Plant species diversity and occurrence in young, mature and old-growth Douglas-fir stands in western Oregon and Washington

Spies, Thomas A. 1991. Plant species diversity and occurrence in young, mature and old-growth Douglas-fir stands in western Oregon and Washington. In: Ruggiero, Leonard F.; Aubry, Keith B.; Carey, Andrew B.; Huff, Mark H., tech. eds. Wildlife and vegetation of unmanaged Douglas-fir forests. Gen. Tech. Rep. PNW-285. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 111-121.