This is a good early sign that you’re looking at a walnut tree. People have long cultivated black walnut trees for their rich-tasting nuts and for hardwood. The bark does tend to stay on winter-cut trees better, though. The black walnut tree is native to the eastern United States. Don't take black walnut bark by mouth or apply it to the skin. Look out for: the leaflets which have toothed edges. The tree is over 35 years old (homeowner did not know how old the tree was, age is roughly the number of years she owned the house) and about 30 to 40 feet tall. The bark has deep ridges that, from a distance, resemble a diamond pattern. Inspect the tree bark for a deep, diamond pattern. If you remove a little of the gray outer bark from the trunk of a black walnut or English walnut tree, you'll see a rich chocolate brown color underneath. I do my tree cutting in fall or winter just because it's too freaking hot to do it now. If it’s wintertime and you can’t use leaves or fruit to identify a walnut tree, the tree's bark is a distinguishing characteristic. Crushed leaves have a strong smell. A mature black walnut can stand up to 75 feet tall and reach a spread of 60 feet. The walnut twig beetle was first associated with black walnut deaths in Colorado in 2001, and further investigation found that it carried a partner in crime – a newly identified fungus, geosmithia morbida. The splits are occurring on the trunk and branches. Being a dark wood, Walnut won't stain from fungal activity in summer the way lighter-colored woods do, so that's not a concern. To identify a black walnut tree, look at the leaves, nuts and bark. Identified in winter by: the segmented pith, or spongy tissue, inside the twig. The bark of black walnut trees can vary from dark brown to gray while butternuts have white-gray colored bark. Homeowner has a black walnut that is splitting on the south side of the tree. Black walnut bark is POSSIBLY UNSAFE. Black walnut is a large, broadleaf tree which can reach 30–40m high. The twig beetle penetrates the bark of the tree.. The tree gets its name from its dark, heavily ridged bark which occurs even when it is still young.