A utility company wants to cut through 5 acres of mature Doug fir and big leaf maples in a massive Portland urban forest to make way for new transmission lines. Forest Park spans 5,200 acres in the Tualatin Mountains of Northwest Portland. One of the largest urban parks in the United States, it provides important habitat for vulnerable species, particularly Northern red-legged frogs — as well as more than 80 miles of trails for Portlanders seeking easy nearby access to the wilderness…