Portland’s Wildwood Trail runs over thirty miles through Forest Park; this 7.6-mile section through Washington Park’s Hoyt Arboretum is the one most worth a single visit. The arboretum cuts named groves of conifers (Magnolia, Beech, Redwood, Fir) off the main spine, so a slow walk is also a tour through specific trees rather than generic woods. Genuine forest, ten minutes from downtown — the kind of urban-park anomaly that justifies a layover at PDX.