The structure and regeneration of high-altitude Norway spruce forests: a review of Arnborg (1942, 1943)

Abstract

The high-altitude forests along the Scandinavian mountain range were relatively unaffected by the first wave of forest utilization and in the mid-twentieth century some untouched forests still remained. In his doctoral thesis, Tore Arnborg analysed the vegetation patterns and forest structure in two mainly primeval forest stands, Blekaskogen and Granudden, in northern Sweden. The sites represent typical spruce-dominated mountain forest, generally not subject to large-scale disturbance by forest fire. Arnborg's studies were among the first giving data on the structure and dynamics of these forests. Both stands were multilayered and of open character. The fraction of mature, overmature and senescent trees was high and about 18% of the trees were considered to be dying. Although having a similar history, the two stands differed in character, mostly owing to the altitudinal difference. Thus, Granudden, situated about 50Á80 m above Blekaskogen, had a low canopy and was more open in character. In addition to stand structure, Arnborg analysed tree regeneration. He provided very strong empirical evidence for the important role of dead logs in regeneration. Based on logs of known age, he presented an eightgrade decay classification system, focusing on the possibility of seed germination and survival. A major conclusion from his studies is that the forest is in equilibrium and able to regenerate itself by the periodically high abundance of viable seeds and through the presence of logs and disturbed soil patches. Based on his findings, Arnborg argued for initiating clear-cutting complemented with soil scarification of these high-altitude forests. In his time, just before the onset of the clear-cutting epoch, the focus in forest research was strongly influence by management for increased production.

Small‐scale disturbance and stand structure dynamics in an old‐growth Picea abies forest over 54 yr in central Sweden

“…Such work has been carried out in both boreal and boreo‐nemoral forests (Hofgaard ; Linder ; Brūmelis et al. and Jonsson & Hofgaard ) and in temperate forests (Peterken & Jones , ; Runkle & Yetter and Franklin & DeBell . Recently, using the LiDAR technique, Vepakomma et al.…”

Density and height structure of seedlings in subalpine spruce forests of Central Europe: logs vs. stumps as a favourable substrate

“…CWD also creates seedbeds for seedling establishment. One of the first studies on the role of CWD for regeneration was performed by Arnborg in Swedish subalpine forests during the 1930s (Jonsson and Hofgaard 2011). Thereafter, the suitability of CWD for tree establishment has been documented in different ecosystems around the world (Lonsdale et al 2008).…”

History and Productivity Determine the Spatial Distribution of Key Habitats for Biodiversity in Norwegian Forest Landscapes

“…As a result of this, dead wood and old trees became scarce, dead wood probably reaching a historically low level in the first half of the twentieth century [33]. However, modern forestry practices, including clear-felling of whole stands and subsequent afforestation with seeding or planting, replaced selective logging around the middle of the twentieth century (e.g., [34,35]). After this shift, the volume of dead wood has increased [15].…”