Bulldozers and Sawmills

[JMH2001]

Hello,
I would like to hear from anyone who has worked with portable sawmills or
small bulldozers.  I am familiar with some brand names; wood-mizer, timber
king, magna-trac etc.  I am interested in using these machines in a
suburban forest setting that will require minimal environmental impact. 
Please respond if you have any experience using these types of sawmills or
bulldozers in a forestry setting.

Thanks,

J. Hamrick
JMH2001 at AOL.COM