Popular Science, toukokuu 1930
The domestic supply of tannin has been threatened by the blight of chestnut trees. But the United States Department of Agriculture, cooperating with chemists of the tannin industry, finds that the trees retain their tannin content sometimes as long as twenty-five or thirty years after they die, although they soon lose their bark and sapwood.
Prospects of finding and growing enough blight-resistand chestnuts to continue the extract industry are slight, seachers say. Work is being continued with promising trees and sprouts, although it appears that most chestnut trees, at best, are fortunate in merely escaping blight; they do not resist it.
Tannin is used in the dyeing and tanning industries and is the basis of ink and astringents. Chestnut extrac contains fourteen to twenty percent of this valuable substance.