Tree death across the globe
By Drs. Robert & Sonia Vogl
President and Vice President,
Illinois Renewable Energy Association
While environmentally essential, the war on carbon emissions has obscured a related problem which occurs in our immediate environment: the global decline of forests and trees. Some us remember the devastating impact of dutch elm disease on elms lining the streets of Midwest cities. While they have not totally disappeared, a forester friend suggests young elms last about 25 years before the disease prematurely ends their lives. We see their remains, stripped of bark, slowly decaying in our woodlands.
An existing threat to our woodlands is the loss of mature oaks thought to be the result of oak wilt. Many of them lived for hundreds of years. A scenic woodland in central Wisconsin which we observed for over 50 years was recently eliminated in an effort to prevent nearby oaks from succumbing to disease. A more recent threat, the ash borer, is decimating trees in towns and woodlands.
Many of our healthy looking trees drop limbs or fall over from intense winds associated with storms hitting the area. It is common to see the center of the trees rotten, which contributes to their vulnerability.
Drought is also seen as a culprit contributing to the death of mature trees, unable to secure enough moisture and nutrients from the ground during dry periods.
While cutting carbon emissions should help stabilize the climate, reduce the intensity of storms and reduce associated pollutants including mercury and sulfur, air pollution must be more aggressively controlled. It circles the globe having adverse effects on plants, animals and the land. While upper atmosphere ozone is essential to maintaining life, ground level ozone produced by burning fossil fuels is lethal. An overview of the serious damage to global forest ecosystems can be found on the internet as “Air pollution and forest health notes from around the world.” A Nature Conservancy study pointed out the adverse effects air pollution has on eastern US forests.
Acid rain with sulfur particles alters soil and water chemistry, also adversely impacting life forms. It depletes important soil nutrients essential to the ability of trees to resist disease. The ecological effects are subtle and take a fairly long time to appear in trees but become obvious as the impacts become more noticeable. At this point many of the insects and diseases we associate with tree loss are readily identifiable. While a single factor is often blamed for the death of trees, some believe that deteriorated air quality is undermining the overall health of the trees and reducing their ability to resist diseases and insects.
Trees perform many valuable services: absorbing air pollutants, regulating the flow of water through the soils, providing food and shelter for birds, mammals, including people, insects and herptiles. They are worth our efforts to preserve them and their health. We should continue to plant new trees for the future as well as protecting those we already have. The Rock River Trail Initiative project of distributing oak trees for restoring the oak woodland is an important and worthwhile effort.