Autumnal Foliage Can Be Pretty Tree-Killers
Scientists Find the Secret of Red Fall Leaves: Aboreal Assassins
The rapid encroachment of this shrub "may be largely due to the end of the tree's allopathic influence," Clinton says.
Other Botanical Killers
Other trees known to poison their competitors include sycamore, eucalyptus, hackberry, and the notorious black walnut.
Black walnut produces the chemical juglone, which can spell trouble for a wide variety of trees and plants.
Researchers have found, for example, that black walnut can inhibit corn production even if the trees are some distance from corn stalks.
However, lest we be accused of slamming only deciduous trees, it should be noted that even pine trees are not without their chemical weapons.
Pine needles decompose after falling to the ground, releasing an acid that leaches into the soil. That keeps almost anything from sprouting near the tree's roots.
And lastly, the next time someone tells you how broccoli is good for you, tell them that broccoli plants leave a residue in the soil that makes it difficult for some other crops to follow.
It may be a super-food, but it's not without its faults.
Lee Dye's column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.
