felling = bringing a tree down to the ground; bucking = cutting a felled tree into logs

• [pdf] "The Craft of Tree Felling" — really good
• [html] lotssss of good advice
• [video] very good overview
• [video] steering with a backcut
• [html] Precision Tree Felling
• [pdf] Felling Techniques
• [pdf] Tree Felling Handbook
• OSHA rules [ppt]
• lots more