10/30/2026
Day three concluded the 2026 Rinntech Arboricultural Summit in Frankfurt, Germany!
Frank Rinn spoke for the morning on advanced wood anatomy- one of the most fascinating topics for the conference! Decades of forestry research shows that the allometric growth of wood tissue is anisometric (varying cells in orientation in response to environmental conditions or other stimuli as they have different strengths along differing axes) as well as differing cell-wall thicknesses local to different areas of stems (at differing ages!). At least one study shows that trees respond within 6 hours to a change in site conditions with new growth (in the case of the study, increased wind-loads due to adjacent tree loss)! The complexity this adds to models makes generalization nearly impossible. However, models were discussed for relative self-comparison of trees by calculating loads for intact stems to compare against stem areas with conditions of concern. This ingenious method utilizes relative assumptions to reduce complexity by understanding that tissues built under the same conditions will have similar anatomical characteristics.
Linda Chalker-Scott (Professor Emeritus, Oregon State University) joined remotely to discuss retrenchment pruning (Linda’s message: the research says, “Don’t do it!”) and care of ancient trees. Linda recently retired from OSU, where Mitch is attending the Botany and Plant Pathology program.
Sebastian Koerber ended the afternoon, speaking about hits and misses he has experienced managing high-value ancient trees for municipalities, including support systems custom designed by engineering firms for trees that are central to public sites visited by thousands of people, yearly.
We learned so much at this conference, and met so many excellent, kind, and generous arborists from all over the world. We look forward to future opportunities to learn from European arboriculture.
