Science of Arboriculture

Starting with the National Arborist Association’s (TCIA) cabling standards in 1944, the industry standards have now expanded to include numerous aspects of tree care and safe work practices. The process of creating a standard and its corresponding Best Management Practice guide is discussed in this podcast.

Regardless of your stance on climate change, the consideration of how specific tree species could be either adversely affected or more effective in a changing urban environment provides a thought-provoking forum. Dr. Ferrini discusses the evaluation of tree species that have been traditionally planted in urban settings in various parts of the world to determine which species may be more adaptable and beneficial in the event of climate change.

For several years tree experts have tried to assess breakage and uprooting failure potential of trees based on technical measurements. Such calculations may seem reliable at first glance, but a more detailed analysis shows many ‘hidden’ problems.

Determining the necessary branch diameter to support a specific load is crucial for safety during tree climbing, cabling, and for appropriate tree risk assessment and mitigation. In this presentation, Andreas Detter talks about differences between tree species and other parameters affecting tree strength and stiffness during wind events in urban environments.

Trees are well suited to become a part of a city’s rainwater management system, but must have sufficient soil resources and large canopies that reduce the impact of rainfall by absorbing and retaining water and decreasing peak flows into regional water systems. Urban foresters and arborists can be key initiators in the use of trees for rainwater management.

During which types of storms are tree failures most likely to result in human fatalities? Dr. Schmidlin discusses the unique characteristics of specific windstorms, such as thunderstorms, hurricanes, and tornadoes. Study results identify the numbers of human deaths from falling trees or tree parts in relation to each type of windstorm and the U.S. locations most affected.

What are the results of root pruning on root ball quality and the stability of trees planted from containers? Dr. Gilman presents two research studies that evaluate root pruning effects on root defects and tree stability of hardwoods.

Visual assessment of trees for signs of decay is essential, but it may not be enough. Once decay indicators help identify trees that require further testing, implementation of sounding, probing, and advanced assessment methods is recommended. Following the “trail of indicators” and using testing devices in the proper locations on a tree can result in more accurate detection of the incidence and severity of decay.

Trees, Hurricanes, and Risk to Electric Power Systems: An Engineering Perspective - by Seth D. Guikema, PhD