Interestingly enough, Arbor Day began in a place where there were virtually no trees. The holiday, which honors trees and is celebrated by planting more of them, started on the plains of Nebraska with a pioneer who loved trees and encouraged his neighbors to plant them for shade, fuel, and erosion control. Today Arbor Day is mainly celebrated in schools, where it's used as an educational tool.

Trees have always been important, but today they're being used for ever more interesting things. In the controversial field of biotech forestry, for instance, scientists are developing trees that can soak up toxins from the soil in order to clean up polluted sites. And as climate change becomes an increasing concern, trees have a crucial role to play as storehouses of carbon.

Not to put a damper on your Arbor Day celebration, but I was fairly dismayed to see that one of the biggest tree-planting initiatives - prominently displayed on the web site of the National Arbor Day Foundation - is sponsored by Bayer Advanced, manufacturer of a line of pesticides containing the chemical imidacloprid (known by the brand names Marathon, Merit, Advantage, and others). Bayer Advanced's "Help Restore America's Trees" campaign is a month-long effort to plant trees in backyards, parks, and "areas devastated by insects, diseases, hurricanes, wildfires or urban sprawl." Hard to argue with that goal - except that imidicloprid is a highly toxic pesticide that is deadly to backyard and domestic birds and mammals, and all the bugs that are crucial to the health and survival of the very ecosystems trees are meant to anchor. It kills bees, which pollinate the flowers; ladybugs, which feed on "bad" bugs like aphids; and earthworms, which break down organic material and help make the soil fertile.

There are plenty of nontoxic methods of controlling garden pests. Some you can make yourself, from common household ingredients. Others are available at garden centers or online.

Image credit: National Arbor Day Foundation