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Forestry & Society Silviculture HORT/RGSC 302 J.G. Mexal Fall 2008
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Forestry & Society Silviculture/Outline Allowable Cut Effect Harvesting –Clearcut –Shelterwood cut –Single-tree selection Site Index (SI) Regeneration Stocking Thinning Fertilization Competition Control Pruning Wood Quality Agroforestry
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Forestry & Society Allowable cut / Kimmins Allowable Cut = 1/6/decade Function of: site index, silviculture, tree improvement, rotation age
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Silviculture Even-age management: Mixed hardwoods/ Oliver 2008 A. B. C. Young, even-aged mixed species stand –Striped = shade intolerant dominants –Black = shade intolerant; overtopped and die! –Gray = intermediate shade tolerance –White = extreme shade tolerance
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Forestry & Society Silviculture/Change is Inevitable / Mich. Forest Ecology 1964 Trees/acre B.A. ft 2 /ac
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Forests Change with Time- Pisgah Natl For Loftis et al. RMRS-P-34, p.235, 2004 Stand Age (Years) Trees/ 2 acBasal Area (ft 2 /ac)
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Forestry & Society Silviculture/ Change is Inevitable Forest Ecology, 1964 Year DBH (in) D DDD Pseudotsuga menziesii - NZ
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Why do we clearcut? It’s cheaper Allows for tree improvement Favors shade intolerant species (e.g. pine, Doug-fir) Cost ($/CCF) SJAF 18(4):168:’94
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Stumpage Value in PNW/ Ralston et al. Silva Fenn. 38(1):55:’04 DBH Class (cm) Stumpage Value ($/tree)
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Harvest method affects costs in Washington W.J. Appl. For. 22(3):204:2007 Harvest Cost ($/mbf) Treatments: Clearcut— take it all~ Patch cut + thin = 20% removal in 1.5-5 ac w/ thinning between openings Two-age = uneven aged w/ ~15 tpa retained Group selection = similar to Patch cut with <1.5 ac openings Conclusions: Harvest costs increase as retention level increases and patch size decreases
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Forestry & Society Silviculture/Harvest Marking Costs / USFS SO-112, 1994 $/100 ft 3 Southern Pines/ Ouachita N.F. AR Harvesting Method
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Forestry & Society Silviculture/Harvest Costs / SJAF 18:168-174: $/CCF Southern Pines/ Ouachita N.F. AR Harvesting Method Cable Skidder Grapple Skidder Felling
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Forestry & Society Silviculture/Thinning Method vs Damage/ WJAF 15:27-33:2000 Residual Stand (tpa) Scar Area (ft 2 /ac) Pseudotsuga menziesii- OR
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Forestry & Society Silviculture/Management Affects Runoff /Erosion in Alabama Grace, JSoilWaterConsv 59:160:04 Rainfall event (mm) Runoff (mm)
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Forestry & Society Silviculture/Management Affects Runoff /Erosion in Alabama Grace, JSoilWaterConsv 59:160:04 Rainfall event (mm) Erosion (t/ha) Erosion Control = 0.07 t/ha/yr (20 mo) Clearcut = 0.8 t/ha/yr (20 mo)
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N leaching beyond 20 cm and 100 cm depth following urea fertilization (224 kg N/ha) to Douglas-fir forest / Flint 2008 Leaching (kg N/ha/yr)
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Whole tree harvesting impacts N balance Powers et al. RMRS-P-34, p.235, 2004 Forest Type Biomass Removed (Mg/ha)Nitrogen Removed (kg/ha)
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Biofuel from wood residue For. Oper. Rev. 10(1): 21:2008 ParameterClean chips GrinderPCT chips Limbs & Tops L & T + Hdwds Ash (%) 0.305.900.970.781.94 Cellulose (%) 51.750.247.748.549.1 Hemicellulose (%) 18.719.921.620.725.1 Lignin (%) 28.224.125.027.414.8 Bacterial EtOH (g/L) 8.07.08.89.311.0 Fungal EtOH (g/L) 7.05.56.58.0 Pyrolysis bio-oil (%) 66605265 Pyrolysis syngas (%) 17152320
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Forestry & Society Site Index Site Index is a measure of site productivity and refers to the height of dominant and codominant trees in even-aged stands at a particular index age, usually 25, 50, or 100 years. Site Index is a function of environmental factors (soil depth, rainfall, tree species, growing season).
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Forestry & Society Site Index (SI 50 )/ Wenger 1984 Years Height (ft) Loblolly pine Douglas-fir in WA
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Forestry & Society Site Index (SI 50 )/ Wenger 1984 Years Height (ft) Ponderosa pine in CA SI 50 SI 100
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Forestry & Society Silviculture/Site Quality/ Schultz 1997 Southwide Flatwoods (heavy clay) Plantation age (yrs) Southern Pines SI 25
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Forestry & Society Silviculture/DBH vs Hgt & Biomass - Shepherd1986 Biomass (kg) Height (m) 24 20 16 12 8 4 DBH (cm) Pinus radiata- NZ-16 yr plantation
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50 607080 Site Index Dry Weight (ton/ac) Age Needles Branches Total Forestry & Society Silviculture/Site Quality vs Biomass Distribution/ Tree Physiol. 3:42:1987
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Improvements in Southern Pine Silviculture J.For. 105(7):337:2007 Total Yield (ft 3 /acre)
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Artificial vs Natural Regeneration- Subalpine Forests Canada W.J. Appl. For. 23(1):46:2008 Planted 1,500 t/ha Stocking = 9,360 t/ha Seedlings/ha Clearcut Regeneration This is what they planted on 6 clearcuts Why plant when natural regeneration yields over 9,000 tree/ha? Sufficient seed rain occurs only within 70m of forest edge. Keep clearcuts <140 m wide! What species do you want?
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Natural regeneration after fire in Oregon J. For. 105(3):139:2007 Seedlings/ha Broad leaved vegetation (% cover)Distance from seed source (m) Upper boundary? Why do these 2 species react differently to cover?
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Forestry & Society Silviculture/Outline Allowable Cut Effect Site Index (SI) Regeneration Stocking Thinning Fertilization Competition Control Pruning Wood Quality Agroforestry
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Silviculture You can have either a bunch of little trees, or a few big trees. Not both!! 10 5025 100 1,000 10,000 100 Reineke’s -3/2 slope Norway spruce Scot’s pine DBH (cm) quadratic Stocking (trees/ha) For.Sci. 50(6)848:’05
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Forestry & Society Silviculture/Natural Regeneration Time 2,000,000 200,000 20,000 2,000 200 No./ha Volume Growth (m 3 /ha/yr) 5 10 15 20
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Forestry & Society Silviculture/Artificial Regeneration Time 2,000,000 200,000 20,000 2,000 200 No./ha Volume Growth (m 3 /ha/yr) 5 10 15 20
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Forestry & Society Silviculture/Clearcut does not eliminate species (necessarily)/ Bettis, 9th So.Silv.Res.Conf. Planted 600 tpa Stems/acre Pine Oak Ridge, TN
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Forestry & Society Silviculture/Clearcut does not eliminate species (necessarily)/ J.For. 24(1)37-44:2000 Stems/acre Coastal Plain, AL * * Planted 300 tpa
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Forestry & Society Old Orchard Plantation (NC)/Pinus strobus March1899April 1999 thinned J. For. 98:18-23:2000 SI 75 SI 56 SI 71 thinned BA (ft 2 /ac) Years
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Forestry & Society Old Orchard Plantation (NC)/Pinus strobus 1 % = % standing volume (gross volume less removals and mortality)
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Forestry & Society Conversion from Even-Aged to Uneven- Aged/ GTR SO 118, 1996 Southern Pine - 50 yrs old Removed 2,114 b.f. Reproduction DBH (in) Before After
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Forestry & Society Conversion from Even-Aged to Uneven- Aged/ GTR SO 118, 1996 Southern Pine - 50 yrs old Reproduction
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Forestry & Society Silviculture/Changing Harvest Strategies/ USFS SO-112, 1994 Ouachita Nat’l For. Harvested Acres Clearcut
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Annual productivity in PNW under different scenarios Ralston et al. Silva Fenn. 38(1):55:’04 Management Regime Even-aged –Unthinned –Thinned –Shelterwood Uneven-aged –Low diameter limit –Current diameter distribution –Heavy BDq selection Productivity (m 3 /ha/yr) –10.3 –10.9 – 6.2 –11.8 –10.0 – 8.3
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Forestry & Society Silviculture/Outline Allowable Cut Effect Site Index (SI) Regeneration Stocking Thinning Fertilization Competition Control Pruning Wood Quality Agroforestry
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Silviculture You can have either a bunch of little trees, or a few big trees. Not both!! 10 5025 100 1,000 10,000 100 Reineke’s -3/2 slope Norway spruce Scot’s pine DBH (cm) quadratic Stocking (trees/ha) For.Sci. 50(6)848:’05
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Forestry & Society Silviculture/ Stocking affects Growth/ Shepherd 1986 Basal Area DBH Stocking (trees/ha) DBH (cm) or BA (m 2 /ha)
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Forestry & Society Silviculture/ Stocking affects Growth/ USDA Hndbk 713, 1997 Trees/ha DBH (cm) Pinus taeda
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Forestry & Society Silviculture/ Stocking affects Biomass Distribution/ Shepherd 1986 92 127 171 190 (tons/ha) Pinus resinosa- (27 yrs) k
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Forestry & Society Silviculture/ Stocking affects Biomass Distribution/ Shepherd 1986 Pinus resinosa- (27 yrs) 2.4m 1.7m 1.2m 1.0m Trees/ha 550 107022204330 crown diameter 170 kg 120 kg80 kg40 kg Biomass
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Forestry & Society Silviculture/ Stocking affects Volume Growth/ Shepherd 1986 Basal Area (m 2 /ha) Volume growth (m 3 /ha) Pinus radiata- NZ
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Forestry & Society Silviculture/ Stocking Sue Nichols Lincoln National Forest
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Forestry & Society Silviculture/Outline Allowable Cut Effect Site Index (SI) Regeneration Stocking Thinning Fertilization Competition Control Pruning Wood Quality Agroforestry
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Forestry and Society The Future/Intensive Management Forest Fertilization
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Forestry and Society The Future/Intensive Management 2001 1.3 million acres fertilized in the SE 103,000 tons of urea applied –Cost: $50/ac in 2004 Fertilizer ≈ $20 (~150 lb/ac) Application ≈ $30 Mendell, SJAF 30(3):142:’06
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Forestry & Society Silviculture/Fertilization/ Shepherd 1986 Fertilizer Regime Height (m) Pinus radiata - 3.5 yr)
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Forestry & Society Silviculture/Weed Control & Fertilization/ New For. 14:233:’97 Herbaceous Cover (kg/ha) Tree Volume (m 3 )
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Ponderosa pine growth after 31 yrs vs competition/ PSW-RP-231, ‘97 Survival = 99% DBH = 7.8 cm Cover = 24,000 ft 2 /ac Pine cover = 100% Survival = 98% DBH = 6.11 cm Cover = 24,200 ft 2 /ac Pine cover = 50% Survival = 98% DBH = 4.56 cm Cover = 33,500 ft 2 /ac Pine cover = 33% Survival = 81% DBH =2.148 cm Cover = 33,150 ft 2 /ac Pine cover = 12%
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Forestry & Society Silviculture/Fertilization + Weed Control/ Shepherd 1986 Fertilizer Regime Height (m) Pinus radiata - NZ(4 yr)
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Forestry & Society Silviculture/Fertilization + Weed Control/ Shepherd 1986 Height (m) Pinus radiata - NZ(4 yr)
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Forestry & Society Silviculture/Fertilization vs Growth/ Schultz 1997 DBH (cm) Southern Pines
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Forestry & Society Silviculture/ Stocking affects Volume Growth/ PNW-RP-513, 1999 Treatment (initiated @ Age 9) Volume (cu ft) Douglas-fir-OR Plantation age
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Forestry & Society Silviculture/Outline Allowable Cut Effect Site Index (SI) Regeneration Stocking Thinning Fertilization Competition Control Pruning Wood Quality Agroforestry
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Forestry & Society Piece Size vs Value/ Barbour, USFS- 1999 8 foot log small end diameter (in) Value/log ($) veneer lumber pulp fuel
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Forestry & Society Product vs Value
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Forestry & Society Silviculture/Pruning vs Diameter Growth/ Shepherd 1986 DBH (cm) Yr-6 Yr-7Yr-8Yr-9 Pruning Year C CCCPPPP 52% 40% 32% 26% % pruned Pinus radiata/NZ
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Forestry & Society Silviculture/Pruning vs Clear wood/ Shepherd 1986 Pinus radiata/NZ 7 6 5 4 3 2 1 1st lift 2nd lift 3rd lift 0 10 20 Diameter from center (cm) Height (m) Clearwood zone Knotty core
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Forestry & Society Silviculture/Outline Allowable Cut Effect Site Index (SI) Regeneration Stocking Thinning Fertilization Competition Control Pruning Wood Quality Agroforestry
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H/R 302 Forestry & Society Agroforestry Systems/ Hardwood Matters July2001, p.4
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Agroforestry
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H/R 302 Forestry & Society Agroforestry Systems/ Clason & Robinson JF98:2000 Yr 20 520 tpa BA = 209 ft 2 Ht = 58’ DBH = 8.6 “ 250 tpa 27 cords/ac Yr 25 100 tpa 3 cords + 1,600 BF/ac Yr 30 50 tpa 1 cords + 2,100 BF/ac Yr 35 0 tpa 1 cords + 3,100 BF/ac Yr 25 50 tpa 3 cords + 2,000 BF/ Yr 30 50 tpa 0 cords + 3,000 BF/ Yr 35 0 tpa 0 cords + 4,000 BF/ 100 tpa 33 cords/ac Silvopasture Silviculture + 1 - 4 tons forage/ac/yr Establishment costs of pasture = $260-$470/ac @ yr 20 Annual fertilizer application ($60/ac/yr) to pasture also increases wood yield
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H/R 302 Forestry & Society Agroforestry Systems/ PSW-RP-242, 1999 Year Height (ft) Ponderosa pine, CA
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Forestry & Society Silviculture/Review Questions Define: allowable cut, site index, BA, rotation age, false ring, clear cut Describe different silvicultural practices (e.g. fertilization, weed control, etc), their uses and forest response. Describe the process of conversion from even-aged to uneven-aged management to a forest. Why would you want to do that?
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Forestry & Society Silviculture/Review Questions Discuss the changes in species composition, stocking and size over time in a forest ecosystem. Discuss the effects of clear-cutting and planting only one species on tree species diversity. Discuss the advantages and disadvantages of low stocking (300 trees/acre) compared to high stocking (1,000 trees/acre). What is agroforestry and why is it practiced? Compare natural vs artificial regeneration.
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Forestry & Society Silviculture/Review Questions What is the average DBH of sugar maple in a forest where there are 200 tpa with a BA of 60 ft 2 /ac Discuss the costs both economic and biologically of different harvest strategies.
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Change in harvest pattern for OR & WA Science Findings #89 / Jan’07 Time Period Annual Fraction of Forestland Harvested
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Forestry & Society Silviculture/Foliage Biomass vs Height/ Shepherd 1986 Height (m) Needle/total biomass (%)
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Forestry & Society Silviculture/Foliage Biomass vs Age/ Shepherd 1986 Plantation Age (yrs) Foliage Biomass (t/ha)
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Forestry & Society Silviculture/Changing NFS Harvest Strategies/ Policy Studies J. 23:274:1995
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