Romet Vaino is a tour guide, hobby photographer and a blogger who writes about nature. Recently he put together a complete guide of Estonian mires, bogs and wetlands for any tourist dreaming about hiking there. He'll explain what is a bog, what's the story behind it, when to go there and which bogs to go to.
Estonian bogs have gone through a large-scale transformation from being seen as a horrific place to becoming one of the most loved landscapes. Our bogs are the top-of-the-list attraction for every tourist willing to discover the Estonian countryside and wildlife.
What is a bog?
The bog is the oldest organic landscape in Estonia, reaching in some cases up to 10 000 years of age. The first bogs started to emerge here right after the last ice age. As the 1 km thick glacier ice sheet was melting towards the North pole, the meltwater as a leftover was collected in depressions previously created by the glacier ice. Over the next thousands of years, plants grew and died within those shallow and oxygen-deprived meltwater lakes. As a result, the dead plant material didn't become decomposed but rather created ever-lasting peat/turf and turned the water acidic. Every year, one layer of partially decomposed organic material is accumulated underneath the mossy surface of the bog and this effect has taken place since the very beginning!
In Estonian bogs, the pace at which the peat accumulates is roughly 1 mm annually. In most Estonian bogs, the peat layer is 5-7 meters on average, which equals about 5000-7000 years of age. Over the course of thousands of years, this landscape goes through a series of transformations. At the very beginning, this peat accumulation landscape does not have a significant effect on plants – the peat layer is just too thin and flora is able to reach to the nutrient-rich groundwater. After millennia or two, the peat layer becomes thicker and filters out more demanding plants. The visual of the landscape is about to change. Birch trees will give up and pines will slowly start to take over. This middle stage is called transitional mire.
Later the peat layer gets just so thick that only the toughest plants will survive. The third stage is called bog or raised bog. Here you can see a lot of bog pools or lakes inside this huge organic sponge. The landscape is entirely independent, meaning that the plants don't have access to nutrient-rich groundwater and all they have is rainwater stored in the ground. Bogs can be seen as huge sponges that can store huge amounts of water. Mainly because the sphagnum moss, also known as the "bog builder plant" is able to absorb almost 20 x its body mass. So in some ways, bogs are also giant water reservoirs.