By Brian Clark Howard
America's Eastern forests from Maine to Florida were once lorded over by the mighty native chestnut tree, which readily grew bases four feet across and sent sturdy trunks 120 feet into the air. American chestnuts lived for centuries, provided beautiful, high-quality wood that was much prized by builders and craftspeople, and supported an array of wildlife, sustaining them with its nutritious nuts. Remember the lyric "chestnuts roasting on an open fire?" Few Americans alive today even remember what they tasted like (currently available varieties come from related species, especially Asian ones). Similar to the way non-native Dutch elm disease wiped out American elms, an invasive blight killed some 3.5 billion chestnut trees between 1904 and 1950. In subsequent years, the species survived largely as a few stumps with sprouts that barely resembled shrubs. But now, scientist Fred Hebard, called by some the Johnny Appleseed of the chestnut, has made great strides in carefully breeding blight-resistant trees. He has high hopes for hybridized chestnuts now growing in Virginia, and believes an invigorated chestnut can repopulate the East. Besides the ecological and scenic values of returning a keystone species to its native habitat, this story has far-reaching lessons. It goes to show how devastating invasive species can be. True, plants, animals and microbes have always been dispersed throughout the world naturally on the winds, after storms, and on the backs of migrant creatures. But mankind's incredible mobility, voracious appetite for resources and ever-burgeoning population has greatly accelerated these processes. The natural world is already under great stress from human activities, not to mention global climate change, so it goes to show how important it is to mitigate the effects of invasive species.