Strengthening our Community Tree Canopy Through Education

Module #9: Root Barrier Selection & Installation

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 Barrier Selection / Installation

Root Barriers – the Need Installed

vertically Prevent root

penetration, redirect growth

Protection of new and existing utilities

Photo: UF Laura Sanagorski

Root Barriers – the Need Tree

relocation Deflecting

roots near sidewalks

Large trees planted near foundations

Photo: UF Laura Sanagorski

Root Barriers - Types Chemical Physical

Two dimensional

Three dimensional

Inhibitors – fabric embedded with herbicide (often trifluralin)

Traps – (woven nylon / copper screen) allow penetration but not enlargement

Deflectors – physical barrier: redirect growth

Coarse gravel

Root Barriers: Configuration

Linear – Along Narrow Trench

Circular – Around ball of Newly Planted Tree

Photo: NDSPhoto: Root Barriers

Brisbane

Root Barriers - Design

Vertical ribs – deflect roots downward

Locking wings or tabs

Newer barriers have more rugged tops

Photo: NDS

Root Barriers - Homemade Coarse gravel Tubing Screen Fabric

Image: Justin Morganroth

Root Barriers – Testing Treatments

Biobarrier – most effective at deflecting roots deeper

DeepRoot – not effective in reducing root growth in top 4” of well-drained or poorly-drained soil

Polyethylene Plastic - not effective in reducing root growth in top 4” of well-drained or poorly-drained soil

Clean gravel- only one effective

No effect on root diameter Photo: Biobarrier

Adapted from Gilman, 2006.

Root Barriers - Installation Recommended

to be done by a qualified tree professional

Gilman (2006) recommends installation at deeper than 12”

Strengthening our Community Tree Canopy Through Education

Module #9: Root Barrier Selection & Installation

Laura Sanagorski, Environmental Horticulture Extension Faculty