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 groups around the world are based upon American Forests guidelines. The Native Tree Society measurement guidelines also generally follow the American Forests prescription, with some additional elaborations. Many trees have burls bumps, and knots along their trunk. If these occur at the 4.5 feet girth measurement height, including them in the measurement would falsely inflate the girth measurement. The girth measurement should then be taken at the narrowest point below the odd growth and the height of the girth measurement noted. In some cases a girth taken just above the odd growth will be more representative of the actual girth