Department of Biological Sciences (Humboldt State University)

Large spotted A. flavipunctatus are found in southern inland Mendocino and Lake counties. Photo by M. Mulks

Black Salamanders Show Biodiversity of Redwood Forest


The range of the black salamander (Aneides flavipunctatus) almost perfectly overlaps with the historic range of redwoods along the Central and Northern California coast. While most animals live on the Earth’s surface, this well-hidden amphibian travels mostly up and down in the rocks and soil. Its vertical approach to life comes in handy when the weather is hot or dry: the salamander moves deeper into the Earth until conditions are more to its liking. Learn more about this research.

Mill Creek. Photo by Evan Johnson

Thinning Speeds Recovery to Old-Growth


Dr. Christopher Keyes and Andrew Chittick have found that thinning—removing select trees in a second-growth coast redwood forest—speeds up the forest’s development of old-growth characteristics, which include tall and bulky trees, small gaps in the canopy through which sunlight can penetrate, trees of varying heights, thicker tree branches, understory shrubs and ferns, and healthy young saplings. Learn more about this research.

Photo by Miguel Vieira, Flickr Creative Commons

Big Trees: A Bank for Soil Bugs


Legacy trees, old-growth trees left standing in second-growth redwood forests, could serve as a habitat refuge for terrestrial microarthropods, miniscule bugs that live in the forest floor and maintain healthy soils, not to be confused with the bigger arthropods like spiders and bees. Dr. Michael Camann, Karen Lamoncha and Laura Hagenhauer have found substantially more and a wider variety of the soil bugs underneath these so-called legacy trees than beneath surrounding second-growth trees. Learn more about this research.

Wandering salamander. Photo by Dan Portik

Wandering Salamanders Choose Direct Route to Good Food


Wandering Salamanders (Aneides vagrans), in addition to dwelling on the ground, have been found in high-up patches of humus moss mats in trunk crotches, on limbs, under bark, and in the cracked and rotting wood of coast redwood trees. They may inhabit forest canopies, the researchers of this study speculate, because of a more profitable food resource available there. Learn more about this research.

Canopy view of Jedediah Smith Redwoods State Park. Photo by Stephen Sillett, Institute for Redwood Ecology, Humboldt State University

What limits redwood height?


In the upper reaches of their crowns, coast redwoods struggle to lift water and nutrients into their leaves. This struggle begins a process that limits tree growth, according to a team of researchers studying redwoods in Prairie Creek and Humboldt Redwoods State Parks.

The evergreen fern Polypodium scouleri grows in thick mats high above the ground. Photo by Stephen Sillett, Institute for Redwood Ecology, Humboldt State University

Sponge-like Mats Make Good Habitat in Redwood Canopies: Wandering Salamanders Benefit


Based on their research in Pairie Creek Redwoods State Park, Anthony Ambrose and Stephen Sillett have found that mats of humus soil deposited as high up as 265 feet in the crowns of coast redwood trees moderate the climate around them. This makes the mats habitable to a wide variety of insects and animals more commonly found on the forest floor. Learn more about this research.

Sitka Epiphytes.

Epiphytes Provide High-Up Base for Biodiversity


William Ellyson and Stephen Sillett found evidence that demonstrates that epiphytes—plants that use other plants for mechanical support—play a crucial role in maintaining the biodiversity of redwood forest canopies. It’s well known that these hangers-on thrive in the old-growth Douglas-fir forests of Oregon and Washington, in places amassing the weight of two concert grand pianos per acre. Ellyson and Sillett reveal in this study that Douglas-fir has a rival in Sitka spruce, a tree that grows in and among northern coast redwood forests and supports a shockingly high diversity of epiphytes.