Recovery Plan for the Northern Spotted Owl - DRAFT
Recovery Plan for the Northern Spotted Owl - DRAFT Recovery Plan for the Northern Spotted Owl - DRAFT
Live crown ratiobecent)6050IStand A4030201001 3 5Treatment7 9Heavy thinning No No thinningUnderstory biomass(pounds per acre)6,400Stand B5,6004, 8004, 0003, 2002, 4001,60080001 3 5 7 9TreatmentHeavy thinning IM No thinning\1 -I/- - ---....--....................................... I'll.."Figure G.6. Effect of thinning intensity on: average live crown ratios of Douglas-fir trees(Stand A) and understory shrub biomass (Stand B). Hoskins, Oregon, levels of growing stockstudy (Marshall 1990). Sutli (unpublished data).intervals, b) moderately (22 percent volume removed) at 6-year cycles, and c)heavily (31 percent volume removed) at 9-year intervals. About the sameamount of volume was removed in all three treatments. After 18 years, therewas no difference in net volume growth compared to the controls, indicatingthat young stands can respond positively to a range of thinning regimes.Studies by Dilworth (1980), Nystrom et al. (1984), and Greene andEmmingham (1986) suggested that the effects of density on the development ofyoung western hemlock and western red cedar stands are similar to effects onDouglas-fir (see King 1986).498
20Heavy thinning15 | Stand A | (treatment 1)15 Hoskins, OregonLight thinnrgAve rage 10 (treatment 7)diameter 1(inches)No thinning5 (treatment 9)010 20 30 40Age (years)2 0Heavy thinningStand B (treatment 1)Average 15 Skykomish,diameter Washington Light thinning(inches) (treatment 7)10No thinning5 (treatment 9)020 30 40 50Age (years)I 11 "I'll,'----- I . . ....- ................. I.... 1.111- 1- .............. -1.1-...... 11 ... "I -...- -.1...... 1.1.111, IFigure G.7. Average doarneterfoUowing three intensities of thinning in two levels of growingstock studies (Curtis and MarshtU 1986).Other work has shown that development of older Douglas-fir and westernhemlock stands can be regulated by stand density control and careful thinning.Williamson and Price (1971) summarize information collected 5 to 38years after thinning in 70-to 150-year-old Douglas-fir. Thinning intensityranged from a control with no thinning to 55 percent of total basal area removed,and included both crown thinning (removing large trees) and lowthinnings (removing small trees). Thinning reduced mortality caused by barkbeetles, indicating that stand vigor was improved. Similarly, Williamson (1966and 1982) studied growth response after thinning in a 110-year-old stand ofDouglas-fir. Nineteen years after light and heavy thinnings, volume growthwas nearly equal that of the control, suggesting that stands this age can bevigorous and are able rather quickly to occupy space made available by thinning.Newton and Cole (1987) reconstructed stand development to providefurther evidence of the ability of thinned Douglas-fir stands to produce largetrees. Stands 50 and 70 years old were thinned to less than 40 trees per acre.At time of thinning, trees were about 14 to 24 inches in diameter. Seventyyears later, diameters ranged from 24 to 50 inches (average 35 to 40 inches).499
- Page 464 and 465: InsectsDiseasesInsects in this subr
- Page 466 and 467: __hardwoods are immune. Shade toler
- Page 468 and 469: pests (Schowalter 1988). Black stai
- Page 470 and 471: tion and initial attack. If manipul
- Page 472 and 473: log and snag density was likely low
- Page 474 and 475: B. Management Effects on StandsMana
- Page 476 and 477: units (underburning or lop/scatter)
- Page 478 and 479: In the higher elevation White Fir a
- Page 480 and 481: growth often increases (Reinhardt a
- Page 482 and 483: 50rcc4*0-cC)2M CmZ13010-yearI ,...*
- Page 484 and 485: In the East Cascades subregion fore
- Page 486 and 487: The introduced disease, white pine
- Page 488 and 489: VI. Conclusionsmortality will resul
- Page 490 and 491: Baker, F.A. 1988. The influence of
- Page 492 and 493: Habeck, J.R. 1990. Old-growth ponde
- Page 494 and 495: Perry, D.A., and J.G. Borchers. 199
- Page 496 and 497: Weatherspoon, C.P., and C.N. Skinne
- Page 498 and 499: 482
- Page 500 and 501: 484
- Page 502 and 503: area, structure, ages, location; ne
- Page 504 and 505: Stand AFigure G.2. A--unthmnned Dou
- Page 506 and 507: figure 0.3. Effects of thinning Dou
- Page 508 and 509: II. Review of Natural Vegetation an
- Page 510 and 511: western hemlock, and sometimes othe
- Page 512 and 513: year intervals (Appendix F). With t
- Page 516 and 517: Basal area growth continued to incr
- Page 518 and 519: technology probably will allow some
- Page 520 and 521: Stand A. No activities (west side 3
- Page 522 and 523: Stand A. No activities (west side o
- Page 524 and 525: acre, 4 to 12 inches in diameter),
- Page 526 and 527: allow redwood sprout clumps maximum
- Page 528 and 529: KAge 15 years - 511 trees per acre,
- Page 530 and 531: 6Stems per acre100 _ Stand A. Natur
- Page 532 and 533: Basal Area(square feetper acre)50 1
- Page 534 and 535: * Opening the canopy in small patch
- Page 536 and 537: Drew, T.J. and J.W. Flewelling. 197
- Page 538 and 539: Miller, R.E.; D.L. Reukema, and R.L
- Page 540 and 541: Tappeiner, J.C., P.M. McDonald, and
- Page 542 and 543: 526
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- Page 546 and 547: 6. Timber supply curve and economic
- Page 548 and 549: scientifically credible biological
- Page 550 and 551: E. Summary of Preliminary Estimates
- Page 552 and 553: II. General Economic Principles for
- Page 554 and 555: practices may be able to show how s
- Page 556 and 557: Economic patterns show the efficien
- Page 558 and 559: The sustainable yield concept that
- Page 560 and 561: A. Previously Estimated Economic Co
- Page 562 and 563: County receipts were estimated to d
20Heavy thinning15 | Stand A | (treatment 1)15 Hoskins, OregonLight thinnrgAve rage 10 (treatment 7)diameter 1(inches)No thinning5 (treatment 9)010 20 30 40Age (years)2 0Heavy thinningStand B (treatment 1)Average 15 Skykomish,diameter Washington Light thinning(inches) (treatment 7)10No thinning5 (treatment 9)020 30 40 50Age (years)I 11 "I'll,'----- I . . ....- ................. I.... 1.111- 1- .............. -1.1-...... 11 ... "I -...- -.1...... 1.1.111, IFigure G.7. Average doarneterfoUowing three intensities of thinning in two levels of growingstock studies (Curtis and MarshtU 1986).O<strong>the</strong>r work has shown that development of older Douglas-fir and westernhemlock stands can be regulated by stand density control and careful thinning.Williamson and Price (1971) summarize in<strong>for</strong>mation collected 5 to 38years after thinning in 70-to 150-year-old Douglas-fir. Thinning intensityranged from a control with no thinning to 55 percent of total basal area removed,and included both crown thinning (removing large trees) and lowthinnings (removing small trees). Thinning reduced mortality caused by barkbeetles, indicating that stand vigor was improved. Similarly, Williamson (1966and 1982) studied growth response after thinning in a 110-year-old stand ofDouglas-fir. Nineteen years after light and heavy thinnings, volume growthwas nearly equal that of <strong>the</strong> control, suggesting that stands this age can bevigorous and are able ra<strong>the</strong>r quickly to occupy space made available by thinning.Newton and Cole (1987) reconstructed stand development to providefur<strong>the</strong>r evidence of <strong>the</strong> ability of thinned Douglas-fir stands to produce largetrees. Stands 50 and 70 years old were thinned to less than 40 trees per acre.At time of thinning, trees were about 14 to 24 inches in diameter. Seventyyears later, diameters ranged from 24 to 50 inches (average 35 to 40 inches).499
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