12 Days of Conifers: Where the Forest Meets the Sea: Seabirds, Conifers, and Wildfire

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It’s Day 12 of 12 Days Of Conifers and today we feature a tale of land and sea, involving two conifers and the little seabird that nests in their highest branches.

Looking up at the branches of a redwood tree

Redwood tree in northern California

(Courtesy: Allie Weill)

Today we have two conifers: the coast redwood (Sequoia sempervirens) and the coast Douglas fir (Pseudotsuga menziesii var. menziesii).

The coast redwood is, of course, famous as the tallest tree species in the world, reaching recorded heights up to about 380 feet. But the Douglas fir isn’t too shabby when it comes to height, either-it’s the second tallest conifer in the world, reaching heights of about 327 feet (two non-conifers, a mountain ash in Australia and a yellow meranti in Borneo, are a couple of feet taller).

The coast redwood and Douglas fir both live in the foggy forests along the Pacific coast of California, from the northern border of the state south to the Santa Cruz Mountains (the coast Douglas fir is much more widespread than redwood, extending north to British Columbia inland to the Sierra Nevada, and there’s also a Rocky Mountain variety of Douglas fir).

Small dark brown and white seabird swims away from the viewer

Marbled murrelet

(Courtesy: Alex Rinkert)

The two trees provide habitat to many species, but one of the most mysterious is the federally threatened Marbled Murrelet (Brachyramphus marmoratus). Marbled Murrelets  have a very unusual nesting behavior for a seabird—breeding pairs fly inland to nest alone (most seabirds are colonial) and females lay a single egg on the broad, moss- and lichen-covered branches of old growth forest trees. The Marbled Murrelet’s surf-n-turf lifestyle illustrates how terrestrial and marine ecosystems are connected. But it also means that this little seabird faces threats on land as well as on the ocean.  

This past summer’s wildfires in the Santa Cruz Mountains are one example.  Though it’s too early to tell the extent of the damage or the impact it will have on the population, the fires burned through swaths of important Marbled Murrelet nesting habitat, which is already quite limited. The map below shows areas where this year’s fires and marbled murrelet habitat intersect.

Large redwood and Douglas fir have thick bark that is provides good insulation against fire. Redwoods in particular are very well-adapted to fire, with the ability to resprout from the roots or from branches. So a wildfire often doesn’t mean major losses for these forests, even when the trees appear to be badly charred. It can take a long time to know for sure what trees will die and what trees will survive after a major fire, like those that burned in the Santa Cruz Mountains 2020.

But these trees are best adapted to low-severity fires. And most of the area that burned this year in the Santa Cruz Mountains hadn’t burned in a century, priming the forests for more severe fire this year. That means a higher likelihood for damage to even the biggest redwoods and Douglas firs and to remaining, limited marbled murrelet habitat

USGS scientists are monitoring both marbled murrelets and coastal forests and working to understand how to help managers mitigate threats to both.

Learn about USGS marbled murrelet at-sea surveys here.

Learn about USGS coastal forest research here.

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Map showing areas of the Santa Cruz Mountains where fires overap marbled murrelet habitat

Map showing areas of the Santa Cruz Mountains where fires overap marbled murrelet habitat

(Credit: Jon Felis, USGS Western Ecological Research Center. Public domain.)