Data Recording and Calculations when Counting Individual Plants to Determine Density

Only a simple field sheet format is required when following the approach of counting individual plants to determine density that includes one column for species identification and additional columns to tally the number of individuals found in each quadrat (or transect). If nested quadrats are used, more than one column is needed to separately recorded each quadrat. Additional information on vegetation structure can be obtained by recording seedlings apart from mature plants (especially if the inventory or monitoring program is conducted soon after germination and seedling survival is uncertain) or by separating a species into discrete height classes (most appropriate for woody species). Including information about sample unit size is important for future calculations.

Once field work is completed, data is summarized to estimate density for the sample. Part of the data summary involves adjusting values according to sample unit size, so that density is expressed on a standardized area (ie., m2, ft2, ha, acre).

Procedures followed to summarize the data depend upon definition of the sample unit.

References and Further Reading

Bonham, C.D. 1989. Measurements for terrestrial vegetation. John Wiley Sons, New York. pp. 145-146.

Bureau of Land Management. 1996. Sampling vegetation attributes. Interagency Technical Reference, BLM/RS/ST-96/002+1730. pp. 101-102.