Intensive monitoring of forest ecosystems.

Abstract

Pollution inputs and their impact on Irish forests are intensively monitored at four forest ecosystems. The sites, in Cork (Ballyhooly), Mayo (Brackloon), Galway (Cloosh) and Wicklow (Roundwood), supply stand and other environmental data to assist in interpretation of forest health surveys. They also contribute to research on the effects of plantations on freshwater stream ecosystems. The chemical composition of water, from the incoming rain, through the forest ecosystem and out through the soil is monitored. Results here are for three years for Ballyhooly and one year for the others. There is significant pollution at Roundwood. At Ballyhooly, ammonium, apparently much of it from local dairy farms, has a potentially damaging long-term impact. Rain at the western sites is relatively clean, although there is evidence of a small but significant pollution influence in the region. The marine influence is strong at all sites, with very high inputs of the main marine ions, sodium and chloride, at Brackloon and Cloosh. The forest intercepts substances in the atmosphere and by this and other processes, deposition of ions on the forest floor (and consequently to forest soils and adjoining ecosystems) is generally greater than on open, non-forested land. This process is clearly seen at Roundwood where nitrogen inputs are augmented to the point where degradation of the ecosystem is likely to occur. Nitrogen inputs at the western sites are very low, but high salt inputs here may acidify adjoining freshwater ecosystems. Long-term support for intensive monitoring is needed. There is a real risk of damage to forest ecosystems, and via forests to other ecosystems. Deposition and its impacts vary greatly with weather conditions, and, as with climatological monitoring, good evidence for effects which take many years must be based on several years' continuous monitoring.