CORVALLIS, Ore. — Trees to know in Oregon and Washington, the most popular publication in the Oregon State University Extension Service catalog, celebrates its 70th anniversary with a new edition.
Author and professor emeritus Edward Jensen, who taught tree identification from 1976 to 2014 in Oregon State University’s College of Forestry, expanded the book to include rare species from southwestern Oregon. He also updated botanical names, added information on Washington’s forests, and included a new section on the potential impacts of climate change on Pacific Northwest forests.
Each entry includes multiple photos, an identification key to narrow down genus, and narrative descriptions.
Jensen inherited the publication in the 1990s from original author Charlie Ross, when it was still a stapled guide with black-and-white line drawings. This new edition — Jensen’s third — is in full color, with most photos taken by the author.
The 173-page guide features more than 125 tree species. Each entry includes multiple photos, an identification key to narrow down genus, and narrative descriptions. Jensen also shares stories related to plant uses, Indigenous knowledge, history and tree characteristics.
“This is more than a tree ID book,” Jensen said. “The joy of it is that there’s enough information that allows people to ID trees and enough about natural history and ecology that can get them excited about learning about trees and the forest they comprise.”
Jensen collaborated with Oregon State University forestry professor David Shaw on a chapter addressing how Northwest forests may respond to climate change.
The book covers trees from Oregon, Washington, much of British Columbia and the Idaho panhandle. While the southern boundary stops at the California border, Jensen includes several species that extend into Southern Oregon — such as the rare Hinds walnut, found along creeks near Medford and just south into California.
The guide also describes four cypress species that are rare in Oregon. Some have only a few known specimens and were added to the state’s botanical literature as recently as the 1990s. Though common in California, these species are not new arrivals. Instead, they are believed to be remnants of ancient populations that date back to at least the Pleistocene epoch, which ended more than 11,000 years ago.
“They each tell an interesting story,” said Jensen, who spent a year working on the new edition. “A lot of them are at risk from climate change, wildfires and flooding.”
New to this edition are additional ornamental trees commonly found in urban and suburban settings. While many people recognize iconic native trees such as bigleaf maple and Douglas-fir, most trees in developed areas are non-native species planted for landscaping.
Jensen recommends the book for its accessible approach. Other tree guides may be either too brief or overly technical.
Trees to know in Oregon and Washington offers an easy-to-read format for outdoor enthusiasts, gardeners, and newcomers to the Northwest. Its compact size makes it a convenient companion for hikes throughout the region.
