However, other standard heights are also used. Some researchers in grazing and agriculture use bole size at 0.3 m or 0.7 m above the ground as their standard height. For example, the volume of the tree bole may not be correlated with a measurement at a height that corresponds to a fork in the tree or a fire scar. If the fork is above breast height, treat the tree as a single stem with multiple leaders. When swelling at breast height occurs due to multiple leaders, the breast height measurement is conventionally taken where the bole diameter is smallest below the swelling.
Special instructions are also necessary where buttressing and fluting is common.
Measurement is commonly made above the influence of the buttress or fluting. Where this influence extends well up the bole, an arbitrary height is specified. Take two measurements equally distant above and below the nominated height. If there is little difference between these measurements, take the mean value as the representative size. If the difference in bole diameter at these two heights is relatively large, then a quadratic mean may be more appropriate.