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Despite a wealth of published research on the nature of woodland soils, little is known about the nature of soils on sites that have supported woodland for many hundreds of years, namely ancient woodland. The properties and variability of soils in three ancient woods; one in the New Forest. Hampshire and two in Berkshire, were compared with those under recent woods. The acidity of ancient and recent woodland soils was high and remarkably similar. Only where cultivation of soils had preceded woodland establishment was soil acidity lower. The quantity of carbon in the soils studied was inversely related to soil acidity and the ancient woods had accumulated larger quantities of carbon than their recent counterparts. The quantities of Ca?', M&+ and K + were larger in the ancient woods except where prior cultivation had taken place. Total and organic phosphate contents of the ancient woodland soils were also consistently larger. The nature and pattern of soil variability in ancient woodland soils was quite distinct from that found in recent woods. Overall, the variability of soil acidity, carbon content and organic phosphate was larger in the ancient woodland soils but the pattern of variability differed between the soil properties. No clear association existed between the pattern of soil acidity and individual trees. At the surface of some of the woodland soils, however, carbon distribution appeared to be associated with individual trees. At depth in the ancient woodland soils, the association with the existing vegetation cover was not so clear. It is probable that the ancient woodland soils retained relict features of previous vegetation cover. Organic phosphate distribution was very strongly associated with the present vegetation cover. The pattern of distribution of organic phosphate appeared to be stronger than that of soil acidity and carbon content.

A field monitoring study was carried out to follow the changes of fine root morphology, biomass and nutrient status in relation to seasonal changes in soil solution chemistry and moisture regime in a mature Scots pine stand on acid soil. Seasonal and yearly fluctuations in soil moisture and soil solution chemistry have been observed. Changes in soil moisture accounted for some of the changes in the soil solution chemistry. The results showed that when natural acidification in the soil occurs with low pH (3.5-4.2) and high aluminium concentration in the soil solution (>3-10 mg l −1 ), fine root longevity and distribution could be affected. However, fine root growth of Scots pine may not be negatively influenced by adverse soil chemical conditions if soil moisture is not a limiting factor for root growth. In contrast, dry soil conditions increase Scots pine susceptibility to soil acidification and this could significantly reduce fine root growth and increase root mortality. It is therefore important to study seasonal fluctuations of the environmental variables when investigating and modelling cause-effect relationships.

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