Maple Tree Soil Applications Research Project

2012 | Dr. Yvonne Boldt, Providence Academy

The Maple Tree Soil Application Research Project is designed to study the impact of fertilizer and organic amendments on tree growth and health, and on the biological community of microorganisms that both compete and cooperate with the trees in an urban soil ecosystem. The project is utilizing 54 Autumn Blaze maple trees planted on Providence Academy (PreK-12  school) property. The site is ideal for an outdoor experiment due to many naturally occurring controls.  The trees are planted in a row, equally spaced, watered regularly, and have no other vegetation except grass competing for nutrients or sunlight. The experiment utilizes a random block design with six trees in each block.  Each block has a bare soil control and five test groups which include: 1. compost (C:N ratio 22:1), 2. compost (C:N ratio 35:1), 3. wood mulch (C:N ratio 114:1), 4. fertilizer (TN booster), and 5. fertilizer plus wood mulch. We have collected data on tree growth and health (trunk diameter, leaf chlorophyll, leaf area and mass, leaf mineral content) and soil physical and chemical properties for two summers (2010, and 2011).  In 2011 we collected soil samples to initiate a metagenomics (DNA based) analysis of microorganisms, especially bacteria and fungi, present in the soil. This data will enable us to determine the impact of organic amendments and fertilizer on the soil community.  From this data we propose to determine which type of application – compost, wood mulch, or fertilizer – most positively enhances both tree growth and health, and the health of the soil ecosystem as a whole. These results will form a basis for the arboricultural industry to make better decisions regarding the use of soil amendments in promoting tree growth and health in urban environments.


For more information on this project, contact the researcher via TREE Fund at