Can someone give me a quick lesson on scottish/northern english forestry and sitka problems? What issues with watercourses? What is the crop used for, pulp or timber. Only used to how things are here in Scandinavia. TIA.
Our silvicultural systems are completely different here, we grow trees on a relatively short rotation. A Sitka rotation here will be 40 years which is probably half (at least) the time of a rotation in Scandinavia. Sitka Spruce is (usually) so well suited to our conditions that it grows twice as fast. It’s frost hardy, relatively unpalatable and will grow with minimal effort by the forester. In short, it’s a safe bet. If you plant 100ha of SS, you’re quite likely to grow at least 80ha of viable product with minimal intervention and minimal risk. The main risk is windblow, so the intention is usually to let the tree get to MMI (maximum mean increment) and then fell it. That is, once it stops growing optimally, we clearfell and replant.
I don’t know much about Scandinavian forests but I think you have much smaller coupes to fell, much longer rotations and much older forests on much more stable ground.
Because we started off with mass expansion of forestry in the way that we did (finding a super fast growing crop and then treating it as you would a field of wheat) we’ve painted ourselves into a corner with what we can do with these forests. We’ve developed a processing industry that relies on uniform, quickly grown Sitka Spruce (which is used predominantly in building but also in paper, biomass etc) and it has shed (or never developed) the ability to process other species.
The silvicultural system that we use and the processing industry (demand for timber) means that we are (historically) driven to produce more and more of the same thing. This has numerous issues. Pests and Diseases are rife when you establish monoculture. A far bigger problem than deer for Sitka is pine weevil. A large clearfell area is ideal for promoting and sustaining very large populations of weevil and we have clearfell areas of 100ha in some parts. There is a risk of acidification of watercourses if too much of the catchment is planted with conifer forests because they take nitrogen out of the air and it washes off them into the watercourses. Too much shading of the riparian areas because of Sitka makes the water too cold and is thought to inhibit the success of fish populations.
I think the main issue with Sitka Spruce forestry is that it’s too profitable. It’s too much of a sure thing and it means that forestry investors want to maximise profits by maximising Sitka. It’s very hard for a forester to persuade a faceless investment company to reduce their profit and risk more of their capital to improve the diversity of their woodland. The investor will just move on to the next forestry company who will fight for every inch of Sitka that they can get. Even on the national forest estate, where diversity is actually very good, there is immense financial pressure to make profits.
As for how deer management fits into the picture, deer are a very immediate problem. You’ll have a forest sit for 30 years, accumulating a deer population because it isn’t at immediate risk, notwithstanding sika deer which can make a mess at any stage in the rotation as pointed out above.
The forester will only really ever consider the deer a problem when it comes to felling and restocking. We need to address the underlying high populations on a landscape scale.
Perversely, all of these factors are sometimes used to promote Sitka Spruce as the only thing that should be grown.
Deer will eat anything else that I plant.
I can’t sell any other type of timber.
Sitka Spruce is the only thing I can grow here.
As I said, painted into a corner.