Recovery Plan for the Northern Spotted Owl - DRAFT

tion and initial attack. If manipulation is contemplated (for salvage, thinning),slash treatment should be considered on a minority of sites.WindInsectsDiseasesMost potential DCAs already have some clear-cut units within them. From awind protection standpoint, adjacent areas are at risk. One option is to simplyleave the existing units alone and accept the windthrow risk in the hope thatadditional damage will be limited to a couple of tree lengths into the stand.Another option is to enter adjacent stands along susceptible edges and"feather" the edges. The objective of feathering is to divert or break up the flowpattern of wind so it is not continually encountering a "wall" of trees. For aseveral-tree length reach, susceptible species or crown classes of trees can bethinned out. Residuals can be mechanically pruned; those on the leading edgecan be pruned on alternate whorls to reduce wind pressure in the crown. Allthese techniques open the stands and reduce owl habitat for perhaps decades,but may stop an otherwise decades-long advancing wall of windthrow. Moststands affected by wind tend to rebuild wind resistance in this same manner.Such intensive management to build wind resistance has not generally beenpracticed in the Pacific Northwest, and its economics are unknown, but suchmanagement may be useful in areas bordering DCA units. Local expertise willbe invaluable in designing wind-protected units.Partial cutting may be employed in intervening areas between DCAs or potentiallywithin a DCA (management directives not available as of the date of thisreport). Coastal areas (see Figure F. 5), particularly the western Olympic Peninsula,are at greatest risk for accelerated windthrow. Recent experience is lackingin the Pacific Northwest, but guidelines from southeast Alaska (Harris1989) may be relevant until more local experience is available: 1) stay out ofareas with evidence of past blowdown; 2) avoid those stands exposed to stormwinds (usually from southwest in our area): 3) avoid thinning more than 30percent of the basal area of closed-canopy, even-aged stands; 4) thin from belowand concentrate on trees with stilt roots, decay, or lean; 5) avoid damage tothe residual stand: and 6) thin heavily at an early age to provide good rootingopportunity for residuals. Western redcedar seems to be relatively windfirmalong the coastal margin (Harris 1989; Franklin, pers. comm.).Windthrown areas have increased fuel hazards and higher potential fire behavior.The guidelines for slash treatment after partial cutting, summarized in theprevious section, should be implemented in windthrown areas: treat slash in aminority of areas.Under most conditions, active management for control of insect populationswill not be necessary in DCAs. In the event of major windthrow where accessis possible, some down timber should be removed to prevent large buildups ofDouglas-fir and ambrosia beetle populations. Salvage could be done withoutnegative impacts on fire hazard, but must be weighed against other habitatvalues of the windthrown trees.Foliage diseases are not likely to be epidemic. No sprays are recommended. Itmay be desirable to control root rots in some areas to prevent tree death andrapid stand succession. In some areas with good access, stump removal hasbeen employed to maintain a relatively healthy stand, especially in areas with454