Grand fir (GF) - Forest Research

Native range

Native to north-west USA and south-west Canada.

Provenance Choice

Provenances from coastal Washington should be preferred.

Site Requirements

A shade tolerant species which shows high growth rates and yields on suitable sites, but whose timber quality has a poor reputation. Best growth will be found in regions with more than 1000 mm rainfall, but will grow in drier regions provided there is adequate soil moisture. However, drought crack is common in stands in drier areas. Susceptible to spring frost and sensitive to exposure and pollution. Prefers well-drained and deep mineral soils of poor to medium fertility, but sensitive to heather check on sites of very poor nutrient status. Does not tolerate waterlogged or calcareous soils.

Pests and Pathogens

Generally shows appreciable resistance to decay by Heterobasidion (Fomes root and butt rot), although this may reflect the absence of H. abietinum (the fir form of the pathogen) from Britain. More recently, grand fir has proved susceptible to infection by Phytophthora ramorum, although only when grown in close proximity to other infected plants which are a major source of spores.

Occasional reports of infestation by balsam wooly aphid, and some trees may become severely infested and suffer dieback.

Use

A shade tolerant, fast growing species suited to regeneration or underplanting in continuous cover forestry. There is a growing recognition that it has a place in upland forest diversification and is consequently being more widely planted. A species that is unlikely to benefit greatly from climate change.

Grand fir is categorised as a Secondary tree species. These are species that have been planted on a much smaller scale than the principal species but are reasonably well understood and have demonstrated their suitability for forestry in terms of stem form, growth rate and hardiness under current conditions and so have potential for wider use in future.