A low gargle echoes against granite cliffs and resounds in the wooded canyons. Each pull of a starter handle and squeeze of a throttle is punctuated by the crack of splintering wood as another dead tree falls in a forest that’s changing all too rapidly. Niles Kant stands at the base of a red fir. Its crown, a thatch of brown needles, rises nearly 175 feet above a collection of cabins in the national forest.