Finnish Forest Research Institute  Metla
Press release 27.07.2006

Above-ground biomass of the understorey vegetation can be estimated based on coverage

Estimating the percentage cover representing the above-ground vegetation in boreal coniferous forests enables non-destructive determination of the biomass. The ratio between biomass and percentage cover can be applied to create models of the forest ecosystem or carbon cycle.

Forests in the boreal coniferous zone play an important role in the global carbon cycle. Forest vegetation and soil can be significant sinks of atmospheric carbon dioxide because they sequestrate or bind carbon. Depending on land use, forest management and environmental conditions, forest vegetation and soil also release carbon dioxide, in which case they act as carbon sources.

When direct biomass measurements are not available, the method based on percentage cover can be used to gain quick estimates of the above-ground biomass in the bottom and field layers in upland forest or in peatland forest soils. The bottom layer classification consists of lichens and bryophytes. The field layer vegetation consists of grasses, herbs and dwarf shrubs. The model, developed by the Finnish Forest Research Institute (Metla) is applicable in conditions equivalent to the Fennoscandic boreal vegetation zone.

A wide variety of vegetation analyses is available based on percentage cover estimation. In Finland, information has systematically been collected in National Forest Inventories (NFI) on the percentage cover of above-ground vegetation.

This Metla study utilized previous reports, in which the percentage cover of above ground parts of understorey vegetation had been visually determined either by exploring individual species or groups of species, such as lichen. Observations on vegetation were made on a total of 224 test plots on upland forest soils and 195 test plots in peatland forests.

Publication: Muukkonen, P., Mäkipää, R., Laiho, R., Minkkinen, K., Vasander, H. & Finér, L. 2006. Relationship between biomass and percentage cover in understorey vegetation of boreal coniferous forests. Silva Fennica 40 (2): 231–245.

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