Thinning to fatten profits
I find it very satisfying to see a farmer's forest thinned for the first time. Rather than trees going into the ground, it is good to see timber coming out of a forest - putting money in the farmer's pocket.
A first thinning will also set the forest up very nicely for the coming years: a good quality road into the forest has been created; by removing trees, more space has been provided for the remaining trees; and, above all, it will give you a pretty good idea of the quality of your crop and which trees need to be removed the next time.
Gradually removing these poorer quality trees over time will provide more growing space for the remaining better quality trees.
This will create a forest of fewer trees but of greater quality, size and biodiversity value.
In a forest that has been thinned throughout its life, there should be about 500 trees per hectare at the time of clearfell, with each tree having a volume of 0.7-0.8 m3.
This is twice the size of trees in an unthinned plantation. This results in a more valuable crop as larger trees command a much higher price. Not thinning will result in a larger number of smaller sized trees, with a likely reduction in crop value.
A question that I get asked several times a week is when does thinning need to take place? Well, I prefer to thin early, especially in the west of Ireland. This will help creating a more stable forest.
However, such advice is not very popular as it makes the thinning operation commercially less attractive for both the farmer and the contractor. First thinning of sitka spruce is usually carried out when trees are between 10 and 12 metres in height. In a strong-growing crop, this can be as early as 13 to 15 years, while it can also be as late as 22 to 24 years on a less productive site.