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Educational Sessions

Arboriculture Research and Education Academy (AREA)

Using Stereo Photogrammetry to Measure Strain through the Branch Connection Zone
Wednesday, 12 August 2015
1:20 PM — 1:50 PM
Osceola 1, 2, 3
A, T, L, Bs

Branch failure is common issue in arboriculture, whether commercial, municipal, residential or utility. Modeling how branches withstand loads such as wind and ice, or fail, requires understanding how loads move along a lateral branch and into the parent stem/branch. This talk will discuss the findings of a research project designed to determine how loads move across the branch connection zone and into the parent stem. The research will utilize stereo photogrammetry (ARAMIS) to measure strain in the branch connection zone and parent stem. While strain (deformation of a material) is not a direct measurement of loading, it can be used as a surrogate as deformation is a direct result of loading.

The investigation will concentrate on mapping the magnitude of strain as a load is applied to a lateral branch. Specifically looking at how strain may differ between the top and bottom regions of the branch connect zone. Additionally, we will measure the dissipation of the strain as the load moves into the parent stem. We hope to address whether the strain follows a linear path down the parent stem (along a radial zone directly beneath the branch) or does the load fan out and move toward the back or opposite side of the stem.

Understanding how load moves along branch connection zones will add to the growing body of knowledge of how trees withstand or fail during loading events. 

Presenter Information

    • Greg Dahle
      Dr. Dahle is an Assistant Professor of Arboriculture and Urban Forestry in the Division of Forestry & Natural Resources at West Virginia University. His research utilizes biomechanical approaches to understand how urban trees grow and survive environmental loads such as those from snow and ice storms. Greg is a Board-Certified Master Arborist and has worked as a commercial and utility arborist in Northern California. 

Presentation file information