City of Audubon Park

Urban Tree Care Guide

OutlinePurpose and Mission 2

Why Trees and Why Permits 3

Why plant smaller trees? 3

Recommendations for Easement Plantings 4

How to Water 5

How to Mulch 8

Mowing/String Trimming Around Trees 9

Structural Pruning 10

Emerald Ash Borer 10

FAQ 11

Purpose and MissionMission: To maintain a canopy from shade trees over all public ways of Audubon Park, so that we can continue to walk under majestic high branches and leaves from trees that may be older than we are – and to plant the trees that will continue as a heritage for our children and grandchildren.

The Forest Board was established by ordinance in 2002. It was tasked with preservation and renewal of the urban forest in Audubon Park – with specific emphasis on the city’s parks and street easements. As part of its mission, the ordinance also established a Forest Board, comprised of 6-12 resident members (who serve staggered terms of four years), to oversee the preservation and renewal of the City’s urban forest. Under its mandate, the board was charged with developing a forest management plan and a tree inventory and to serve as an advisory group to city government. Members of the Forest Board provide a valuable educational resource to residents on the proper care and treatment of trees such as how to plant, appropriate selection based on height limitations and site specifics, how to properly prune and other topics.

Why Trees and Why PermitsThe benefits of trees in an urban environment is difficult to overstate. The many

benefits of planting trees include cleaning the air from urban pollutants and reducing the air temperatures between 3 °F to 12 °F. This reduction in air temperature coupled with the shade trees provide may reduce energy needs by thirty percent. The leaves that provide this shade help to absorb nearly 150 kg or CO2 annually, and the roots that supply these leaves with water and nutrients help intercept over 5000 gallons of rainfall per year. Additionally, tree ecosystems provide homes to hundreds of native animals and insects, increasing biodiversity while also increasing our own home values by up to 20 percent! http://www.fao.org/3/a-c0024e.pdf

To protect these many benefits that trees provide, the City of Audubon Park and the Forest Board require permits for any tree planting, pruning, or removal in the city easement areas. The permits allow the city, in conjunction with the city forester, to ensure our urban trees are cared for and maintained properly, as improperly pruned trees can greatly reduce the health of a tree and can potentially create hazards for homeowners and the city. Additionally, permits allow the city to ensure companies working on our city’s trees are properly insured to mitigate any financial risk to the homeowner or city that may occur in the event of an accident. Residents who fail to obtain a permit for any tree planting, pruning, or removal in the city easement areas are subject to fines.

Why plant smaller trees?For better survival and health, trees should be planted at a small size. There are several sound environmental, physiological and economic reasons for planting smaller sized plants. Smaller is a relative term so what is meant by smaller? For most trees, heights that measure from 3ft to 7ft are a good size for planting. This size is easy to handle, responds quickly after transplanting, is affordable but is large enough to visually fill the planting space.

When a small tree is planted more of the root system is retained with the plant, and the root system is more in balance with the above ground portion of the tree. A good thing to remember is that any plant is only as good as its root system. A tree can only grow leaves and branches if the root system can

supply the needed water and nutrients. The roots of a small plant quickly establish in the surrounding soil and can then support new growth of the leaves and branches. For this reason smaller trees often catch up to and surpass the growth of trees that were planted at a larger size. The growth of the tree will adjust to the soil and moisture conditions where it is permanently planted, not to where it was grown in the nursery.

The economics of size, survival and time dictates that a smaller sized tree will cost a fraction of the cost of a large caliper tree. A large tree costs more due to the number of additional years it grew in the nursery and the added risk of covering the replacement cost of trees that do not survive transplanting. It takes more labor and the use of heavy equipment to dig, handle and ship a large tree. For nurseries, fewer larger trees are sold, so a higher mark up is charged per tree to turn a profit. Smaller trees can be lifted and moved by hand whereas larger trees normally require the use of a tractor, chain and bucket. One person can easily dig the planting hole for a small tree by hand but a large tree may even require a backhoe.

For these reasons, the Forest Board plants smaller trees in the city easements to promote the long term health of individual tree specimen and the cities urban tree canopy.

Recommendations for Easement PlantingsEasement Trees Over 40’ Tall

Bald Cypress Pecan

Sweetgum Rotundiloba Sassafras

Tulip Poplar London Plane

Sweetgum Sycamore

Tupelo Cucumber Magnolia

River Birch -Single Stem Katsura

Basswood – American Linden American Beech

Osage Orange “Whiteshield” Ginkgo

Littleleaf Linden Catalpa

Sugar Hackberry Hackberry

Kentucky Coffee Tree Lacebark Elm

Norway Spruce Cherrybark Oak

Willow Oak Chestnut Oak

Swamp White Oak White Oak

Chinkapin Oak Sawtooth Oak

Nuttall Oak

Trees Under 40’ Tall (Not for Easement Plantings)

Downey Serviceberry American Hornbeam

American Hophornbeam American Smoketree

Goldenrain Tree Redbud

How to WaterWatering Newly Planted Trees and Shrubs

By Alan Siewert, Urban Forester ODNR Div. of Forestry

Introduction

Transplanting trees and shrubs is not a natural process. Trees in the wild do not grow with dense root systems waiting to be dug. Nurseries work very hard to create a plant which will survive the difficult and stressful process of transplanting. But even with the best nursery practice only 10% to 30% of the tree’s existing root system is captured in the root ball that comes with the tree.

The time it takes to regenerate these lost roots depends on the size of the tree that was transplanted. Studies have shown that trees in Ohio take about one year for every inch caliper to re-grow the lost roots. That means a two inch tree will have to survive on a reduced root system for two years and a 6 inch tree at planting 5 years after planting. Bigger is not always better.

Need for Water

Water is the life blood of the tree. The nutrients it carries are crucial to carry on photosynthesis which in turn produces carbohydrates to re-grow the roots lost during transplanting. This water is extracted from the soil around the roots. Newly planted trees must get 100% of its water from 20% of its original root area. The soil in the root ball is heavily “mined” for water during the reestablishment stage and can dry out long before the surrounding soil does. Routine watering is essential for newly planted trees even if established trees are doing fine. Transplanted trees rely almost entirely on root ball moisture for much of the first growing season. Root ball soils dry out more rapidly while backfill remains moist.

The Long Term Effects of No Water

The tree’s trunk, branches and roots are made of long cells. These cells form tubes that reach from the roots to the leaves. When these tubes are formed by the cambium they are full of water. As water evaporates from the leaves water is sucked up the tree. When water is pushed into the roots through osmosis, water is pushed up the tree in these columns.

When there is no water in the soil to be pushed into the roots the leaves keep sucking on the columns of water. Wind and low humidity cause the leaves to suck harder and the tension on the column of water increases. Like a rubber band the water column can only be pulled so hard before it snaps. Once broken the water column will never form again.

Trees live on water columns which were formed in the past two to three growing seasons (spring and early summer). Loss of these columns through a careless watering schedule can affect the trees health and reestablishment by reducing their ability to move water. Forgetting to water once can have a significant effect for the next three years if it does not kill the tree outright.

Water

How Often

Trees should be watered, elementally after planting or within 4 to 6 hours of planting. Even if it is raining during the planting the tree still needs additional water. Root balls dry out very quickly while above ground.

After planting, the trees should be watered once a week from the time they are planted until they lose their leaves in the fall and the pull of water is gone. Water may be skipped in a given week if the tree receives 1 inch or more of rainfall in that week. Rainfall credit does not accumulate. If the tree receives 3 inches of rain in one week and no rain the next 2 weeks you must still water in the weeks there is no rain.

In some cases such as sandy soil or bare root trees, biweekly watering may be beneficial.

How Much

The quantity of water needed each week depends on the size of the tree. The rule of thumb is a tree needs 5 gallons of water plus 5 gallons for each caliper inch. For example, a 2 inch caliper tree needs 15 gallons of water per week. That would be 5 gallons for the tree and 5 gallons times 2 inches (10 gallons) which equals 15 gallons total.

Size of tree Quantity of water per week

1 inch 10 gallons

2 inch 15 gallons

3 inch 20 gallons

4 inch 25 gallons

5 inch 30 gallons

Too much water can kill the tree. Saturated soils have little oxygen and the roots can literally drown.

Speed of Application

The single greatest mistake made in watering is putting the right amount of water on too fast. The water must be given time to soak into the soil and if applied too fast not enough water gets into the root ball. Water must be applied at a rate less than 2 to 3 gallons per minute. In some cases the water may still run off the surface of the root ball and the rate must be reduced. Water should be applied to the surface of the soil. Deep root watering can put the water too deep and leave critical surface roots dry.

Five gallon buckets with two or three 1/8 inch holes drilled in the bottom can deliver an accurate amount of water to the tree. A slow trickle from a garden hose can also be effective. Calibration of the flow is well worth the effort. Too much water can wash a watering berm or mulch away, cost extra money in water bills and kill the tree. Using a known volume container, open the valve on the garden hose a known amount like 1/8 of a turn. Measure the time it takes to fill the container. If a small volume is used, less than 1 gallon, make several measurements to account for changes in water pressure. Using these measurements calculate the time needed to apply the right amount of water for the tree and use that time for watering each tree.

Other Cultural Techniques to Help Establish New Trees

Mulch

A 2 or 3 inch deep mulch layer can greatly benefit the establishment of a new tree. In 2 years the trees growing in mulch beds will have 4 times as many roots and 3 times the trunk caliper of their counterparts growing in grass.

How to MulchWhen done correctly, mulching is one of the best things we can do to improve the health of our trees. When done incorrectly, it can be one of the worst things we do to our trees.

Many landscape companies and gardeners employ a mulching technique called volcano mulching. Volcano mulching is an improper mulching technique where mulch is piled high against the trunk of a tree. This is often seen in commercial landscapes and can be extremely harmful to trees. Mulch should not touch the trunk of the tree. Piling too much mulch against the tree trunk can slowly kill your tree. The mulch touching the trunk of the tree will keep the bark moist, making it more attractive to rodents, insects and fungus. It may also result in the failure to develop a normal root flare which stabilizes the tree. These trees may be more likely to fall during a storm. Additionally, mulch that is more than 4” thick actually prevents water from getting to the roots.

Proper mulching encourages the development of additional roots that do not thrive under the grass. These additional roots are used to provide more nutrients and water to the tree. Proper mulching also keeps the soil temperature more consistent, insulating against cold and heat.

Spread mulch 2-4 inches deep to the drip line of the tree if possible; do not let the mulch touch the trunk. The mulch should form a flat donut with the trunk in the center. Another guide is the “3x3x3 rule” or 3 inches of mulch, 3 inches from the trunk, in a circle 3 feet wide. Organic mulches (bark mulch, wood chips, leaves, etc) are preferred over stones or other inorganic products. Just don’t use too mulch of a good thing! A graphic representation of proper mulching techniques from the Morton Arboretum is shown below, with a link to the arboretum’s website for additional details.

https://www.mortonarb.org/trees-plants/tree-and-plant-advice/horticulture-care/mulching-trees-and-shrubs

Mowing/String Trimming Around TreesJust as insects and disease threaten trees, human activity does as well. One serious, but very preventable threat is damage by mowers and string trimmers. Mechanical damage to a tree can be very serious since the living tissue of the tree and the structures that carry food and water lie just under the bark.

DON’T DO THIS TO YOUR TREE!

Trees are much more easily damaged in the spring when the tree is putting on new growth. Young trees can be seriously damaged by small wounds, especially with repeated injury. Damaged trees can grow poorly and branches may die. Wounds provide entry points for pathogens and decay. In the worst cases, the fungal decay may become severe enough to compromise the long-term health or structural integrity of the tree.

REDUCE THE RISK TO YOUR TREES

Instead of allowing grass to grow under trees, use mulch. You won’t damage the tree with lawn care equipment if there is no grass to mow there, and the tree will benefit from the mulch as well.

Also, trees and grass compete for nutrients and moisture – another win for the tree if the grass is gone! Remove weeds or grass by hand when necessary. Use protective guards on young trees if mowing nearby must be done.

Structural PruningIn urban environments, trees often receive more light than they would in their natural forest setting. This causes the trees to develop multiple, forked branches, trunks, and leaders. These closely spaced limbs cause the tree to become susceptible to mechanical breakage and decrease the longevity of the tree. Structural pruning is a technique used to develop a strong tree structure similar to what one would see in a forest. For additional details on the benefits and process of structural pruning, please see the attached publication from the University of Florida.

https://hort.ifas.ufl.edu/woody/documents/structural.pdf

Emerald Ash BorerEmerald ash borer (EAB)is an exotic beetle that was discovered in southeastern Michigan near Detroit in the summer of 2002. The adult beetles nibble on ash foliage but cause little damage. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients, ultimately killing the tree. Emerald ash borer probably arrived in the United States on solid wood packing material carried in cargo ships or airplanes originating in its native Asia.

The Forest Board has reviewed the recommendations on Emerald Ash Borer (EAB) treatment and has reviewed the Park ashes with several experienced Certified Arborists. We have identified an active epidemic in Audubon Park.

Effective treatments for EAB depends on the size of the tree and almost all of the ashes in Audubon Park are substantial trees (larger than 6-8 inches in diameter at 4.5 feet from the base of the tree). Mature trees require treatment by an experienced Certified Arborist. Emamectin Benzoate appears to be the most effective treatment.

Treatment currently costs about $8 per inch of diameter. A tree of 30 inch DBH is approximately $240. It is suggested to treat at two year intervals and then resume three year treatments after most trees are removed in our area. It is recommended the tree be treated for its entire life-span.

In general, you should not treat a damaged or compromised tree, particularly a tree with major wounds or areas of visible or developing rot. Your arborist can evaluate whether the tree is worth treating. If you do remove an ash, please ask that it be inspected carefully if EAB contributed to its decline. Let the Forest Board know if you had EAB identified in your tree.

You are making an investment in treating your tree, and it can be difficult to assess and weigh the costs of long-term treatment compared to the cost of removal of the tree. Sometimes it will be better to remove the tree and get replanting done. A certified professional arborist can help you with this decision. There are many online resources that look at the cost-benefit of various strategies.

FAQI just moved into Audubon Park and I would like to PLANT A TREE

● If you are new to your home or are an existing member of our neighborhood and would like to

plant a tree, please contact the Forest Board chair, Michael Blum, by phone, text, or email at 502-396-4029 or michael.blum13@gmail.com

● The Forest Board is knowledgeable of appropriate trees to plant and can help you select the

right tree for your property

● “Easement/Right of Way” trees will be planted by the Forest Board, and the tree will be

maintained for 3 years after planting. After that, the care of the tree is the responsibility of the homeowner.

I just moved into Audubon Park and I would like to REMOVE A TREE

● If the tree is in the front of your property on the “easement/right of way”, you are required to

have a permit that will be issued by the city.

● The permit can be obtained by visiting City Hall or by going to the City of Audubon Park website

and then going to the “Forms and Signs” tab and clicking on the “Easement Tree pruning or removal” tab to complete the application.

● Please allow 2 weeks for the permit to be processed and issued before work begins to remove

the tree.

● In addition, once the permit is issued, you will be contacted by a member of the Forest Board to

discuss replacement of the removed tree. Audubon Park is committed to replacing and sustaining our tree canopy.