Just hopping on this thread, hope y'all don't mind...
The conversation reminded me of the Chestnut Blight.
You all are familiar with the words to The Christmas Song "Chestnuts roasting on an open fire"? I can remember my old daddy, now passed to his reward, he told me of the great steam trains when he was a boy - before the diesel electric engines killed all the romance - that would come huffing and chuffing out of the Appalachian Mountains, towing many cargo carriers, all of which were filled to capacity with newly harvested Chestnuts.
Bound for New York and other metropolitan areas, these trains would offload their cargoes of Chestnuts - millions of tons, combined - and the Chestnuts would eventually find their way to street vendors with their little pushcarts. These vendors would roast the chestnuts right there on the spot and sell them to passers-by in little paper bags, like popcorn. The Chestnut was an important staple, not only for wildlife, but also for folks like us - those of us who live in or near the Appalachian Mountains (I live in the foothills just to the West of the mountains proper).
Then the Blight got going good... it was imported into the US, they're guessing, around the turn of the century. But, nobody knows for sure. The legend is that one example of a foreign chestnut - either Japanese or Chinese - was brought to the botanical gardens in NY City. It carried the blight. The blight broke containment. It advanced 50 miles a year, relentlessly. Everything that was tried to stop it, failed. It killed only adult American Chestnut trees.
By the 1940's, billions of trees were dead and gone. It was one of the greatest ecological disasters of the 20th century for North America.
The end of the story hasn't been written yet... the American Chestnut still survives- barely - and there are many different groups attacking the problem from several different fronts - from backbreeding (which seems to be working) to genetic manipulation (also effective, but very new).
Thought I would relate the story... it seemed to fit the subject.
I've never seen an actual, live Chestnut tree. To see the old pictures of them, they were so huge, they blotted out the sun, and several adults standing shoulder to shoulder wouldn't span the width of some trunks...
Here... notice the size of the men standing at the base of the trunks of these trees... http://media.npr.org/assets/img/2012/12 ... s6-c30.jpg