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Pacific Northwest heat wave sets up 'grim' migration for salmon on Columbia, Snake rivers

Lynda V. Mapes, The Seattle Times on

Published in Weather News

After the last sockeye meltdown in 2015, the Fish Passage Center concluded in a 2016 memo that a drawdown of the Lower Granite reservoir offers significant potential for reducing the water temperatures at the dam, and possibly contribute to overall lower temperatures at the other downstream Snake River sites.

The idea, so far, has not gained traction.

A GOP Congressman, Mike Simpson of Idaho, has proposed going further, to take out the Lower Snake dams and replace their benefits to boost survival of salmon and steelhead at risk of extinction, a proposal generating plenty of heat of its own.

TREES STRESSED BY HEAT

Trees are also suffering.

Trees are already stressed after a spring drought. March and April were the fourth driest on record in Washington State since 1895, according to the state Department of Ecology.

 

Then June — long called Juneuary by locals West of the Cascades for its relentless cool, wet gloom — instead came on hot and dry and now is punishing trees with baking heat.

Hot dry weather pulls water out of trees, and with inadequate moisture in the soil, the interior plumbing of trees ruptures, or cavitates, noted Tom Hinckley, former director for the UW Botanic Gardens' Center for Urban Horticulture and emeritus professor at the UW School of Environmental and Forest Sciences.

Stressed trees are more vulnerable to bugs and pathogens. Of course the worst tree killer is fire — and conditions this year are set for fire, with dried out vegetation and soils.

Even if trees die back but survive this year, they will be stunted in next year's growth. That is because this is the time when trees need to be growing their strongest, and socking away food stores for next year's spring growth spurt. But they have little moisture with which to power photosynthesis, by which they make food and grow new tissue.

The suffering of trees this spring and summer will be recorded. Not only on a landscape that will see more dead trees and trees dying back, usually from the top down. But in rings that in the future will show a harsh season with little growth, as the tree hunkers down, just trying to survive.

©2021 The Seattle Times. Visit seattletimes.com. Distributed by Tribune Content Agency, LLC.
 

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