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Production After Thinning in Bottomland Hardwood Stands in the - - PowerPoint PPT Presentation
Production After Thinning in Bottomland Hardwood Stands in the - - PowerPoint PPT Presentation
Prediction of Epicormic Branch Production After Thinning in Bottomland Hardwood Stands in the Southern United States Steve Meadows USDA Forest Service Center for Bottomland Hardwoods Research Stoneville, Mississippi Thinning Objectives
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Thinning Objectives
- Improve species composition
- Improve stand health, quality, and value
- Increase growth of residual trees
- Enhance quality and value of residual trees
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Study Sites
- Two sites in Alabama – Westervelt Company
- Southeastern Arkansas – Potlatch Corporation
- East Texas – Temple-Inland Forest Products
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Species
Cherrybark oak CBO Quercus pagoda Water oak WAO Quercus nigra Willow oak WIO Quercus phellos
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Sample Sizes and Range in DBH (cm)
Unthinned Thinned TOTAL Species n Dbh n Dbh Cherrybark oak 79 14-94 150 14-90 229 Water oak 93 14-80 209 16-81 302 Willow oak 187 14-66 376 14-84 563 TOTAL 359 735 1094
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Epicormic Branches
2 4 6 8 10 12 14 16 1 2 3 4 5 6 7 8 9 10
Epicormic Branches Years Since Thinning
CBO Unthinned WAO Unthinned WIO Unthinned CBO Thinned WAO Thinned WIO Thinned
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Epicormic Branches
Cherrybark Oak
2 4 6 8 10 12 14 16 1 2 3 4 5 6 7 8 9 10
Epicormic Branches Years Since Thinning
D/CD Unthinned INT Unthinned D/CD Thinned INT Thinned
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Epicormic Branches
Water Oak
2 4 6 8 10 12 14 16 1 2 3 4 5 6 7 8 9 10
Epicormic Branches Years Since Thinning
D/CD Unthinned INT Unthinned D/CD Thinned INT Thinned
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Epicormic Branches
Willow Oak
2 4 6 8 10 12 14 16 1 2 3 4 5 6 7 8 9 10
Epicormic Branches Years Since Thinning
D/CD Unthinned INT Unthinned D/CD Thinned INT Thinned
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Epicormic Branches
Dominant/Codominant
2 4 6 8 10 12 14 16 1 2 3 4 5 6 7 8 9 10
Epicormic Branches Years Since Thinning
CBO Unthinned WAO Unthinned WIO Unthinned CBO Thinned WAO Thinned WIO Thinned
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Epicormic Branches at Year 9
Dominant/Codominant
Simple Linear Regression – r2 CBO WAO WIO Unthin Thin Unthin Thin Unthin Thin Initial DBH 0.23 0.10 0.23 0.07 0.37 0.23 Initial Epics 0.49 0.13 0.32 0.43 0.81 0.46 Residual BA
- 0.03
- 0.02
- 0.02
Percent Cut
- 0.01
- 0.05
- 0.04
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Epicormic Branches at Year 9
Dominant/Codominant
5 10 15 20 25 30 5 10 15 20 25
Epicormic Branches Pre-Existing Epicormic Branches
CBO Unthinned WAO Unthinned WIO Unthinned CBO Thinned WAO Thinned WIO Thinned
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Epicormic Branches at Year 9
Dominant/Codominant – Thinned Only
CBO E9 = 5.11 + 0.93(E0) – 0.08(D0) r2=0.18 WAO E9 = 0.32 + 1.10(E0) + 0.19(%BA) - 0.07(D0) r2=0.49 WIO E9 = (-9.86) + 0.73(E0) – 0.21(D0) + 0.32(%BA) + 0.67(BARES) r2=0.56
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Preliminary Conclusions
- Species differed in the number of epicormic
branches produced on the butt log in both unthinned and thinned stands
- Crown class (indicator of tree health) strongly
influenced production of epicormic branches
- Number of pre-existing epicormic branches was
the most accurate single-variable predictor of epicormic branch production in dominant and codominant trees of all three species
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Preliminary Conclusions
- Stand density variables had little or no effect on
epicormic branch production in dominant and codominant trees after thinning – especially true for cherrybark oak
- Multiple regression did not greatly improve the
prediction model relative to the simple regression model with number of pre-existing epicormic branches as the single independent variable
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Factors Affecting Epicormic Branching
Species Sunlight Stress
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