Head Lean : One of the two natural leaning forces found in most trees. Head lean is the most prominent outward slant or lean of a tree in reference to its base.
US Department of Labor, Logging eTool: Glossary, Occupational Safety & Health Administration OSHA, Washington, D.C., USA 2010. https://www.osha.gov/SLTC/etools/logging/glossary. html, (OSHA/ Logging - Amer) {620}
