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I have a group of 3 birch tree's in my backyard, Jacksonville, FL. Last year I noticed that there was a center section, on the entire group, that did not have leaves on the branches. I have River rocks at the base of the trees. This year there are only a few branches at the bottom and a few at the top that have leaves. The bare center section has gotten larger and spread higher up.

Last year when I was watering and noticed there were large air pockets by the roots. So, I pulled back the rocks and added 3 bags of top soil, watered well and replaced the rocks.

I also sprayed for Borer pests, without evidence of their existence. This year it is worse. However, there is new growth at the base of the trunk, on all 3.

1st Picture is 2022, 2nd is 2023.

I have tried to find an Arborist, but not one has returned my call or email.

What can I do to save these trees? Any ideas would be most appreciated. TIA

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    Birch borer typically kills from the top down, so you'd have dead branches at top and luxuriant growth on the bottom third of the tree before it eventually completely dies. If those are river birch (Betula nigra), then borer shouldn't be a concern anyway.
    – Jurp
    May 23, 2023 at 13:09

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It is possible that it's just the shading effect from each other. Perhaps they are just trying to get past the shade. The large trees do tend to form canopies in the wild. I have never grown birches in groups, only as feature plants, where they don't exhibit this behaviour.

I have planted Pinus Radiata and Acacia Melnoxylon, in groups to force them to grow taller. Once they are a certain height, you thin them, ie remove 75% of them. I have noticed that if I was a bit late, they suffered from what's called crown shyness, where the trees just bend away from each other, trying to get out of each other's shade.

I googled for studies and found this

A different hypothesis proposed that the buds of trees have light receptors to sense when nearing adjacent vegetation and stop growing to avoid getting too close. The avoidance of growing into neighboring trees is believed to be an adaptive response to maximize access to sunlight while minimizing the harmful effects of competition (Franco, 1988).

From Crown Shyness: When Trees Need Personal Space

It's only a theory but may account for it.

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  • Rohit, birch clumps are a "thing" in the US (redbuds are now also being sold in clumps). The behavior the OP is seeing is probably not a shade effect from the trees in the clump but COULD be a shade effect from the larger trees that are obviously shading the clump for at least part of the day (evidenced in the photo). So, +1
    – Jurp
    May 23, 2023 at 20:41
  • Thanks, truly appreciate the insight. I was also told that they need a lot of water and that might be the issue.
    – Don G
    May 23, 2023 at 23:41

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