Locomotive steam whistles echo no more in the forests of the north California coast. A century ago, Humboldt and Mendocino Counties had more than 40 railroads bringing logs out of the forest to mills at the water's edge. Only one single railroad ever connected to the outside world, and it too is gone. One railroad survives as the Skunk Train in Mendocino County, and it carries tourists today instead of lumber. Redwood and tan oak bark were the two...