We use some essential cookies to make this website work.
We’d like to set additional cookies to understand how you use forestresearch.gov.uk, remember your settings and improve our services.
We also use cookies set by other sites to help us deliver content from their services.
Preparing to search
A critical load has been defined by Nilsson and Grennfelt as ‘a quantitative estimate of the exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge’.
In other words, the level of input below which damage to the tree, soil or ecosystem is thought unlikely is known as the critical load. Where a critical load is exceeded, it does not always mean that damage will occur. Critical loads are set to protect ecosystems in the long term; the effects of pollutants can take many decades to appear, and thus if damage does occur, it is may not be immediately apparent.
Critical loads are set for:
Forest critical loads are set to protect specific receptors. We are working to develop critical loads for woodland that are appropriate to both the semi-natural woodland and forest management practices adopted in the UK.
The critical load approach is a key element of emissions reduction policy. It has proved to be very useful in policy development since its ‘effect based’ approach allows the environmental benefits of emission reductions to be evaluated. The critical loads approach has been adopted by the UNECE Convention on Long Range Transboundary Air Pollution (CLRTAP) to target pollutant reduction targets and it is now one of the main drivers of emission control agreements under the UNECE CLRTAP, the EC European Acidification Strategy, and Clean Air for Europe.
Cookies are files saved on your phone, tablet or computer when you visit a website.
We use cookies to store information about how you use the dwi.gov.uk website, such as the pages you visit.
Find out more about cookies on forestresearch.gov.uk
We use 3 types of cookie. You can choose which cookies you're happy for us to use.
These essential cookies do things like remember your progress through a form. They always need to be on.
We use Google Analytics to measure how you use the website so we can improve it based on user needs. Google Analytics sets cookies that store anonymised information about: how you got to the site the pages you visit on forestresearch.gov.uk and how long you spend on each page what you click on while you're visiting the site
Some forestresearch.gov.uk pages may contain content from other sites, like YouTube or Flickr, which may set their own cookies. These sites are sometimes called ‘third party’ services. This tells us how many people are seeing the content and whether it’s useful.