Trees of life: tiny beetles turn Californian forests into tinder for energy
California’s record four-year drought has primed its coastal forests
for a bug invasion. Millions of native bark beetles, which thrive in
warm conditions, are burrowing into trees weakened by a lack of water,
leaving in their wake dry, dead wood that becomes natural tinder. The
beetles and drought
have already killed off 29m trees, with tens of millions more
expected to become casualties. Pacific Gas and Electric (PG&E), a California company, decided to turn the serious fire hazard into a source of low-carbon energy. It received the state’s approval last week. PG&E plans to clear away dead or dying trees close to its power lines and use them to produce electricity. The scheme is an unusual way to reduce wildfire risk, which grew so
high because of the persistent drought that Governor “We constantly monitor vegetation and its impact on our gas and
electric transmission and distribution systems,” said Wildfires pose serious threats not only to power lines and stations but also to nearby residents and their homes. PG&E is facing lawsuits and compensation claims totaling hundreds of millions of dollars over its role in last year’s Butte fire, which killed two people and incinerated more than 900 structures. A state investigation found that the company didn’t properly maintain trees surrounding its equipment, leading one pine to fall on a power line and start the blaze. But fire isn’t purely an enemy. Research shows that it can be nature’s way of clearing dense growth from a forest to let in more sunlight, enrich the soil and reduce competition among trees so that they grow bigger and healthier. To reduce risks and improve wildlife habitats, forest managers have historically carried out controlled burns to selectively clear forests that seem prone to fire. Related: US Forest Service stretched to breaking point after record year for wildfires Managing fire risks will become a bigger challenge because of climate
change. Caused by rising temperatures from manmade emissions, climate
change will likely
increase the number and intensity of wildfires. That has prompted
scientists and fire officials to recommend
various ways to minimize risks, such as limiting home construction
near areas with high fire risks. “We must reduce the global warming pollution that feeds more fire activity. At the same time, it is critical to return our forests to more natural conditions and fire-cycles, step up protections for people and properties, and prepare to jump start new forest growth,” said a National Wildlife Foundation report on global warming and fire risks. The cost of federal agencies putting out fires alone rose to $2.13bn in 2015 from $398m in 1990. Sending diseased trees to power plants is a newer approach, and California isn’t the first to try it. A few years back, the US Forest Service launched a project to ship trees killed by mountain pine beetles in a national forest in Colorado to a power plant, an effort that the forest service planned to replicate in the western US. The federal government manages about 640m acres of forests nationwide, with most of them in Alaska and western states. PG&E’s plan to cull sick trees for energy generation, a first by the company, will help it meet a state mandate to increase its renewable energy supply to 33% of its total by 2020. It’s contracted with Sierra Pacific Industries for the project. Most of the diseased trees will come from the eastern part of the state between Fresno County and Placer County, Paulo said. Its contract with Sierra Pacific, which will end in September 2019, allows the power company to deliver up to 206,000 bone dry tons – the term “bone dry tons” refers to the weight if moisture was removed – of wood each year. The fuel will generate 187 gigawatt hours of electricity total annually, enough to power about 31,000 average homes per year. PG&E wouldn’t divulge the project’s cost. “It’s not cheap to do this,” said Harvesting diseased trees to reduce fire hazards has its downsides,
however. Allowing sick trees to fall on their own and stay can be vital
to a forest’s health, said “Snags are often important habitats for various bird and insect species,” he said, “and the decomposition of downed trees is also an important part of natural forest ecosystems.” Related: California wildfire triples in size as heatwave looms The heavy equipment used to transport logs can scar the land and its wildlife denizens, Stewart said. Paulo said most of the tree removal will happen close to civilization, within 20 feet of the road and 100 feet of houses. The company will hire foresters and biologists to oversee the project. Ridding forests of diseased trees isn’t a fail-proof way to prevent fire, research suggests. Other factors, such as strong and persistent wind, can prove a bigger problem than dry, rotting trees. A case in point: windy conditions whipped up a devastating fire that burned thousands of acres and destroyed hundreds of homes in southern California in October 2003, an area that had undergone a removal of beetle-ravaged trees only a few months earlier. Crystal Kolden, a geography professor at the University of Idaho and an expert in wildfire management, was doing field research in that area at the time. Kolden said that ultimately, good intentions to manage forests and prevent wildfires don’t always produce desirable results. “We know from paleo-ecological studies that a widespread forest die off has occurred in the past due to drought and insects, and the forest has recovered on its own,” she said. “But the potential negative impacts of heavy machinery and the loss of snags to serve as habitat and nurse logs for new seedlings is concerning. What if our attempts to try and save the forest only hasten its demise?”
http://www.energycentral.com/functional/news/news_detail.cfm?did=39196373 |