Morton Arboretum scientists unearth links of plant life

Discovery is part of most trips to the Morton Arboretum in Lisle, but nowhere is it more evident than on a visit to meet the scientists who work there.

Senior research scientist Gary Watson, urban soil scientist Bryant Scharenbroch and plant systematist and Herbarium curator Andrew Hipp share an enthusiasm for their field of study, a probing curiosity and offices adjoining science labs with microscopes, computers and test tubes.

Andrew Hipp

Andrew Hipp always knew he wanted to work outside.

"I was an English major but took classes in botany to land a job outside," he said.

Working as a ranger at an arboretum opened his eyes to the variations in plants even within a species. He returned to academia to concentrate on plant evolution and ecology.

Similar to a human family where parents may have children with different hair and eye color, there is a lot of genetic variability within species having the same parentage, Hipp finds. He extracts a plant's DNA to study its genetics.

Analysis of those variations provides Hipp with insight into the diversity and relatedness of natural populations.

"When restoring a prairie, wetland, woodland or savanna, what species to plant is only one layer of the question," Hipp said.

Consideration given to the genetics of individual plants is important to the natural resource's overall health.

As the Herbarium curator, Hipp is particular about the plant specimens that go into the arboretum's herbarium. He calls the Chicago region the best location to study plants because it's where the north woods, deciduous forest and prairie all collide.

"In all of the state of California, with its mountains, deserts and ocean sides, they have half as many kinds of plants as our region," he said.

The Herbarium, similar to a rare books room in a library, documents the diversity of plants from throughout the world.

Gary Watson

Gary Watson enjoys the opportunity at the arboretum to pursue projects he feels are important to his field of study. His current focus is the root systems of landscape trees.

In high school, Watson took the science courses everyone takes, with no defining moment that encouraged him to concentrate on science. In college, he majored in biology and later narrowed his studies to botany and plant pathology.

At the arboretum, the scientist is doing leading research in the field of tree roots. He helped change the dated concept that tree roots sink deep into the soil and mirror underground a tree's crown.

Tree roots still serve to absorb water and nutrients to sustain the plant, and provide the structural support a tree needs. But think of a tree more as a wine glass on a dinner plate with the extensive tree root system located within the first 3 to 12 inches of soil in a horizontal spread two to three times the branch spread. The major portions of a tree's roots are naturally shallow and widespread.

"On a typical residential lot with a couple well-established trees, most anywhere you do something on your property it will affect one of your trees," Watson said.

His rule of thumb for planting a tree is to "plant not bury." The top of the root ball should be at the same level as the ground line with a couple of inches of mulch over the top. Proper tree root depth is crucial to the longevity of a healthy tree.

Watson also is experimenting with compost tea that may help promote all the good fungi and bacteria found in a forest system where trees thrive. The arboretum created nearly an acre of compacted soil like that encountered in urban landscapes as a place to conduct controlled experiments such as with the compost tea.

Bryant Scharenbroch

Bryant Scharenbroch is the arboretum's point man on soils. Every plant needs soil to thrive and trees are no exception.

Scharenbroch came to be interested in the field from an agricultural background influenced by his grandparents' dairy farm in Wisconsin. He studied both forest management and urban forestry leading to his advanced study of soil science and ecology.

Since urbanization influences the air, water and plants, Scharenbroch is studying urban soil and testing its biological structure by amending its composition with compost and mulch.

"Current research at the arboretum is to characterize the heritage of the urban soil in our area and look at different organic amendments and how well they do in fixing urban soil problems," Scharenbroch said.

The research is an opportunity to look carefully at a plant's response and then study any impact on the environment or water supply that may occur.

Compaction is a constant question in soil studies. Something as simple as driving on wet soil can compact it.

Scharenbroch sees the trend toward composting as an asset to the home gardener.

"Adding organic matter is always a good idea, but it needs to be done right," he said.

"Something homeowners can do for getting landscape trees established is to water," Scharenbroch said. "Proper watering and mulching is important."

The research of all three scientists encourages improved practices for planting, maintaining and learning about trees -- the very focal point of the Morton Arboretum.