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ŠUMARSKI LIST 3-4/2008 str. 44     <-- 44 -->        PDF

increasing. These areas are subjected to the spontaneous expansion of less valuable
tree species and shrubs, classified as pioneer species. Being the first to
occur, they are spontaneously followed by transitional species. The 100-yearlong
process ends with the occurrence of principal or climatogenic species (fir,
beech, oaks).

Pioneer and transitional tree species gradually convert degraded forest
soil into forest soil suitable for climatogenic or principal species. The basic
tree species that bear the characteristics of pioneer species are those from the
genera of alders, willows, poplars, birches and others. Domestic, autochthonous
tree species from other genera, with the exception of the genera of oaks,
beech and fir, belong to transitional tree species. Together with pioneer species,
they gradually colonize abandoned agricultural and other lands.

Forest cultures should be established on abandoned agricultural areas in
order to increase their market and non-market values. These cultures are established
by planting broadleaved species from the genera of wild cherry, pear,
apple, as well as maple, ash, lime, whitebeam, rowan, service tree, wild
service tree, bird cherry, walnut, and others. Coniferous species to be planted
include species from the genera of spruces, larches and pines.

The choice of the tree species depends on the site conditions that prevail in
the treated area, where the soil and the climate have a decisive role.

The pioneer, transitional or secondary tree species have an important role
in the structure of all Croatian natural forests. They are particularly suitable
for the establishment of cultures which supply good quality and valuable timber.
Timber of all these species is applied in mechanical and chemical processing
industries, and in energy production. The establishment of energy forests
with short rotations and small planting distances will gain increasing importance
in Croatian forestry.

Due to the present energy crisis, the share of timber in the energy balance
of the most developed European countries is constantly growing. Timber from
forests has been accepted everywhere in Europe as an important and renewable
source of bioenergy.

Although the Croatian forestry is making initial, modest steps in this field,

there is no reason
nn tha
tt forest owners in Gorski Kotar should not be included
in this European
nn trend
trendtrend.. They have at their disposal about 3,000,000 m3 of growing
stock, the annual increment of 80,000 m3, and the prescribed annual
yield of about 40,000 m3, of which 40 % or 16,000 m3 is wood of thinner dimensions
suitable for energy. At present, the major portion of this wood remains
in the forest and perishes. This alone provides sufficient motive for the
owners to pool forces, fight for their place on the market and join the chain of
bioenergy producers for both the domestic and foreign markets.

Ke y w o rds : selection forests, regular forests, uneven-aged forests, tending,
regeneration, pioneer species, forest cultures, bioenergy

o f
Šumarski list br. 3–4, CXXXII (2008), 121-146