Emerging Issues in
Arboriculture
Bob Polomski, Ph.D.
Clemson Extension Horticulturist
Clemson University, South Carolina
September 12, 2010
Emerging Issues in
Arboriculture
 Tree selection
 Production
 Planting
 Establishment
 Urban soil management (“soil
restoration”
 Plant Health Care
http://hort.ufl.edu/woody/planting
Tree Selection
 The search for the perfect
landscape/street tree
continues….
--evaluation of new
species and cultivars
Tree Selection
Biomechanics: study of
the structural behavior of
trees
 Study branch failures
 Learn why some trees
stay upright in a storm while
others fail;
 Prune to prevent storm
damage
Tree Production
 Effects on successful
tree establishment and
longevity
--evaluate container
types and container
treatments to reduce/
eliminate circling roots
Planting and establishment
An estimated 80 percent of all landscape
tree problems originating below ground
relate to quality and placement of the
root system. Structural root defects and
root planting depth issues can occur
during all stages of tree production and
establishment including nursery
propagation and production, landscape
specification development and planting,
and post‐planting and transplanting
maintenance.
Tree Selection
Tree Planting
• Bare root
--Develop methods and
products to use for bare-rooting
trees at planting time (root
washing, pressure washing,
and air excavation)
Bassuk, N. L. 1998. Creating the urban forest: the bare root method. 1998.
Urban Horticulture Institute Cornell University Ithaca, NY.
Tree Planting
 Bare rooting--technique to reveal tree
roots prior to finishing the planting or
transplanting process
 Need to see root defects--if possible,
correct and adjust planting height
“Bare Root to Bare Root – Coming Full Circle”
(www.mortonarb.org/deeptreeroots/pdf/LBG_Abstracts.pdf)
Tree Planting
 Bare rooting--technique to reveal tree
roots prior to finishing the planting or
transplanting process
 Need to see root defects--if possible,
correct and adjust planting height/depth.
“Bare Root to Bare Root – Coming Full Circle”
(www.mortonarb.org/deeptreeroots/pdf/LBG_Abstracts.pdf)
Tree Planting
 Plant trees at the
proper depth
--Deep roots of
landscape trees: A
comprehensive guide
to current research
and practice
(www.mortonarb.org/deeptrees)
Planting too deep is deadly
 93% of professionallyplanted trees (Smiley
and Booth, 2000)
 75% of nursery-grown
trees (Maynard 1995)
Tree Planting
 Container-grown
--evaluate root pruning
strategies: slicing,
shaving, bare rooting,
or butterflying
Alleviate root defects after planting and
ensure survival and vigorous growth of
trees after planting.
Planting and establishment
 Container-grown
--evaluate root pruning
strategies: slicing,
shaving, bare rooting,
or butterflying
Post-planting
survival and
establishment
• New technologies to
improve post-plant
survival and stress
resistance in urban trees,
e.g., biostimulants,
humectants, mycorrhizae,
etc.
Established Trees
 Urban soil management (“soil restoration”)
--Root Invigoration®
Established Trees
 Urban soil management (“soil restoration”)
--Root Invigoration®
Established Trees
Planting and Establishment
 Urban soil management (“soil restoration”)
--Root Invigoration®
--Aerated Compost Tea (ACT)
www.masslaboratory.org/mass_015.htm
Planting and establishment
 Urban soil management (“soil restoration”)
--Root Invigoration®
--Aerated Compost Tea (ACT)
--Biochar – carbon-rich product (wood,
manure, leaves) heated in absence of O2
Planting and establishment
http://abcnews.go.com/GMA/Jus
tOneThing/video/green-plantsoil-biochar-11486209
Plant Health Care: Pests
 Emerald ash borer
(Agrilus planipennis)
--Native of China and Eastern Asia
--Michigan in 2002
-13 states and parts of Canada
www.agri.ohio.gov/divs/plant/eab/eab-index.aspx
PHC: Pests
 EAB management
www.emeraldashborer.info/files/Multistate_EAB
_Insecticide_Fact_Sheet.pdf
PHC: Pests
 Walnut twig beetle and
thousand cankers disease of
black walnut (Juglans
nigra)—insect-disease
complex
Geosmithia sp.
Fusarium solani
PHC: Pests
 Walnut twig beetle and
thousand cankers disease of
black walnut (Juglans
nigra)—insect-disease
(Geosmithia sp. and Fusarium solani)
complex
 1990s Utah
 2001 New Mexico
PHC: Pests
 Walnut twig beetle and
thousand cankers disease
--Black walnut decline
PHC: Pests
 Asian long-horned
beetle (Anoplophora glabripennis)
--native to Japan, Korea, and China
--1996 discovered in Brooklyn and Amityville, NY
--Maples and horsechestnuts, also ash, poplar, willow, elm,
mulberry, and black locust
PHC: Pests
 Asian long-horned beetle
PHC: Pests
 Asian long-horned beetle
Plant Health Care
 Novel disease control compounds to
reduce pesticide usage in the
arboricultural industry:
--“Biopesticides” - synthetic or natural
compounds such as plants, microorganisms,
and certain minerals
control pest and foliar diseases.
Arboricultural Research
 Research
 More research
 Even more research
Application
“With great power…
Comes great responsibility.”
Only you can speak for trees.
Angel Oak, Charleston, SC