Colorado State Forest Service 719.383.5780
http://csfs.colostate.edu/pages/lajuntadist.html
Trees, Turf and ConcreteMaintaining and Growing Healthy Urban Trees
A forum for grounds maintenance crews in Southeastern Colorado
http://csfs.colostate.edu/pages/lajuntadist.html�
Resource LinksNational Arbor Day Foundation www.arborday.org (links to
planting, pruning, and other tree care information) International Society of Arboriculture, Tree Care Information
http://www.treesaregood.com/treecare/treecareinfo.aspxPruning-Dr. Ed Gilman, University of Floridahttp://www.sactree.com/assets/files/greenprint/toolkit/a/pru
ningComplete.pdf International Society of Arboriculture
www.isa-arbor.comColorado Tree Coalition www.coloradotrees.orgTree Information for Southeastern Coloradohttp://csfs.colostate.edu/pages/lajunta-community-
forestry2.html#arboriculture
http://www.arborday.org/�http://www.treesaregood.com/treecare/treecareinfo.aspx�http://www.sactree.com/assets/files/greenprint/toolkit/a/pruningComplete.pdf�http://www.sactree.com/assets/files/greenprint/toolkit/a/pruningComplete.pdf�http://www.isa-arbor.com/�http://www.coloradotrees.org/�http://csfs.colostate.edu/pages/lajunta-community-forestry2.html�http://csfs.colostate.edu/pages/lajunta-community-forestry2.html�
3
Maintaining Healthy TreesGuidelines for Keeping Trees Healthy
(BTW: There is no such thing as a maintenance-free Tree!!)
4
From Arbor Age Magazine, November 1999
Remember how nutrients and water travel within a tree
5
Avoid Lawnmower and Weed-trimmer Damage!!
• When the bark of trees is damaged, it also damages the cambium layer: this layer of cells is what transports water and nutrients to the rest of the tree.
• Trunk girdling of trees by lawnmowers and weed-trimmers is the NUMBER ONE cause of tree decline and death!!
6
Give Trees Their Own Space to Grow
9
Minimize Weed/Grass Competition and protect tree trunks by Mulching
Mulching Options:• Install water permeable weed barrier in a 6’ diameter
area around new tree plantings, or older plantings that are struggling for water resources in lawns or weedy areas.
• Organic mulch, such as wood chips, can also be utilized in the same manner to help conserve moisture.
• Rock mulch is also a great option. • OR combine both weedbarrier and mulch!• Mulch also minimizes grass from growing around the base
of trees and thus minimizes the need to mow or weed-whip right next to tree trunks.
Synthetic weedbarrier mulch, plus rock mulch, plus protective edging
Weedbarrier must be cut back slightly from the base of the tree every few years to prevent
girdling of the trunk
Woodchip Mulch• 3 to 4 inches deep• Keep away from trunk of tree• Mulch WIDE, not deep
Courtesy of ISA “Trees Are Good”
13
Proper Watering for Trees• Tree roots ARE NOT like carrots!
• Water absorbing roots occur within the top 12-18” of the soil, and can spread up to 4 times the height of a tree if given the opportunity.
• Trees must be DEEP WATERED: this means establishing soil moisture within the top 12-18” of soil, and doing this within the critical root zone.
• Shallow frequent watering, such as is done with lawns much of the time, is not sufficient enough to keep a tree healthy.
• During the fall and winter trees must also be watered when it is dry.
14Critical Root Zone
Picture Courtesy of www.watersaver.org
15
Deep WateringTrees must be DEEP WATERED: this means establishing
soil moisture within the top 12-18” of soil, and doing this within the critical root zone, or drip line.
Drip Line
Water Here
The length of time it takes for water to reach 12-18” into the soil depends on site conditions:Type of soil, possible soil compaction.
Sandy soils will need more frequent watering thanLoamy or clay soils, with clay soils retaining water the longest
17
Weed Control Around Trees• Repeated applications during a growing season of
any broad-leaf herbicide (such as 2-4D) can eventually cause health decline in trees.
• Applications of soil sterilents, such as dicamba or imazapyr, can cause severe tree decline and death with only one application.
• It is recommended to use only glyphosate (such as Round-Up®) at a 1% solution within tree root zones. Do not let herbicide come into contact with the trunk or foliage of the tree, and do not use during high temperatures (above 80 degrees), windy conditions, or during temperature inversions.
18
Tree Death Caused by soil sterilant (dicamba) applied within root zones of trees
19
2-4D and Banvil damage to hackberry
20
Staking• Tree staking is generally not recommended• Never use wire or hose, or any other stiff material to
stake trees: these rub on the bark, causing damage and entry points for insects and disease.
• Only use soft materials, such as nylon strapping, old jeans, ect.
• Do not ‘cinch’ down the tree with the staking materials: give the tree room to ‘sway in the breeze’, but keep tight enough so if the wind blows hard, the stakes will keep the tree from bending.
• Ideally, stakes should be removed after a year, or if you feel you still need them, loosen the ties every year so they do not become tight around the tree.
STAKING Staking trees not always necessary
-Causes less trunk taper-Causes smaller root system- Tree more subject to breaking,
tipping-May injure the tree
Staking needed in some situations-bare root trees-large conifers-windy sites-sandy soils-tall trees-reduce vandalism-Remove after 1 year!
Photo Courtesy South Dakota State University
Fertilizing
Remember Trees ARE NOT an annual crop or grass
-Woody
-Slower Growing
-Large
-Long lived (decades/centuries)
They do not need the large doses of fertilizer, especially Nitrogen, that are often applied to
crops and lawn grasses
Basic Material Composition of Trees
• 80% Water mostly taken up from soil
• 19% Carbon, Hydrogen, Oxygen derived from water and carbon-dioxide gas
• 1% Essential elements mostly taken up from soil
Source: Dr. Kim Coder, Warnell School, U of Georgia
SE CO Soils/Water• Typically high alkaline content• Typically high clay content• Typically high salt concentrations in water• If you really want to know what your soils are
lacking relative to TREES, do a soils test; find out what TYPE of soil you have in areas where trees are growing or in potential growing sites, and find out the concentrations of elements: Calcium, Magnesium, Phosphorus, Sulfur, Nitrogen, Potassium
Most Fertilizers are in the form of SALTS
• We have alkaline soils• We have high salt content in our water• Many trees are not tolerant of high salt
concentrations
• Add excess salty fertilizer and your trees will begin to stress
• This a very common problem of Pines, especially ponderosa pine, in SE CO
Questions to ask before tree fertilizing• Do your trees actually show a symptom of
deficiency? (discoloration of leaves, leaf scorch)• Is your tree suitable for the soils it is planted in?
(silver maples do not like clay/alkaline soils)• What is the “normal” color of your trees leaves
(may differ at different times of the year)?• What is the “normal” growth rate of your tree?• Is lack of deep watering actually the cause
of stress?
Do your trees truly need fertilizing?
• Most trees, if adapted to a site, should really not need much, if any, fertilizing
• If fertilizer is deemed necessary (typically by soils testing, and/or tissue testing by a lab), then fertilize your trees:
-once a year just before bud break
-Use a LOW nitrogen fertilizer
-Use a slower release fertilizer
Over-fertilizing Impacts to Trees
• Excess salt stress• Excess nitrogen unnaturally pushes a tree
to grow more foliage. This is at the expense of other tree functions, like root growth and insect and disease defense mechanisms.
• Research has shown that over-fertilized trees tend to show more stress and insect and disease problems.
Basic Pruning GuidelinesThere is a science behind pruning. Knowing
where to make your cuts is critical for tree health.
32
33
Sources for Pruning Presentation
1. Gilman, Edward F. An Illustrated Guide to Pruning Second Edition. USA: Delmar, 2002. Website: www.hort.ifas.ufl.edu/woody/pruning
2. Shigo, Dr. Alex L. Pruning Trees Near Electric Utility Lines. New Hampshire: Shigoand Trees, Associates, 1990.
3. Shigo, Dr. Alex L. Caring for Young Trees From Nurseries to Landscapes. New Hampshire: Shigo and Trees, Associates, 1990.
4. International Society of Arboriculture. (a)Pruning Young Trees (1997), (b)Pruning Mature Trees (1997), (c) Why Topping Hurts Trees (1997), (d) Why Hire an Arborist(1995). USA: International Society of Arboriculture. Website: www.isa-arbor.com
5. Fazio, Dr. James R. (a)Tree City USA Bulletin No.1: How to Prune Young Shade Trees(2000). (b) TCUSA Bulletin No.2: The Way Trees Work (1998). (c) TCUSA Bulletin No.8: Don’t Top Trees (1999). Nebraska: National Arbor Day Foundation. Website: www.arborday.com (go to ‘trees’ and choose ‘Pruning Guide’)
6. Dr. Whiting, David. Colorado State University, Landscape/Horticulture Department
34
Pruning Objectives
• Most Important: To Develop Structure in Young Trees
• Removal of Codominant Stems
• Removal of Included Bark
• Maintain Structure in Mature Trees
• Removal of Dead or Diseased Branches
• Removal of Crossing and Rubbing Branches
• Removal of Hazard Limbs
• Safety Clearance (road signs, pedestrians)
• Electrical Line Clearance
1. Step Away from the Tree
2. Determine WHY the tree needs pruning—What are your OBJECTIVES
35
Pruning for Structure Prune early in the life of a tree
Source 5a
Pruned When Young
Not Pruned When Young
36
Structure . . .
Poor Structure = multiple stems (trunks) and many ‘V’ connected branches
Good Structure = one main stem (trunk) and nicely spaced, ‘L’ connected, scaffold branches
37
The Basic Pruning Cut:
•ID the Branch Bark Ridge
•ID the Branch Collar
Source 2
Use care not to wound the trunk when pruning
Make 3 cuts to remove large branches
38
The Basic Pruning Cut
Source 2
Collars grow at different angles. Identify the collar, and make your cut just outside of the collar.
39
Make the final cut just outside the branch collar.
Source 6
Branch Bark Ridge
Branch Collar
Final Cut-just outside of collar
40
Make the final cut just outside the branch collar.
Source 6
Branch Bark Ridge
Branch Collar
Make Final Cut-just outside of collar
42
Do not make flush or stub cuts. These cuts compromise the function of the collar. The collar contains a ‘chemical boundary’ which resists the
spread of fungi and helps the wound close.Source 3
Tree Cross SectionChemical Boundary
Stub Cut
Flush Cut
Correct Cut: just outside collar
43
Flush Cuts, Stubs, and Wound Painting . . . Poor Pruning Practices
Flush Cut = removing the collar and/or the branch bark ridge
Wound Painting has not been found to decrease the likelihood of decay.
Stub Cut = leaving too much of a branch beyond the collar
Source 1 Source 3
44
Codominant Stems . . Branches that are missing collars
45
Codominant StemsCodominant stems do not form a ‘chemical boundary’ because they do not have a collar—they have grown too close together.
Source 1
Non-Codominant branch unions: The “L” or “U” Connection-STRONGER. Has collar.
Codominant Stems: The “V” Connection-WEAKER. No collar.
46Source 1
Pruning Codominant Stems
To remove one stem, begin from point #1 and cut up to point #2 (red line), just to the outside edge of the bark ridge.
Point #1 should be even with point #3 (blue line), which is the base of the bark ridge.
2
1
3
*Remember, for branches greater than 1 inch diameter, cut the weight of the branch off first before making the final cut*
47Source 1
Included Bark
Stems with Included Bark: Missing BOTH Collar AND Bark Ridge
Included bark: branches with bark pinched between the trunk and the branch—they are “squeezed” together.
The bark does not grow together.
Branches with included bark actually “push” against one another, have no collar, and do not have a bark ridge.
These are very WEAK branch unions!!
48
Included bark with no bark ridge or collar
Base of included
bark
Begin your cut at point #1 and cut up
to point #2 (red line)
21
Pruning Included Bark
Source 1
49
Strong Unions Vs. Weak Unions
This is a weak union. These are codominantstems. They are shaped in a ‘V’. There is not a branch collar present.
This is a strong union. The union is more of a ‘L’ shape. There is a branch collar present.
It took twice as much load to break the smaller, ‘L’ shaped branch (56 kg), than it did to break the larger ‘V’ shaped branch (27 kg). Your goal is to try to remove codominant and included bark stems and branches BEFORE they become very large. The larger they get, the more of a chance they will break off during high wind storms, causing serious damage to the tree and whatever else is in its path.Source 1
50
Crossing and Rubbing-remove any time
Avoid the “Pom-pom”(Technical term = Lion’s Tailing)
52
When pruning ‘up the trunk’, always keep at least 1/2 of the foliage in lower 2/3s of tree.
Pruning up too fast:
-Causes Less trunk taper
-Increases wind sail-Increases sunscald-Causes the tree to be
structurally unstable1/3
53
• Dead and Diseased Wood . . . Prune at Any Time
• Crossing and Rubbing. . .Prune at Any Time
• Hazard Limbs . . . Prune at Any TimeA HAZARD TREE has a structural defect that may cause a portion of the tree or the entire tree to fall on someone or something—A TARGET.
Pruning Tips . . .
• When to PruneWINTER Pruning during dormancy is the most common practice. It results in a vigorous burst of new growth in the spring. It also helps to avoid insects that are attracted to fresh wounds (bronze birch borer). Do not prune during freezing weather.
SUMMER To direct the growth by slowing the branches you don’t want, or to slow or ‘dwarf’ the development of a tree or branch, pruning should be done soon after seasonal growth.
FALL Because decay fungi spread their spores profusely in the fall and closure of wounds seems to be slower on fall cuts, fall is generally not recommended.
FLOWERING TREES To enhance flowering: 1. For trees or shrubs that bloom in the summer or fall on current year’s growth, prune in winter. 2. For trees that bloom in spring from buds on one-year-old wood (most fruit trees), prune when flowers fade.
Source 5a
54
Pruning Tips . . . continued• How Much Should You Prune?Typically, no more than 25% of a tree’s mass at one time.
• Prune Early in the Life of a Tree! So pruning wounds are kept small and you can direct growth easier. Avoid pruning within the first year of planting. As a rule, small cuts do less damage to a tree than large cuts.
• Keep Your Tools Sharp and Clean! We recommend sanitizing your tools between cuts on a tree that may be diseased (fire blight), and always between trees. A stiff wire brush and a bottle of Lysol work well. Quality brands of pruning tools include Corona, Stihl, Felco.
• Remember, No Branch Should be Removed Without a Reason!Routine thinning does not necessarily improve the health of a tree. Trees produce a dense crown of leaves to manufacture the sugar used as energy for growth and development. Removal of foliage through pruning can reduce growth and stored energy reserves. Heavy pruning can be a significant health stress for the tree.
Sources 4a, 4b
55
During Drought…
Do NOT prune living tissues during drought stress
56
Hiring an Arborist
Consider Several Things When Hiring an Arborist . . .• Membership in Professional Organization such as ISA: Certified Arborists are experienced professionals who are knowledgeable in all aspects of tree care
• Ask for Proof of Insurance: personal, property damage, workers comp.
• Ask for References
• Get more than one estimate (especially if you are hiring an arborist for the first time)
• Be wary of people who go door-to-door and offer bargains for performing tree work
• Don’t always accept the low bid: determine the best combination of price, work to be done, skill and professionalism
Source 4d
57
Tree Topping A common practice, but NOT recommended
http://www.treesaregood.com/treecare/topping.aspx
Source 5c
http://www.treesaregood.com/treecare/topping.aspx�
58
Why Not to Top . . . .1. Topping Causes Decay:
Topping causes trunk and root rot
Source 3
59
The main reason for topping is to reduce the size of a tree. Manyhomeowners feel their large trees have become too big, and
reducing the size will mitigate the perceived hazard. However,topped trees become more of a hazard in the long run because of
the excessive shoot growth at the topped location. These shoots are weakly attached and are attached to a limb that is beginning to decay
because of an improper pruning cut: a hazardous combination.Source 5c
2. Topping Promotes Weak Limbs:Topping CREATES Hazards
60
Regrowth is Structurally Unsound
61
3. Topping is Expensive:In the short run topping may seem inexpensive, but in
the long run it is extremely expensive.
•Topping causes rapid new growth: new shoots developprofusely below a topping cut. These new shoots quicklygrow to the original height of the topped limbs, increasing the need for pruning and maintenance.
•Topping may very well cause the tree to die. You will pay tohave it topped and then pay to have the entire treeremoved—Very expensive.
•Topping increases the risk of liability due to weakenedbranches.
•Topping decreases property value.Source 5c
62
Key Terms to Remember•Bark Ridge•Branch Collar•Codominant Stems•Good Structure: the ‘L’/’U’ vs. ‘V’ connections•Crossing/Rubbing
Key Things To Avoid•Stub Cutting•Flush Cutting•Wound Painting•Topping•Planting large trees under power lines!•Waiting to prune trees until they are mature: start young!
63
Tree Pruning Guide Animation
www.arborday.org/trees/pruning/animation/launch.cfm
http://www.arborday.org/trees/pruning/animation/launch.cfm�
Slide Number 1Slide Number 2 Maintaining Healthy TreesSlide Number 4Avoid Lawnmower and Weed-trimmer Damage!!Slide Number 6Give Trees Their Own Space to GrowSlide Number 8Minimize Weed/Grass Competition and �protect tree trunks by MulchingSynthetic weedbarrier mulch, plus rock mulch, plus protective edgingSlide Number 11Woodchip MulchProper Watering for TreesCritical Root ZoneDeep WateringWeed Control Around TreesSlide Number 18Slide Number 19StakingSTAKING Slide Number 22Slide Number 23FertilizingBasic Material Composition of TreesSE CO Soils/WaterMost Fertilizers are in the form of SALTSQuestions to ask before tree fertilizingDo your trees truly need fertilizing?Over-fertilizing Impacts to TreesSlide Number 31Basic Pruning GuidelinesSlide Number 33Slide Number 34Slide Number 35Slide Number 36Slide Number 37Slide Number 38Make the final cut just outside the branch collar.Make the final cut just outside the branch collar.Slide Number 41Slide Number 42Slide Number 43Slide Number 44Slide Number 45Slide Number 46Slide Number 47Slide Number 48Slide Number 49Slide Number 50Avoid the “Pom-pom”�(Technical term = Lion’s Tailing)When pruning ‘up the trunk’, always keep at least 1/2 of the foliage in lower 2/3s of tree.Slide Number 53Slide Number 54Slide Number 55Slide Number 56Slide Number 57Slide Number 58Slide Number 59Slide Number 60Slide Number 61Slide Number 62Slide Number 63
