How did Taft disappoint the reformers on conservation?

The major way in which Pres. Taft dissapointed reformers
who cared about conservation was in his firing of Gifford Pinchot.  Gifford Pinchot was
the highly respected head of the Divison of Forestry.  Pinchot engaged in harsh and
public criticism of his boss, the Secretary of the Interior (Richard Ballinger). 
Ballinger had opened public lands to private development.  This angered conservationists
like Pinchot.

Because of Pinchot's repeated criticisms of
Ballinger, Taft fired Pinchot.  This made conservationists angry and it also annoyed
Theodore Roosevelt, who had appointed Pinchot when he was
president.

By angering these people, Taft helped split the
Republican Party, leading the party's defeat in the 1912 presidential
election.