By Maria Dolan
Austin, Texas, and King County, Washington, are testing carbon credits for planting and protecting urban trees.
The evidence is in: Urban trees improve air and water quality, reduce energy costs, and improve human health, even as they offer the benefit of storing carbon. And in cities across the country, they are disappearing.
A recent paper by two U.S. Forest Service scientists reported that metropolitan areas in the U.S. are losing about 36 million trees each year. The paper, by David Nowak and Eric Greenfield, was an expansion of the same researchers’ 2012 study that found significant tree loss in 17 out of the 20 U.S. cities studied.
This arboreal decline is happening even in some areas that promote “million-tree” campaigns, Arbor Day plantings, and street-tree giveaways. Cash-strapped municipalities just can’t find enough green to maintain the green. Additionally, many cities are adjusting to population booms, and to temperature increases and drought due to climate change—both conditions that can be hard on trees (while increasing their value as sources of cooling and cleaner air). There’s also a growing recognition of the inequity of tree-canopy distribution in many cities, with lush cover in wealthy neighborhoods and far fewer trees in disadvantaged areas.
To find more funding for urban trees, some local governments, including Austin, Texas and King County, Washington (where Seattle is located), are running pilot projects with a Seattle-based nonprofit called City Forest Credits (CFC). The nonprofit is developing a new approach: generating funding for city tree canopies from private companies (and individuals) that wish to offset their carbon emissions by buying credits for tree planting or preservation.
The vast majority of forest carbon credits worldwide have been issued for trees in tropical rainforests and other forests far from urban areas. A study released last year of the forest offsets in California’s cap-and-trade program found that they are effective at reducing emissions.
By Theodore Endreny
Megacities are on the rise. There are currently 47 such areas around the globe, each housing more than 10 million residents.
More than half the global population now lives in urban areas, comprising about 3 percent of the Earth. The ecological footprint of this growth is vast and there’s far more that can be done to improve life for urban residents around the world.
When it comes to natural spaces, trees are keystone species in the urban ecosystem, providing a number of services that benefit people. My research team has calculated just how much a tree matters for many urban areas, particularly megacities. Trees clean the air and water, reduce stormwater floods, improve building energy use and mitigate climate change, among other things.
For every dollar invested in planting, cities see an average of US$2.25 return on their investment each year.
By Darryl Fears
Over several decades in the past century, city populations swelled as Americans moved away from rural forests. Now the forests are moving farther away from Americans.
A new study of satellite images taken over 10 years starting in 1990 shows the rural forest canopy disappearing. Forest space disappeared from the United States in such big chunks that the average distance from any point in the nation to a forest increased by 14 percent, about a third of a mile.
While that’s no big deal to a human driving a car with a pine-scented tree dangling from the rearview mirror, it is to a bird hoping to rest or find food on epic seasonal flights across the globe, according to the study published Wednesday in the journal PLOS One.
But forests aren’t just for the birds. They improve the quality of life for fauna and flora, from bears to flowers. Altering forests can change the dynamics of ecosystems and can potentially “affect water chemistry, soil erosion, carbon sequestration patterns, local climate, biodiversity distribution and human quality of life,” a statement announcing the report said.
The Food and Agriculture Organization of the UN (FAO) Forestry Department and its partners published ‘National Socioeconomic Surveys in Forestry: Guidance and Survey Modules for Measuring the Multiple Roles of Forests in Household Welfare and Livelihoods’. The Sourcebook aims to fill the data gap on the contributions that forests and wild products make to livelihoods and well-being. The modules and guidance presented aim to build the capacity of national statistical offices to integrate forest values into national household surveys, in particular surveys based on the World Bank’s Living Standards Measurement Study (LSMS).
Planting trees is a cost-effective way to tackle urban air pollution, which is a growing problem for many cities.
A study by US-based The Nature Conservancy (TNC) reported than the average reduction of particulate matter near a tree was between 7% and 24%.
Particulate matter (PM) is microscopic particles that become trapped in the lungs of people breathing polluted air.
PM pollution could claim an estimated 6.2 million lives each year by 2050, the study suggests.
Lead author Rob McDonald said that city trees were already providing a lot of benefits to people living in urban areas.