Larch Disease

Greyhen in a larch - picture from Wikipedia, obviously...
Greyhen in a larch – picture from Wikipedia, obviously…

Interesting rumours beginning to come through of a massive cull of Galloway larch trees as a result of the major phytophthora outbreak which has taken place in the Galloway Forest Park. I posted about this a few months ago when I came across a huge area of dead larches on the Border between Galloway and Ayrshire.

In an attempt to control the spread of this hugely destructive water mould, the forest authorities are apparently seeking the destruction of what will amount to tens of thousands of hectares of larch trees, in addition to the huge amount that has already been killed. Larch is a particular species of concern for foresters since it transmits the dangerous spores to other trees, unlike most other plant species which merely die and have a limited infection capacity. As a result, the tree is called a “sporulating host”, sharing this ability to infect and transmit phytophthora spores with rhododendron and (worryingly) blaeberry.

Aside from the logistical enormity of felling millions of trees, there will be huge knock-on effects for supposed “forest” species like black grouse. Although I remain totally unconvinced that commercial woodland has any real value for black grouse whatsoever, larch trees are one of a few mitigating factors which have meant that birds can get some value from plantations. Despite the fact that larches are not native to Britain, they have been here for centuries. Peter Hawker shot black grouse from a stand of larch trees above Moffat during the early 1800s, and the link between blackgame and larches is nothing new. Greyhens use the larch buds before laying in the spring, and the fresh, emerging needles are a welcome nutritional addition to the all-important moss crop which appears in March and April. Blackcock are also fond of the fresh shoots, and I have seen birds using younger trees with great enthusiasm.

Add to this the fact that larches are deciduous, allowing some growth to persist beneath their branches. Heather won’t really thrive under the shade of a larch, but the more shade tolerant berries sometimes manage to produce some forage, and there is something to be said for a young crop of larch trees, particularly during a cold winter’s day when the needles are off. On balance, it would be better to have willows or birches, but if it has to be a “commercially viable” softwood, larch is not the worst thing.

Aside from anything else, larches traditionally break up the relentless uniformity of sitkas, creating some all-important habitat edge in a world of straight lines and regimented planting. Unfortunately, their value decreases as the plantation matures, although they are never quite as useless as sitka spruce trees.

It will be very interesting to see what comes of the proposed larch cull in Galloway. Sadly, the future of black grouse in the south west of Scotland is now intrinsically bound to the vagaries of commercial forestry, and any decision made by the foresters will have far reaching effects on the few remaining birds. More will follow in due course.

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