The transfer of applied loads is currently being investigated in order to learn how load and resulting strain moves from the stem into the roots. Little information is readily available on how trees manage load and resulting strain across the root-stem transition zone and in turn how current arboricultural practices may influence tree stability. Tissue differentiation within the root system, including vascular transitioning and cell arraignment, occur in preparation for vertical alignment. As fibers are strengthened by decreased cell size in anticipation of supporting vertical loading, the transition zone from multiple roots into the main stem may play a vital role in tree stability. Determining how the root-stem transition zone contributes to overall tree stability will assist in the continued refinement of the responsible care and management of trees.

Our research will involve non-destructive static pull tests to measure strain across the root-stem transition zone on mature trees during the summer of 2015. Strain will be measured with an ARAMIS 3D optical stereophotogrametry system.  The expected outcomes of this study include: 1) a determination of how sampled trees mange applied load and resulting strain across the root-stem transition zone, 2) how strain is transferred into first order roots in the windward, leeward, & tangential directions in relationship to the pull, and 3) an evaluation of torsional strain occur across the sampled tissue area. Although not all statistical data and results will be completed by the time of the conference, preliminary analysis of a number of trials will be presented.