Welcome from the Northland
Trees, Roots, Myths, and Mayhem
22nd Annual Northwest Urban Forestry Workshop
March 31, 2006 – Crookston, MN
Richard Hauer, Ph.D.
College of Natural Resources
University of Wisconsin-Stevens Point
Sometimes the Obvious is Wrong!
What’s the Worst that can Happen!
Scandinavian Irrigation
Bulldozer Bob Sez, Never Killed a Tree!
What’s Wrong? Is it the Tree, Site, or Person?
1
Silvics:
The Why and
Where Trees Grow
Trees and Woody Plants Are Adaptable!
Biology is the Basis of How Much They Adapt!
What do
you want?
Silvics of North America:
http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm
Genotype + Phenotype = What you Get
Is this what you want?
1) Goals
2) Vision
3) Desires
How Does a
Tree Grow?
Trees are the oldest and largest (ancient sitka spruce)
Tree Defense Mechanisms
Why do
Trees Die?
The Decline
or Mortality
Spiral
2
Non Apparent
Norway Maple Decline
Advanced
It started with a request
to verify verticillium wilt.
“most functioning roots
were near the surface”
and injury would result
if these were buried
1618, William Lawson
A New Orchard & Garden
What’s the Problem?
The Plant’s Response
• Genotype versus Phenotype
• Normal versus Abnormal
Tree Care
Based on
Tree Biology
What is the Tree Treatment and it’s Merit!
3
Tree Biology 101
(aka Tree Structure and Function and
associations with the Environment)
Basic Tree Biology: Anatomy
• Anatomy
• Physiology
• Pathology, Entomology, Environmental
Factors (aka Bugs and Crud)
• Ecology
Leaf Cross Section
Meristems
Trees are Generators and Regenerators
Basic Tree Biology: Physiology
How Does Water Move in Plants?
Soil
Plant
Atmosphere
Continuum
H2O Loss
Trees Manufacture and Respire
Basic Tree Biology – PHC
(PHC = Plant Health Care)
Environmental
Factors
CO2 entry
Basic Tree Biology: Ecology
• Trees and Associates
• Trees and People
Pathology
Entomology
4
System Approach to
Understand Trees
There are two types of growth in plants:
Primary growth and Secondary growth
Growth defined…
• What is a System?
kinetic + CO2 + H2O
energy
• System: orderly collection of parts and
processes
CH2O + O2 + potential
energy
Kinetic Energy: from the sun
Potential Energy: in bonds in chemical compounds
• Energy keeps systems in order
Stress, Strain, and Askenasy
Energy Reserves: Storage
Growth
Starch a
measurable
indicator of
Tree Health
The Plant Connection System
Symplast
(Living)
Apoplast
(non-living)
Plant Growth Regulators
• Also called plant hormones
– http://www.plant-hormones.info/
• Examples
–
–
–
–
–
Auxin
Gibberellins
Cytokinin
Abscisic Acid
Ethylene
5
Pruning at Planting
an Auxin Story (Walmsley 1985)
Tim the Rhizologist asks …
What and Where
are Tree Roots
and Why?
Red maple (Acer rubrum) structural roots
Surface roots of green ash (Fraxinus pennsylvanica).
6
Adventitious roots and shoots (Tilia cordata).
Green ash adventitious roots.
Sugar maple adventitious roots.
Mulch line
Soil line
Structural Roots
Wilson, B. 1967
Roots graft to roots!
Stems graft to stems!
7
Root and stem tissue do not graft!
Sudden tree failure(s) from SGR’s during wind storm.
Norway maple (Acer platanoides) sudden failure from SGR’s.
Decline of green ash (Fraxinus pennsylvanica), SGR induced.
Percent of Stem Encircled by Roots Related to Depth.
Mean Percentage of Stem Girdled by Roots
Borst and Johnson 1999
100
35
Ash
90
Ash
30
Linden
80
25
Percent Encircled
Percent Girdled
Linden
Both
20
15
10
70
60
50
40
30
20
5
10
0
0
1
2
3
4
5
Depth (inches)
6
7
8
9
0
0
1
2
3
4
5
6
7
8
9
10
11
Depth (inches)
8
Percent of Total of Depth to
First Main-Order-Lateral Root
Storms of 1998 and Tree Failures,
Trees Planted to deep and SGR’s
25
881 Sampled Trees
Percent of Total
20
Sources (Johnson and Johnson
1997, Borst and Johnson 1999,
Minneapolis Park and Recreation
Board 2000)
15
• 73% of Little leaf linden’s
• 17.8% of all tree failures
10
• 30.1% of all tree failures outside of storm center’s
5
0
0
1
2
3
4
5
6
7
8
9
10
11
• 50% of trees in 6 to 10” DBH with SGR’s
Depth (inches)
Stem Girdling Roots and Tree Loss:
What practitioners said in 1997 survey
• Tree decline and death
82% of time
• Sudden failure of tree
18% of time
Did you Get What you Paid for? Measuring a B&B root ball.
Finding structural roots in B&B nursery stock.
9
End result of
root system
examination.
Use of compressed air to examine root systems/removal soil.
The End!
10