Overview
Although not related to tree ferns, several other fern species in New Zealand can form short trunks.
Leptopteris hymenophylloides (single crape fern), L. superba (Prince of Wales feathers fern), Pneumatopteris pennigera (gully fern), Polystichum vestitum (prickly shield fern), Todea barbara, and Blechnum discolor (crown fern) all sometimes form trunks; in some cases to c. 1 m tall, but usually much less.
Blechnum fraseri regularly produces a trunk, but it is a smaller, daintier fern with shorter fronds than any of the above species. The trunk is very narrow and although it may occasionally reach 1.5 m tall, it is usually less than 0.5 m.