Urban forest planning simplified by new database

Urban forest planning has been simplified by a new manual and extensive database helping city personnel with improved planning for their forests.

For some cities, trees grow into a lot of trouble. Their roots lift sidewalks, their branches tangle into power lines, and they drop limbs and leaves on everything below. Anyone who has spent time walking the streets of Los Angeles can attest to all of these issues.

In extreme cases, “problem” trees are removed and replaced with species deemed less “troublesome” – but if replacements aren’t carefully chosen, the problem will just repeat further down the road.

A new manual and an extensive database released by the U.S. Forest Service’s Pacific Southwest Research Station aims to make those problems a thing of the past.

The projects are the result of 14 years of research into urban forests across the U.S., according to the U.S. Forest Service.

The study goes far beyond any previous attempts, said lead author Greg McPherson, a research forester with the Forest Service. In total, researchers analyzed more than 14,000 trees. The data they collected was used to create a database with more than 170 tree species of several different ages and across 16 climate zones.

Researchers also developed new methods of statistical modeling to predict each tree species’ growth. In the past, a tree’s diameter or age was generally used to estimate its expected growth. The Forest Service’s new manual and database use 365 different sets of equations to estimate tree growth, meant to help planners with urban forests. Each set includes step-by-step instructions for their use, so anyone can use the manual without extensive training.

With the help of these new tools, city personnel in charge of urban forest planning can determine how tall a tree is expected to grow well before thinking about purchasing and planting it. That way, cities can make better use of tree-planting resources and city residents can enjoy mature, lush urban forests with less impact on lifestyle.

The manual also offers information on the amount of each tree species’ foliage, which can be used to determine how well the trees clean pollution from the air.