The assessment criteria that are presented here are intended to aid the interpretation of chemical and biological data on forests and forest soils.
The principal impacts on the forest landscape and its fauna and flora are those caused by the forestry industry, but there are also impacts from atmospheric pollutants.
Forestry alters the tree species composition and age structure of the forest, generally resulting in a loss of biodiversity. Forest species diversity is largely dependent on the presence of elements such as broad-leaved trees, dead wood (standing and fallen dead trees), and intact stands of old-growth forest.
Many of the assessment criteria presented here refer to such elements, which with few exceptions are significantly rarer today than they were in the past.
The most serious impacts of pollution on land and water in the forest landscape include acidification, elevated levels of heavy metals, and the leaching of nitrogen from nitrogen-saturated forest soils to nearby waters. These impacts are also among the assessment criteria.
Individual assessment criteria have been established for:
- old-growth forest
- presence of broad-leaved trees
- dead wood
- large and hollow trees (rotted-out tree trunks)
- soil acidification
- heavy metals
- nitrogen leaching
More information about assessment criteria for the forest landscape, including sampling and data collection routines, can be found in Swedish EPA Report 4917, Bedömningsgrunder för skogslandskapet. (The report, whose title in English would be “Environmental Quality Criteria for Forest Landscapes”, is written in Swedish. It can be borrowed from the Swedish EPA library.)
Environmental Quality Criteria for Forest Landscapes, summary in English