TGR treatments Help SDG&E Meet Cost, Compliance and Customer Service Goals

SAN DIEGO GAS & ELECTRIC

Implementing a Tree Growth Regulator program saves San Diego Gas & Electric time and money, while boosting customer service.

The Challenge

With an area that covers 3.3 million customers, SDG&E has approximately 430,000 trees in its inventory. Approximately 25% of trees on SDG&E’s system require annual pruning to maintain compliance with minimum clearances mandated by California regulations.

The Solution

Since tree removal in these San Diego neighborhoods may not always be desired or an ideal solution for SDG&E, the Davey Resource Group proposed another tactic. The company suggested treating its fastest growing trees with Tree Growth Regulators (TGRs).

TGRs gently and predictably slow the vegetative growth of trees by inhibiting gibberellin biosynthesis, reducing shoot growth and extending their pruning cycle. These products are also known to increase root density, improve drought and heat resistance and boost tree tolerance to insects and diseases. Usually applied by soil injection or soil drench, TGRs can also increase the longevity of trees growing in stressful environments and particularly benefit trees that are too large for their growing sites.

Davey Resource Group’s solution was three-fold:

  • Begin a pilot program in 2011 and expand its scope over the next four years as the company tracked positive results.
  • Push the program system-wide by 2015, targeting a variety of tree species, particularly those that needed TGR treatment because of fast-growing attributes or those too large for their locations.
  • Carefully monitor tree response along the way and report findings to SDG&E.

The Results

Since 2015, the Davey Resource Group has treated approximately 6,000 trees (mostly eucalyptus). And the program has proved to be a huge success for SDG&E.
First, SDG&E wanted to prune less yet maintain line clearance safety standards to elevate customer service. The Davey Resource Group program boasted an 80 percent success rate in reducing annual pruning for the client since 2015. This also resulted in a 6-figure cost savings of over the three years.

In addition to those major benefits, the TGR program helped reduce compliance infractions, limit impacts on customer properties and increase tree contractor safety.
But don’t take our word for it. According to Michael Daleo, system forester for SDG&E, “In the implementation and management of SDG&E’s Tree Growth Regulator program, the Davey Resource Group has helped develop and leverage key strategies to create positive developments in cost, compliance and customer service metrics in our Vegetation Management operations.”

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