Girth (tack) slightly too small, a girth extender may be used. A girth extender attaches to the billets of the saddle and lengthens them, so that a shorter girth may be used. Most jumping saddles have three billets. This not only allows the rider a spare should one break, but can also provide an adjustment option. For horses on which the saddle sits nicely, neither slipping forward or back, the first and third billets should be used. On horses where the saddle slips back, the first and second billets should be used. The second and third should never be used together, as
Tree girth measurement Converting the girth measurement to a diameter will always overstate the cross-sectional area of the trunk, therefore it is best to record the raw girth numbers directly rather than convert them to diameters. The conversion of girth values to approximate diameters can always be done later if needed for other types of analysis. Measuring tree girth directly is a common educational technique allowing students to learn about their local environment in a practical manner. It is often used in the primary setting to introduce topics such as measuring, using numbers and simple calculation. Simple techniques can be used to estimate