The Fall semester of S.E.T. School is now halfway over! The students have all worked hard and hopefully had fun as well. It's great to see everyone's eager faces when they come to class.
We had some spooky science fun at our Halloween party: slime, spider eggs, strobe lights, and a laughing robot skull. A big thanks to the parents who helped out with food and activities!
And students have made their first Web Design pages, as well as several short videos in Science of Special Effects class.
Now, I'd like to take a moment to talk to you about chestnuts, a traditional food this time of year, and just becoming available in the grocery stores.
But the chestnuts in the stores today aren't the chestnuts in the song.
After the ice age ended, the native Americans on the eastern half of this continent found themselves living in forests thick with chestnut trees. The trunk could be as thick as ten feet in diameter and the tree grew to a height of one hundred feet with massive branches. These majestic trees greeted the Vikings when they arrived thousands of years later, and when European colonists arrived in America hundreds of years after that, they too marveled at the American chestnut.
Historically, the American chestnut made up around one-fourth of the trees in the eastern forest, making it by far the most common tree species. A mature tree produces an enormous quantity of nuts, and does so every year. Most nut trees aren't so consistent. Oak trees are one of the worst, with trees all producing enormous numbers of acorns one year and none at all the next. Any creature trying to live on acorns as their main food source would find themselves starving one year, so from the tiny mouse to the giant bear, animals relied on chestnut production for a stable food source.
Humans relied on it as well, with many poor rural communities depending on the chestnut for their livelihood, selling the nuts and making everything from houses to furniture from the wood. Chestnut wood is much lighter than oak and almost as strong, and it can last for centuries without rotting.
Other parts of the tree are just as vital to the forest ecosystem. The leaves are much more nutritious than most tree leaves are, making them the preferred food of many insects. As the leaves decompose in autumn, they enrich the soil and create the type of soil associated with woodlands. Many shade-dwelling plants also evolved to shelter under the tree's huge branches.
They even benefit aquatic ecosystems. Leaves from maples turn the water brown or even black. This blocks the light, preventing plants from photosynthesizing and suffocating many aquatic animals. American chestnut leaves, in contrast, don't stain the water, and their incredibly rot-resistant branches fall to create hollows for fish and other creatures, as well as making much better dam material for beavers.
In 1904, a scientist observed an American chestnut tree's bark had begun to split and brown.
The damage spread rapidly. A deadly fungus had infected the tree, destroying the cambium layer under the bark. This is the layer containing the tubes that convey food and water to nourish the tree. Without the cambium layer, the tree dies of thirst.
It was chestnut blight, a fungus that had reached America from one of the Japanese chestnut trees being imported at the time. Japanese chestnut trees can fight off the disease, but no American chestnut survived it. The fungal spores spread by wind. The disease expanded fifty miles a year. Within a few decades, the American chestnut were dead.
Some of the long-dead trees can still be found standing today, a testament to the strength of the wood and its legendary resistance to rot.
A few trees survived in remote areas outside the usual range. They had been planted in places as far as California, and for a while, they were outside the blight's range. The last remaining large stand of American chestnut trees is in Wisconson, planted by a settler from the east. Unfortunately, the blight finally reached them in 1987. Since then, scientists have tried desperately to save the trees but can only slow the spread.
Many attempts have been made to restore the American chestnut to its original range. Replanting wild chestnuts failed, as none of them possessed any resistance against the blight. Crossbreeding the American chestnut to its fungus-resisting Chinese cousin, a project began in the 1920s, also failed to produce trees that could survive the disease. Finally scientists isolated a gene in wheat that nullifies acid, which the fungus uses to devour the tree. They gave this gene to American chestnut trees in the hopes they'd survive an infection.
And for the first time in a hundred years, they lived. Not only can they survive the disease, they're not even weakened by it, shrugging off the fungus that killed billions of trees. Perhaps the most wonderful thing about this is that the transgenic trees have not had to sacrifice any of their original DNA the way hybrid crosses would. If we spread this new tree across the country, it'll be as if the chestnut blight never happened.
If you think that sounds like something you want to support, then spread the word about the Ten Thousand Chestnuts Challenge, a fundraiser aiming to produce 10,000 new chestnut trees to begin reforesting.
