Current issue: 52(3)
Under compilation: 52(4)
The literature on the most prominent forest damage related to even-aged and uneven-aged forest management regimes was reviewed. A questionnaire to expert researchers was conducted to estimate risks in even-aged and uneven-aged forest management chains in Finland. There are only a few empirical comparisons of damage risks in even- and uneven-aged stands in the literature. The results from the expert survey showed that the damage risks were higher in even-aged management in Norway spruce and Scots pine. However, the variation in the risks between individual chains and between individual causes was high. The highest risks in Scots pine were caused by moose (in even-aged chains) and harvesting damage (in uneven-aged chains). In Norway spruce, root rot caused the highest risks in both even-aged and uneven-aged chains. The higher risks in even-aged forestry are largely due to the many associated practices which favour various types of damage. However, there are some important exceptions: the damage risks may be higher in some uneven-aged stands, especially in Norway spruce stands infected with root rot where the utilization of undergrowth or natural regeneration can be risky. Moreover, the repeated thinnings in uneven-aged stands may lead to increased mechanical damage.
Ungulate browsing results in important damages on the forests, affecting their structure, composition and development. In the present paper, we examine the occurrence of browsing damage in Norwegian forests, using data provided by the National Forest Inventory along several consecutive measurements (entailing the period 1995–2014). A portfolio of variables describing the stand, site and silvicultural treatments are analyzed using classification trees to retrieve combinations related to browsing damage. Our results indicate that the most vulnerable forest stands are young with densities below 1400 trees ha–1 and dominated by birch, pine or mixed species. In addition, stand diversity and previous treatments (e.g. thinnings) increase the damage occurrence and other variables, like stand size, could play a role on forest susceptibility to browsing occurrence although the latter is based on weaker evidence. The methods and results of our study can be applied to implement management measures aiming at reducing the browsing damages of forests.
Increase in the elk (Alces alces L.) population and the problems of its grazing has called for detailed research. The present study concentrated on three observation areas representing northern, western and eastern parts of Finland. There were 28 field observers watching 68 elks.
Earlier investigations in Finland indicate that aspen (Populus tremula L.) is the staple diet of elk. This study reached different conclusions, probably largely because of aspen is gradually becoming an increasingly rare tree species in Finland. According to this study, the principal food of elk in the winter is willow (Salix sp.). In the whole country, willow accounts for about 70% of elk’s nutrition. In the Far North the percentage is approx. 90. Of the other tree species, the order of preference is: aspen, Scots pine, mountain ash, juniper and birch. In addition, in Western Finland where snow is less deep, lingonberry and blueberry shrubs are on the menu. Beard moss on the spruce was frequently eaten locally. Elk seems to have eaten mainly the last annual shoot of trees and bushes. In few cases it has gnawed the bark of Scots pine, aspen and willow. Elk consumes in average 340 twigs or terminal shoots per day in the winter. This corresponds to about 1.8 kg of food.
The problem of elks damaging Scots pine seedlings has been observed in Western Finland, were the elk population is higher. The article suggests that suitable feeding places would be left for elk in places that are unsuitable for agriculture or forestry. Leaving, for instance, birch seedlings in Scots pine stands has been noticed to attract elks and to increase the damage to pine.
The article includes an abstract in English and a summary in Swedish.