Why has my crab apple tree split?

Karen Bowden, by email

Stefan says: Your fairly young crab apple tree has suddenly developed a very bad split in the bark. Apparently, the tree already has several small splits, though the leaves seem to be all right and some small fruits are developing. You wonder if you should be worried.

This is certainly dramatic, so let’s look on the bright side first. No pest or disease has caused this and my suspicion is that it is a response to this season’s extraordinary weather, with the extremely hot and dry conditions and possibly the alternation of these conditions with either rainfall or the tree being watered. The danger is that fungal infection may now gain entry to the stem. I suggest you use hoops of strong tape – like duct tape – to bind the bark in place, then ensure the tree has plenty of water in the hope it will develop wound-healing tissues.