Trait plasticity enables trees and shrubs to live as epiphytes throughout the coast redwood canopy

The radiation of plants into epiphytic niches has largely been studied by comparing closely related taxa that contain both epiphytic and terrestrial species. While these studies have led to important insights, they leave unanswered an important question - what traits allow for the initial colonization of the epiphytic niche? Our study addressed this knowledge gap in an old-growth coast redwood (Sequoia sempervirens) forest which has few obligate epiphytes but an abundance of accidental epiphytes. We measured structural and water relations traits in four woody species that are largely terrestrial but also commonly exist as epiphytes in the canopy of coast redwood forests: Vaccinium ovatum, V. parvifolium, Gaultheria shallon and Tsuga heterophylla. We also measured these traits on one obligate epiphytic fern Polypodium scouleri, and one obligate terrestrial fern, Polystichum munitum. Traits were measured across a height gradient from ground level to the upper canopy (68.9-92.4 m). We foun..., Site Description
Our study took place in Jedediah Smith Redwoods State Park in Northern California. This property contains ~10,000 acres of old-growth forest at the northern edge of the range of Sequoia sempervirens. The region experiences cool, wet winters followed by warm, dry summers. The average high temperature, in August, is 18.9º C and the average low temperature, in January, is 4 C (weather.gov).  Annual precipitation averages 1803 mm per year (weather.gov). In addition, forest vegetation intercepts coastal fog that frequently moves through this habitat; these inputs comprise approximately 30+% of the overall water budget (Dawson 1998). Since epiphyte colonization is often associated with the time that supporting architectural features have been in place, these groves support the greatest density of vascular epiphytes (Sillett 1999; Williams & Sillett 2007).
Nine old trees were chosen for this study. Diameter, which was measured a few meters above the ground at a height..., # Data from: Trait plasticity enables trees and shrubs to live as epiphytes throughout the coast redwood canopy

Dataset DOI: [10.5061/dryad.70rxwdc8j](https://doi.org/10.5061/dryad.70rxwdc8j)

## Description of the data and file structure

### Files and variables

#### File: Trait_averages_by_individual_2025.xlsx

The \"Trait_averages_by_individual_2025_dryad.xlsx\" file contains functional trait data (columns J-P) for several species of plants that live either as terrestrially or as accidental epiphytes in coast redwood trees. Below, find an explanation of each column heading

* ID= unique identifier for each plant

- Life form= category refering to whether the study individual was living on the ground or epiphytically

* Tree= Host tree #

- Taxon=Two letter abbreviation refering to the first letter of the genus and the first letter of the species. See published paper in Ecosphere for details

* Taxon 2=The only difference here is that PM and PS are grouped together as \"Fern\" 

- Ind=T...,