Horse collar of the Oseberg ship burial). The problem with a breastcollar harness was that the actual shafts of the cart, chariot, or other vehicle are attached to a surcingle around the barrel of the horse. The breastplate primarily kept the surcingle from slipping back, not as the primary pushing object. This results in the horse literally pulling the load, a less efficient use of the animal. The modern breastcollar has traces which transfer the pull directly from the breastcollar, but a horse collar still is more effective for pulling heavy loads. After the breastcollar harness, the next and final evolutionary stage
Tree girth measurement the measurement description [17] The height of this measurement point above the standard base point at midslope should also be noted. If measuring a mountaintop forest of stunted trees only six feet tall, a girth measurement made at 4.5 feet would be meaningless. In the case of these stunted trees a girth taken at 1-foot above the base might be more appropriate. The point is that the girth measurements should be taken at the standard heights whenever possible. Where this measurement is not meaningful, an additional girth measurement should be taken at a more appropriate position and that height noted.