Failing trees have been a persistent topic in MG Clinics and on the online Ask an Expert service during the past 6 or 7 years. Overall, it\u2019s been an issue of continuing higher than normal temperatures combined with less than normal rainfall. Then, too, few homeowners realize that the continuing heat and drought affects their landscape trees in spite of being watered with the lawn sprinklers. <\/p>\n\n\n\n
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<\/figure> Fig 1 (right): Western red cedar, Thuja plicata<\/em>, with thinning crowns most likely due to climate changes and continuing drought. (\u201cWhy is My Tree Dying? \u2013 Western Redcedar (Thuja plicata<\/em>)\u201d – April 2019; https:\/\/www.oregon.gov\/ODF\/Documents\/ForestBenefits\/TreeDeclinesRedcedar.pdf<\/a>) <\/p>\n<\/div><\/div>\n\n\n\n In order for trees to thrive, they should be irrigated\nseparately from grass, with at least one watering to about 10 inches deep to\nthe soil below the canopy every 3 weeks during our dry season. Indications of a\nwater deficit is revealed by multiple signs and symptoms, among them wilted leaves;\nleaves with curled and\/or dry edges; early fall color; leaf yellowing and early\nleaf drop.<\/p>\n\n\n\n Foresters have been puzzled by problems with Western Red\nCedar (Thuja plicata<\/em>) which normally do well on moist sites. The most\nrecent thought is that these trees are finally succumbing to stress from many successive\nyears of heat and drought stress. <\/p>\n\n\n\n Several recent Ask an Expert responses have noted \u201cWe are\ngetting many reports of western redcedars dying this year, and the consensus\nseems to be that the combination of extreme heat and drought experienced since\naround 2013 through last summer is an important factor. Although this summer\nwas mild, it often takes a year or so for a tree to show any signs of distress\nfrom drought.\u201d<\/p>\n\n\n\n Another expert, in a response to a different client, said it this\nway: \u201cWestern redcedar are dying in some areas due to a complex of climate\nstress and other issues, with no clear primary agent of mortality.\u201d<\/p>\n\n\n\n Fig 2 (right): Two healthy Western red cedars (Thuja plicata<\/em>) on the Oregon State University campus, southeast of Fairbanks Hall. ( OSU Landscape Plants; https:\/\/landscapeplants.oregonstate.edu\/plants\/thuja-plicata<\/a>) <\/p>\n<\/div><\/div>\n\n\n\n In general, the foresters responding through Ask an Expert are\nincluding a link to a publication released in April 2019: \u201cWhy is My Tree\nDying? \u2013 Western Redcedar (Thuja plicata<\/em>)\u201d which, in summary, states: <\/p>\n\n\n\n Top-dieback,\nbranch mortality, crown thinning and whole-tree mortality in all ages of\nwestern redcedar has [sic] been observed recently at lower elevations in the\nWillamette Valley and beyond. Although it is common to see \u2018spiked\u2019 or dead\ntops in older western redcedar, usually there are living lateral branches and a\nfunctional crown. No single factor has been identified in these more recent die\noffs, but a combination of poor or unsustainable growing conditions may be to\nblame. Redcedar may simply be growing in areas or within microclimates outside\nof their preferred range or areas that are no longer sustainable for long-term\ngrowth under current climate conditions.<\/p>\n\n\n\n Then, too, it suggests that alternate species for red cedar\non generally dry sites include incense cedar, sequoia, and big leaf maple; on\nmore moist sites which don\u2019t dry out in the summer, western white pine, maple,\nalder, ash, or cottonwood. <\/p>\n\n\n\n Resources <\/strong><\/p>\n\n\n\n – Abiotic Disorders of Landscape Plants\u201d (#3420 UCANR); pages\n51-59. A copy is in each of the metro MG offices. <\/p>\n\n\n\n – \u201cThuja plicata<\/em> (Western Red Cedar)\u201d outlines a basic\ndescription of this native conifer (50-70 feet, or more) which thrives in sun\nto part shade on moist soils, with numerous images of a healthy tree. https:\/\/landscapeplants.oregonstate.edu\/plants\/thuja-plicata<\/a><\/p>\n\n\n\n –\n\u201cWhy is My Tree Dying? \u2013 Western Redcedar (Thuja plicata<\/em>)\u201d – April 2019\n– https:\/\/www.oregon.gov\/ODF\/Documents\/ForestBenefits\/TreeDeclinesRedcedar.pdf<\/a>\n<\/p>\n\n\n\n – \u201cPruning Drought Stressed Shade Trees\u201d encourages caution to remove as little wood as possible from a stressed tree, in part because it already has limited reserves, with precious little remaining to \u201cspend\u201d on otherwise unneeded wound repair. https:\/\/droughtresources.unl.edu\/droughtpruning<\/a><\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" Western Red Cedars Dying Jean R. Natter, OSU Extension Master Gardener Failing trees have been a persistent topic in MG Clinics and on the online Ask an Expert service during the past 6 or 7 years. Overall, it\u2019s been an issue of continuing higher than normal temperatures combined with less than normal rainfall. Then, too,… Continue reading ![\"Two](\"https:\/\/osu-wams-blogs-uploads.s3.amazonaws.com\/blogs.dir\/2080\/files\/2019\/10\/Fig2-red-cedar-habit-a-3.jpg\")
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