Trees to more than 20 m tall; trunk to 1 m (or more) d.b.h.; bark reddish brown to light grayish brown, thin, flaking in long strips; crown ovoid-pyramidal when young, broadly rounded or irregular when old. Leaves 1-3 mm, apex bluntly pointed; facial leaves rhomboid, with a conspicuous, linear, glandular groove at center abaxially; lateral leaves overlapping facial
ones, boat-shaped, ridged, apex slightly incurved. Pollen cones yellowish green, ovoid, 2-3 mm. Seed cones when immature bluish green, subglobose, ca. 3 mm in diam., when ripe reddish brown, subovoid, 1.5-2(-2.5) × 1-1.8 cm; proximal 2 fertile cone scales 2-seeded, distal 2 fertile scales 1-seeded. Seeds grayish brown or purplish brown, ovoid or subellipsoid, 5-7 × 3-4 mm, slightly ridged. Pollination Mar-Apr, seed maturity Oct.
Platycladus orientalis is most probably a species of the transitional open woodland zone between the steppes of Inner Mongolia and the deciduous oak, oak-birch, and oak-pine forests of NE China. Even within its natural range it is now almost invariably found in secondary vegetation or, nearest to its original habitat, in more or less degraded woodland and forest. As a pioneer species which is relatively long-lived, it can dominate certain slopes for a long time if further disturbances remain absent. Elsewhere it grows together with Pinus tabuliformis, less frequently with P. armandii and Juniperus rigida; Betula chinensis and Populus tremula are followed in the succession by Quercus spp. (some of which may be evergreen) and Castanea. The most arid and steepest slopes may only be covered with Pinus tabuliformis and Platycladus, accompanied by Juniperus rigida and other shrubs, and this vegetation may not represent a seral type, but an edaphically determined climax. The climate in NE China is above all characterized by very cold winters. As a pioneer of relatively dry, open vegetation on often unstable slopes, P. orientalis has found abundant opportunity over much of China, and even beyond (e.g. NE Iran), to establish itself and spread after introduction. It is much used in afforestation in NE and Central China and commonly planted in Central Asia. Buddhism has been instrumental in its spread especially in the SW of China, where it can be abundant on steep slopes of river valleys, but is usually never very far from settlements, monasteries or temples