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 • Improve species composition • Improve stand health, quality, and value • Increase growth of residual trees • Enhance quality and value of residual trees

Study Sites • Two sites in Alabama – Westervelt Company • Southeastern Arkansas – Potlatch Corporation • East Texas – Temple-Inland Forest Products

Species Cherrybark oak CBO Quercus pagoda Quercus nigra Water oak WAO Willow oak WIO Quercus phellos

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

Epicormic Branches 16 14 Epicormic Branches 12 10 8 6 4 2 0 0 1 2 3 4 5 6 7 8 9 10 Years Since Thinning CBO Unthinned WAO Unthinned WIO Unthinned CBO Thinned WAO Thinned WIO Thinned

Epicormic Branches Cherrybark Oak 16 14 Epicormic Branches 12 10 8 6 4 2 0 0 1 2 3 4 5 6 7 8 9 10 Years Since Thinning D/CD Unthinned INT Unthinned D/CD Thinned INT Thinned

Epicormic Branches Water Oak 16 14 Epicormic Branches 12 10 8 6 4 2 0 0 1 2 3 4 5 6 7 8 9 10 Years Since Thinning D/CD Unthinned INT Unthinned D/CD Thinned INT Thinned

Epicormic Branches Willow Oak 16 14 Epicormic Branches 12 10 8 6 4 2 0 0 1 2 3 4 5 6 7 8 9 10 Years Since Thinning D/CD Unthinned INT Unthinned D/CD Thinned INT Thinned

Epicormic Branches Dominant/Codominant 16 14 Epicormic Branches 12 10 8 6 4 2 0 0 1 2 3 4 5 6 7 8 9 10 Years Since Thinning CBO Unthinned WAO Unthinned WIO Unthinned CBO Thinned WAO Thinned WIO Thinned

Epicormic Branches at Year 9 Dominant/Codominant Simple Linear Regression – r 2 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

Epicormic Branches at Year 9 Dominant/Codominant 30 Epicormic Branches 25 20 15 10 5 0 0 5 10 15 20 25 Pre-Existing Epicormic Branches CBO Unthinned WAO Unthinned WIO Unthinned CBO Thinned WAO Thinned WIO Thinned

Epicormic Branches at Year 9 Dominant/Codominant – Thinned Only E 9 = 5.11 + 0.93(E 0 ) – 0.08(D 0 ) r 2 =0.18 CBO r 2 =0.49 WAO E 9 = 0.32 + 1.10(E 0 ) + 0.19(%BA) - 0.07(D 0 ) E 9 = (-9.86) + 0.73(E 0 ) – 0.21(D 0 ) + 0.32(%BA) r 2 =0.56 WIO + 0.67(BA RES )

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

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

Factors Affecting Epicormic Branching Species Stress Sunlight

Questions? Steve Meadows smeadows01@fs.fed.us Merci beaucoup, y’all !!