Economic Value of an Urban Forest: $80 billion
From “Environmental contribution of Tennessee’s urban trees: $80 billion” by James Holloway:
A study published by the US Forest service values the State of Tennessee’s urban forest at $80 billion thanks to its contributions to the environment. With an urban population of 284 million, that equates to a mean value of $282 per tree.
The total is based on a number of costs that are to some extent offset by the presence of Tennessee’s urban forest (its urban tree population, in other words). These include $350 million-worth of carbon storage based on the current standing stock, over $204 million every year in pollution removal, $18.4 million per year in additional carbon sequestration, and $66 million per year in energy savings-”the most significant contribution” made by the urban forest, according to State Forester Steven G. Scott. But how are the environmental benefits of the trees evaluated?
Data was collected and analyzed using the Forest Service’s own i-Tree Eco software. Using a mobile app providing strict protocols for data collection, researchers took information from 2418 trees and saplings across 255 field plots. Variables noted include species, diameter at breast height (or DBH—taken at 1.4 meters above ground), height, crown dimensions, foliage transparency, damage, and proximity to buildings. The pool of sample data is assumed to be representative of the total population, and from there the software crunches the numbers using “peer-reviewed equations” to paint a macro-scale picture of the urban forest, based on quantifiable characteristics that describe its structure, condition and function.
>>Read the full article by James Holloway on Ars Technica.
>>Read the US Forest Service study.