Farming Magazine - April, 2012
FOREST PRODUCTS EQUIPMENT
Preventing Erosion Problems
Tools and techniques for loggers
Thankfully, the topic of erosion control on logging jobs has become much better understood than it was in past years. Today, there are a number of best management practices (BMPs) for controlling erosion in all aspects of a logging job, from skid trails to roadways to log landings.
Wattles feature a fiber material (straw, in this case) stuffed inside a net wrapper. They are staked into position, and once they absorb water their weight helps these products to stay in good contact with the ground to capture runoff and prevent erosion.
Many of these erosion control strategies are simply a matter of common sense: shutting down operations when soils are saturated; skidding logs across rather than up and down slopes whenever possible; maintaining filter strips along roads to capture sediment-laden water before it runs into streams; creating roads and skid trails on gentle slopes whenever possible and using switchbacks on steeper slopes; choosing landing sites with a slight slope to shed water and that are well away from streams; and many other similar examples.
Other erosion control strategies involve constructing simple site-built features, such as open-top culverts (ditches angled slightly downhill often framed by logs on both sides); broad-based dips (gentle mounds often built up with logs that can collect running water without hampering equipment travel); using slash to protect dry streambeds from tire ruts; constructing water bars and turnouts to direct any flowing water off of roads; staking in hay bales in areas where the flow of water needs to be slowed and filtered; to name just a few.
There also may be times when specially designed and manufactured products are required to adequately control erosion on logging sites. It may not be as common to see such products on logging sites, and it is true that there is a financial cost involved, but the performance of these products may provide a value that outweighs their cost.
East Coast Erosion Control (www.eastcoasterosion.com), headquartered in Pennsylvania, is one supplier of various products used in logging and other industries for erosion control. John Ravert, the company's director of technical services, joined East Coast Erosion Control after 21 years of work with a county conservation district in Pennsylvania. "I had a chance to see many good logging jobs, but also a chance to witness the devastating erosion caused on bad jobs," he explains.
Here, straw erosion control blankets cover a water bar, while a coconut erosion control blanket has been placed in the direction of the flow of water. These products help to control erosion while vegetation can regrow on the site.
Ravert says that one of the most useful erosion control products for logging sites are erosion control blankets. "On the log landing area, if [the logger] is going to push off any slopes, which oftentimes they have to do, erosion control is a concern," explains Ravert. "Here in Pennsylvania, if the log landing area has a slope greater than 3:1, [the logger] is required to put down erosion control blankets." He recommends the use of a single-net straw blanket for these situations. "They really help to get the slopes vegetated," Ravert points out. Erosion control blankets are available for different slope ratios and with varying longevity, depending on how long erosion control protection is needed.
Wattles (sometimes spelled waddles) are another highly effective erosion control product that holds value for logging jobs, according to Ravert. "In the industry they are known as 'sediment retention fiber rolls' or 'surfers' or 'coir logs,'" he explains. These sediment logs are "sausage-like" products (fiber stuffed inside netting) and typically come in 12, 16 and 20-inch diameters. "We often see them used in lieu of silt fencing," says Ravert. "The nice thing about wattles is that they really fit and shape to the contour of the ground very well. In forested areas, there's very seldom a piece of completely flat ground, so a silt fence can be a waste of time. The wattles do a really good job."
In addition to forming a more continuous bond with the ground, Ravert adds that wattles also are easier and quicker for loggers to install than silt fence. "Typically, you just lay them down and stake them in. Once they get wet, the weight of the wattle conforms with the surface of the ground."
Beyond use surrounding the landing area, Ravert says that wattles have also proven useful in restoring skid roads after the logging job is done. "Sometimes you'll see them put in as water bars to keep water off as the loggers are trying to restore the road to bring it back to whatever state the regulations require - typically you need to reseed and get vegetation started," he explains. "Rather than going through all the energy and effort [of building a traditional earthen water bar], you can put a wattle across the roadway to intercept the flow of water and kick it off into a secure area."
East Coast Erosion Control manufactures and offers a number of different types of wattles. Straw wattles are constructed with the waste straw left over from the assembly of straw erosion control blankets. "For the stuff that falls on the floor during manufacturing of the blankets, we have a conveyor belt that takes that straw to our wattle area," says Ravert. "It's just like making sausage: there's a big auger feed that we put a net on and then feed the straw into it."
Hydroseeding often produces better germination results than traditional broadcast seeding, which can help areas such as log landings and other disturbed sites to recover and revegetate more quickly.
A similar process is used in the construction of the company's excelsior wattles: the stringy, fibrous waste aspen wood left over from the construction of excelsior blankets is used to make the sediment logs. Another wattle option is coir logs (made of coconut fiber). "The nice thing about the coir logs is that the entire thing is biodegradable. You have coir fiber inside and coir twine on the outside; it is all organic based, and eventually it will just rot away to nothing," states Ravert.
The other types of wattles typically feature polyethylene netting, which will break down, but takes longer to do so. Because of the heavy weight of the wattles once they absorb water, they are not designed to be reusable, but rather are intended to stay on the site where they are initially installed. "They get very, very heavy, and that's what you want," explains Ravert. You want them to have some mass to them so they don't float around."
Ravert says the hydromulches are another effective method of controlling erosion on logging jobs. "If you're in an area, like a log landing, where you can get a hydromulching truck in, you can just spray everything," he explains. For example, East Coast Erosion Control offers a HY-C 1 hydromulch that comes in four different grades. "This is a straw and recycled cotton-blend mulch application. You put that in one of the tanks, add water, fertilizer and seed, then you go out and shoot it. It gives you good germination very quickly," says Ravert. The mulch provides a good seed-soil contact, which is critical, he stresses.
Herbie Brewer, owner of H.E. Brewer Pulp & Logging in Freeport, Maine, purchased a 300-gallon Turbo Turf hydroseeder to help in his erosion control efforts on log landings. He's also found many other applications for the equipment, which he mounts on the back of 1-ton pickup truck.
Courtesy of H.E. Brewer Pulp & Logging.
Brewer Logging in Freeport, Maine, is one logging contractor that utilizes hydroseeding as a key part of its erosion control measures. "When I'm disturbing soil in a sensitive area, I use my hydroseeder," explains Herbie Brewer. "It really does a great job." He uses a 500-gallon Turbo Turf hydroseeder mounted on the back of a 1-ton pickup, which lets him gain easy access to the landing area and even other parts of the logging job.
While the primary erosion control function of a hydroseeder is to assist in the revegetation of sites, Brewer says it's not always necessary to add seed to the mix. "Sometimes I'll mix up a batch with just the paper fiber and the polymer, which keeps everything together on the ground. I'll shoot that out and it really holds everything down and provides erosion control in itself," he explains. This approach is best if erosion control is needed while a logging job is still ongoing and there's a chance the area - the outer edges of a landing, for example - will be disturbed again. "If I'm not quite done with a site but I just want to stabilize everything, this works great," says Brewer.
Once the job is done, the area can again be hydroseeded, this time with seed included in the mix. "If I'm seeding, it will seed about 4,000 to 5,000 square feet," he explains. On landings he typically uses a field mix with clover in it. "If it's on slope, I'll put more annual ryegrass in to get it established quickly," Brewer adds. He says he sometimes even takes soil samples on the landing and will add liquid lime if the pH needs to be adjusted. In addition to the environmental benefits of getting the site revegetated quickly in order to control erosion, Brewer says he also uses his hydroseeder as a marketing tool and says landowners appreciate the quick aesthetic restoration of a site after logging.
Brewer also uses the hydroseeder for other applications, including on his farm and when he's contracted to provide hydroseeding services on landscaping and other construction sites. "A hydroseeder is a multipurpose tool; you can really do a lot of things with it," he says. "I'll even use the hydroseeder for dust control - just wetting down the area where we're working when it's really hot and dry out." He also notes that, when compared to most equipment used in logging, a hydroseeder "can be purchased rather reasonably." Brewer says he paid about $5,500 for his new hydroseeder and points out that pre-owned units are available for even less.
"I can actually get grass growing in seven to 10 days," says Brewer. He's found that soaking the seed in water the night before application will gain him several days in terms of germination. "And if the forecast shows that it's not going to rain for several days, there are gel pellets you can add to the mix that will keep everything moist," he notes. Brewer credits his local material supplier - Allen, Sterling & Lothrop in Falmouth, Maine - with helping him learn how to use the hydroseeder and providing formulas for all of the various mulch, seed and other specialty materials that can be added to achieve specific results.
Most loggers in the area choose to broadcast spread seed and then cover it with mulch hay, says Brewer. "With that method, sometimes you get grass to grow and sometimes you don't," he observes. While there is an up-front cost to purchase a hydroseeder and some expense for the materials added to the mix, Brewer says it's cheaper than having to return to a site one or two more times to reseed. "When I finish a job, I want to be done with that site," he concludes. "I feel that if I'm going to go through the effort to put seed down, I want it to grow. If you have vegetation growing, that will stop the water and absorb the sediment."
Patrick White is a freelance writer based in Middlesex, Vt. Over the past 10 years, he has covered a wide range of agricultural operations around the Northeast. He is always on the lookout for unusual stories and cutting-edge installations. Comment or question? Visit www.farmingforumsite.com and join in the discussions.