Basal area 

Basal ares is the area of a given section of land that is occupied by the cross-section of tree trunks and stems at the base. In most cases the measurement considers diameter at breast height (1.3m or 4.5 ft) of a tree above the ground, and includes the complete diameter of every tree, including the tree’s bark.

Measurements are made for a sample plot. The plot is scaled up to 1 hectare of land and the data is used to compare and examine productivity and growth rate of the forest, among other things. The basal area of a stand is found by adding the calculated basal areas of all of the trees in an area and dividing by the area of land in which the trees were measured. Basal area is generally expressed as ft²/acre or m²/ha.

When working in sample plots with the ultrasound technology used in Haglöf Sweden’s instruments the DME, the Vertex IV and the VL5, you can select one of the pre-set factors available in the instruments and measure the tree’s distance from the plot center, and then calculate the minimum diameter of the tree to be included in the sample plot. The ultrasound method allows measuring with precise results also in forests with thick underbrush and dense vegetation, which is a great advantage for all foresters.