Trees' tropism for water is one basic law of their lives (others are for air and light), since all their food must be in aqueous solution. Species vary widely in their need for moisture, from desert cactus to pond side willow. Some will go to extravagant lengths to slake their craving. The most impressive case of tree thirst I ever saw was a ninety-foot Carolina poplar, eight feet through the butt, whose owner sorrowfully called us in to take it down. This tree's enormous, brittle head towering over his house was a dire menace in every windstorm, but that was the least of the client's worries. Trouble was, he explained, that the giant had drunk dry not only his own well but also the wells of his neighbors.

The nearest neighbor's well was more than 200 feet from the condemned tree. Unbelieving, we investigated. Sure enough, the well was dust dry and the invading poplar roots that had sucked it so had formed a matted plug that choked the well-spring shut. When we cut the huge bole and counted its annual rings we found that this tree was only forty-seven years old instead of the century or more that it looked. We learned that it had been bought for twenty-five cents from an itinerant peddler of poplar "whips" and planted for future shade as a quick-growing yard tree. Through its lust for water and aggressiveness in finding it, the supposed blessing had become a curse on its vicinity.