Winter is perfect time for gardeners to maintain trees with good pruning

There are many chores to do around the yard during the winter months.

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Many gardeners spend their time wishing it was spring so they could get started. But there are some aspects of gardening that are best done during winter.

One of these is pruning trees.

Trees are dormant in winter. Therefore, pruning them at this time will not cause the stress as pruning when they are actively growing. Before pruning, ask: Why, when, and how should a tree be pruned?

Pruning is the most common tree maintenance procedure. In a natural forest, trees grow well with little or no pruning. Some trees, such as pine trees, are self-pruning; when a branch doesn't get enough sunlight to produce food for the tree, the limb will die.

But in our landscapes, tree pruning is often desirable or necessary to remove dead branches, improve tree structure, enhance vigor or improve the safety of the tree.

But most pruning is done to satisfy us and not for the health of the tree. Trees in landscape or urban situations have stresses that trees growing in forest do not have. So, human safety and aesthetics dictate why a tree should be pruned.

Before going out and randomly pruning a tree, think about how that pruning cut is going to affect the tree. Improper pruning can cause damage that will remain with the tree. Changing the shape of the tree can be detrimental, as the reason most of these trees are selected for landscapes are the shape that they will have when they reach maturity.

Improper pruning cuts can lead to open wounds that let insects and decay organisms into the tree. Removing limbs removes foliage that produces food for the tree; therefore, it will slow down the tree's growth rate. At the same time, growth after pruning takes place on fewer shoots, so parts of the trees that were unpruned will grow more.

For most trees to maintain a good growth rate, at least 50 percent of their height should have limbs. For young trees, this percentage should be kept around 70 percent. The best time to train trees into a desired shape is when they are young. This is really true of fruit trees.

As I mentioned earlier, winter is the best time of the year to prune. But if the aim is to slow down the growth of trees, that can be accomplished by pruning in the fall before the tree goes dormant. Some gardeners will do this to their peach trees to make them dwarf trees.

Plant growth can be reduced if pruning is done at the first flush of growth in the spring. The tree has used a great deal of energy putting on new foliage and new shoots, and the removal of these shoots can stress the tree. Some species of trees will bleed greatly if pruned close to the time their buds swell. Maples and River birch will bleed. This bleeding has little or no affect on the growth of these trees, but it makes the tree look bad.

One of the biggest mistakes I see is improper pruning cuts. Pruning cuts should be made close to the branch collar. This is a raised area where the limb is attached to the trunk of the tree. This collar is where the growth will come from that will cover the wound made from pruning. Cutting into this collar can prevent the wound from healing properly, and insects and decay organisms can enter.

Almost as bad as cutting too close to the tree is cutting too far from the trunk, leaving a stub of a branch sticking out. I have seen these stubs up to a foot in length. The tree can't heal itself if a stub is left.

If the limbs being pruned are large, it is best to use a three-cut method of pruning. The first cut should be made on the bottom side of the limb 1 to 2 feet from the trunk of the tree. This cut is very important. Without it, the weight of the limb as it falls could peel the bark off the trunk of the tree. This first cut breaks the bark and prevents the tree from being damaged.

The second cut is made on the top of the branch slightly farther out on the limb. Once the limb is on the ground, make the last cut at the trunk, being sure to not damage the branch collar.

Remove dead limbs in the same manner as living limbs.

Once pruning cuts have been made, leave the tree alone. There is no need to paint or seal the wounds from pruning. Research has shown that painting or sealing the wounds slows down the healing of the tree.

Charles Phillips is a retired Columbia County Extension Service agent and operates Hort Consulting. He can be reached at cphillipshort@comcast.net.