Riders of the Whistling Pines(1949)

When an insect plague ravages the forest, evil loggers plan on harvesting protected land. They murder a forest ranger so they can carry out the plan, and they frame Gene Autry for the crime. Autry is cleared, but the loggers' devious plan continues when they spray the forest to kill the insects, yet wind up killing much of the wildlife, too. Autry must step in and utilize his patented brand of cowboy justice.