There are two forms of forest restoration: active forest restoration and passive forest restoration. With active forest restoration, people plant seedlings with the intention to speed up the restoration process. On the other hand, with passive forest restoration, people leave the forest on its own and natural processes set the speed and structure of restoration.
Almost 70 years ago, a long-term active tree line forest restoration program was launched in the Tatra National Park, Slovakia. After several centuries of forest exploitation, the management of the newly created Tatra National Park came to the decision to actively restore the tree line. The park management gradually banned commercial forestry and grazing in a large part of the park. In the next step, the park management planted systematically, year by year, thousands of seedlings in the previously logged and grazed areas.
Please also read: Tatra National Park
Complexity of the tree line forest restoration
A study of forest history, including pollen analysis, helped to restore the structure and species composition of mountain forest. This study also helped us to better understand to the previous extension of the tree line. That became a base for the long-term active tree line forest restoration program in Tatra National Park.
The park management in that time gradually removed all disruptive factors, such as grazing sheep, cows and horses and simultaneously started with the active tree planting. After decades, besides active tree planting, the natural succession also did a great job. Large areas all over the Tatra National Park got a new forest cover. That had a positive impact on the water regime, soil erosion and even partially on avalanche control. However, the most interesting was an opportunity to see and study the spontaneous natural processes, including dynamics and changes of vegetation and habitats.
Termination of the tree line forest restoration program
Ironically, the main reason to terminate the tree line forest restoration program in the 1970’s, were the changes caused by spontaneous natural processes. That was a time when the voices to make a step backwards and allow active grazing (also in the strict reserve) started to be more and more frequent. The reason for that shift in the management objectives, was to protect man-made biodiversity.
This approach ignored the complexity of biodiversity and Wilderness concept. Biodiversity is not only the variety of plant and animal life in a particular habitat. An important aspect of biodiversity is habitat and ecosystem dynamic. Changes of the habitats and ecosystems, caused by the spontaneous natural processes, have consequences on species composition and biodiversity. This is often neglected, even today, when we are discussing the protection of natural processes.
The management of the Tatra National Park stopped the long-term active tree line forest restoration program after several decades. The result to stop the active tree line forest restoration was that all man-made restoration activities ceased to exist. Luckily, the new management strategy did not include removal of already planted trees (15-20 years old). Nevertheless, despite this decision the passive tree line forest restoration continued, as the restoration of active grazing never happened. Actively planted seedlings in the 1950’s and 60’s became a good starting point for passive forest restoration. Thanks to the follow-up passive forest restoration the tree line significantly changed in the following decades.
Since beginning of tree line forest restoration program the mountains landscape in the Tatra National Parks significantly changed as well. Large areas of tree line recovered and mugo pine, cembra pine and spruce trees occupy large areas. Nowadays, these mountain forest with open fragments display a new range of biodiversity, different from the biodiversity 60-70 years ago. As a result, it is more spontaneous, more dynamic, and more natural…