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Tree of Heaven
The Tree of Heaven (Ailanthus Altissima) is a very common tree in the
in the upper midwestern part of the United States.
 
This is a good example of an impressive tree cultivated mainly for its lovely foliage. Its timber, pale brown, soft and weak, is rarely used. The flower spikes are lax, with only tiny blossoms, but the autumn fruits can clothe the dark green foliage in a brilliant cloth of gold.
Native to China, the tree of heaven was introduced to Europe, america and various subtropical countries about the middle of the eighteenth century. It soon became a popular tree for street, park and garden planting because it grows vigorously, tolerates town smoke and presents a rich exotic appearance that
suggests some warm 'tropic' land.
This is largely due to its huge compound leaves, which may reach a length of 24in on normal trees, or a full meter on coppiced shoots. Each leaf resembles a branch; it has up to fifty small side leaflets, plus a solitary one at its tip. When the leaves open very late in spring, they are bronze in color.
They soon turn dark green, and break up in autumn without changing color, leaving their midribs attatched, for a while, to the tree's real branches. Each leaflet has a short stalk and a broad base which bears two swellings or glands that serve no known purpose.
The flowers open in midsummer, in large, loose panicles of tiny white blossoms, all of one sex, though both sexes can occur on one tree. They have a rather acrid, unpleasant odor. Each blossom may be male, with ten stamens bearing yellow anthers, or female, with a central pistil.
They soon fade and the tree then attracts little attention until early autumn, when the large seed-wings turn from green to gold; at the same time the central zone of each wing, holding one small round seed, becomes a rich orange-crimson shade.
When the wind-borne seed sprouts next spring the wing remains attached to it, resting on the surface of the ground. A little shoot springs up, bearing two green, oval seed-leaves. These are succeeded by the first true leaves, which have only three leaflets each; larger and longer compound leaves follow.
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