Portland's urban forest is slowly disappearing. Here's why that matters

MAINE PUBLIC • September 15, 2026

It's only 78 degrees in Portland on this summer afternoon, but on the sidewalk, it's hot enough to melt a box of crayons. Under the cover of a massive maple tree on the city's Eastern Prom, in the shade, with the sudden breeze, it feels cooler. That's because of the urban heat island effect. "Lots of heat washes off all that pavement," says Portland City Arborist Mark Reiland. The pavement and buildings in a city absorb the sun's heat and then re-emit it. Urban neighborhoods without trees to shade the sun can be up to 10 degrees hotter than neighborhoods with lots of trees. Portland's urban forest is facing myriad challenges: changing temperatures due to climate change, drought, pests, storm damage, nutrient-deficient soil, development, invasive species and more. "So we asked for help from the Portland Parks Conservancy, and they agreed immediately to help fund a urban forest master plan," Portland Parks Department Director Ethan Hipple says.