Moreover, with the first discovery of invasive gall midges from North America in summer 2022, the list of Douglas fir pests has been extended further. This is reported in the new issue of Waldschutz Aktuell . The Douglas fir from North America is considered an important future tree species for Swiss silviculture, as it tolerates drought better than local conifers. However, it has been shown that it is quite susceptible to frost in spring. This spring, Forest Protection Switzerland received numerous reports of conspicuous reddening of the needles (Fig.
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