Q+A: Apple Trees

We recently bought a farm with apple trees on it. The apples they yielded this year were full of bugs and blight of some kind. Some of the tree trunks seemed to have a kind of mould. I have pictures of the trunks.

In the first photo I see a couple things:

• First of all, what you described on the bark is lichen. It’s harmless, anchoring itself on bark, but taking nothing from the trees. Walking through the forest you’ll often see lichens. They’re actually a combination of two organisms, fungi and algae.
• Now the second thing I see in the first photo are some large cracks in the bark. These can come about through rapid changes in temperature (I’ve heard them referred to as frost cracks) or careless pruning that damages the tree.

In the second photo I see some careless pruning.

Look at the bough on the bottom left: You’ll see a short piece of branch extending outwards. It was pruned, but not all the way back to the trunk.

What happens when you don’t prune it back all the way is that this little stub can die, begin to rot, and, eventually the rot can reach trunk. If, on the other hand, you prune it back to the main branch, it will heal over. I see where a branch was properly pruned, towards the bottom right of the photo. See how the bark is beginning to grow over the cut? In time, it will completely cover it.

Photo three: main thing I see here is that there are lots of shoots that can be pruned out. As you read about fruit trees, you’ll see reference to the architecture of the tree. That means that you’re pruning so that branches don’t cross, and that the inside of the tree is fairly open, permitting movement of air and penetration of light.

Air movement helps minimize fungal diseases, while light helps colour up the apples.

Last photo: Lots of stubs from branches that weren’t pruned back all the way. Take the time to see how trees are pruned in a commercial orchard—then you can visualize what you want to achieve.

Steven Biggs
Gardener, Garden Writer, Garden Coach, Horticulturist

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