When the Linden trees around the Field Museum of Natural History were put in 16 years ago, it was controversial. Too many trees are going to mar the facade, said the Chicago Tribune's architecture critic.
Now that the Field Museum wants to tear down the trees and replace them with native plantings, another controversy is sprouting.
Who in their right mind would tear down a beautiful grove of healthy trees? Trees that could even be native. (There are some Lindens that are native to the midwest.)
I thought it best to consult one of my best friends on the matter: Charlotte Adelman, a native plant advocate from Wilmette, who has co-authored two books on the subject of native plants with her husband Bernard Schwartz--The Midwestern Native Garden and Prairie Directory of North America. A third book about native trees and shrubs is due to be published next year.
She consistently gives gardeners and arborists a piece of her mind via articles and talks. She is also responsible for a magnificent public prairie garden in Wilmette. And is vilified--yes, it comes with the territory--by certain neighbors for having a magnificent prairie garden of her own that surrounds her home.
This is what she said:
"Most people have no idea about the value of prairie flowers and grasses to the environment. Removing healthy trees is always a painful decision. In the Midwest, native Midwestern trees perform better than nonnative trees from Europe and Asia and also provide wildlife with benefits not available from species native to Eurasia.
"Although native trees are vitally important and should be planted in areas where they do well, the fact is despite their height their root systems generally go down only about three feet. Although they are important elements in sequestering carbon dioxide they don't compare to prairie plants whose roots extend up to 20 feet down.
"Even if the Lindens are native, the Field Museum plan sounds like a good idea. Having a monoculture of one species of trees brings risks, including enabling a disease to attack all of the trees at the same time. An example is Dutch elm disease, caused in 1928 by Asian beetles hidden in a shipment of logs. The disease reached Chicago by 1960, devastating the city's tree lined parkways. Another example is the Emerald Ash Borer from China. In 2002, scientists noticed fungus caused by this nonnative insect infecting local ash trees.
"Choosing a variety of plantings is one sensible way to help avoid these tragedies.
"Why choose native plants--trees, shrubs, flowers, grasses and sedges? As evolution explains, native plants co-evolved with native wildlife and each is dependent on the other for good health and survival. A good example is the Monarch Butterfly, the state insect of Illinois. She only lays her eggs and reproduces on the species of native milkweeds with which she co-evolved. No native milkweed? No monarch butterflies. Well planned planting of a variety of native species chosen to support numerous native pollinators and other creatures is a smart solution to many of our environmental problems.
"Ecologists are finally beginning to realize that the significance of native plants includes in great part the insects (many of them important pollinators) and other wildlife they support. If the Field Museum plants true native plants (not cultivars/nativars) that excel at supporting native butterflies, bees, moths, beetles and other beneficial insects--and other native creatures like birds--they will be improving the environmental health of Chicago.
"The museum will also be setting a fabulous example for Chicago residents--beautiful native species they can plant in their own yards. Presumably the museum will provide information about their plantings to inspire and help those interested in creating healthy and authentic Midwestern gardens, landscapes and even container gardens. And hopefully the museum's example will help banish Gingko trees (origin: China) and other trendy but ecologically useless nonnative species.
"If the museum concentrates on prairie plants, they will be helping to combat global climate change. Why? Because prairie plants absorb and hold (sequester) toxic materials for about 100 years. Called Carbon Sinks, plantings of deep rooted prairie plants are among the best ways to help end air pollution and combat global climate change.
"However, I must say I am surprised to hear about the Field Museum's plan. I thought they were broke and had fired many experts due to a lack of money."