Thuja plicata is among the most widespread trees in the Pacific Northwest. It is associated with Douglas-fir and western hemlock in most places where it grows. It is found at the elevation range of sea level to a maximum of 2,290 m (7,510 ft) above sea level at Crater Lake in Oregon. In addition to growing in lush forests and mountainsides, western redcedar is also a riparian tree, growing in many forested swamps and streambanks in its range. The tree is shade-tolerant and able to reproduce under dense shade.