Vegetation height is one of the methods contained within the Monitoring Manual for Grassland, Shrubland and Savanna Ecosystems and is intended to support the additional methods described in the manual. Click here to for more information about the all of the methods in the Monitoring Manual.
Plant height is measured with a graduated survey rod or measuring stick with a 30cm disc affixed to the top of the measuring tool. An imagery cylinder extends from the disc's circumference to the ground. The highest point of any plant (living or dead) that falls within this cylinder is recorded. Woody and/or herbaceous plants are differentiated. If both woody and herbaceous plants are present underneath the disc, the tallest point of each type of plant is recorded. If no plants are present, a value of “0” is recorded. Transects are established at regular intervals (5m is recommended) with a minimum of 30 height measurements per plot.
Once the data is collected, an average height of all species is calculated as well as an average height of woody species and herbaceous species. Values of 0 (no vegetation present) can be discarded when calculating average heights if desired.
Electronic record keeping is recommended. The Database for Inventory, Monitoring & Assessment (DIMA) contains data entry forms which can be downloaded as part of an MS Access database. DIMA is compatible with PDAs and tablets. Alternatively, a paper version of the plant height inventory form can printed from the appendix of the Monitoring Manual for Grassland, Shrubland and Savanna Ecosystems.
Vegetation height is often measured with gap intercept and line-point intercept to provide a complete picture of vegetation structure. This data can be useful in wildlife habitat suitability analysis. Vegetation height and canopy gaps are also indicators of a site's vulnerability to erosion. See Okin 2008 for a description of using vegetation height data to predict the impact of wind erosion.
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