Dead western red cedar
Kimberly Cauvel wrote a nice article on the die back of western red cedar in western Skagit County here: /warm-dry-summers-taking-toll-on-area-trees-plants.
Western Skagit County is partially within the rain shadow of the Olympic Range and hence a bit drier than some other parts of western Washington. Seabacher (2007) noted western red cedar die back on eastern Vancouver Island is similar dry sites.
Much of the die back I have observed in Western Skagit County has been on glacial marine drift soils near Bayview and and Samish Island (above picture). Many of these trees appear to have had previous stress as many of the trees have dead leads. But many now, such as the tree above, have completely died. The tree pictured above was one of six nearby cedars that have died within the past year or two. Within a quarter mile of this site are dozens more that have died.
Glacial marine drift soils in the area are silt and clay dominated. The silt and clay holds water and perched groundwater develops on these soils such that seasonal wetlands are common. However, the soils will become desiccated in the summer. A slight increase in overall temperature particularly in the spring and summer may be just enough to push the ability of some western red cedars to survive.
3 comments:
we've lost six on our own property and see them here in Cowlitz county wherever we go.Thank you for explaining why.
We haven't had any die on our property on Discovery Bay yet. We do have some that have lost leads in the past and they have appeared stressed the last couple of years so we worry about their being vulnerable to drier summers. One thing we've noticed in recent years is a decrease in summer fogs rolling in off of the bay here. That comforting sound of water dripping off of the trees that we used to hear in mid/late summer has been mostly absent.
We've started to map the dieback of western redcedar as part of the Forest Health Watch program. Readers can share their observations through a project on iNaturalist.
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