Posted by Jon on February 11, 2009 at 12:58:31 user Jon.
In Reply to: Re: Sitka spruce (was: Four firs) posted by andyb on February 10, 2009 at 18:53:49:
May I ask for a clarification?
Are you asking why Sitka Spruce only grows close to the saltwater tideline in Canada while it grows wherever planted in the UK? If so, I suspect that the differing climates, geologies and associated topographies are major factors.
It's native to temperate rainforests, which, in the Pacific NW of North America, are generally coast-hugging. Once you get to higher elevations (and the area is famously mountainous) the conditions are less favourable both due to the temperature and to the steep terrain having a fairly shallow soil profile (side effect - can't hold as much water, which also would contribute to its unsuitability).
In the UK, the terrain is less rugged, the climate is more temperate, and elevations aren't as great, so it can flourish in moist, relatively level areas with a deeper soil profile.