Peat bogs: windows to the past – preserving the future

International Bog Day was conceived in Scotland in the early 1990s as a way of engaging the public in the wonders of peatlands, which had up to that point been very undervalued. Scotland holds the majority of the UK’s peatlands and about 12% of the globally rare blanket bogs, found in our uplands. The National Trust for Scotland supports peatland conservation work through policy initiatives such as the IUCN UK Peatland Programme, awareness-raising events, provided by our ranger service, and also by land management restoration work on our upland properties.

This year, the coronavirus pandemic has curtailed our public engagement, so there has been little opportunity to show people the magical world of our peat bogs. Hopefully this description of our superb patterned bogs at Inverewe gives you a flavour of why our peat bogs are so special ...

What do the Inverewe peat bogs look like?

The wilderness of Wester Ross and the Flow Country contains some wonderful pristine peat bogs, unaltered by man and steadily becoming ever deeper as time moves on. At some sites in this landscape the peat has been forming since soon after the ice retreated, which means peat depths of 8–10 metres.

We took a stroll over the moorland at Inverewe to the closest of the patterned bogs. The glistening pools appeared before us as we approached over a rocky outcrop. The bog habitat supports a specialised and wonderful array of wildlife – to demonstrate this, a pair of keeled skimmer dragonflies swept over the sphagnum-rich bog pools in a frantic flight. Bogs are not in a hurry, but these creatures were making the most of the sunshine.

Sphagnum moss forms the building blocks of peat formation. These splendid mosses range in colour, from yellow, green, orange, red and crimson. A mossy sphagnum hump can be a radiant patchwork of colour. It’s in a very wet bog that the plant really comes into its own as it can absorb twenty times its weight in water. And these bogs are still growing! As the sphagnum plant material decays, it forms peat at an average of 1mm every year.

How do we know how old the peat is?

Five drain rods were improvised and fastened together to probe the depths. As we drove the rods down through the peat, we reflected on the world events as this peat bog was forming: the Highland Clearances, the building of Hadrian’s Wall, Stonehenge – you get the picture. The fifth rod eventually started to reach more solid ground, so we estimated the bog had begun forming around 5,000 years ago. We had reached the Neolithic period! This would fit with the scientific evidence that the climate became much wetter in Britain from around 4000BC.

There are a number of other clues to the age of peat bogs. I’ve gazed through the murky depths of water to fix my eyes on mysterious tree stumps embedded in the bottom of lochans. These are the remains of fossilised trees, traditionally called ‘bog fir’, and give an indication of a very different historical landscape. Pollen grains may be identified through a microscope to provide yet another window to the past, giving us a picture of the vegetation in the landscape thousands of years ago.

Our amazing peat bogs also harbour incredible human artefacts, such as ancient treasure troves of jewellery or swords cast into the bog thousands of years ago, perhaps as offerings to the gods? Another curiosity that has often been found by peat cutters is that of ‘bog butter’ in earthen pots. It may have been left in the bog to keep cool when supplies were not so plentiful. Peat bogs are anaerobic so they have a wonderful ability to preserve. The most incredible example of the bogs’ ability to preserve is the numerous ‘bog bodies’ that have been discovered all around the globe. Some of these souls have met a grisly end, with some bodies having rope still intact around the neck. We can only surmise at the reason for their demise.