Study - Iconic Yellow Cedar Dying Across 1,500 Square Miles In Temperate BC/AK Rainforest

[hatrack]

Yellow cedars, iconic temperate rainforest trees that can live 1,000 years, are dying over vast swaths of warming Alaska and British Columbia. Now, for the first time, there are maps showing the full distribution of yellow cedars, the extent of their long-term decline and projections for future losses. Despite its name, yellow cedar is actually a type of cypress, not cedar. Cedars and cypresses both have outstanding rot resistance, and while they have similar appearances, they're not closely related.

The maps and calculations, described in a study published online in the journal Global Change Biology, show over 1,500 square miles of yellow cedar forest has been stricken with die-offs associated with a warming climate. "It had never been mapped before, so we really didn't know how big the decline was," said Brian Buma of the University of Alaska Southeast, the lead author.

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The study combines information from aerial and on-the-ground surveys in Alaska, British Columbia and points south, and it evaluated decades-long climate trends and projections of climate change decades into the future.

Yellow cedar stands are found along the north Pacific coastline, with specimens scattered from northern California mountain sites to Prince William Sound, as the new mapping shows. But the heart of its habitat is coastal Southeast and British Columbia — and that is where the die-off is concentrated, with mortality exceeding 70 percent in many areas. Mortality is spread over a region spanning latitude 50 to latitude 60 north, the new mapping shows.

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https://www.adn.com/alaska-news/environment/2016/11/26/new-mapping-shows-extent-of-yellow-cedar-die-off-analysis-forecasts-big-losses-in-the-future/

[PearliePoo2]

1. I'm fairly familiar with Yellow Cedar. I've found logs washed up on beaches and used it for projects

It has a very unique smell that identifies it, as well as its color. It is very durable and rot resistant. Many a boat has been decked with this incredible wood. It's so disturbing, alarming and sad to hear about these forests dying off.

[riversedge]

2. Their future does not look good.

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The problem for the trees is annual snow-cover is becoming thinner and shorter-lasting. Paradoxically, the warming climate is exposing yellow cedars' roots to freeze damage.

Much of the trees that exist today "are in areas where they're not going to have snow anymore," Buma said.

But in the northern part of the range, from about Juneau to the Sound, the few yellow cedars that exist appear to be healthy, he said. There, snow is more dependable, and some trees considered young — 200 or 250 years old — have been growing.

Could yellow cedar spread farther north to stay with the snowpack? Signs do not seem encouraging.

Just as yellow cedars' death is slow, so is their growth. Seeds do not spread or sprout easily, and there is little evidence of new seedlings beyond the areas where the trees are already growing, Buma said.

Almost all the seedlings he has found have been close to existing stands, maybe no more than 10 feet away, he said. "If you go an hunt for seedlings, you barely find any outside the boundary," he said.