Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in Europe: an overview of management practices

Abstract

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), one of the most commercially important tree species in western North America and one of the most valuable timber trees worldwide, was introduced to Europe in 1827. It became a major species for afforestation in Western Europe after WWII, currently grows in 35 countries on over 0.83 million ha and is one of the most widespread non-native tree species across the continent. A lower sensitivity to drought makes Douglas-fir a potential alternative to the more drought-sensitive Norway spruce so its importance in Europe is expected to increase in the future. It is one of the fastest growing conifer species cultivated in Europe, with the largest reported dimensions of 2.3 m in diameter and 67.5 m in height. Pure stands have high productivity (up to 20 m3 ha-1a-1) and production (over 1000 m3 ha-1). The species is generally regenerated by planting (initial stocking density from less than 1000 seedlings ha-1 to more than 4000 ha-1), using seedlings of European provenance derived from seed orchards or certified seed stands. As the range of end-uses of its wood is very wide, the rotation period of Douglas-fir is highly variable and ranges between 40 and 120 years. When the production of large-sized, knot-free timber is targeted, thinnings are always coupled with pruning up to 6 m. There is an increasing interest in growing Douglas-fir in mixtures and managing stands through close-to-nature silviculture, but the species’ intermediate shade tolerance means that it is best managed through group selection or shelterwood systems.

Beneficial effects of native broadleaved forests on canopy beetle diversity are not reduced by admixture of non‐native conifers

“…Here, we studied temperate forests in Germany, Central Europe, where plantations of Norway spruce (Picea abies (L.) H.Karst.) dominate forestry for several 100 years (Fuchs et al, 2022;Nicolescu et al, 2023). Although native in high-mountain areas in Germany, Norway spruce does not naturally occur in central European lowland regions, and many of those planted monocultures died due to high vulnerability against drought-stress events and subsequent bark beetle infestations (Fuchs et al, 2022).…”

“…In German forestry, Douglas fir was introduced in the 19th century and can be found all over the country (Nicolescu et al, 2023), but regulated planting of non-native tree species and established native conifer plantations prevented major economic importance of Douglas fir (Thomas et al, 2022). To assess the compatibility of such novel tree species mixtures with biodiversity conservation, we investigated the canopy beetle community in 40 plots of monospecific and mixed stands of European beech, Norway spruce and Douglas fir.…”

Assessing the growth response to climate of Douglas fir under European temperate oceanic conditions

“…It is best adapted to the temperate oceanic climate which is characterized by milder winters and wetter summer months than in its native region (Nicolescu 2019). The species is most productive when the mean annual temperature is between 7 and 11°C and when annual precipitation exceeds 750 mm (Nicolescu et al 2023). Growth is limited when the average summer temperature (June to August) is above 18°C, and precipitation during the same period is below 270 mm (Eckhart et al 2019).…”