Situation
Finland falls within the boreal coniferous zone where fire
has always played a decisive role in natural forest stand
succession (Zackrisson, 1977). The boreal natural forests
have been burnt over, caused mainly by lightning, at
average intervals of 50–100 years. The areas burnt have
varied between a few hectares and thousands of hectares.
The opening of landscape has ensured the regeneration and
the survival of pioneer tree species, birch (Betula pendula
Roth.) and Scots pine (Pinus silvestris). The fire frequency
was highest in the era of slash and burn cultivation
beginning in the 15th and ending at the beginning of the
20th century. By means of slash and burn agriculture,
extended to pristine Norway spruce (Picea abies) forests,
middle Finland was settled during this time period.
Finland was the major tar producer of Europe in the 18th
century. Pine stands especially in the western part of the
country were affected by tar production. In the middle of the
1800s forest industrial activity started with saw-milling of
the biggest logs. During the first few decades of the 20th
century the pulp and paper industry began to use smalldimension conifers as raw material. Hardwoods, mainly
birch were used for energy until the 1950s. From that time
hardwoods were used also for papermaking.
Practical forestry gradually forgot the way of nature to
regenerate old forests. In contrast to large disturbance, fires
were prevented and only the biggest trees were cut for logs
and papermaking. This kind of silviculture resulted in lowproductive and technically poor quality stands, due to poor
regeneration. Due to the impoverishment of stands, this kind
of single tree selection harvesting was totally abandoned in
Finland in 1948. After that year the only recommended way