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Large, old trees are an important part of the history of our country and communities

JUL 04, 2019 | 8:00 AM
Large, old trees are an important part of the history of our country and communities
Large, old trees, such as this magnificent bur oak, are an important part of the history and heritage of our country and communities. (unknown)
The history we share is in our celebrations — fireworks, flags, hot dogs, parades. It’s in our treasured old buildings and grand old parks. And it’s in our trees.
Large, old trees are often called “heritage trees” because they have stood through decades of history and because they are greatly valued for the beauty and other benefits they bring to their communities, according to Lydia Scott, director of the Chicago Region Trees Initiative (CRTI), based at The Morton Arboretum in Lisle.
These old trees often are of scientific value. For example, researchers at the arboretum are investigating the Chicago region’s climate history by studying the wet and dry years recorded in the growth rings of old trees. They use a drill that extracts a pencil-thin sample core without harming the tree.
Another CRTI project is enlisting public help to locate “witness trees” that were noted as landmarks by surveyors of the area in the 1820s and 1830s. Scientists already have used the survey records to map out the natural landscape that existed in the Chicago region before it was heavily settled. Now, the project is trying to find out how many of those landmark trees still exist. Learn how you can participate at
Surviving stands of old native trees, such as oaks, in forest preserves and other natural areas, are particularly rare and useful, according to Scott. “Those trees support a whole community of other plants and wildlife,” Scott said.
The trees that stand in parks, along streets and in our own yards are equally important. “Wherever they are, our big old trees are valuable,” Scott said. Most of the benefits we get from trees come from large, mature trees.
It’s when trees have had time to mature and grow large that they most effectively capture and hold stormwater, filter air pollution, shade homes, save energy, and cool streets and sidewalks, research has shown. Large trees are also the ones we value most for making our communities beautiful.
“Planting trees is wonderful, but new trees can’t do what old trees do,” Scott said. “It takes many years for a tree to mature enough to develop its full powers. That means that protecting our large, mature trees is critical.”
Homeowners can take steps to safeguard their own big trees. “The most important thing is to protect the roots,” said Julie Janoski, manager of the Plant Clinic at the Arboretum. “Many people don’t realize that the roots of a mature tree extend much farther out than the span of the branches, through the soil under your lawn and garden.” Whenever you plan to dig or do other work on your property, consider how you can protect the roots of your big trees.
Spreading a wide, even layer of mulch around the tree will keep its roots and bark from harm and improve the soil. If the weather is dry, even mature trees can use watering. “A tree that is well cared for is better able to resist pests, diseases and other stresses,” she said.
With help, trees that have stood through our families’ history and our communities’ history can continue to live long, valuable lives.
For tree and plant advice, contact the Arboretum’s Plant Clinic (630-719-2424 or
Beth Botts is a staff writer at the Morton Arboretum in Lisle (
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