Losing a branch through storm damage or from the weight of too much fruit can create unwanted gaps in the canopy. Cut Three in our Guide To Best Pruning Practice, is useful when you want to stimulate the growth of new shoots so that the tree can develop a replacement limb. This particular cut needs to come with a health warning, though, as it is the most misunderstood and misused pruning cut. Unlike Cut One, you will be pruning two-year or older wood so it is important to understand how the tree will respond.
The key point to grasp with Cut Three is old wood responds differently to one-year-old wood when pruned.
To understand why it responds differently (please note that the author is aware that some liberties have been taken with plant physiology in this explanation) imagine a four or five-year-old branch with smaller branches radiating off it each sprouting leaves. As these leaves suck up sap all the living tissue between the roots and those leaves can take advantage of the sap as it flows past. When a branch is pruned it needs sap to heal the cut. Because the leaves above the cut no longer exist, the tree responds by producing new growth to get the sap flowing again to heal the wound. Put another way, if you shut the M5 at junction 5, there will suddenly be lots more traffic on the A38 and surrounding roads.
This response can be very useful. Old trees can be reinvigorated by promoting new growth and young trees which have gaps in their framework branches can be encouraged to produce new shoots to work with. The number of shoots and how vigorous they are depends on a lot of factors, but the tree will produce new shoots however often these will be in unexpected places, such as half way down a bare branch or trunk. As a general rule, the older the wood you cut, the more new shoots you get and the nearer to the roots they are likely to appear. So in 2 or 3-year-old wood, you tend to get new growth right behind the cut.
Knowing when to use Cut Three is as important as understanding when not to use it. A common mistake – and tree surgeons who are not used to pruning apple trees do this a lot – is to reduce the canopy to a nice, neat, ball-shape by cutting the ends off branches as below.
If the wood is two years old or older the tree will respond by producing a mass of new vertical growth as it searches for light. The result is a tree which very rapidly is as tall as it used to be, but with masses of new growth producing no fruit and shading out the lower branches.
Another bad outcome from this cut occurs when a branch is not pruned back to the branch collar but is pruned leaving a stump. If the tree does not respond by pushing out new shoots – which can happen- the tissue gradually dies, and a characteristic “teardrop” shape hole appears. This is can cause the parent branch to fail catastrophically.
Summary for Cut Three
Why: To encourage new growth
How: Pruning older wood
Response: The branch will produce new shoots
When: Apples and Pears: in the winter
Stone fruits: Late spring or summer
Equipment: Secateurs, pruning saw or pole saw depending on the diameter of the branch