A monoecious tree up to 40m tall, with a d.b.h. up to 1m when mature. Pyramidal when young and developing a very distinct open, candelabriform crown with a clear bole as it matures. Bark thick, light grey and often peeling in horizontal plates.
Adult leaves 1–2.5 x 1–2cm, lanceolate to ovate with an acute apex; stomata in bands at the base and apex of the leaf along the upper surface of leaf. Foliage usually clustered on small branches at the end of primary branches.
Female seed-cones up to 12cm long, terminal, borne on very short branches; bracts with prominent tips to 1cm; maturing January and February. Male pollen-cones 8–25cm long, terminal, maturing July to August.
A. montana can be confused with A. laubenfelsii, however, the different stomatal patterns on the upper leaf surface (seen through a hand lens) can be used to distinguish them. In A.montana they are only present at the base and apex of the leaf and are not organised in bands, whereas in A. laubenfelsii they are in intermittent rows organised into bands of 3–5 rows each and most of the rows extend throughout the length of the leaf, or at least from the base to the middle.