Tree Crown Structure and Vascular Epiphyte Distribution in Sequoia sempervirens Rain Forest Canopies


Sequoia sempervirens
temperate rain forest

How to Cite

Sillett, S. (1999). Tree Crown Structure and Vascular Epiphyte Distribution in Sequoia sempervirens Rain Forest Canopies. Selbyana, 20(1), 76–97. Retrieved from


Crown structure and vascular epiphytes were studied in eight large (82-97 m tall, 3.3-7.2 m dbh) redwood trees (Sequoia sempervirens) in old-growth temperate rain forests, using rope-based methods of access. The trees had complex individualized crowns consisting of multiple (12-62 per tree) reiterated trunks arising from other trunks and branches. Trunk-to-trunk and trunk-to-branch fusions were common, and the diameter of a trunk above a fusion was often greater than below the fusion. Thirteen species of vascular plants, including a spike-moss, three ferns, four shrubs, and five trees, grew as epiphytes. Many of the species were accidental epiphytes whose primary habitat was the forest floor. They grew in deep humus accumulations on large branches and in crotches formed by multiple trunks. Three species dominated epiphyte assemblages. The deciduous fern Polypodium glycyrrhiza was abundant on two of the trees, where it was always restricted to lower crowns. The evergreen fern Polypodium scouleri, the most abundant vascular epiphyte, occurred in the upper and lower crowns of all eight trees. The ericaceous shrub Vaccinium ovatum also occurred on all eight trees but was abundant on only four trees with large quantities of decaying wood in their crowns. Polypodium ferns were more frequent on living branches, while ericaceous shrubs were more frequent on trunks and dead branches. Complex crown structure clearly promoted humus accumulation and vascular epiphyte abundance, but much of the tree-to-tree variation in epiphyte distribution was attributed to differences in tree age, stand-level microclimate, tree health, and dispersal limitations.


Open Access and Copyright Notice


Selbyana is committed to real and immediate open access for academic work. All of Selbyana's articles and reviews are free to access immediately upon publication. There are no author charges (APCs) prior to publication, and no charges for readers to download articles and reviews for their own scholarly use.  To facilitate this, Selbyana depends on the financial backing of the Marie Selby Botanical Gardens, the hard work and dedication of its editorial team and advisory board, and the continuing support of its network of peer reviewers and partner institutions.

Authors are free to choose which open license they would like to use for their work. Our default license is the Creative Commons Attribution-NonCommercial 4.0 (CC BY-NC 4.0). While Selbyana’s articles can be copied by anyone for noncommercial purposes if proper credit is given, all materials are published under an open-access license with authors retaining full and permanent ownership of their work. The author grants Selbyana a perpetual, non-exclusive right to publish the work and to include it in other aggregations and indexes to achieve broader impact and visibility.

Authors are responsible for and required to ascertain that they are in possession of image rights for any and all photographs, illustrations, and figures included in their work or to obtain publication or reproduction rights from the rights holders. Contents of the journal will be registered with the Directory of Open Access Journals and similar repositories. Authors are encouraged to store their work elsewhere, for instance in institutional repositories or personal websites, including commercial sites such as, to increase circulation (see The Effects of Open Access).