Trees are our Heroes

Super Trees to the Rescue! – Plant a tree for Arbor Day

By Amy McDowell

Crime fighters are standing sentinel over our homes, parks and gardens. But these heroes wear canopies of leaves and corky bark, not wind-cracking capes and spandex tights. It’s true: trees fight crime. Researchers at the Human – Environment Research Laboratory at the University of Illinois Urbana – Champaign have proven it.

When researchers Frances E. Kuo and William C. Sullivan began studying green space and crime statistics in central Chicago in the early 1990s, the Chicago Police Department (CPD) said they could predict the results. More landscaping equals higher crime, they said. Trees and shrubs can conceal perpetrators. Remove their cover and you’ll reduce crime, they predicted.

The CPD was wrong. In fact, the relationship between trees and crime was exactly the opposite: the presence of green space and trees around buildings reduced overall crime by 52 percent—that was 56 percent fewer violent crimes and 48 percent fewer property crimes during the 9 years of their exhaustive research project.

Trees apparently do much more for us than providing beauty, shade, shelter, wildlife habitat and resources like fruit, nuts, maple syrup and wood. In addition to increasing property values, converting carbon dioxide into oxygen and reducing storm water runoff, trees can dramatically reduce crime. So isn’t it time you plant one?

In Iowa, Arbor Day is the last Friday in April—that’s April 30 this year. However, many cities declare the following Saturday as their official Arbor Day to promote community celebrations and tree planting activities.

To plant a container or balled and burlapped (B & B) tree, first brush back the soil on the top of the tree’s root ball to find the first major roots. To get the planting depth correct, you’ve got to look for those roots because often when nursery trees are grown and prepared for sale, excess soil ends up on top of their roots. Because of this, trees are frequently planted too deep and they not only fail to thrive, but they often die. The planting hole should be just deep enough to place these roots at ground level.

Dig the planting hole at least twice the width of the root ball. If the soil is clay or compacted, three to five times the width of the root ball is better. Another option in heavy soil is to dig four or five trenches that radiate five feet out from the planting hole like spokes of a wheel. Fill the trenches with compost.

Set the tree into the hole. For B & B, remove the twine and as much burlap from the root ball as you can. Fill in the hole with the same soil you dug out, adding some compost if you wish.
Mulch with 2 to 4 inches of an organic mulch like wood chips, keeping it at least and inch or two away from the trunk. Water thoroughly and check the soil weekly through the first season. If it is dry, water it.

If you stake the tree, leave the supports on for no longer than six months. University research has proven that tree canopies need to sway in the wind in order to promote far-reaching anchoring root systems. Use canvas or burlap strips to tie the trees to stakes and check for girdling (strangulation of the trunk) every month until the supports come off.

This Arbor Day, invite a super hero to come live in your garden.

Amy McDowell is an Iowa Certified Nursery Professional. She has a degree in horticulture and has worked in the field for ten years. She lives and gardens in Polk County, Iowa.