Apologies for the long absence from this blog. I’ve been in Haiti where I was documenting progress on a reforestation project that I helped establish there in 2009. I’m excited with how far we’ve come and I’m hoping we can find the support we need to scale up our efforts within the next year.
Here’s an update from the field:
Finals are upon us, which means I’m swamped with work. So I’m piggybacking off of a blog post from ImagineHaitian.org. The website focuses on a reforestation project that I helped establish when I lived in Haiti in 2008-2009.
Here’s the text of the post: “A month ago, our project manager, Josue, sent me this photo of our largest field of jatropha trees. Earlier today, I read Wendell Berry’s 2012 Jefferson Lecture in the Humanities. Together, I thought Josue’s trees and Berry’s words beautifully summarized what Imagine Haitian is striving to accomplish. I will be traveling to Haiti in one month and can’t wait to see the trees in person.”
Here’s the postcard (click on the image to enlarge it):
If you’re curious to learn more about the complicated history of environmental degradation in Haiti, you might want to read an essay I wrote for Consilience: The Journal of Sustainable Development. The essay, “Poorest in the West,” examines Haiti’s past and future in light of my experiences in the city of Gonaives during the devastating 2008 hurricane season.
Finally, if you’ve never heard of Wendell Berry, I highly recommend delving into his long list of fiction, poetry, and essays. His work features a strong sense of place and an unflinching environmental ethic in the face of modern materialism.
Spring is in the air. Daffodils are waving their sunny heads. Trees are bursting into bloom. And with temperatures soaring into the 80s in parts of the Midwest and East Coast, summer seems to be coming fast on the heals of spring. But all of this frenzied growth is bad news for many plants, animals, and people who depend on the normal seasonal cycles.
What is “normal” anyway? Weather is notoriously difficult to predict, and climate change has added to the complexity of weather patterns, altering the meaning of “normal” when it comes to seasons. Any given weather pattern, including the current heat wave, cannot be conclusively linked to climate change. But the overall trend is clear. Global temperatures are rising in sync with emissions of carbon dioxide and other heat-trapping gases. The increase in these gases is linked to a variety of human activities, including gas-powered transportation and coal-powered electricity generation.
Climate change is disrupting many natural cycles. For example, mild winters and early springs lead to the early melting of snow in the Rocky Mountains. In turn, the early snowmelt leads to the early growth of flowers. These early bloomers are vulnerable to frosts, resulting in a decline in the number of wildflowers and in the butterflies who depend on them for nectar. The warming climate also disrupts the annual salmon run in the Pacific Northwest. Hotter than usual summers create pockets of fatally warm waters known as “thermal roadblocks” that prevent the fish from reaching their spawning grounds.
The effects are not all bad. An early spring can give some animals a competitive advantage. For example, when the ground warms up early, hibernating animals, such as marmots and ground squirrels, can emerge from hibernation early and put on extra weight. However, the advantages of a longer feeding period must be balanced against the risks of being eaten by a coyote or other predator.
Humans are not immune to the impacts of a warming climate. There can be serious economic consequences to an early spring. For example, the high temperatures can cause agricultural pests to hatch early, threatening crop yields. In addition, an entire crop of early blooming fruit trees can be wiped out by a post-bloom frost. An early bloom can also cut short the maple syrup season, reducing syrup yields. Finally, mild winters result in exploding populations of pine beetles, which decimate valuable timber in western forests. On the positive side, the warm weather is a boon to golf courses. But then, ski resorts suffer when the snow melts early.
The mild temperatures and spring flowers are a welcome relief after winter. Many people in northern regions suggest that a warmer climate might not be so bad, and I’ll be the first to admit that I enjoy opening my windows to let in the fresh spring air. But when the benefits of an early spring are balanced against the costs, I’d willingly accept a few more weeks of winter.
Across the Northern Hemisphere, leaves are turning vibrant shades of yellow, red, and purple. When did you last stop to ponder the causes of this annual phenomenon? Probably not since grade school. For those who have been out of school for awhile, here’s a quick primer on the science behind fall foliage.
The autumnal changes are triggered primarily by shrinking daylight hours rather than by colder temperatures. As the days become shorter, trees develop a wall of cork-like cells along the boundary between their leaves and their branches. These thick cells form an “abscission layer,” which blocks the transport of nutrients between the leaves and the rest of the tree. Eventually, the abscission layer becomes so dry and brittle that the leaves snap off–but not before putting on a colorful show.
The colors are caused by pigments, such as xanthophylls (yellow pigments) and carotenes (orange pigments–the same pigments that make carrots orange). These yellow and orange pigments are present in leaves throughout the summer but they are hidden by large amounts of chlorophyll, the green pigment that captures sunlight so it can be transformed into carbohydrates. In the fall, the abscission layer disrupts the flow of nutrients into the leaves and stops the production of chlorophyll. The remaining green chlorophyll fades in the sunlight, allowing the other colors to become visible.
What about red and purple leaves? These colors are caused by pigments called anthocyanins. Unlike the yellow and orange pigments, anthocyanins are not produced until the fall when the abscission layer prevents carbohydrates in the leaves from travelling into the rest of the tree. The extra carbohydrates trapped in the leaves are transformed into anthocyanins, producing a burst of red and purple color. Eventually, all of the colorful pigments fade, leaving only brown pigments called tannins.
Although cold temperatures don’t trigger these changes, weather patterns do influence the duration and intensity of fall foliage. Important factors include temperature, sunlight, and rainfall. According to the U.S. National Arboretum, “A growing season with ample moisture that is followed by a rather dry, cool, sunny autumn that is marked by warm days and cool but frostless nights provides the best weather conditions for development of the brightest fall colors.”
If the colors aren’t vibrant in your part of the country this fall, you can always check out the foliage in other regions through live cameras posted in scenic spots throughout the U.S.
Palm, Carl E., Jr. Why Leaves Change Color. State University of New York College of Environmental Science and Forestry. 2011.
United States National Arboretum. The Science of Color in Autumn Leaves. 2011, Oct. 6.
A satellite view of 2010 fall colors in the Northeastern United States, courtesy of NASA’s Earth Observatory.