What’s going on?
Something is trying to kill the great trees of America. The latest is the American ash, which has become the prey of the emerald ash borer whose larvae kill the tree from the inside and when it dies the borers move on to the next tree.
The emerald ash borer is native to Asia. Since it was first spotted in Michigan in 2002, it has spread to 12 other states in the Midwest and mid-Atlantic and threatens not only a $25 billion industry – and the source of our baseball bats – but the existence of the tree as a species. The ash constitutes a measurable percentage of our forests – up to 60 percent in some parts of North Dakota.
There are billions of ash trees at risk in the United States, Canada and Mexico.
Mark Wirdlechner, a horticulturist for the U.S. Agriculture Research Service and an Iowa State professor, is leading an effort to save the ash if the worst happens by collecting seeds that must be harvested in the fall, and putting them in secure storage after first freezing them. Thus, there would be an ash bank to draw on once we find a way to kill or control the pest.
The seed collection began in New England in 2007 and has grown to include several federal agencies, state forest services, American Indian tribes and people who just want to save the ash trees.
For some years now, an effort has been under way to reintroduce the elm into American life. Every city of a certain age is almost certain to have an Elm street. Rows of the huge, vase-shaped trees defined the American Main Street.
The close proximity of the elms to one another allowed Dutch elm disease to spread quickly when it arrived in the 1920s and by the ’70s well over half of the elms were gone.
Nurseries have had some success in identifying and growing disease-resistant elms and the trees are slowly making a comeback.
They adapt well to cities, able to withstand extremes of cold and heat, resistant to road salt and air pollution.
Similarly, forestry departments and tree nurseries are reviving the American chestnut, nearly wiped out by a blight, first seen in 1902, that in the next several decades killed perhaps 3 billion trees, driving it to near-extinction.
It is a matter of some excitement when an original American chestnut is discovered in the wild and at least one forest service keeps their location secret.
As with the elm, the best hope for the chestnut is the development of new, disease-resistant strains.
Sadly, the woes don’t stop there. The butternut tree is under serious threat from a fungus and the flowering dogwood from a fungus and a borer. Something is after our great trees.
Scripps Howard News Service