February 15, 2004 | General

Preventing Erosion While Preventing Fires

Robert Rynk
BioCycle February 2004, Vol. 45, No. 2, p. 48
Many forested areas of North America are in rough shape. Particularly in Western regions, the wildfire hazard has grown to dangerous levels due to a combination of conditions that include drought, insect infestations and short-term management strategies. As described in the first part of this article (see “California Fires Fuel Wood Recycling,” January 2004), years of forest fire suppression have created unnaturally dense stands of trees and brush that compete for sparse water, especially during periods of drought. The moisture-stressed trees become susceptible to attack by bark beetles. Magnified by development in forested communities, the dry conditions, dense stands and beetle-killed trees have set up a situation for potentially disastrous fires, as occurred in California this past autumn.
The fire-prone conditions in the forests have prompted foresters, communities and utilities to reduce wildfire fuel sources – the dead, dying and dense trees and brush. The recent California fires have only hastened the pace of activity. Efforts are underway to use the harvested wood to its highest value. For instance, as reported in Part 1, communities in southern California are enticing lumber mills, pallet manufacturers and biomass energy facilities to communities near to the forests. In addition, branches, limbs and whole trees are being chipped and shipped to distant markets such as biomass, mulch and composting amendments.
However, the magnitude of the problem is huge. The enormous quantity of wood that must be harvested surpasses the processing capacity and markets in most forested places. Suitable processing facilities are often located too far away to be economical outlets; the cost of transportation exceeds the value of the materials. Therefore, faced with so much wood, and insufficient processing capacity, communities and forest managers are seeking local uses for the harvested material.
Among the local options, erosion control has become a logical choice. Not all wood residuals cut for fire protection leave the forests. Loggers may take the logs but leave behind the branches and tops. In many cases, it is impractical to transport brush and small trees off-site for processing and disposal. Thus, much of the wood residue from forest thinning activities is being ground in place by mobile grinders and then immediately spread on land near the grinding station. While this practice might appear to squander good wood, it is, in fact, a logical and beneficial use. Many slopes in forested areas are susceptible to erosion, especially after clearing and harvesting equipment has disturbed the soil. In addition, where a wildfire has occurred, the soil is prone to erosion. When raindrops impact scorched vegetation and soil in a burned area, they dislodge debris or soil particles by their splash effect. A one-inch to three-inch blanket of organic material (e.g., compost and/or wood chips) would do much to protect a deteriorated ecosystem from a fire’s aftermath. If re-establishment of a ground cover is desired, a seed mixture could be incorporated with the compost, wood chips, or rice straw during or following the application of the thin-layered organic material. Grinding wood residues for erosion control is not just an easy strategy, it is often the best management practice.
One example is a California Edison project in Southern California that involves clearing trees from the power line right of way (eventually removing approximately one million trees). The project involves a number of subcontractors, each with a role in harvesting, processing and transporting the wood residuals. The lumber-grade logs are being harvested and trucked to the Sierra Forest Products mill in Terra Bella. Lesser quality logs are being processed in the area by a portable sawmill for pallet stock. The remainder is being chipped and spread on site. Greg McDonald of McDonald Trucking hauled his grinder down from Wisconsin to perform the latter function.
McDonald’s job in the project is to grind the brush, trimmings and trees that are not milled into wood. His tool is a portable 540 hp horizontal-feed grinder with an integral operator’s cab and knuckle boom loader (Bandit Industries’ model 3680 Beast Recycler). Despite the goal to mill as much wood as possible, McDonald’s task requires grinding some large trees, sometimes as large as 16 inches in diameter. As McDonald explains, “For whole trees, or round wood as we call it, you need to chip the wood. A hammermill will not do the job.” When the whole trees are part of the feed mix, the grinder is fit with what McDonald calls a cutter drum. The drum has 60 carbide teeth that slice the wood into chips. When grinding only brush, the cutter drum is replaced with a hammermill. For the moment, the grinder is fit with a screen that produces three-inch minus chips. As the project continues, McDonald notes that a smaller screen may be needed. The chips are spread by another subcontractor within the project area and adjacent forest land as an erosion cover.
Brad Bauder of Bradco Industries also is making mulch, currently in the area around Lake Arrowhead, California. In Bauder’s case, the wood residuals are generated by clearing strips of land around communities for fire breaks, sometimes called fuel breaks. This approach to clearing involves bulldozers as much as chainsaws, tree fellers and skidders. After the large trees are cut, the dozers clear the firebreak by pushing the cuttings and brush into piles on one side of the break. The width and location of the fire breaks vary with the terrain and fire hazard. They may vary from 100 to 200 ft. on level ground to over 300 ft. wide on slopes.
In most of the projects that Bauder has worked throughout the West (California, Nevada and Arizona), marketable trees are being harvested but it is not always a priority. Where it is difficult or uneconomical to remove the timber, large trees are simply left on the ground or pushed into the fire break piles. Fortunately, Bauder’s equipment can handle the large stuff. His biggest weapon is a track mounted whole tree drum chipper (Morbark model 50/48). The chipper has a 900 hp engine and 48-inch chipping drum that processes slash and trees up to 30 inches in diameter. The length of the trees is unlimited except for the lifting capacity (8,800 lbs.) of the grinder’s knuckle boom loader, which feeds the tree into the cutting drum chamber. The chipper can process trees at a rate of up to 100 tons per hour.
Although Bauder has produced chips for biomass fuel and soil amendment, in the firebreaks, the chips are used to cover the soil for erosion control (which is usually well torn up by the bulldozers and other equipment clearing the breaks). Because the track-mounted chipper is self-mobile, it can move through the clearing and processes the trees and brush as they are cleared. “Sometimes we follow right behind the tree feller and chip the trees as they are cut,” explains Bauder. “In other cases, we will sit at the debris pile, process the wood and then track over to the next pile.” Generally, the chips are cut to a two-inch minus size and simply blown over the surrounding ground. Chips exit the machine via a blower and adjustable discharge chute, which can be rotated and set to throw the chips in a wide pattern or concentrated in a pile. “Usually we spread the chips evenly over the area that needs to be covered but we try to keep the depth of application to something less than four inches,” says Bauder.
The greatest need for mulch is in the large areas that have already been scorched by fires. These soils are highly susceptible to erosion by wind or water, to the point where mudslides are a potential threat. Caltrans realized the urgency of the situation relative to protecting the highways transecting the denuded landscapes. Contractors were quickly hired in 2003 for hydroseed, mulch and various fiber—based product applications to protect the most crucial roadside slopes. California Integrated Waste Management Board staff recommended to the U.S. Forest Service (USFS) and local government that the beetle-damaged trees on unburned acreage should be chipped and applied with pneumatic equipment to control erosion on scorched hillsides in southern California. However, the USFS has opted for another solution, especially to protect mountain reservoirs — rice straw.
Rice growers in northern California have an abundance of straw because rice stubble can no longer be burned in the fields. Enterprising growers have suggested rice straw for burned slope protection. As for the short term, USFS staff have found this erosion option more attractive than chipped wood because the rice straw, which carries few noxious weeds, can be dropped from helicopters on the scorched hillsides of less than 55 degrees slope. How successfully the straw can be distributed from the air is currently being evaluated. CIWMB’s Pat Paswater sees both options as promising; “Hopefully, a side-by-side comparison of the effectiveness of both materials on burned slopes can be undertaken in the next few months, and the economics of using each material can be documented when aerial dispersal is not the determining factor.” Perhaps useful information will come from the current use of wood chips by utilities, communities and private land owners in fire prevention projects, like those reported above.
While the California fire situation has captured the recent headlines, the fire hazard extends well beyond California. Each state and province in western North America seems to be dealing with its own species of bark beetle as a result of the prolonged regional drought. Similar problems are being experienced, as in California, and similar solutions and projects are being pursued.
Santa Fe County in New Mexico is dealing with millions of dead piñon pine trees, killed by extended drought and bark beetle infestations. Recognizing the fire hazard, the county fire department has implemented a program of periodic “clean up” events in various locations to help residents with the task of removing the dead and dying trees. In the past two years, 20 such events have taken place. For these events, the county public works department provides the location and means for dealing with the harvested trees. According to James Lujan, Public Works Director for the Santa Fe County, once the county’s portable grinders are set up at a staging area, residents or tree removal contractors bring the trees to be chipped by the county. According to Lujan, “most of the chips go back to the property owners for landscape use or to cover bare ground.” Apart from these events, the county maintains a second grinder to process brush and trees brought in by residents and haulers. The chips produced at the transfer station, which range in size from two to four inches, are used by the county for landscape mulch, dust control, soil stabilization and final cover on the landfill. Lujan adds: “We usually spread the chips in layers of one, two or three inches depending on use and the amount available. The chips that were used at the landfill produced a nice cover of vegetation.”
The dual-grinder approach is relatively recent for the county. The onslaught of beetle-damaged trees and the clean-up programs necessitated new equipment. The county recently purchased two horizontal grinders (Vermeer HG365), replacing an “older” tub grinder that was parked at the transfer station. These 365 hp grinders can grind logs up to 12 inches in diameter and 10 ft. in length. “Our volume of feedstock for grinding has almost doubled and the clean up is expected to last six to seven years,” says Lujan. “We had to have new equipment that could handle large trees and grind them quickly.”
In Whitefish, Montana, Travis Gray operates in a different climate but in similar situations. Gray’s company, TB Gray Inc., originally began in the landscape business and expanded into the forests to also provide logging and tree thinning services. Beetle infestations are less prominent here than in the Southwest but there is still concern about wildfires, drought and the abundant fuel in the forests. As Gray notes, “There is a lot of wood in the forests going to waste, but the problem is that most of it is in the middle of nowhere. It is a challenge but we try to find the best uses for it that we can.”
Gray has been hired for numerous wood reduction projects on public lands and private property, using the harvested trees opportunistically. “Unless we are working in a remote area, we save the lumber grade trees for sawmills, the rest we chip and hopefully find a market for,” says Gray. The operation uses a mobile, self-tracking horizontal grinder (Peterson 2410 HC) with a 460 hp engine and a rated throughput of 35 tons/hr. The grinder is loader by an excavator with a clamshell bucket or by the skid loaders that are used to transport, or “skid,” the harvested trees.
Gray has sent chips to numerous outlets including composting facilities in Flat Head and Missoula, Montana plus biomass plants and sawmills that burn the chips for energy, which generally prefer larger chips of four to six inches. The location and nature of the job often requires that the chips stay on site. As Gray describes, “We sometimes spread the chips out for erosion control or just for aesthetics. On some jobs the owners want us to leave no sign of the harvested trees, what we call ‘parking out.’ In this case, we cut the tree stumps flush to the ground, leave the vegetation intact and either spread the chips evenly over the ground or sell the chips for hog fuel.” In addition, the company has used chips as base for horse trails (spread by hand, carried by wheel barrows) and is working with ski resorts to begin using them as a base on ski trails to prevent slope erosion. Gray has even tried composting on his own on a small scale, mixing chips with aged manure to produce a compost or mulch product.
What is ultimately done to reduce the fire threat in the forests, and to make use of the harvested material, will be largely determined by money. The anticipated costs of removing and processing high-hazard trees killed by bark beetles can take a big bite out of federal, state and local government budgets. For instance, San Bernardino County estimates that it will spend $6 million annually over the next five years on forest thinning and wood processing activities. The cost is also high for private land owners. A homeowner may pay $500 to $1,000 to have a single tree cut and removed.
Everyone in and outside of California is looking for financial relief in this battle. Given the visibility and high hazard of the fire situation, more public money is likely to be made available to help on both public lands and private property. One source that many are looking toward is the federal “Healthy Forests Restoration Act,” which was passed in November (see sidebar). Still, the enormity of the task will quickly deplete public funds. Finding high value uses for the residuals can help offset this cost, as long as those uses are in the neighborhood. Meanwhile, air curtain destructors, where the wood is incinerated quickly (see Part 1) and burial in landfills offer the only possibility of less cost. Opportunities exist, in southern California and elsewhere, for entrepreneurs who can find cost-effective ways to use the lumber, wood chips or wood fiber from the forest residuals for consumer products.

Many fire and forestry professionals and landowners are looking to the U.S. Healthy Forests Restoration Act (HFRA) for a morale and financial boost in the battle to reduce the fire hazard in wildlands. This legislation, which was passed by Congress in November, is intended to address the current forest health crisis, which is contributing to the increased risk and severity of wildfires.
Fuel reduction is a key, if not the key, objective of the HFRA. It authorizes the U.S. Forest Service and the Bureau of Land management to spend over $760 million on treatments to reduce “hazardous fuels” within 20 million acres of public land. The funding can be allocated to projects on federal land that either: interfaces with communities; is in a fire prone condition and is located close to a municipal water supply; is susceptible to catastrophic wildfires due to damage from insect infestations, windthrow, blowdown and ice storms; or contains habitat of endangered species that can be either harmed or helped by fire. According to a fact sheet issued by the American Forest & Paper Association, at least half of the funding will be used to protect areas near homes and communities. Congress must appropriate the funding annually.
Some other provisions of the HFRA deal with control of insect infestations, environmental regulations, watershed protection, biomass use, assessment of forest conditions and assistance for private landowners in maintaining forests. In the interest of advancing fuel reduction projects, the legislation relaxes some environmental review and appeal procedures and judicial challenges to fuel reduction projects. Technical and financial assistance will be made available to private forest owners to follow forestry “best management practices” in order to protect water quality in the watershed. These provision include establishment of a “watershed forester” in every state to provide technical assistance. Through the “Healthy Forests Reserve Program” created by this legislation, private land owners can obtain cost-share funds to restore degraded forests to a healthy state, especially for endangered species protection. Another feature is the promotion of the gathering and dissemination of research information regarding insect infestation.
The HFRA also provides incentives for using the biomass generated by fuel reduction projects as energy sources and other substitutes for petroleum-based products. It establishes grant programs for using biomass as an energy source and for adding value to biomass products.

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