The trouble began in the 1870s, when Americans began importing chestnuts from Japan to New York. The Japanese trees were shorter, making for a better orchard crop, as their nuts could be more easily reached. Unfortunately, those trees harbored Cryphonectria parasitica, a fungal blight to which they were resistant, but to which the American variety was highly susceptible. The fungus would attack a tree at a wound and then spread beneath its bark, releasing a toxin known as oxalic acid that would poison the tree and reduce it to a mere stump that would occasionally send out shoots, but could never grow tall. The blight was discovered in 1904 in what is now the Bronx Zoo by a scientist named Hermann Merkel. Within five decades of that date, the fungus had spread across the entire range of the American chestnut, from Maine to Mississippi.

American Chestnut Foundation

Since the blight's discovery, countless efforts have been made to control the blight or somehow re-instate the trees. Early on, before it had spread too far, people tried cutting firebreak-like gaps into forests, such as a mile-wide chestnut-free zone etched into Pennsylvania -- but the fungus lived on oaks too (though it did not kill them) and made its way across the divide just the same. In more recent decades, scientists have tried cross-breeding the tree with its Asian counterparts, hoping to create a variety that is as American as possible, while retaining the Asian resistance. But though they've made some progress, none of those trees have gained full resistance.

The genetic engineering effort alone has gone on for more two decades, researchers at SUNY's College of Environmental Science and Forestry have been trying to build a better American chestnut, one that would be resistant to the blight.

"At that point, genetic engineering of trees was really in its infancy," William Powell of the SUNY lab told me. "There were only one or two trees that had been what we call transformed -- had a gene put in."

He and his colleague Charles Maynard had to begin before the beginning, figuring out first how to get new genes into their specimens' genomes, and then they could move on to seeing what manipulations might increase resistance. "I like to tell people we had to build the boat before we went fishing," Powell jokes.

They, along with Scott Merkle at the University of Georgia (no relation to Hermann), began by trying to figure out how they could grow a tree from a single cell, since they would be putting the new genes into just one cell. For whatever reason, chestnuts were a tough nut to crack (no pun intended). "For example," Powell explained to me, "if you were to genetically engineer poplar, you can regenerate whole plants just from leaf tissue." With chestnuts, not so much. Instead, they had to harvest an immature nut, remove the embryo, put it in a special medium that allows it to replicate until they had multiple embryos. They worked for 16 years, developing the techniques that would enable them to actually begin genetic engineering.