Portland has increased its number of street trees by 15% over the past decade, according to a new street tree inventory released Monday.
Much of the increase comes from recent expansion of street tree planting, city officials said.
The city's Urban Forestry division mapped, measured and identified more than 252,000 street trees - those planted in public rights of ways, the strips of land adjoining city streets - across the city in a three-year surveying effort.
In addition, the division estimates the city has another 81,000 trees along roads in forested areas and natural areas that are not easily inventoried.
The count shows the city has 15% more street trees than in 2016 and that about 90% are in good or fair condition.
The survey also showed a somewhat greater species diversity than in the previous count, with 354 unique species documented, the most common being the Norway maple. But the maple, cherry and plum species still make up 33% of all street trees, leaving the trees vulnerable to pests and climate change.
The inventory also revealed areas to improve: Many planting sites remain underutilized, especially large ones where small species are often planted instead of larger shade trees.
The city's earlier comprehensive effort to count street trees took place between 2010 and 2016, cataloguing 218,602 street trees. That count also found a lack of species diversity and few mature trees.
Urban Forestry previously found a decline in the city's overall tree canopy between 2015 and 2020, likely due to hotter, drier summer conditions and the fast pace of development.
Street trees make up a small portion of the urban forest, about 333,000 out of more than 4 million trees in the city. More than half of Portland's trees grow on private property.
In recent years, the city has engaged in more tree planting efforts, recently announcing it would spend more than $40 million to plant at least 15,000 trees over the next three years and another $70 million to maintain existing trees.
Trees provide shade, clean the air, contribute to stormwater reduction and are home to birds and other wildlife.
The inventory was completed in part with money from the Portland Clean Energy Community Benefits Fund, the city's climate fund.