Silviculture and Cinegetics Review - Societatea Progresul Silvic

FORESTRY BELTS SILVICULTURE AND CINEGETICS REVIEW XVII/30/2012
which they spread laterally, showing numerous
superficial fascicular roots when mature.
It is very sensitive to the attacks of the cryptogamic
agents, especially to the elm fungus (Ophiostoma ulmi,
O. novo-ulmi). It sprouts and suckers quite weakly.
Although it is an economically valuable species,
because of the low resistance to Dutch elm disease, its
use in protection belts developed in the forest steppe
zones should be considered with caution.
Turkestan Elm (Ulmus pumila var. pinnato-ramosa)
was used mainly in the communication ways protection
belts in the study area, but also in the central part of the
field belts (Bărăganu Station), intimately mixed with
shrubs or tree species like Tartarian maple, field maple,
flowering ash, cherry-plum and even black locust. Its
temperament is moderately open. Being resistant to
drought and frost and having large amplitude of
adaptation to edaphic conditions led to good results on
heavy, compact soils, on soils with high content of
calcium carbonates and even on those with a lower
degree of salinization.
It sprouts but does not suckers. When young, its growth
is very fast (almost twice as fast as the growth of the
field elm). Thus, in steppe stations on typical
chernozem (Bărăganu Station), at 15 years old it reaches
height of 12-13 m and core diameter between 12 and 24
cm and at 55 years old, it reaches height of 17-18 m and
diameter between 30 and 52 cm (Traian Sat – Brăila,
Balta Albă – Buzău).
Its roots are tap-lateral spread, very well developed,
both laterally and in depth, capitalizing well the soil.
The crown is rich, with dense and regular branches that
protect the soil and prevent grassing. An important
quality is that it does not suffer from the Dutch elm
disease.
Being quite resistant to both site conditions and pests, it
is recommended for field and communication protection
belts, in arid vegetation conditions and even on salty
soils.
Common ash (Fraxinus excelsior) was used frequently
in the road or field protection belts (Bărăganu Station),
in their inner corridor, intimately mixed with shrubs or
tree species (Photo 8). It shows great adaptability to
climatic conditions but is demanding to edaphic
characteristics, vegetating well on chernozem soils.
When young, on fertile soils, it manifests as a shade
species, but when mature it becomes very sensitive to
shading, which puts it among the trees with an open
temperament.
Ash was invaded in the interior rows when mixed with
elm, black locust, maple and oleaster (at 13 years old–
Bărăganu Station), maintaining better on the postmarginal
rows. When the oak was planted in the central
rows and the ash in the post-marginal ones, at ages over
50 years, the ash achieved a better resistance and greater
dimensions than oak (core diameter up to 40 cm and
height up to 20-22 m), especially on the northern side of
the forest belt (Bărăganu Station).
It is sensitive to frost and insect outbreaks (Lytta
vesicatoria, which causes defoliation, and Zeuzera
pyrina, which attacks the sprouts and the young stems).
It shows slow growth the first two years after plantation
(cca. 20 cm high), after which it becomes more active
(over 0.5 m/year), achieving the maximum between 30
and 40 years old. It sprouts strongly.
Although the most active growths are carried out in
floodplains with fertile, eutrophic, slightly or
moderately moist to humid soils, deep, permeable and
loose soils, ash also has an active vegetative state on
less humid plain soils (argillic chernozem).
Common ash is resistant to flooding and even stagnant
water; it vegetates satisfactory on alluvial and even
gleyied and pseudo-gleyied soils. It is one of the
enduring species (over 200 years).
The roots are strong, well branched and deep, with a
dense network of shallow thin roots that capitalize
strongly the soil and dry its upper horizons. Because of
this, if intimately mixed with oak, the latter is strongly
challenged by the highly efficient rooting of the ash.
Particularly valuable species from an economical point
of view, its use in the protection forest belts is
recommended especially on soils well supplied with
water, mainly in the central part of the field and road /
railway protection forest belts.
Pennsylvania ash (Fraxinus pennsylvanica) was found
in the alluvial soils floodplains areas, in the central
corridor of the river banks and road protection belts,
intimately mixed with shrubs and tree species. Being a
rustic species with high adaptability, less demanding to
edaphic conditions, resistant to frost and drought, and
supporting satisfactory the floods, it gave good results
on protocols and alluvial soils. It is less demanding to
the fertility and soil humidity than the common ash.
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