Six things to know about forest soils

Andy Moffat was the author of the first Forestry Commission Soil Guidelines, and has written many other books, papers and articles about forest soils.  He recently helped to assess FC publications for their suitability to underpin the most recent UKFS Soil Guidelines

By Andy Moffat · June 1, 2018

Hampshire soil (FC/Crown copyright)

1)      The forestry sector depends on the soil, its preservation and respect.

This is self evident, but many take soil for granted, as free as oxygen and water.  Nevertheless, we can easily lose soil through erosion, or damage or contaminate it, sometimes irreparably.  Soil ‘health’ is now a hot topic – the recent ‘25 Year Environment Plan’ gives information on how the Government is planning that all soils will be managed sustainably, and soil health improved.  Soils are an integral part of the forest ecosystem, and below-ground processes are intimately bound with above-ground ones through complex biogeochemical relationships.  Forest soils therefore differ in many respects from those under agriculture, usually possessing a pronounced accumulation of organic material above the mineral layers.  The biology and microbiology of forest soils is also very different to agricultural ones.

2)      In general, forestry best practice is good for the soil.

But bad practice is certainly not!  UK forestry practice has moved a long way since the days when new sites were there to conquer through radical drainage and deep ploughing.  Following best practice described in the UK Forestry Standard, research shows that soil condition or health can be maintained or improved using sensitive and appropriate management to the site and soil conditions.  However, bad practice, for example using traditional or ‘standard’ methodologies irrespective of soil conditions, can easily damage forest soil.  These are sound reasons why you need to know the nature of the soil – how can you manage what you don’t know?!

3)      Forest soils present a series of ‘ecosystem services’, not just primary (timber) production.

The sector depends on timber production, but it can offer many other ecosystem services.  We now know that carbon sequestration is really important –  there is more carbon in forest soils in Great Britain than in the trees themselves.  Forest soils also contain important archaeological evidence, and help in water purification and flood regulation.  They do much more than this but that would require another blog!

4)     The ‘Right Tree in the Right Place’ principle

This depends on adequate knowledge of the nature of the soil into which the tree will be planted. The task of matching tree species to soil type is supported by several well established Decision Support Systems such as Forestry Commission’s Ecological Site Classification (ESC) and the Right Trees for a Changing Climate.

5)     Sustainable forest management and UKWAS depend on appropriate management of the soil.

The Forestry Commission has published guidance on appropriate forest soil management for many years, including the first ‘Forests and Soil Conservation Guidelines’ in 1998.  The United Kingdom Forest Standard contains a 15 page section on soil management, including 31 formal requirements.  Similarly, certification under UKWAS requires auditable adherence to a range of soil protection measures.  The Scottish Government has produced some useful webpages which cover practical application of soil knowledge in forest management here.

6)      Forest soils are very variable and you need to explore what type(s) there are before embarking on forest management decision making.

As already said above, you can’t manage what you don’t know, and you won’t know until you look!  The Forestry Commission has produced user-friendly guidance on soil recognition in the forest here.

Andy Moffat

Andy Moffat is both a Fellow of the British Society of Soil Science and a Member of the Institute of Chartered Foresters, and holds a degree in Geography and Soil Science. He started his career as a Soil Surveyor for the Soil Survey of England and Wales before taking up a position as Soil Scientist at the Forestry Commission Alice Holt Research Station.