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How to Identify Oak Trees in Northern California

oak image by Vaida from Fotolia.com

Oaks are one of the most common trees that grow in rural parts of Northern California. California oaks can vary greatly in appearance, making identification of oak trees more difficult. For example, coast live oaks are tall trees with shiny, prickly leaves, while leather oaks look like shrubs with fuzzy leaves. According to the Hastings Field Station of the University of California, identification of oak trees can be made more challenging because two species of oak may produce an intermediate hybrid that does not have many of the characteristics associated with oak trees. Carefully exam a tree to determine if it is an oak.

Examine the branch of your tree. While oaks such as the scrub oak produce leaves that do not resemble traditional oak leaves, all oak plants produce leaves that are arranged spirally on the tree.

Look for long, hairy, string-like flowers. These flowers, which are called catkins, are produced in the springtime on oak trees and shrubs.

Examine the oak tree nut, called an acorn. An acorn is a brown, oval nut held in a cup-like cap. Oak trees begin to produce acorns after they have matured 20 years. Since young oaks do not produce acorns, absence of an acorn does not necessarily mean that a tree is not an oak. But the presence of acorns is a definite sign that the tree is an oak tree.

Oak Trees

Oak trees are in our poems, songs and legends. Oaks are part of the Quercus genus, and there are about 600 species. The Roman poet Virgil once wrote, “Full in the midst of his own strength he stands, stretching his brawny arms and leafy hands.” Red oaks have leaves with pointed lobes and small bristles at the tip. Black oak trees have smooth, gray bark and its leaves turn bright red in the fall. Willow oaks have thin, straight leaves, resembling those of a willow tree. Willow oaks grow 60 to 75 feet tall. These oaks prefer the warm, coastal Southeast, but they will grow inland in protected areas. Pin oaks make a nice shade tree. Acorns mature after a year, and these trees sprout soon after falling to the ground. Varieties include chinkapin, post oak, bur oak and white oak. But one day, it will be 50 feet high. This oak will be found further north and west than other oaks. Live oaks are often seen draped in Spanish moss and bring to mind images of southern weddings and historic small towns. Symptoms are most severe in dry summers because the bacterium blocks the water-conducting vessels that move water from the roots to the leaves. Leaves usually remain on the tree until they drop in the fall. Symptoms show on red, scarlet, black and pin oaks. It is spread by root grafts, so it affects trees in close proximity. Because of their size and longevity, oaks are symbols of honor, nobility and wisdom. Later, many parishes adopted an oak to be the Gospel Oak, and springtime ceremonies would take place beneath it. Plant oak trees where they’ll have a lot of room to grow. A good rule of thumb is to give an oak space to grow 80 feet tall and 80 feet wide. Most oaks can grow as far north as zones 4 and 5, and some varieties can grow in zone 3.

Oak Trees

Oak trees are in our poems, songs and legends. Oaks are part of the Quercus genus, and there are about 600 species. The Roman poet Virgil once wrote, “Full in the midst of his own strength he stands, stretching his brawny arms and leafy hands.” Red oaks have leaves with pointed lobes and small bristles at the tip. Black oak trees have smooth, gray bark and its leaves turn bright red in the fall. Willow oaks have thin, straight leaves, resembling those of a willow tree. Willow oaks grow 60 to 75 feet tall. These oaks prefer the warm, coastal Southeast, but they will grow inland in protected areas. Pin oaks make a nice shade tree. Acorns mature after a year, and these trees sprout soon after falling to the ground. Varieties include chinkapin, post oak, bur oak and white oak. But one day, it will be 50 feet high. This oak will be found further north and west than other oaks. Live oaks are often seen draped in Spanish moss and bring to mind images of southern weddings and historic small towns. Symptoms are most severe in dry summers because the bacterium blocks the water-conducting vessels that move water from the roots to the leaves. Leaves usually remain on the tree until they drop in the fall. Symptoms show on red, scarlet, black and pin oaks. It is spread by root grafts, so it affects trees in close proximity. Because of their size and longevity, oaks are symbols of honor, nobility and wisdom. Later, many parishes adopted an oak to be the Gospel Oak, and springtime ceremonies would take place beneath it. Plant oak trees where they’ll have a lot of room to grow. A good rule of thumb is to give an oak space to grow 80 feet tall and 80 feet wide. Most oaks can grow as far north as zones 4 and 5, and some varieties can grow in zone 3.

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