THE HISTORY OF SCOTS PINE ENCROACHMENT AND RETREAT IN OMBROTROPHIC BOG RECORDED IN WOODY DEBRIS

摘要

Using the characteristic of accumulated woody debris, data on vegetation, and data on previous climate fluctuations, we reconstructed the history of Scots pine (Pinus sylvestris L.) encroachment and retreat in a raised bog. The available patchy information on plant cover allowed us to pinpoint events in the development of pine seedlings and the first cases of trees dying off on the time scale. The results obtained show that the process of natural bog afforestation and deforestation was very dynamic and lasted only 22 years. These short-term changes in the tree populations were clearly linked to short-term climate fluctuations. The annual precipitation and mean temperature of winter months were the most important variables and the main factors directly influencing the young woodland. We assumed that the woody remnants represent the last stage of the contemporary phase of high germination and dying-off (GDO) of pine trees. The spatial distribution of woody debris and its characteristics indicate the naturalness of vegetation during this temporary 'woodland phase'.