But things changed drastically for the chestnut in 1904, when trees in the Bronx Zoological Park succumbed to a mysterious ailment. The disease, first revealed as " blighted" branches of shriveled brown leaves, quickly spread to the south and west. By 1914, chestnut blight had reached North Carolina and the western border of Pennsylvania; by 1929 it had gained hold in the Pacific Northwest and was fully entrenched in the Deep South.
The culprit proved to be a fungus previously unknown to the U.S., Endothia parasitica. Native to southeast Asia, it was apparently imported into New York harbor on nursery stock. While the fungus causes only minor damage to the Asiatic chestnuts with which it evolved, American chestnuts showed no such resistance, appearing totally helpless before the onslaught.
Entering cracks, the fungus spreads quickly through the inner bark and cambium, forming cankers on twigs, branches, and the main trunk, girdling those areas and killing the tissue beyond. Young cankers exude sticky yellow strings of asexually produced spores (pycnospores); orange or reddish brown clusters appear in older cankers, indicating that sexual spores (ascospores) are ready for dissemination. Insects and birds, attracted to the damaged bark, carry the pycnospores from tree to tree, while ascospores rely on wind currents for dissemination.
As details of the blight's life history became known, numerous schemes were designed to impede its progress. Among these were inspection of nursery stock, enforcement of interstate quarantines, eradication of advanced infections, and surgical removal of diseased tissue. But American chestnuts were still doomed, dying by the millions, the gaping holes in the canopy gradually filled in by oaks, hickories, tulip poplars, and ashes. In the Eastern United States, no other creature (besides humans) has caused such destruction.
Despite the devastation of the blight, the American chestnut has not completely disappeared from Eastern forests, including Alabama's. Living roots with decay-resistant trunks and stumps remain, sending up sprouts that may reach the stature of small trees. (An occasional specimen even grows large enough to produce a crop or two of nuts.) Unfortunately, the chestnut blight fungus likewise
remains part of our forests, growing contentedly on dead chestnuts and related species, such as chinquapins and post oaks. The stump sprouts will be killed, and new ones will take their places, only to be killed in turn.
Which means that Longfellow's chestnut tree--both symbolic and real--is now long dead. It was killed by an Asiatic fungus that still lurks in our forests.