The Commercial Forest Cycle

Grizedale is a working forest containing trees grown to produce timber and then harvested before the ground is re-planted.  As well as producing a steady supply of timber which generates income which helps to maintain the whole forest, this cycle of felling and replanting ensures that there is a range of habitats for many woodland species.  Not all of the forest is managed with timber production in mind, we create and manage broadleaf woodland for visitors and wildlife with large parts set aside as wildlife reserves.

So how does this cycle work?

The starting point:

Clear felled sites can look like areas of devastation but they are the starting point for new growth.  Following clear felling there is an opportunity to re-design the forest.  We can choose to replant conifer trees, to restore broadleaved woodland or to leave nature to decide upon the future of the site, if you want to know more about how we make this choice then check out this blog.  Whatever we choose to do, life quickly asserts itself on the clearfell site.  The felling of the trees means more light reaches the forest floor than in the past 50 years.  Ferns, grasses and wildflowers take advantage of this light and space and insects benefit from the new vegetation.  Eventually older stumps will be decomposed by fungi, in fact, next time you’re here check out the different fungi growing on the felled tree near the visitor centre.

Where replanting with conifers is planned, felled sites are left for 3 years before replanting. This allows the needles and branches left over from the felling to decay which provides nutrients for the next generation of young trees and makes planting easier.  Waiting for 3 years also protects the next trees to be planted from pine weevils, an insect pest which is very common in recently clear felled sites and damages young trees.  For species which are vulnerable to damage by deer, including Pines and Firs, fences are built to keep the deer out and prevent them from eating the young trees.

Planting:

Three years after clear felling a big excavator (digger) creates mounds that the trees will be planted into, that’s 2700 mounds per hectare.   These mounds provide good conditions for the tree and kills weeds saving us from using herbicides.  The mounds also make it easier fro the planters to plant.  .  Each tree is planted by hand using a small spade and a good planter can plant 2000 trees a day!  The young trees come from Forestry Commission nurseries in Yorkshire and Cheshire which may be grown from seeds collected from the forest here in Grizedale and are planted when they are dormant, between November and March.  We will be replanting a large area in March so keep your eye out for blogs about that which will include some photos of our work.

Checking up on young trees:

About 5% of trees die in the first year.  These dead trees will be replaced the following season, a process known as “beating up”.  After this, the crop doesn’t normally need any help for about 20 years.  Once the trees have been growing for 20 years, the decision may be taken to ‘thin’ the crop.  Thinning means taking out some of the weaker, smaller trees which gives the bigger trees more space to grow.  .  After a crop has been thinned once, it may then be thinned every five years or so for the rest of its life with each thinning resulting in larger and better quality trees.

Clear felling and extraction:

Conifer trees will typically be felled when they are between 45 and 70 years old, depending on the particular crop (called a ‘stand’).  This is the age at which they are most useful and valuable to the timber-using industries such as sawmills. Trees are cut down using a harvester, and are stacked up to be removed from the forest.  This brings us back to a clear felled site and the start of another forest cycle.

We hope that you might now see clear fell sites in a different light.  If you have any topics that you would like us to blog about then please let us know by posting a comment below or tweeting to us using @FCGrizedale