Acer palmatum, the Japanese maple tree, produces leaves prized for their striking colours in spring and fall. A number of varieties allows growers to choose from differing sizes of the tree.
A Japanese maple turning brown at the edges of the leaves may be suffering from leaf scorch, a condition caused by high temperatures and extreme wind combining to burn --- or scorch --- the leaves. The damage usually begins at the edge of the leaves, although the first symptom of the problem may be a browning of the veins of the leaf.
The problem is exacerbated in trees that are already stressed or suffering from poor hydration. "Older trees in poor sites, i.e. 'street trees,' will often show chronic leaf scorch as will any tree suffering from drought and/or a poor root system," advises the Purdue University Cooperative Extension Service.
Japanese maple leaves will often scorch in USDA hardiness zones 7b and 8 unless the tree is protected by shade and well-irrigated during times of drought. More direct sun can be tolerated in the northern part of the zones' range, according to the University of Florida.