While horizontal grinders have become the latest fad for recycling green waste on jobsites, chippers still provide an attractive alternative for some site clearing operations. Though they can't handle root balls and are sensitive to dirt and debris, chippers are very efficient with clean wood.
"We are seeing an increase in contractors purchasing wood chipping equipment to reduce costs and minimize time spent on the job," says Jason Showers, regional sales manager, Morbark.
"A chipper is much more efficient at getting rid of your above-ground material," says Jerry Morey, president, Bandit Industries. "The feed rate of most of the whole-tree chippers are in the area of 120 fpm. A grinder is generally getting rid of it at the rate of 25 to 30 fpm."
In addition, the operational costs are lower. According to Morey, it takes more horsepower and quite a bit more fuel to grind wood vs. chipping it.
Bob Campbell, sales manager, Woodsman Chippers, adds, "The grinder produces a shredded material created through hammering or busting the material apart vs. cutting it. When you are cutting the material, it is a lot easier to process with less horsepower and less fuel consumption."
The initial purchase price for a chipper is also generally a lot less than a grinder. "Grinders are a lot more money because they have to be built much heavier," says Campbell.
Not all chippers are created equal. Some contractors prefer disc-style chippers, while others prefer drum-style models. "The disc chippers chip easier with less fuel and require less horsepower," says Morey. But drum-style chippers tend to have larger infeed openings. "The advantage is when you get to the crotches in the tree. They go through the drum a little easier than they do the disc."
Drum-style chippers can also be more compact. "With the drum-style chippers, you have the ability to process larger diameter trees without the whole machine increasing in size," says Campbell. "Every time you increase the disc size, the whole machine all the way around has to get much larger. The drum-type chipper is more of a versatile machine because of its compactness."
In-feed size is also an important issue when choosing a chipper. "Chippers in the 19- to 21-in.-diameter range are popular," says Mark Rieckoff, environmental segment manager, Vermeer Mfg. Co. "Contractors can tow them down the street and work on tree takedowns, then go out on a 5-acre site development project and process trees and brush."
Showers indicates, "The majority of contractors in the Northeast are purchasing 18- to 20-in. machines. Generally, these machines are built heavier and can handle being fed with auxiliary equipment such as an excavator, reducing the contractor's need for additional equipment and manpower."
To make sure you're purchasing the correct machine, Showers advises consulting with your sales professional and reviewing your options to determine the size and type of equipment that best suits your individual needs and budget.
The end results
The end products from a grinder and a chipper are different. "A grinder offers endless options to change the size of the end products by simply changing screens. Grinders can also be equipped with coloring systems that further enhance the value of the resulting end product."
These differences can make ground products more profitable. "If possible, the end product should also create a revenue stream for the contractor," says Rieckoff.
Consequently, chipped product has traditionally been viewed as less valuable, often being spread back on the site. "A chipper is for product reduction," says Rieckoff. "The ROI comes from the job, such as a tree takedown or site clearing."
However, this is starting to change in certain areas. "Because of the high energy prices, they are putting in a lot of wood-fired power plants," says Morey. "Those guys are competing mainly for the same type of material. The chip is actually a better fuel wood product than ground material in most cases, although we have customers selling fuel wood out of both the chippers and the grinders."