Climbers' Corner • Tree Academy
Monday • Tuesday • Wednesday
Evaluation of Established Trees Planted in Structural Soils
Summary
Loam
Soil under Suspended Sidewalks (LSSS) and Sand Based Structural Soil (SBSS) are
currently used to improve the growing conditions of street trees. There has been little evaluation of the effectiveness
of these approaches and both are currently being used in many locations around
the United States. The LSSS approach was first used on a large scale in
Bethesda, Maryland. Between 1983 and 1990, approximately 25 blocks of street
trees were planted during a series of citywide streetscape improvement
projects. In Boston, Massachusetts, a
large number of projects including the Rose Kennedy Greenway were built between
2003 and 2008 using the SBSS approach.
During this same period a number of other Boston projects including one
block of the Greenway and the Convention Center were built using the LSSS
approach. In each city, the number of
trees is sufficiently large, of reasonable maturity and consistency in
construction, and with sufficiently diverse species to provide a set of
conditions to be the basis for a case study of each approach. Data was collected in Boston in 2011 and
2013. The Bethesda data was collected in
2013. Approximately 400 trees were
evaluated for their growth rates and general health. This data along with information on how each
approach was constructed and maintained will be presented as a comparative case
study. The presentation will include the
results of the growth and health ratings, as well as a discussion on
construction, lessons learned and cost.
Presenters
James
R. Urban, ISA, FASLA
James Urban specializes in the design of
trees and soils in urban spaces. He has written and lectured extensively on the
subject of urban tree planting and has been responsible for the introduction of
many innovations including most of the current standards relating to urban tree
plantings. His 2008 book ‘Up By Roots:
Healthy Trees and Soils in the Built Environment’, is becoming one of the
principle tree and soil references.
James
Urban was instrumental in the development of structural cells and structural
planting soils for use under sidewalk pavements, and is credited with helping
to re-awaken the profession of landscape architecture to the skills required to
successfully plant trees in difficult urban soils. In 2007 he was awarded the
ASLA Medal of Excellence for this contribution the profession of Landscape
Architecture. He is the 2013 recipient of the ISA Award of Achievement for
long-term contributions to the profession of arboriculture.
Dr. Tom Smiley is an arboricultural
researcher at the Bartlett Tree Research Laboratory in Charlotte, NC and an
adjunct professor of Urban Forestry at Clemson University.
Dr. Smiley
is active in the arboriculture industry and has co-authored the ISA’s Best Management Practices for Tree Risk
Assessment, Lightning Protection, Fertilization, Support Systems and
Construction Management.
His research has lead to improved
methods of increasing sidewalk longevity near trees, protecting more
trees from lightning damage, improving tree root growth in compacted soil using
the patented Root Invigoration
process, and predicting tree failures.
Climbers' Corner • Tree Academy
Monday • Tuesday • Wednesday