How Are Trees Represented?

LANDIS models do not simulate the establishment and growth of individual trees. The scales that LANDIS was designed for (> 1000 ha) preclude such detailed representation.

Instead, LANDIS models and LANDIS-II represent trees as cohorts. A cohort is a bin which contains some information about the age and species of trees. At a minimum, this bin indicates whether a particular species of a particular age range (eg, ages 1-10 or 81-100) exist at a site (ie are present or absent).

Cohorts can also encompass additional data. For example, an amount of aboveground live biomass can be associated with a cohort. In this case, a cohort could represent sugar maple, ages 81-90 with an aboveground biomass of 10 Mg/ha, for example. To date, LANDIS-II extensions that include additional cohort data are: aboveground live biomass (Biomass Succession extension) and aboveground wood and aboveground foliage (Century Succession extension).