Diagram of the rings of Pinus rigida 212-45-C, the state's champion pitch pine at the Washington Park Arboretum, succumbed to climate change: steadily warming and drier summers, that stressed the tree in its position atop a droughty knoll. Red turpentine beetles, catching the scent of stress chemicals emitted by the tree as it struggled, bored in. Graphic: Emily M. Eng / The Seattle Times

By Lynda V. Mapes
13 May 2017

(The Seattle Times) – It saw the flight of Boeing’s first jet; the World’s Fair, the founding of Microsoft. It survived the eruption of Mount St. Helens, witnessed the state’s centennial, and the confession of the Green River Killer.

But after 72 years, Pinus rigida 212-45-C, the state’s champion pitch pine, has died and will be cut down at the Washington Park Arboretum.

The cause of death was climate change: steadily warming and drier summers, that stressed the tree in its position atop a droughty knoll. Red turpentine beetles, catching the scent of stress chemicals emitted by the tree as it struggled, bored in.

The beetles chewed and fed on the tree’s phloem, conduits just below the bark for the tree’s life-giving juices. Just as damaging, the beetles were vectors for fungus that plugged up other conduits carrying water into the tree. It wasn’t long before arborist Clif Edwards, making his usual rounds, noticed something amiss in the pinetum, the collection of pines at the arboretum.

“I saw this big orange (tree) canopy in the sky, got closer to investigate, and got the not-so-good answer,” Edwards said.

He alerted other experts at the arboretum, who confirmed by the plethora of exit holes about the size of the point of a crayon that the tree was badly infested with beetles. Now the tree must be removed before the infestation spreads to other trees in its grove, noted David Zuckerman, manager of horticulture for the arboretum.

Since 2005, the arboretum has lost some 40 pine trees in just this way, as warming average temperatures combine with summer’s drought to stress trees. The arboretum has not in the past irrigated its collection of pines. But staff will begin pouring on the TLC with mulch and water this season to help its collection of stressed pines, Zuckerman said.

But for this big old pine, it’s too late. [more]

Farewell, giant pine: Climate change kills a champion at Washington Park Arboretum

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