Woodlot management
After making yesterdays post and showing it to a friend, I got the question back “How can you have a wood lot, cut it down and expect it to regenerate itself?”
Here is my simple explanation of how it works. I am not an arborist so some of the terminology may not be pure of explanation, but it will give you the gist.
In forestry management there are 2 techniques used to cut timber and allow the root stock to regenerate. “coppicing” and “pollarding”. Both of these techniques are used by savvy gardeners so they can enjoy the foliage of what would become a massive tree in a manageable and renewable way.
Both of these techniques result in regrowth from the stump of a felled tree. Depending on the species in the woodlot, these processes may be carried out many times with a typical loss of 10% of stumps each time the lot is cut. Cutting can be timed to suit the use of the timber, for firewood 15cm diameter trunks may be ideal, for lumber the trunks may be allowed to grow larger to ensure good straight wood can be processed from the trunks.
We are hoping 5 years between cuts will give us good sized firewood and allow us to maintain the woodlot sustainably.
It is important to make any cuts to the trunks at an angle so water does not pool on the cut stump which can encourage rot in the timber.
Pollarding
This technique involves felling the tree in a traditional manner, leaving half a metre or more of the stump. What then happens is dormant buds in the bark of the stump shoot new growth and these eventually become the new trunks of the regenerated tree.
Careful selection of the shooting growth is then done and the strongest 3-4 are allowed to continue growing while the weaker shoots are smashed off the trunk with a blunt instrument. These are not cut, since the clean cut would encourage more shoots to start from this point.
The disadvantage to pollarding is the resultant growth can be extremely unstable and easily broken away from the trunk. The advantage is in areas with a lot of frosts the buds are higher from the ground and may be more likely to survive.
Coppicing
With coppicing the tree is cut as close as practical to the ground, preferably with no more then 15 cm of the trunk remaining. Again, dormant buds in the bark will shoot and new trunks for the tree will be formed.
Elimination of all but 3-4 of the new shoots happens in an identical way for the same reasoning.
The disadvantage to coppicing is the new shoots are more likely to suffer in frosts and also more likely to be eaten by wildlife. The major advantage is the remaining trunks are stronger than with pollarding and a tree subject to coppicing generally survives more generations of regrowth.
Major advantage of both techniques
Both techniques allow for quick regrowth off of the cut stump. While some root die back will occur, the large root system of the original tree allows for quick water and nutrient uptake into the new trunks. Growth is quick and vigorous.
Major disadvantage of both techniques
The downside to both comes from the ability to regrow new trunks with amazing vigour. Soil nutrient is very quickly depleted around the root zone and heavy applications of manure and mulch to replenish these is required.
So for those who were also curious about just how a woodlot can be regenerated I hope my lay-mans explanation has answered your questions.