1. The peat stratigraphy of seven bog woodland sites was surveyed. The sites were located across a bioclimatic gradient from the west Highlands through Speyside to the Black Isle. All of the sites bar one were characterised by pine. Lòn Lèanachain contained a birch wood.

2. Tree growth at every site was established on genuine mire peat and did not represent tree growth on mineral substrates masked by superficial cover of fresh Sphagnum, or trees restricted to peripheral mineral ground transitions to mires.

3. All sites except Mar Lodge were considered to fall within the compass of the definition of 'bog woodland' adopted for the survey although the hydrology at Lòn Lèanachain is not consistent with the definition used for the selection of candidate Special Areas of Conservation. Mar Lodge was excepted because it appeared to represents invasive colonisation of desiccating peats by trees, rather than a stable bog-wood system.

4. The sites exhibited marked stratigraphical variation. A common feature of many of the eastern Highland sites was the disturbed nature of the upper peat stratigraphy. Monadh Mor, Pitmaduthy and Inshriach appear to exhibit the most extensive and systematic disturbance to the peat stratigraphy, probably from ancient peat cutting. It is therefore possible that many of the bog woodlands, or parts of them, are therefore comparatively recent in origin (i.e. <150 years old). The Western Highland sites of Loch Maree islands and Lòn Lèanachain appeared to be the exceptions, as here no truncation to the peat stratigraphy was detectable.

5. Although evidence for peat cutting was absent at Lòn Lèanachain, there is circumstantial evidence that a combination of past grazing pressures and burning may have formerly discouraged birch growth in the peripheral areas of the bog. It is possible that the recent relaxation of such pressures might have allowed the establishment of the modern bog woodland. Evidence that burning had affected the vegetation in the past was also present in most of the sites examined.

6. The Rothiemurchus peatland sites might also represent areas which are returning to some kind of wooded equilibrium after centuries of intense grazing pressure and burning (as well as some peat cutting), following recent changes in management practice.