Rehabilitation of Severely Compacted Urban Soil to Improve Tree Establishment and Growth

Land development restricts tree growth by damaging soil structure and removing organic matter. Mechanical loosening and organic amendment may improve soil physical properties and tree establishment and growth. Effects of typical post-construction practice and improved methods of soil restoration on tree growth and soil properties were evaluated over two years. Treatments included undisturbed soil (UN); minimum effort (ME) (10 cm topsoil); enhanced topsoil (ET) (ME + rototilling); and profile rebuilding (PR) (compost, subsoiling, topsoil and rototilling). Pretreatment included removing topsoil and compacting subsoil to 1.95 g/cm3 bulk density. Acer rubrum L. (red maple), Quercus bicolor Willd. (swamp white oak), Ulmus 'Morton' (Ulmus japonica (Rehd.) Sarg. x Ulmus wilsoniana Schneid.) (Accolade® elm), Prunus 'First Lady' (Prunus xincam x Prunus campanulata) L. and Quercus macrocarpa Michx. (bur oak) were planted in each plot. The PR treatment reduced soil bulk density at 15-20 cm depth and increased soil C/N ratio, pH, and CEC. Mean canopy projection and cross-sectional trunk area in PR plots ranged from 32% to 226% and 16% to 71% greater, respectively, than those in ME plots. PR treatment increased Q. bicolor photosynthesis rates. Greater root presence was observed in deeper soil layers of ET and PR treatments for A. rubrum and of UN and PR for Q. bicolor; root distribution was not measured for other species. Rehabilitation improved soil physical properties and tree growth after two years. Species variation in growth rate and environmental tolerance appeared to influence early growth treatment effects. Long-term data is needed to fully understand effects of soil rehabilitation.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Horticulture

Department dc:contributor.department

Horticulture

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2010

Author dc:creator

• Layman, Rachel Montgomery

Chairs dc:contributor.committeechair

• Harris, James Roger
• Day, Susan D.

Committee members dc:contributor.committeemember

• Wiseman, P. Eric
• Daniels, W. Lee

• canopy
• tree roots
• minirhizotron
• organic amendment

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Dc Identifier Other

etd-12142010-150948

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/76910