Allegheny County lost 10,000 acres of tree canopy between 2010 and 2015, according to a survey released last year by Tree Pittsburgh, a nonprofit group aiming to restore at least some of that shade. The group is offering free trees through November in Allegheny County communities that lost the most tree cover since 2010. The trees are available to any resident in one of those communities. A grant from the Colcolm Foundation will pay for the nonprofit to give away 4,000 trees in 2019 and 2020 to help restore the urban forest canopy.