Strengthening our Community Tree Canopy Through Education Module #7: Root Pruning Laura Sanagorski, Environmental Horticulture Extension Faculty

Strengthening Our Community Tree Canopy 2012 Urban Forestry Series This series is a part of a project titled “Strengthening Our Community Tree Canopy Through Education”. This project is made possible by  a grant through the 2011 National Urban and Community Forestry Grant Program and the Florida Department of Agriculture and Consumer Services, and the Florida Forest Service.

Root Pruning

Root Pruning – the Need Correct defects at planting Reduce size of rootball for transplant Address conflict with hardscape

Root Pruning – Defects discovered at planting Circling roots Matted roots deflected downward Excess soil on top of rootball Circling / Girdling – roots that grow around the trunk of a tree rather than laterally away from it that constrict the other roots or the trunk, restricting growth. Photo: UF Laura Sanagorski

Circling / Girdling root systems often cause failure Photo: UF Laura Sanagorski

Circling / Girdling root systems often cause failure Photo: UF Laura Sanagorski

Circling / Girdling root systems often cause failure Photo: UF Laura Sanagorski

Circling / Girdling root systems often cause failure – can this be avoided? Photo: UF Laura Sanagorski

Planting space, planting depth, and/or improper mulch can cause circling / girdling root systems Photos: UF Laura Sanagorski

Root Pruning – Equipment Sharp Shovel Pruning Shears Air Spade / Air Excavator Trench cutter 

An arborist using a tree spade to root prune air excavator ( ) An arborist using a tree spade to root prune Luana Vargas, International Society of Arboriculture, Bugwood.org

Root pruning at planting - Slice & remove outer ½ - 1” of rootball – preferable to radial slicing Photo: UF Laura Sanagorski

CIRCLING ROOT REGENERATION Defective roots can often be cut as remedy

Root pruning – How Much? No more than 25% - 30% Severance of major support roots may compromise integrity As trees age, they can’t withstand as much Photo: UF Laura Sanagorski

Root pruning - staking A must if major roots or large percentage are cut Photo: UF Laura Sanagorski

Strengthening our Community Tree Canopy Through Education Module #7: Root Pruning Laura Sanagorski, Environmental Horticulture Extension Faculty