Recovery Plan for the Northern Spotted Owl - DRAFT

years old. A successional sequence involving dwarf mistletoes and decay fungiin coastal western hemlock forest is shown in Figure F.6D. Dwarf mistletoesstrongly affect tree growth and branch habit, but usually do not cause muchmortality. Trees in the coastal area tend to grow to large sizes and ages, especiallyin areas protected from high winds. They typically have considerabledefect caused by diseases; large and irregular branches, dead tops andbranches, broken tops and snags created by wind, butt rot and decay fungi.Arrnillaria root rot may contribute to whole tree blowdown in old-growth forests.B. Management Effects on StandsStand manipulation in the West Cascades subregion has occurred since the1850s, when the first extensive logging began in the Douglas-fir region (Ficken1987). Management effects on stands still in a "natural" condition include firesuppression effects, of cutting pattern on adjacent stands, and the spread ofinsect and disease problems.Fire protection in most areas became effective only after 1910. With naturalfire return intervals in the hundreds of years, the effect of 80 years of successfulfire exclusion has been minimal. In the remote and rugged Olympic Mountains,Agee and Flewelling (1983) estimated that park fire protection this centuryhad "saved" only several thousand acres. Many of the stands in thesubregion would not have burned even if fire protection had not been in place,but protection has had subtle effects on the mosaic of age classes present.This subtle effect on the landscape has been overwhelmed by the effects ofclear-cutting in the subregion.Escaped slash fires have been an important component of recent wildfire acreagein the West Cascades subregion. For example, of the 14 major fires in theMt. Hood National Forest in 1960-75, all started or gained momentum in loggingslash (Dell 1977, Deeming 1990). Debris burning was responsible forabout 15 percent of wildfire acreage in Oregon and Washington in 1960-80(Agee 1989). Recent declines in area slash burned, due to air quality restrictions,as well as very large fires from other causes in the 1980s, may likelyreduce these percentages in the future.The effects of management on wind have been to accelerate windthrow alongsusceptible edges where clear-cuts border protected forest. For example,Ruediger (1985) noted that blowdown adversely affected small owl managementareas on the Gifford Pinchot National Forest, particularly in locationswhere the forest was fragmented by timber harvesting. On the Bull Run watershednear Portland, Oregon, 43 percent of large blowdown areas after a 1973storm and 81 percent after a 1983 storm were associated with boundaries ofexisting clear-cuts and roads (Franklin and Forman 1987).Management of stands in the West Cascades subregion has had considerableinfluence on diseases and a lesser influence on insect populations. The Sitkaspruce weevil strongly influences the successful establishment of Sitka spruceplantations. Populations of the Douglas-fir beetle probably have increasedslightly as a result of logging but not usually to epidemic proportions. However,root diseases, especially Phellinus root rot, appear to have increased considerablyas more and more of the landscape has been converted to younggrowthDouglas-fir forests. Stumps created by logging harbor the fungus,allowing it to remain viable (Tkacz and Hansen 1982, Thies 1984). Manyyoung plantations of Douglas-fir are now at risk. Management activities suchas thinning seem to have increased the incidence of Armillaria and black stainroot disease. Reducing the variety of tree species in forests tends to promote451