tree height is 30 – 40 m, crown is massive, widely spreading, planted higher in the stand
bark is reddish-brown later light gray and smooth
bork is dark gray to blackish, firm, coarsely longitudinally cracked
Buds
the buds are arranged in a spiral, clustered at the end around the terminal bud
they are 4 - 8 x 5 mm in size, oval, blunt to rounded, sitting
in cross-section, they are bluntly pentagonal
the covering scales are several, light brown with a darker edge, closely pressed
Shoots
they are fairly thick, longitudinally ribbed, olive green to reddish-brown;
the lenticels are convex, dotted, and whitish
Leaves (assimilation organs)
they are simple, featherlike lobed to cleft, in basic shape inverted ovate!
leaves are 7 - 15 x 3 - 7 cm in size, lobes are entire at the edges
lateral veins open into lobes and into clefts!
there are 5 to 9 pairs of lateral veins
the petiole is short (2 – 8 mm)
the upper side is dark green, shiny, the underside lighter
the base of the leaf is heart-shaped - ending with two lobes!
Flowers
it is a deciduous tree with unisexual flowers, flowering in May simultaneously with leaf unfolding
♂ flowers are grouped into loose, about 10 cm long hanging catkins
♀ flowers are spherical bud-shaped, grouped in 2 to 3 on an upright stem 2 - 5 cm long
Fruits – seeds
the fruit is an elliptical achene (acorn), 2 - 4 x 1 - 2 cm large, widest in the middle!
the achene is light brown with darker longitudinal stripes, located in a shallow cup
the cups are on 5 - 8 cm long stalks
the achenes (acorns) mature in September – October
germination is 50 - 70%, it lasts for about half a year
the seed germinates hypogeally - underground
Extension
originally almost throughout Europe except for the cold north
in Slovakia from the lowest altitudes (floodplain forests - hard floodplain) up to about 570 m above the sea level
only remnants remain from the original distribution
it is the skeleton (basis) of the hard floodplain where it grows together with slender ash, narrow-leaved ash, elms, linden trees, sugar maples, common hornbeam, and other tree species of the hard floodplain
Ecology
it is light-loving and warmth-loving tree species, demanding on nutrient content in the soil and soil moisture
we respect two ecotypes in terms of moisture requirements:
riparian - dominant tree of the hard floodplain (floodplain forest)
steppe - Záhorská lowland - windblown sands
the summer oak is a long-living tree, reaching an age of 400 to 800 years
the root system is cylindrical, reaching great depths (even several tens of meters)
it is sensitive to late frosts, but also to early frosts (early frosts cause frost cracks).
Significance
the oak is, along with the winter oak, the second most important deciduous tree (especially in terms of quality wood production)
the wood is heartwood, hard, flexible, and the core is dark brown
the summer oak belongs to the group of so-called deciduous ring-porous trees in terms of wood structure
the wood is very high-quality and valuable - it is used for making solid furniture, sliced veneers, barrels, and in the past, ships were built from oak wood
fruit-bearing tree - acorns are a significant food source for wildlife and birds, especially during times when seeds are scarce
