VALLEJO, Calif., June 14 (UPI) -- California is growing money trees. That's what a quick scan of the latest issue of Urban Forestry and Urban Greening suggests, anyway.
According to a study by scientists with the U.S. Forest Service's Pacific Southwest Research Station, the trees lining California's streets provide the state and its citizens with more than $1 billion in benefits.
Scientists with the Forest Service used i-Tree, an online tree inventory, to plot the species, size and location of the Sunshine State's urban trees -- or "street trees." Researchers used the information to tally the value of services provided by the trees.
Some of the most lucrative services provided by trees include: carbon storage, worth $10.32 million; air pollutant filtering, worth $18.15 million; and energy savings, worth $101.15 million. Trees also bolster property values by $838.94 million.
"We've calculated for every $1 spent on planting or maintaining a street tree, that tree returns, on average, $5.82 in benefits," lead author Greg McPherson, a researcher with the USFS, said in a news release. "These trees are benefiting their communities 24 hours a day, 365 days a year."
The study is a reminder of the monetary benefit trees provide cities, communities and their residents, but it's also a tool to be utilized by urban planners and other local decision makers.
California's street tree population has risen over the last two decades, but urban tree density has gone down. There's plenty of room for more trees -- and additional benefits -- the research suggests. While California enjoys a relatively even distribution of tree species, the majority of communities analyzed are over-reliant on a single tree species, making their arbor-derived benefits vulnerable to diseases and pests.
"Municipal foresters can use data from this study to see how their trees compare to other cities in their climate zone or in the state," McPherson added. "It might help allocate resources, whether it be to increase planting to address low density or species diversification, increase pruning to manage predominately younger trees for structure and form, control pests and disease or intensively manage older trees so as to not lose them prematurely."