First of all I want to apologize to my blog followers for not getting a blog written in April. Life became a little too busy and there was no time to sit down and write a blog. This could happen again as there are some things happening that will keep me away from finding much time for some of the things I enjoy. Enough of this, lets move on to the topic of this blog. Back in January I wrote about thinning a softwood plantation. This time I would like to write about pruning white pine, which could easily be substituted for many other softwood or hard wood trees.
The first question you are probably asking yourself is, “Why bother to prune trees at all?” It is very time-consuming and a fair bit of hard work if you have a larger acreage of trees. I hope I can clearly answer the question of why pruning is a worthwhile thing to do. I will focus strictly on white pine for this blog. The main reason we prune pine is to create clear wood in the trunk or bole of the tree. When you go to a lumber store to buy pine lumber or pine wood products, you can usually buy it by grade. In the case of white pine, clear lumber with no knots is the most expensive grade to buy. In manufactuing clear pine has more value for making things like moulding for your house. These clear pieces are more stable and less likely to have any breakage. So if the clear lumber is more valuable then trees that have a higher precetage of knot free wood should also be more valuable.
Knots in lumber are formed from the branches of the tree as it is growing. The tree simply grows new wood each year and if there are branches the tree will grow around the branch and keep doing this as long as the branch is there. When the tree is sawn into lumber we see the encased branches as knots. Some species of trees “self prune” reasonably well but a little intervention can speed up the process. Quite simply we are trying to remove the lower branches as early as possible in the age of the tree. Once the lower branches are removed the tree will grow clear “white wood” with no knots in that part of the tree.
To get the best advantage of pruning it is best to start when the trees are still quite small. But only a few rows of branches can be removed at one time. The trees can be revisited every few years and a few more rows of lower branches can be removed. When the trees are small I like to keep at last 50% of the tree in “live crown”. In other words, do not remove branches more than halfway up the tree. As the trees get older this ratio can be reduced to 30% live crown.
Pruning is best done during the “dormant season”. For white pine in my area this would usually be from October until April Although I have done some smaller trees in May and perhaps even June. It is best if the pruning is done in the colder months as it is less likely to cause a disease entry point where the branch is removed. You should try not to cut too close to the trunk of the tree and be careful not to tear any of the bark. This could cause a decay problem at that point and degrade the lumber from the tree. As the branches get larger it is desirable to make a cut in the underside of the branch first. This will help prevent the bark on the trunk of the tree from tearing when the heavy limb falls.
When I begin pruning small trees I use hand pruners. It is worth buying a high quality pair which should last years and work much better than inexpensive ones. As the trees get taller and the branches larger I move to a pruning saw. You can purchase a small hand pruning saw, a saw with a medium length handle or for really tall trees, a telescoping handle pruning saw works well.
Previously, I had mentioned that the main reason for pruning lower branches is to create higher value wood. There are a couple of other possible reasons to prune white pine. White pine are susceptible to a fungal disease called White Pine Blister Rust. This disease is usually fatal to white pine if they get infected. One way to reduce the incidence of White pine blister rust is to prune the lower branches of the tree. In theory this creates better air flow and drier air around the trunk of the tree and seems to help reduce the incidence of this disease. A third reason to prune trees is purely aesthetics. There is something very appealing about looking up a tall straight tree with no branch for a long way up the tree. They seem to be just a little more majestic when they have a clean trunk with no branches.
There are many things to do in a woodlot to make improvements. Some can be to someday make more money from the sale of our timber or other products. Some small improvements are for aesthetics, which can be every bit as important as making more income for our woodlots. Pruning is just one of those little things that can be done, one tree at a time, to make a small improvement. There are lots of things I would like to write about in future blogs and I hope that many people find this site and find some value in it.
Until next time, keep safe and well.
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