When we look around us at the towering and majestic plants called trees, it’s hard to imagine how we humans could be responsible for their untimely deaths outside of chopping them down. John Palmer, an ISA Board Certified Master Arborist, explained several ways we could unknowingly contribute to their unfortunate demise at a lecture at the midwestGREEN event in Columbus, Ohio.

“I’ve learned a lot – most of it’s from trial and error – and only I am brash enough to actually say almost everything you’ve heard is wrong,” said Palmer, who considers himself a “steward of trees.”

Citing studies about the benefits of trees, including better cognitive health in children, safer cities and even extended life expectancy in areas where trees are present, Palmer insisted that ignorance and insistence will continue to alter our landscape until we are willing to work around trees and consider their needs and behavior.

So what are some common issues with trees, and how can we prevent them?

The first step, according to Palmer, is understanding the trees themselves and the most common issues arborists see when called in about a potential problem. The myth of a deep taproot is common among most trees in North America. Palmer noted most root systems are two to three times the size of the tree canopy, with 75% of most tree root systems growing shallow – within the top 12 inches of the soil. Improper trimming or removal of outlying roots can cause a tree harm in the long run.

Soil compaction and quality, Palmer said, can also lead to poor root growth. Tree roots, unlike their leaves, take in oxygen and give off carbon dioxide, and there needs to be sufficient space within the soil for that gas exchange to happen.

Although there is a rising demand for higher standards in the tree industry, Palmer explained that it is still important to know what issues to look for when in the market for a young tree, whether it’s being grown at a nursery or being sold as an ornamental.

Keeping an eye out for rootbound trees is vital – trees left in small pots for more than a year can end up strangling themselves with their own roots, which can cause drought stress from the tree unable to move water upwards. A rootbound tree may not show signs of stress or trouble for many years, but the outcome is never good. Stress is itself a problem for trees, as it causes them to produce ethanol, which attracts many species of tree-killing beetles.

Palmer also reminded those in attendance that there is an acceptable standard when it comes to pruning. Avoiding large pruning holes is key. Pruning holes can reduce a tree’s ability to bend in the wind, making trees more susceptible to breaking in wind and storms. No matter the tree, it’s always important to follow the current research on sterilization of tools to avoid the spread of infection and disease.

“Lion tailing” is another common issue to look out for when it comes to pruning – where all of the inner branches of a tree are removed, leaving only tufts of leaves and small branches at the ends of the large limbs (resembling a lion’s tail). Using this method can lead to malnutrition, sunburn and the possibility of future limb damage.

Overall, it’s important to choose the right tree for the right space based on the tree’s needs. Beyond that, many species of trees may need continuous care over the span of many decades, and it’s important to keep these factors in mind if we are to follow Palmer’s example as stewards of the trees.

For more information about the benefits of trees and caring for them, visit treesaregood.org.

by Ken Griffin