• Jim Mahannah

BARK BEETLE EPIDEMIC FORCING ELECTRIC UTILITIES TO RETHINK VEGETATION MANAGEMENT PRACTICES

Updated: Aug 4

Climate-change-induced beetle infestations throughout the western US impose challenging hazards to utilities. However, advanced technologies are reducing risks and costs significantly.


A forest of coniferous trees with many dead and dying trees from bark beetle infestation
Bark beetle damage to forests is widespread
Blame Shifting Climate Patterns

The interplay between bark beetle infestations, wildfires, and climate change is complex and not well understood. However, hotter and drier summers baking the western US are stressing trees, weakening their natural defense mechanisms, and making them more vulnerable to beetle attacks. Further, warmer temperatures encourage additional beetle reproduction cycles seasonally and allow larvae to survive milder winters.

What is the future outlook for utilities struggling with beetle-killed forests today?

  • Computer modeling predicts further trending to hotter and drier. The western US is projected to experience mean temperature increases of 1.5–3.5°C by the 2050s (and about 2–6°C by the 2080s). Meanwhile, summer precipitation in these regions is expected to decrease roughly 10–30% over the same period.

  • Severe weather events factoring into these average increases, occurring roughly once every 20 years, are likely to become one-in-five year events by mid-century.

  • A December 2021 article in Wildfire Today references a recently published study citing a new modeling framework that predicts 35-40% more ponderosa pines could die from compromised tree defenses and increased beetle populations for each degree Celsius of warming.

Such news spell yet more trouble for electric utilities operating power transmission and distribution infrastructure running through forested areas.


Changes in mean annual precipitation and temperature for western North America to the 2050s
Courtesy Journal of Forestry, May 2013
Bark beetles devastate forests and feed wildfires

Tree mortality in the western US caused by bark beetles exceeded those caused by wildfires over the past 30 years. Since 2000, estimates blame the mountain pine beetle alone for affecting 25.5 million acres of forests in the western US. Although beetle infestations are a natural cyclic phenomenon, it is widely agreed that this latest infestation is unprecedented in scale.

Beetle-infested trees lose water – twigs and needles of lodgepole pines, for example, can lose 80-90% of their moisture content within a year of being attacked. Such trees become a more viable fuel source for wildfires. Further, as the needles fall from the trees, the reduced forest canopy allows wind-whipped fires to blow fiercely through the forests with devastating impact. Studies implicate beetle infestations with some of the most destructive wildfires experienced over the past decade in the western US states.


Bark beetle-infested forests present unprecedented risks for electric utilities

Some western US electric utilities contend climate-change-induced beetle infestations are killing trees faster than their vegetation management crews can handle. Adding to the problems are increasingly frequent and severe storms toppling compromised trees and blowing debris and trees onto power lines, causing sparks and wildfires. The scenarios unfolding have become an expensive operational nightmare for many power companies.


Consider the case of Pacific Gas & Electric (PG&E) in California. This utility is reportedly responsible for over 1,500 California fires from 2014 through 2019. The multi-billion-dollar wildfire liabilities it faced eventually forced management to seek bankruptcy protection. Since then, the company has deemed it necessary to shut down the power on numerous occasions as a last resort to reduce the risk of sparking wildfires.


Today, PG&E has commenced work on plans to bury 10,000 miles of powerlines at a projected $15-30 billion. By their calculations, this alternative is more economical than facing the costs associated with wildfire risk.


Electric power lines are deemed the third most common cause of wildfires after equipment use and debris burning in California. Increasingly frequent and severe wildfires are challenging regulators to enforce stringent rules on utilities operating in drought-stricken forested areas. New legislation requires utilities to work ever more safely and manage their wildfire risks while funding appropriate mitigation strategies. Priorities include vegetation management and dead tree removal practices. Failure to comply with these new requirements can result in utilities being handed down harsh financial penalties.


Traditional vegetation management practices are falling short

Electric utilities commonly employ aerial reconnaissance, foot patrols, drive-bys, citizen reports, and cyclic trimming programs to manage vegetation encroachment and clear debris within power line corridors. However, vegetation management crews face unprecedented challenges in executing their programs cost-effectively. Electrical demand from an expanding population base requires more transmission and distribution infrastructure. And these often run through forested areas that have been or will be impacted by bark beetle infestations.


More miles of power lines plus drier, hotter climate conditions that accelerate beetle kill and exacerbate drought virtually guarantee more frequent and intense wildfires caused by utility infrastructure. Acquiring better tools to evaluate and reduce wildfire risk from vegetation encroachment, whatever the cause, is paramount for utility operators. Fortunately, advanced technologies are now available that allow power companies to reduce their wildfire risk and spend less money doing so.


Precision data collection and analysis dramatically improve vegetation management results

Progressive vegetation management teams employ high-resolution satellite imagery, machine learning, and sophisticated algorithms to gather data and analyze vegetation for each network span. This high-tech approach helps utilities identify tree species, height, proximity to power lines, and tree health. Accurately predicting vegetation growth and encroachment and fall-in risks become possible. And verifying the work done by tree-trimming contractors is greatly simplified.


Satellite image of a power line with analysis of risks
Satellite image of a power line with risk analysis performed - courtesy Overstory

With this intelligence, operators can prioritize areas exhibiting the highest wildfire risk. Limited and costly resources can be precisely deployed for maximum effect while dramatically reducing wasted effort. Ultimately, utilities can more accurately assess new and unfamiliar risks affecting their network due to climate change and develop appropriate solutions.