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Before man, the forests of north and south Estonia were not different in their species composition. Estonian forests became different with the appearance of cultivated plants.  In south Estonia there is more spruce, in north Estonia more pine and in west Estonia, more birch. According to Mihkel Kangur, Director of the TU Institute of Ecology, we see in Estonia´s green cover the traces of processes that were started 3000 years ago by Bronze Age people who used very primitive tools.

According to Kangur, there are no large primeval forest massifs in Estonia. “The nearest such forests are in Siberia, Russia,” noted Kangur and added that the taiga basically ends in the northeast of Estonia. “Perhaps Alutaguse forests are close to natural forests, but forest fires have taken place there also. A forest fire can also be a natural process, but not when human activity has caused it. There are about a few hundred hectares of virgin forest in Estonia where no signs of human activity can be seen. Old swamp forests can be considered among these if they are located in un-drained swamp massifs, but only 3% of all swamps fall under this category.”

Kangur says that primeval forests are richer in species and more diverse in age structure. Trees from different species and ages grow alternately and there are more plant and animal species. Depending on the type of forest, the forests can be brighter or darker. “The final phase of the succession line or development line of our forests should in general, be spruce forest which is dark and poor in species,” noted Kangur. “Such natural forests catch fire easily, for example, as a result of lightning, and the development of the forest can start again. Therefore forest management is not actually bad – there is not much difference between a forest that is taken down by a storm, disease, fire or people. From the perspective of forest renewal these disturbing changes are very necessary. The question is how the new forest recovers in these areas.”

According to Kangur, the analysis conducted together with several colleagues shows rather convincingly that for the last 2000-3000 years, human activity has noticeably shaped our green cover - more than what we previously thought - and probably even more than climate. “Basically nowadays the forest that grows is the forest that we have planted,” said Kangur. “Estonia is rich in forests, but the majority of forests have been turned into a factory producing raw wooden material.”

A hundred years ago Estonian forest coverage was less than 10%; now it is more than 50%. “We must distinguish between how forests are managed and renewed,” stressed Kangur. “Probably we can say that approximately half of Estonian forests have been sown and half have been planted and a small proportion of forests have recovered naturally by themselves.”

The natural recovery of forest until reaching the harvestable stage takes the longest time, but this kind of forest would be rich in species. In a planted or sown forest one species becomes dominant and the forest becomes a monoculture, similar to a crop field. Management of such forests is simple. Trees are of the same age and species. Often, especially in planted forests, trees are also in straight lines. This makes thinning of the forest easy, but such forests are easily damaged by disease, fire and storms.

Similarly to human society, a forest becomes more viable as its diversity increases. A forest structure consisting of different ages and species endures better in the conditions of a changing environment. “A planted or sown forest is not necessarily bad, but in regard to the natural environment, it is better when forests are structurally more diverse,” explained Kangur.

Since we are living in a constantly changing climate, the experience gained from earlier climatic periods help us to better predict the development of our forests. “For the general population, it might be important to consider the fact that if a Bronze Age man was able to influence the green cover more than the climate did, then what footprints are we leaving on our natural environment with modern technology?” posed Kangur. He is convinced that human influence on forests is not decreasing. “It has been proposed that we should think more about broadleaved forests, because according to more likely climate scenarios our conditions will become a bit warmer and damper, especially the winters, and in these conditions broadleaved trees endure better,” offered Kangur, suggesting a uniform version of a future forest.

Mihkel Kangur has been studying the topic for 15 years. He has mainly addressed such questions as to how we can actually study the history of the development of the green cover, and how to make research results even more precise and reliable. We need to know the history of the green cover in order to evaluate the processes and factors shaping the surrounding environment.