şi prof.dr. W. Zwölfer - Revista Pădurilor

Table 3
Mean height and height corresponding to the median diameter of basal area of initial, marked and remaining trees
Species
European beech
Hornbeam
Other broadleaves
Mean and (min-max) height, m
Initial
trees
17.7
(11.5-22)
16.8
(11.5-20)
19.4
(15.5-
22.5)
Marked
trees
16.7
(11.5-21)
16.7
(11.5-20)
19.4
(15.5-
22.5)
The character of mixed thinning (but mostly from
below) is obvious also in the case of mean heights
that have increased insignificantly for remaining tre-
es (e.g., from 19.1 m up to 19.3 m of hg of European
beech trees).
The stand volume is much higher than the one
from the management plan + increment/5 years (168
cu.m/ha) and reaches about 298 cu.m/ha. The standing
volume of initial trees is composed of 75%
European beech, 9% hornbeam and 16% other broadleaves
(table 4).
Table 4
Volume of initial, marked and remaining trees
Species
Volume
Initial trees Marked trees Remained trees
cu.m/ha % cu.m/ha % cu.m/ha %
European
beech
222.0 75 21.9 35 200.1 85
Hornbeam 27.1 9 17.2 28 9.9 4
Other
broadleaves
48.8 16 23.3 37 25.6 11
Total 297.9 100 62.4 100 235.5 100
As the quality of pioneer species (silver birch and
goat willow) is low, they can be used only for firewood
so their gradual elimination by thinning to improve the
Remaining
trees
19.2
(15-22)
Height corresponding to the median
diameter of basal area hg, m
Initial
trees
Marked
trees
Remaining
trees
19.1 17.1 19.3
- 17.6 17 17.5
- 20.7 20.7 20.7
stand quality and approach the target species composi-
tion (90% European beech 10% other tree species) is
strongly advised.
Regarding the hornbeam, it represents only 9% of
standing volume and is located especially in the lower
canopy. As its trees protect the lower bole of European
beech against the occurrence of epicormic branches or
sun-scorches after the sudden exposure of boles to sun-
light following heavy thinning, they should be removed
only if competing with the dominant species in the up-
per canopy or rubbing the boles of final crop trees.
Considering the thinning marked by the field fo-
resters of Covasna Forest District, three issues are to be
considered:
a. The intensity of interventions varies between
21% (by volume), 22% (by basal area) and 29% (by
number of trees). It is a heavy thinning (intensity higher
than 16% in all cases) but mostly from below, removing
especially trees from the small diameter classes (most-
ly less than 16 cm dbh – figure 1) and heights
20 REVISTA PĂDURILOR • Anul 126 • 2011 • Nr. 2