The residues left in the forest as a byproduct of a timber harvest are often chipped and sold as a boiler fuel. This material is referred to as “fuel chips.” Whole trees are cut and brought to a preprocessing location in the woods known as a “landing.” Here the tree is de-limbed and sawed into logs of various lengths. The logs are loaded onto trucks for delivery to a sawmill (or pulp mill) and everything else, limbs and tops, is put through a chipper and blown into a chip van. If the logging contract calls for a clear-cut, then any non-merchantable trees are also brought to the landing and these trees are put through the chipper.

Some landings are mobile preprocessing plants. The chipper is mounted on a trailer so that it can be readily relocated to harvest a different tract of timber. Loggers try to optimize the in-forest transport of the raw biomass (skidding of whole trees along the ground) relative to the hauling of product (logs and chips) in highway trucks. The quicker they can get the mate­rial off the ground and onto a truck, the lower the total transport cost from stump to final use.

In the past, fuels chips have been sold at a price that basically just covers the cost of chip­ping and hauling, and perhaps a small part of the cost to bring the trees to the landing. The land owner gets his or her portion of the price for the logs but nothing for the fuel chips. The advantage to the landowner is that the site is cleared and ready for replanting when the logger leaves. The logger gets an advantage because the litter (limbs and tops) at the landing is cleared away and does not accumulate to slow operations. The fuel chip market, however, is changing rapidly as new bioenergy options compete for the chips, particularly in the Southeastern United States.

When there are no delays, a chip van can be filled in about 40 minutes. (High performance chippers are available that can fill a van in 15 minutes.) Average productivity is considerably less in a typical operation. Often, the hauler unhooks and leaves an empty van to be filled while delivering a full van. Waiting for the van to be loaded reduces the number of loads a truck tractor can pull in a given day.

The largest wood-fired electric-generating plant east of the Mississippi is an 80-MW plant in Hurt, VA. This plant unloads 150 chip vans on a typical day; their record is 311 vans in one 24-hour period. The trucks are weighed in, dumped by the truck driver, and weighed out. Total time required when there is no queue is about 10 minutes. For any bioenergy plant receiving fuel chips, the key to controlling hauling cost is the operation at the receiving facility. This was discussed previously in “Logistics of biomass feedstock handling at the plant gate " section. Haulers do not like to wait in the queue.

In the Southeastern United States, woody biomass is harvested year-round—it is stored in the forest until needed. Because just-in-time delivery is not practical, some at-plant storage is required. A host of operating variables (weather, traffic, equipment breakdowns) can inter­rupt deliveries. The 80iMW plant operates with about 20 days of aLplant storage in the summer and 45 days in the winter, when the potential for weather delays is greater. The
biomass is piled with two bulldozers that operate during the daytime delivery. These bulldoz­ers push material onto the storage pile and also push material into a twin-screw feedbox that meters material onto the belt conveyor into the plant. This conveyor must run continuously to maintain a flow of fuel into the boilers. The cost penalty for shutdown is very high. One bulldozer operates during the night shift to keep the conveyor feedbox continuously supplied.