Characteristics of Valley Oak / Roble Tree (Quercus lobata) in the Wild

Quercus lobata
Valley oak or Roble (Quercus lobata) is the largest species of an oak tree in North America. The tree is endemic to California, growing in valleys from Siskiyou County to San Diego. Valley Oak is a long-lived tree that can reach up to 600 years of age.

Valley oak tolerates cool wet winters and dry summers but requires plenty of water. The tree will thrive in the rich deep soil at the bottom of the valley below 600 m above sea level. Valley oak is common in dense riparian forests, open foothill forests, and valley savannas. Usually, this tree is associated with various other trees such as Coast live oak (Quercus agrifolia), Interior live oak (Quercus wislizeni), Blue oak (Quercus douglasii), California black walnut (Juglans californica), California sycamore (Platanus racemosa), and Gray pine. (Pinus sabiniana).

Quercus lobata belongs to the evolutionary lineage of white oak, officially known as the subgenus Lepidobalanus. This subgenus consists of many oaks from California and elsewhere, whose species share the same leaves, acorns, bark, and pulp.


Characteristics of Valley Oak Leaf

Quercus lobata Leaf

The leaves are 5-10 cm long, round, and deep. The width of each leaf is about half its length. Each leaf is a matte green with a pale green look underneath. The leaves are covered with abundant downy hair, producing an almost velvety feel. When fresh leaves are rubbed or crushed, an aromatic scent is emitted, evoking the smell of the forest.

During autumn, the leaves change color from yellow to bright orange but brown during mid to late autumn.


Characteristics of Valley Oak Fruit

Quercus lobata Fruit

The seeds are dark to medium brown in color and range from 2-3 cm in length.


Characteristics of Valley Oak Tree

Quercus lobata Tree

Valley oak is a deciduous tree that can grow into a large tree with a height of more than 30 meters and a trunk diameter of up to 3 meters.

The branches are irregular, spreading and curling which creates a leafless silhouette on a sunny winter day. In old age, the branches have drooping characteristics. The corrugated tan-colored leather adds to the attractive aesthetic.

Like most oaks, Valley oak can also tolerate forest fires. Although smaller individuals may die, most mature trees can survive the heat of the fire because of their thick bark.


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