Tree volume is one of many parameters that are measured to document the size of individual trees. Tree volume measurements serve a variety of purposes, some economic, some scientific, and some for sporting competitions. Measurements may include just the volume of the trunk, or the volume of the trunk and the branches depending on the detail needed and the sophistication of the measurement methodology.
Other commonly used parameters, outlined in Tree measurement: Tree height measurement, Tree girth measurement, and Tree crown measurement. Volume measurements can be achieved via tree climbers making direct measurements or through remote methods. In each method, the tree is subdivided into smaller sections, the dimensions of each section are measured and the corresponding volume calculated. The section volumes are then totaled to determine the overall volume of the tree or part of the tree being modeled.
In general most sections are treated as frustums of a cone, paraboloid, or neiloid, where the diameter at each end and the length of each section is determined to calculate volume. Direct measurements are obtained by a tree climber who uses a tape to measure the girth at each end of a segment along with its length. Ground-based methods use optical and electronic surveying equipment to remotely measure the end diameters and the length of each section.
Tree climbers can physically measure the height and circumference of a tree using a tape. The distance from the highest climb point and the top of the tree is measured using a pole that extends from the tree top to the anchor point of the tape. This height is noted and the diameter of the tree is measured at that point. The climber then rappels down the tree measuring the trunk circumference by tape wrap at different heights with the height of each measurement referenced to the fixed tape running down the trunk.