Western hemlock: are we ignoring one of our most useful tree species

摘要

Recent damaging insect and fungal attacks on forest stands in Scotland have highlighted our reliance on a very limited range of commercial tree species and this has initiated discussion on the need to consider alternative species. Western hemlock (Tsuga heterophylla (Raf.) Sarg.) appears to have many of the attributes of a successful commercial timber-producing species. It is adaptable to a wide range of sites, has a good growth rate and desirable timber properties, regenerates freely, and to date has not succumbed to damaging biotic agents. However, western hemlock has a poor image within the forestry sector. This view may in part be based on experience of this species grown in open plantations at relatively wide spacings. In this review we suggestthat the silvicultural attributes of western hemlock are better suited to mixed species stands and irregular structures rather than planted pure on open sites. When grown under appropriate conditions, the evidence suggests that the mechanical and working properties of western hemlock timber are equivalent to, or superior than, other commonly grown species.