Species: Quercus robur L.

(Quercus robur L.)
-> Genus: Quercus -> Family: Fagaceae -> Group: Angiosperms

Habitus

  • 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

From history

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