Over the years, the forests of southern New England have seen several different timber and wood/pulp harvesting systems. Until the advent of the internal
combustion engine, all felling and bucking was done with axes and hand saws; all skidding was done with horses or oxen. In the 1930's, chainsaws and crawler tractors (bulldozers) began to replace axes,
handsaws, and draft animals. In the 1960's, 4-wheel-drive, rubber-tired skidders began to replace crawlers. Now, as we approach the turn of the century, fully mechanized harvesting systems are
beginning to replace chainsaws and skidders. The following will describe and discuss these harvesting systems, all of which (except axes and handsaws) are still in use in this area.
Horses or Oxen
Logs are loaded onto a low-to-the ground sled or attached at one end with choker chains to a 2-wheel forecart which are pulled by the horses/oxen. The animals are specially bred
and have been trained for their work. Some are capable of skidding from stump to log landing and back unassisted.
The main advantage of horse/oxen skidding is the very low level of damage to the
residual trees and the forest soils. The main disadvantage is the low limit on skidding distance for which draft animals are economical. Uphill skidding on grades steeper than 10% is generally
not feasible. Unless skidding distances are very short, draft animal skidding will cost $20-$30/Mbf more than skidder work (i.e., $90-$110/Mbf as compared to $70-$90/Mbf for skidders).
Crawler Tractors
Crawlers run on metal tracks which give them excellent traction and maneuverability. They most often have a cable winch attached to the rear end with several log choker chains
attached to the cable. The chains may be attached to logs (or whole stems) lying close to each other. When the cable is winched in, the logs come together to form a hitch which is then skidded
out to the log landing.
The main advantage of crawlers is that they compact the soil less than rubber-wheeled skidders because their weight is spread out over a much larger tractive surface area.
They are also able to do road construction work with their blades, and their manueverability can help avoid damage to residual stands. The main disadvantage for crawlers, as for draft animals, is the
cost factor. Tracks require more maintenance than wheels and they limit the speed of the machine. Some land is too rocky to operate with crawlers because rocks can damage tracks and the low-slung
undercarriages of crawlers. Crawler skidding will cost at least $10-$20/MBF more than skidder work (i.e., $80-$100/MBF as compared to $70-$90/MBF for skidders).
Rubber-Wheeled Skidders
Skidders use winches in the same way as crawlers to haul out logs or tree stems. Their axles move independently in the vertical plane. They are articulated (jointed) in the middle to allow full
independent movement of front and rear sections. They have high ground clearances so they can operate on all kinds of terrain. They can haul much faster than draft animals or crawlers.
The main
advantages of skidders are their speed and ability to operate under all but the most adverse conditions. Therefore, they are the lowest-cost harvesting systems. The principal disadvantages are
the relatively higher levels of damage to residual stands and skid roads, plus increased soil compaction. However, these disadvantages may be minimized or even eliminated when the equipment is run by a
careful operator who carefully plans his hitches and skid roads, and avoids skidding when soils are wet (to reduce soil compaction). Such careful skidder operation would have a cost at the high end of
the $70-$90/MBF range indicated previously.
Other Systems
In regions of the country with relatively flat, rock-free soils, other harvesting systems have become popular. They are now also
being used in southern New England. Large, hydraulically-operated sawheads and stem gathering systems mounted on tracked or rubber-wheeled tractors are very fast and safe for operators. These
equipment systems, called feller-bunchers, leave bunches of tree stems along skid roads which are run by forwarders or grapple skidders. Forwarders pick up and carry cut logs; grapple skidders drag
whole trees.
A forwarder has a front section like a skidder, but instead of a cable winch, has a hydraulic knuckle-boom log loader behind the cab and a small log deck above the rear axle. Forwarders
are used with conventional chainsaw felling and feller-bunchers. When loaded, the forwarder has a high center of gravity which makes it unsuited to steep or rough terrain. Grapple skidders have a
large grapple mounted on the rear; they may also have a cable winch.
Other Considerations
Many landowners are concerned about the amount of tree tops, or slash, which is left in the woods after a
harvesting operation. Most timber cutting operations will remove the stems down to about 10" diameter in the tip. Cordwood and pulp cutters will remove stems down to about 6" in the
tip. The remaining slash is normally left to lie no higher than 3-4' from the ground. Complete utilization of the tree is generally not practiced in this region, partly because of absence of
markets for the small diameter wood and partly because of the damage caused to the residual stands by removing whole trees.
It is possible and aesthetically desirable to lop or run over the remaining tree
tops so that they will lie closer to the ground. The cost of lopping or flattening will depend upon how high the tops are to be left. Lopping to lie within 2' of the ground would cost about
$5/MBF extra.
Another aesthetic consideration is the appearance of the log landing after the harvesting operation. The normal procedure is to push the chunks (crooked sections cut out in the process
of cutting stems into logs) to the side of the landing and smooth out any ruts; grass seed may also be spread. It is possible to remove all the chunks from the property for an additional cost that will
depend on the number of chunks. Complete seeding of the landing and all major skid roads is also possible for a cost that will depend upon the extent of the skid road system.
