The nation’s forests save more than 850 lives each year, according to a new report from the U.S. Forest Service.
Image courtesy craigcloutier/Flickr
In a study that will be published in the October issue of Environmental Pollution, scientists with the U.S. Forest Service have determined the magnitude and economic value of the effects trees have on air quality and human health. While we have long known that trees remove pollutants from the air, this study shows that in 2010, trees in the conterminous United States removed 17.4 million tons of pollution, with a human health value of $6.8 billion.
In addition to saving more than 850 lives, these trees reduced more than 670,000 incidences of acute respiratory symptoms and 430,000 incidences of asthma exacerbation. Trees also saved 200,000 lost days of school.
Image courtesy pavlinajane/Flickr
A forest’s pollution removal rates can be affected by pollution concentrations, tree cover, weather conditions, length of growing season and other environmental stressors. In general, scientists found that while trees’ pollution removal was greater in rural areas, the economic value of this pollution removal was greater in urban areas. In other words, because of their proximity to people, trees in urban areas have a greater impact on human health.
“More than 80 percent of Americans live in urban areas containing over 100 million acres of trees and forests,” said Michael T. Rains, director of the Forest Service’s Northern Research Station in a media release. “This research clearly illustrates that America’s urban forests are critical capital investments [that are] helping produce clean air and water [and] reduce energy costs and making cities more livable. Simply put, our urban forests improve people’s lives.”
The Chesapeake Bay Program has set a goal to expand urban tree canopy by 2,400 acres by 2025. Indeed, trees can improve air quality, water quality and habitat in ways not discussed in this study. Trees near buildings, for instance, lower energy use. Trees along rivers and streams reduce the amount of nutrients entering local waterways. And trees provide food, shelter, nesting sites and safe migration paths for critters in the water and on land.
“Urban tree planting is part of the Watershed Improvement Plan for six Bay jurisdictions,” said U.S. Forest Service Chesapeake Liaison Sally Claggett. “To reach water quality goals, these jurisdictions are targeting nearly 20,000 acres of new tree canopy by 2025—so the goal of 2,400 acres may be reached early. Partners are planning an Urban Forestry Summit in fall 2014 to help make that happen.”
Solar energy is on the rise in the United States, and one jurisdiction in the Chesapeake Bay watershed has been named a leader in the solar energy revolution.
Image courtesy Mountain/\Ash/Flickr
According to a report released by Environment America, Delaware is one of the ten states that have installed the greatest amount of solar energy capacity per capita. At 82 watts per person, the state is in seventh place.
Since December 2008, Delaware has expanded its solar capacity from 2 to 59 megawatts. According to the Department of Natural Resources and Environmental Control (DNREC), the state has installed 1,600 solar energy systems on government buildings, businesses, schools and homes. What's driving this effort? Legislation, policies and financial incentives that support going solar.
Image courtesy Pacific Northwest National Library/Flickr
Solar energy uses the sun as fuel to create heat or electricity. It’s considered cleaner than coal- or natural gas-fired power plants because it doesn’t burn fossil fuels, which can release emissions that contribute to climate change.
Like other states in Environment America’s top ten, Delaware’s interconnection policies make it easier for individuals and companies to connect their solar energy systems to the power grid. Solar rebates and other financing options help lower the cost of installation, while "net metering" policies compensate consumers for the excess energy they return. The solar market is also moving forward in response to Delaware’s Renewable Portfolio Standard, which calls for the state to draw 25 percent of its power from renewable sources by 2025, with at least 3.5 percent coming from solar.
“Encouraging solar power is the right thing to do for the environment and our economy,” said Delaware Gov. Jack Markell in a media release. “We are aggressively working toward a clean energy future in Delaware, demonstrating we can have both a strong economy and a healthy environment. That means creating a robust market for solar and other clean energy systems, creating clean energy jobs, expanding our solar industry and improving air quality.”
Two additional watershed jurisdictions received special mention in Environment America’s report: New York, whose solar energy market is growing quickly, and the District of Columbia, where new clean energy policies are set to make solar more attractive and accessible to consumers.
During summer months, Chesapeake Bay waters become home to a range of bacteria. One of the most talked-about bacteria is Vibrio, which occurs naturally in warm estuarine waters and can infect those who eat contaminated shellfish or swim with open wounds in contaminated waters. But illness can be avoided. Learn about the bacteria—and how to avoid infection—with this list of five Vibrio facts.
Image courtesy CDC/Wikimedia Commons
1. Vibrio is a naturally occurring bacteria. There are more than 80 species of Vibrio, which occur naturally in brackish and saltwater. Not all species can infect humans, but two strains that can have raised concern in the Bay watershed: Vibrio vulnificus and Vibrio parahaemolyticus. The bacteria are carried on the shells and in the bodies of microscopic animals called copepods.
2. The presence of Vibrio in surface waters is affected by water temperature, salinity and chlorophyll. Because Vibrio prefers warm waters, it is not found in the Bay during winter months. Instead, it is common in the summer and early fall. When water temperatures are warm, algae blooms form, fed by nutrients in the water. These blooms feed the copepods that carry the Vibrio bacteria. When the copepods die, Vibrio bacteria are shed into the water. As climate change increases the temperature of the Bay, both algae blooms and Vibrio could persist later in the season.
3. Vibrio infections can occur in people who eat raw or undercooked shellfish or who swim with open wounds or punctures in contaminated waters. While infections are rare, they do take place and can be particularly dangerous for people with compromised immune systems. The ingestion of Vibrio can cause vomiting, diarrhea and abdominal pain, and in some cases can infect the bloodstream. If an open wound or puncture comes into contact with the bacteria, the area around the wound can experience swelling, redness, pain, blistering and ulceration of the skin.
4. Infection can be avoided. To avoid Vibrio infection, follow these tips:
5. Vibrio symptoms can start 12 to 72 hours after exposure. If you think you’ve been infected with Vibrio, seek medical attention. Make sure to let your doctor know that you have eaten raw or undercooked shellfish or crabs or have come into contact with brackish or saltwater.
The R/V Rachel Carson is docked on Solomons Island. At 81 feet long, the red and blue research vessel stands out against the deadrise workboats that share the Patuxent River marina. Her mission today is to lead researchers from the University of Maryland Center for Environmental Science (UMCES) to the Chesapeake Bay’s dead zone.
Every summer, this so-called “dead zone” forms in the main stem of the Bay. The area of low-oxygen water is created by bacteria as they feed on algae blooms growing in nutrient-rich water. The dead zone persists through the warm summer months because the Bay is stratified into two layers: a surface layer of lighter, fresher water that mixes with the atmosphere, and a bottom layer of denser, saltier water, where oxygen depletion persists. These layers won’t mix until the cooler temperatures of autumn allow the surface waters to sink.
To find the dead zone, Director of Marine Operations and Rachel Carson Captain Michael H. Hulme takes us to one of the deep troughs that run down the center of the Bay. Geologic remnants of the ancient Susquehanna River, these troughs can reach up to 174 feet deep in an estuary whose average depth is just 21 feet. Hulme anchors offshore of Calvert Cliffs State Park.
The boat is equipped with a dynamic positioning system, which holds it in place regardless of wind or waves. This allows the captain to step away from the helm and offer his hands on deck. “Being able to hover over that [specific] latitude and longitude is what makes the Rachel Carson so unique,” said Hulme. It’s also one of the reasons the vessel is so useful to scientists, who often return to the same sampling site again and again over time.
UMCES Senior Faculty Research Assistant David Loewensteiner drops a CTD overboard. The oceanography instrument takes eight measurements per second, tracking conductivity, temperature and depth as it is lowered through the water. Connected to the ship with a cable, the CTD sends data to a laptop in the boat’s dry lab. We measure 2.04 mg/L of dissolved oxygen in surface water, and just 0.33 mg/L at 98 feet deep. Critters need concentrations of 5 mg/L or more to thrive; these are “classic dead zone” conditions.
Dead zones are bad for the Bay. Like animals on land, underwater critters need oxygen to survive. In a dead zone, immobile shellfish suffocate and those fish that can swim are displaced into more hospitable waters. “If you were a self-respecting fish and oxygen was [low], what would you do?” asked Bill Dennison, Vice President for Science Applications and Professor at UMCES. “Swim away.”
First reported in the 1930s, the appearance of the dead zone in the Bay is linked to our actions on land: as we replace forests with cities, suburbs and farms, we increase the amount of nutrients entering rivers and streams. This fuels the growth of algae blooms that lead to dead zones. “Hypoxia [or low-oxygen conditions] is driven by what we do on the watershed,” said UMCES Assistant Professor Jeremy Testa. “The Bay is naturally set up to generate hypoxia because of that [stratification] feature. That said… when there were no people here, there was not much hypoxia.”
While it is our actions on land that created the dead zone, it is our actions on land that can make the dead zone go away. Research has shown that certain pollution-reducing practices—like upgrading wastewater treatment plants, lowering vehicle and power plant emissions and reducing runoff from farmland—can improve the health of local rivers and streams. Scientists have also traced a decline in the duration of the dead zone from five months to four, which suggests that conservation practices gaining traction across the watershed could have very real benefits for the entire Bay.
To view more photos, visit the Chesapeake Bay Program Flickr page.
Images by E. Guy Stephens/Southern Maryland Photography. Captions by Catherine Krikstan.