Current issue: 54(5)
Under compilation: 55(1)
Modern forestry, which mainly consists of clear-cutting, is one of the most important factors influencing today’s boreal forests. In Sweden, the breaking point for modern forestry is generally considered to be around 1950. Recently, our common knowledge of the implementation of clear-cutting in Sweden has increased, and new research indicates that clear-cutting systems were already applied before the 1950s. In this case study, we used aerial photographs from the 1940s to analyze the extent of contemporaneous clear-cuts and even-aged young forests in an area in northern Sweden. Our results show that almost 40% of the study area had already been clear-cut by the end of the 1940s, but also that clear-cutting had been applied to 10% of the forest land in the early 1900s. This implies that the historical development of forestry in northern Sweden is more complex than previously thought, and that certain proportions of the forest land were already second-generation forests in the 1950s. Our results have implications for the use of concepts such as “continuity forest”, suggesting that this concept should employ a time frame of at least 100 years.
The light reflected from the crowns of Scots pine (Pinus sylvestris L.) clones was measured spectroradiometrically during and after growing season. Standard deviations of the spectra of pine clones showing differences in moose browsing intensity were compared. A new algorithm was developed for predicting the browsing intensity of moose (Alces alces).
The PDF includes an abstract in Finnish.
The article is a treatise on use of aerial photography in forestry and its prodpective applications in Finland, based on the writers visit to Techniche Hohschule Dresden in Germany and experiences in his work in Forest Service.
Optimal conditions and principals of aerial photography are described. There is potential in use of aerial photography in Finland. The terrain is relatively flat, and large areas, especially in Lapland, are inadequately mapped. However, to fulfil the current requirements for forest maps, aerial photography should be carried out as aerial stereo photography at a sufficiently large scale. At a certain scale terrain survey becomes cheaper than aerial photography.
In forestry, aerial photography cannot substitute terrain survey, but it complements it. Aerial photographs could, for instance, form a photo archive of a region or be used as a basis for planning drainage of peatlands. In research, aerial stereo photography could become a new discipline.
The article has a German summary.