Recovery Plan for the Northern Spotted Owl - DRAFT
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Recovery Plan for the Northern Spotted Owl - DRAFT

Recovery Plan for the Northern Spotted Owl - DRAFT Recovery Plan for the Northern Spotted Owl - DRAFT

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growth often increases (Reinhardt and Ryan 1988), while residual Douglas-firmay show no change in radial growth lixcrement.If a crown fire does occur, it kills all the trees in the stand. Herbs and shrubsmay dominate the floristics of early succession, with some herbs (e.g.,Epilobium angustifoliurn) peaking and declining within the same decade(Stickney 1986). Western larch has light-winged seeds, which can blow onto aburned site from adjacent stands or from lightly scorched cones in the firekilledstand (Haig et al. 1941). Lodgepole pine, if present on the site, willestablish from serotinous cones in the area. If the crown fires have beenspaced more than 150 years apart, western larch is the most probable treedominant at the time of disturbance, because lodgepole pine, the other earlyseral species with fast growth, is short-lived and may have been killed bymountain pine beetles (Haig et al. 1941). Where the crown fire interval isshorter than 150 years, lodgepole pine will at least share dominance in thepost-fire tree cohort (Gabriel 1976, Antos 1977, Antos and Habeck 1981).However, if the stand is repeatedly underburned after lodgepole pine establishment,lodgepole pine will be eliminated because of its thin bark in favor ofwestern larch, ponderosa pine, and Douglas-fir.If two crown fires occur in quick succession, the site may revert to a brushfield(Antos and Habeck 1981), as neither western larch nor lodgepole pine survivessuch fires in the pole stage (Davis et al. 1980). Where a single crown fireoccurs, stand establishment usually includes individuals of other species aswell as lodgepole pine and larch. On dry sites, ponderosa pine may be included.On average sites, Douglas-fir and grand fir are normally present, andon moist sites western white pine may be a codominant. None of the associatedspecies typically grows as fast as western larch and lodgepole pine (Haig etal. 1941, Cobb 1988). Individual species create different strata over time,although all may establish in the same time period. On a series of even-agedstands in eastern Washington that regenerated after crown fires, Cobb (1988;Figure F.8) found western larch to be a consistent dominant, with lodgepolepine sharing dominance on some sites. Douglas-fir and grand fir showed avariety of stratification patterns but always in intermediate or suppressedcrown positions.Low intensity fires in these stands increase the relative dominance of westernlarch, ponderosa pine, and/or Douglas-fir over their associates because of theircrown position relative to grand fir, and thicker bark than lodgepole pine ondominant trees. Substantial understory development, perhaps after thebreakup of lodgepole pine in the canopy, will encourage an understoryreinitiation stage in stand development (Oliver 1981) which may be associatedwith increased crown fire potential and another set of multiple successionalpost-fire pathways.A successional model of western larch/Douglas-fir forests, including firedynamics was developed by Keane et al. (1990) for the Douglas-fir series inMontana. The model outputs generated by fire return intervals of 10, 20, and50 years, and a no-fire situation are shown in Figure F.9. Ponderosa pine ismost dominant in the more frequent fire return interval simulations. In theDouglas-fir series simulation, Douglas-fir is the most shade-tolerant speciesincluded and dominates the no-fire scenario. In the East Cascades subregion,the Douglas-fir series has little larch, and the fire scenarios would favorponderosa pine with some Douglas-fir. The grand fir series is more commonwhere larch is found; Douglas-fir in this series behaves more like larch whilegrand fir is the most shade-tolerant species. Substituting those species in thegraphs gives a general idea of this alternative succession scenario: for example,in the no-fire scenario, larch, ponderosa pine, and Douglas-fir would declineand grand fir would increase.464

WindThere is no known published information concerning wind in the East Cascadessubregion. This is likely because it is an intermittent and rarely extensivedisturbance factor here. Our experience suggests that most naturalstands and partial cuttings are relatively windfirm. Wind does not appear to bea factor of significant concern in designing a forest protection scheme forspotted owl DCAs in the East Cascades subregion.InsectsInsects in this subregion historically have caused large disturbances. Thefrequent natural fire frequency on the eastern side of the subregion, however,probably did not allow populations to build frequently to the epidemic levelscurrently observed in this area. Insects probably acted as agents of stabilizationin these ecosystems, similar to fire. Endemic populations of defoliatorsWern larchLodgepole pine 1*0- Douglas-fir E303 0 Grand fir20- At a -2010-tX 100 10 20 30 40 50 6030 -3020 20010.: :: .0 10 20 30 40 50 60 0MetersFigure F.8. In these mixed-coniferforests of the eastern Cascades, multiple canopy levelscan befound in young stands (Cobb 1988). These stands are even-aged, both developingafter a stand replacement disturbance. Larch and lodgepole pine dominate these youngstands (100 years old) while Douglas-fir and grand fir are relegated to subcanopy positions... .1 ----- ... ...I465

WindThere is no known published in<strong>for</strong>mation concerning wind in <strong>the</strong> East Cascadessubregion. This is likely because it is an intermittent and rarely extensivedisturbance factor here. Our experience suggests that most naturalstands and partial cuttings are relatively windfirm. Wind does not appear to bea factor of significant concern in designing a <strong>for</strong>est protection scheme <strong>for</strong>spotted owl DCAs in <strong>the</strong> East Cascades subregion.InsectsInsects in this subregion historically have caused large disturbances. Thefrequent natural fire frequency on <strong>the</strong> eastern side of <strong>the</strong> subregion, however,probably did not allow populations to build frequently to <strong>the</strong> epidemic levelscurrently observed in this area. Insects probably acted as agents of stabilizationin <strong>the</strong>se ecosystems, similar to fire. Endemic populations of defoliatorsWern larchLodgepole pine 1*0- Douglas-fir E303 0 Grand fir20- At a -2010-tX 100 10 20 30 40 50 6030 -3020 20010.: :: .0 10 20 30 40 50 60 0MetersFigure F.8. In <strong>the</strong>se mixed-conifer<strong>for</strong>ests of <strong>the</strong> eastern Cascades, multiple canopy levelscan befound in young stands (Cobb 1988). These stands are even-aged, both developingafter a stand replacement disturbance. Larch and lodgepole pine dominate <strong>the</strong>se youngstands (100 years old) while Douglas-fir and grand fir are relegated to subcanopy positions... .1 ----- ... ...I465

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