Issue link: https://www.e-digitaleditions.com/i/1123864
7 more than 25 years, estimates that a number of Central Valley almond orchards (many of them in Kern County) have undergone WOR since 2015. He used an "Iron Wolf" rototiller in his early research, but has since advanced his tree-grinding experiments to include a variety of wood chippers and screen sizes with the use of disking and a spreader to incorporate the chips into the soil. "Right now," Holtz said, "it's costing about $1,000 an acre to grind up orchards and put the wood back into the ground." Why more WOR interest? The growing interest in WOR stems from a chain of events in recent years, from market and regulatory changes to environmental challenges. In 2002, California's Clean Air Act mandated that more power be sourced by wind and solar, which led to changes in energy-market demands. Utilities seeking cleaner energy sources stopped renewing contracts with cogeneration plants that produced electricity from orchard waste. That forced about half of the San Joaquin Valley's eight cogeneration plants to close, and since then the plants that remain have reduced their prices for accepting wood debris. Today, growers are ultimately left with fewer markets for the wood from their ripped-out orchards and are paying double what they used to pay for orchard removal. Moreover, the widespread orchard removals forced by California's multi-year drought produced even more wood with no viable disposal solutions, including burning. Ten years ago, burning was banned in the San Joaquin Valley due to air quality reasons. However, the ban included an exception that states if no viable alternatives are available, growers can apply for permits to legally burn, so some growers have reverted to burning with expensive permits. "There has been a clamor for alternatives," Ludwig said. While WOR is still in its early stages of commercial use, researchers like Holtz believe it offers a sustainable method of tree removal that can benefit both air and soil quality. This idea has support from the San Joaquin Valley Air Pollution Control District, which announced in December 2018 that it would reward growers with $300-$600 per acre, up to $60,000 a year, to implement WOR as part of its Alternative to Agricultural Open Burning Incentive Pilot Program. Growers can visit bit.ly/2VZ8Gbs to learn more. Looking further down the road, Holtz hopes researchers can prove that the benefits to the soil accrue as benefits for the grower as they help to offset some of the initial costs of WOR. That is, he hopes WOR is truly a value-added option for growers. To follow ABC-funded researchers' work and learn more about ongoing WOR projects, visit OrchardRecycling. UCDavis.edu. WOR involves grinding whole almond trees into small chips, spreading them evenly over the ground and then disking them into the soil. LOOKING TO LEARN MORE ABOUT WHOLE ORCHARD RECYCLING? UC Davis' new website focused on WOR offers a hub of the latest research, grower perspectives and outreach opportunities on the emerging practice. For more information, explore OrchardRecycling.UCDavis.edu.