Liquidambar/sweet gum - competing leaders and potential rot in crotches

Question

We have a large, established liquidambar tree with many competing leaders (the trunk is ~1m (3') diameter but 2 m (6') from the ground it divides into 10 or so ~300 mm (12") diameter branches). I've attached some photos.

It dropped a large branch about 1 year ago, exposing some obvious rot in the branch crotch. We are worried because many of the remaining crotches collect a lot of leaves and debris--several containing damp soil when you dig down into it, and with saplings of some other species growing in the soil in the crotch. A few of these remaining branches would land on the house if they fell.

Other than this, the tree seems really healthy.

We would really like to keep the tree--it gives great seasonal shade and really sets the vibe of the whole property--but we also worry every time there's a strong wind.

Any advice on how best to manage the tree would be really appreciated. We've struggled to get a local arborists to assess the tree (the one who comes recommended isn't taking new work, and others seem to only quote for removal). For example:

• Should we be removing whatever soil, etc. we can from the crotches?
• Is there a way we can assess the extent of rot and risk?
• Is heavy pruning an option (one arborist told us removing the top of all leaders would stress the tree too much)?
• Is cabling, or some other reinforcement, an option?

Thanks very much in advance!

Answer 1

Absolutely do NOT top the tree, this will only make things worse. Kudos for contacting arborists; it's a crying shame that they're not helping you.

If this were my own tree, I'd cut off the limbs that have soil and rot in their crotches, exposing the rotten areas to the sun/air in an attempt to help stop the rot and allow the tree to compartmentalize the wounds. If there are a lot of these, I'd cut them off selectively over a few years, first cutting those that are the worst and then those that may fall on the house, leaving any that may fall "harmlessly" for last. This will dramatically change the look of the tree over time but may also save it.

I would do this pruning in the autumn, after the leaves have dropped.

If I remember correctly, the main issue with pruning a liquidambar is that it doesn't callus over the wound very quickly, and a lot of large open cuts on a tree isn't ideal for any tree. At this point, however, I don't think you have much choice.