His slogan "Only you can prevent forest fires" helped reinforce the idea that fire was the enemy. However, there are many critics of Smokey and his campaign.
Critics say that decades of stopping/suppressing fires helped create forests that are unnaturally thick with fuel. Forestry professor Ron Wakimoto of the University of Montana says that forest conditions that we have today are directly the result of that campaign.
A few years ago, Smokey the Bear's message was change to "Only you can prevent wildfires". This makes the distinction that there are bad fires (intentionally or accidentally set) and fires that promote healthy, less combustible forests.