An experimental woodlands project that harvests the whole above-ground portion of trees is providing wood chips for industrial heating in sections of New England.
Further, it is increasing woodlot yields in New Hampshire by 30 to 40 tons an acre.
The process involves the use of chipping machines to process on site parts of trees that were left behind by more traditional methods of harvesting.
Demonstrations of the new process have been held in selected sites in the state, and reactions to the experiment differ. The major drawback is the cash outlay of anywhere from $100,000 to $200,000 for the chipping machine.
The most positive aspect of the new process is the use of cull, or poor-quality, trees. The productivity of the woodlot is increased, and the whole tree is harvested.
John Herrington, executive director of the New Hampshire Timberland Owners Association (NHTO), sees use of the so-called ''bio-mass'' harvesting as practical on about 2 million of the state's 5 million acres of timber.
''The market for the wood chips is slower now because fuel-oil prices are relatively stable,'' he says.
More traditional methods of wood harvesting involve ''skid rows,'' which are laid out to take out portions of trees destined for the sawmill. With bio-mass harvesting, the whole tree, including the branches, is taken out. Roads have to be laid differently to reduce damage to the trees left standing, according to Mr. Herrington.
Some industries in New Hampshire, Maine, and Vermont are already utilizing wood chips as a result of bio-mass harvesting.
The bio-mass project is part of a three-year demonstration in New Hampshire that which began in 1980 and is being conducted by the state Division of Forests and Lands, the University of New Hampshire, the United States Forest Service, NHTO, and the Society for the Protection of New Hampshire Forests.
A $60,000 budget covers the salary for consulting foresters, technical staff, and equipment. One of the aims of the project is to develop guidelines for small woodlot owners. The advantages for residents of the state will be better-looking forests and the financial benefits for woodlot owners.
Elmendorf Board Corporation in Clare-mont, which manufactures Strandboard, a kind of plywood, is already using less than top-grade wood in its manufacturing process.
Richard Kinder, wood manager for Elmendorf, says he is not convinced the wood industry is ready for bio-mass harvesting.
One of his reservations is the cost of the chipper. While ''smaller and less-expensive chippers are in the process of development,'' Mr. Kinder says, ''they will be less productive.
''Chips are simply chopped wood, leaves, and bark from the upper part of the tree,'' he explains. ''In some places this type of harvesting is highly impractical. Woodlots will have to be large enough and have space to accommodate the equipment and the trailer trucks which are used to haul the chips away from the site.
''Any part of the tree that can be manufactured into a higher-use product should be put to that use. This new method is good for low-grade forest material , but I think this process should be a last resort.''
Peter Bloomfield, project engineer with Concord Steam in Concord, sees other types of deterrents to bio-mass harvesting. ''Whole-tree chips cost $18 to $20 a ton, sawdust only $9 a ton, and wood pellets $70 a ton.
''Wood chips in the burning process stick together and don't flow, and sawdust doesn't burn well due to the inconsistency of the material.''
Mr. Bloomfield's favorite wood-burning product is the pellet. While it is the most expensive material, the advantage is in the smooth flow into the burner and the relatively few problems caused in the process.
Both Bloomfield and Herrington see a long-range future for the bio-mass operation and the wood-chips product, however. ''With the price of oil increasing over the long term, wood chips will provide a good alternative,'' Bloomfield says.
''Clearly, wood is cheaper than oil, but the capital investment to burn wood chips is greater,'' he adds.
When oil is burned for fuel, the process is simple and involves shutting and opening oil valves. Burning wood requires more equipment and labor. ''It is no longer just opening and shutting the valves,'' Bloomfield says. ''If you add the costs, wood is roughly half the cost of oil, but if you rely on chips you have to think hard about the cost of the chips as well as the transportation of the material.''
William Samal, district supervisor of Diamond International in Grovetown, N.H., says: ''Diamond is using wood chips for fuel and is working the bugs out of the operation. At the present time we buy wood chips from contractors. We'll make our evaluation on efficiency and cost in a few months.''
Barry Riordan, woodland manager for Diamond, sees the chips as a boon to the wood industry, saying that trees which formerly were unmarketable can now be used.
Another benefit for woodlot owners in the state is that the new process will increase woodlot productivity.
''The process will be productive as well as improve the quality of the woodlot, because the cull is removed,'' Mr. Riordan says. The remaining growth is increased, and quality trees are the result.
Connecticut Valley Chipping in Plymouth has operational yards in Henniker and Ossipee. John Van Loon, a forester with the company, says he has mixed feelings about the bio-mass project and its product.
Pointing to the cost of the equipment, he says ''industry is reluctant to invest that kind of money, because of the state of the economy.'' Also, he says: ''People want guarantees on the wood supply and the price, but you can't guarantee any burnable material.''