British Sign Language Glossaries of Curriculum Terms

BSL Environmental Science Glossary - Leaf Area Index definition

Description: Leaf Area Index (LAI) is a numerical value that is used to work out the total leaf area of a piece of land. In science it helps calculate, for example, how much water is being absorbed, how much oxygen is being released and a number of other things. An example of LAI would be, if we wanted to know, in an area of broad leaf forest, how much area the leaves covered in a 5-metre square and the total area covered by those leaves. By taking samples of the leaves and then measuring them, the estimated total leaf area might be 10m². The LAI is then calculated by dividing 10m² by 5m², which gives an LAI of 2. Another way of looking at this would be to collect all the leaves that would eventually fall into that 5m² area, placing them side by side so that they cover it and then doing this twice.