4. Wind River Field Trip

Field Trip to Wind River

2009 August 8. Avian Silence: Without Birds to Disperse Seeds, Guam's Forest Is Changing. By Brendan Borrell, Scientific American. Excerpt: The forest on Guam is silent.
Sometime after World War II the brown tree snake arrived as a stowaway on this U.S. Pacific island territory 6,100 kilometers west of Hawaii. It has since extirpated 10 of the island's 12 native forest bird species. The remaining forest birds have been relegated to small populations on military bases, where the snakes are kept in check. In the first study of its kind, a rugby-playing researcher named Haldre Rogers is documenting how the forest itself is changing.
...Of the approximately 40 species of trees on Guam, about 60 to 70 percent once depended on birds to eat their fruits and disperse their seeds. The birds may have just nicked and dropped seeds somewhere along a flight path, or they could have swallowed the seeds, digested their tough coats, and pooped them out with a splatter of high-nitrogen urea.
Rogers went to neighboring islands that still have birds along with many of the same trees, collected seeds from the tree Premna obtusifolia, and brought them back to grow in a greenhouse on Guam. She found that seeds handled by birds are twice as likely to germinate as seeds that simply land on the forest floor. They also germinate about 10 days more quickly, giving them a better shot at evading seed-destroying rodents or fungi.
In another experiment, Rogers has found that seeds on Guam now always land directly in the shade of the mother tree and always have an intact seed coat. But seeds from neighboring islands that still have birds can sometimes end up 10 to 20 meters away from the mother tree, where they are more likely to find a sunny niche with fewer enemies. About 80 percent of these have had their seed coat removed, meaning they can germinate more quickly....
..."The brown tree snake is held up as textbook example of how a destructive invasive species can eradicate birds," she says. "This shows that the effects of introduced predators reverberate through the ecosystem."

2009 January 22. Out on a Limb: Global Warming May Be Killing Old-Growth Forests. By Katherine Harmon, Scientific American.Excerpt: The majestic old-growth forests of western North America...may be far more vulnerable to subtle climate change than scientists previously believed. A study published today in the journal Science reveals that these western forests are dying at faster rates as regional average temperatures climb more rapidly than the global average.
"Tree death rates have more than doubled," says study co-author Phillip van Mantgem, a research ecologist with the U.S. Geological Survey (USGS).
He and his team analyzed data (collected from 1955 to 2007) on about 58,000 trees, including firs, pines, hemlocks and others, in 76 old-growth forest plots covering six western states and a Canadian province.... Their findings: 11,000 trees had perished during the observation period, even though no logging, development or other major activities occurred in the study zones.
The researchers pinpointed the rise in regional temperatures as the likely culprit in their demise...
They note that the average regional temperature, though a mere one degree Fahrenheit (0.6 degree Celsius) warmer, translated into less snow, longer dry seasons, and increased soil evaporation, which stress out trees, making them more vulnerable to destructive insects and disease. Meanwhile, bugs and pathogens, which thrive in hotter temperatures, grow stronger, making them an even bigger threat to the fading forests, according to Kenneth Raffa, a professor of forest entomology at the University of Wisconsin in Madison.
...Exacerbating the problem: not enough new trees are sprouting to replace the dead and dying old ones.
...This pattern could eventually lead to sparser forests in which trees are younger and about half the size of what they are now....

2008 February 29. The Giving Trees. By Sharon Levy, OnEarth. Excerpt: ...Mass deforestation, particularly in tropical countries such as Brazil and Indonesia, accounts for more than 20 percent of annual greenhouse gas emissions. Meanwhile, recent studies show that Northern Hemisphere forests, now beginning to bulk up as they recover from centuries of logging, capture large amounts of CO2 from the atmosphere...
People who cut down trees for a living tend to measure their value in dollars and cents. Traditionally, the timber industry has seen mature forests, with massive trees left standing and big logs rotting on the ground, as examples of waste; replanted clear-cuts...represent an ideal of economic productivity. Now global warming has forced foresters to address the impact of logging on the flow of carbon between forests and the atmosphere, and many in the industry have insisted that stands of young, fast-growing trees capture carbon more efficiently than do older forests. Using a recently developed technology called...eddy flux measurement, Bev Law and her colleagues are showing that those assumptions are wrong.
It turns out that forests hundreds of years old can continue to actively absorb carbon, holding great quantities in storage. Resprouting clear-cuts, on the other hand, often emit carbon for years, despite the rapid growth rate of young trees. On the dry eastern face of the Cascades, for example, where trees grow slowly, a replanted clear-cut gives off more CO2 than it absorbs for as much as 20 years. "That's a long time," Law observes, "during which microbes respiring in the soil, rather than trees photosynthesizing aboveground, dominate the carbon balance."
Can we develop a new model of forest economics that draws on this knowledge -- a model that makes sense to foresters as well as the policy makers and conservationists who are now taking the first steps toward developing a viable market in forest carbon? Depending on how we treat forests...they can be either major emitters of CO2 or highly efficient "sinks" that remove the greenhouse gas from the atmosphere. Because financial pressures drive deforestation, the hope is that putting a cash value on the carbon captured and stored by living trees will one day provide an alternative economic incentive to those who do the cutting...

Forest Fires

October 2003. Wildfires in Southern California [1.3MB PDF NASA Lithograph] Uncontrolled wildfire is one of the most destructive natural forces known to mankind. An average of 20,234 square kilometers (5 million acres) burns every year in the United States, causing millions of dollars in damage. But not all wildfire is destructive; prescribed and controlled fires can be beneficial by naturally thinning overcrowded forests and reducing fuel supplies, preparing sites for seeding or planting, managing competing vegetation, and creating varied vegetation patterns that provide diverse habitat for plants and animals.

August 2002. MODIS - Rapid Response [3MB PDF NASA Lithograph] In mid-July 2002, lightning started a fire in the Klamath Mountains in southwestern Oregon that eventually burned over the state line into California and consumed more than 400,000 acres by late August. The Biscuit fire became one of the largest in the state's history, threatening not only human life and property, but also three nationally designated wild and scenic rivers and habitat for several species of plants and animals already at risk of extinction. Firefighters also had their hands full with other fires across the state, including the Tiller Complex Fire to the northeast.

June 1998. Florida Fires [33KB PDF NASA Lithograph] Satellites provide observation capability for monitoring different fire characteristics such as fire susceptibility, active fires, burned areas, smoke, and trace gases. Specifically, the images on the front represent the detection of active fires and smoke associated with wildfires in Florida during June 1998.

May 1998. Mexico Fires [329KB PDF NASA Lithograph] Satellites provide observation capability for monitoring different fire characteristics such as fire susceptibility, active fires, burned area, smoke, and trace gases. Specifically, these images represent the detection of smoke, haze, and pollutants associated with raging fires in Mexico and Central America during May 1998.



 

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