Answer: Based on your description I am not certain what is happening to your tree, however it sounds like it may be suffering from overly dry soil combined with summer heat. Birches require an evenly moist soil, and this is especially important during the first few years while the tree is rooting and becoming established. Make sure the soil is kept evenly moist like a wrung out sponge, not sopping wet and never dried out. Since I have not seen the tree, I would suggest you also consult with your local county extension for a more specific diagnosis. (There might be a contributing problem such as encircling roots, for example, or something unusual may have happened such as accidental chemical exposure.) If additional care is required, they should be able to make recommendations. Or, you could consult on site with a professionally trained and certified arborist with experience in ornamental trees. In the meantime, here is some general care information about birches that you may find helpful. You may need to cut and paste the complete url into your browser to make it work correctly.
Good luck with your tree.
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