In our challenging ecosystem of cold wet winters, hot dry summers, and intermittent fire, the mighty oak reigns supreme. There are ten oaks native to California and four dominant species here in Bryson. January's cool winter afternoons are ideal for a hike and it's a perfect time to distinguish the different varieties of oak in our area. Narrowing down the different species is easier this time of year because half lose their leaves and half remain evergreen.
The majority of oaks are deciduous. Unlike the 80% of flowering plants dependent upon animals for pollination, oaks are wind-pollinated so the absence of leaves facilitates the process. Starting in late November, deciduous oaks begin to yellow and lose their leaves.
Of the deciduous varieties, valley oaks (Quercus lobata) are the easiest to identify because they are the giants of our community. They flourish in the lowlands and can reach heights of 150 feet with trunk widths of 8 feet. Leaves are large and rounded with deep lobes. Acorns are slender and elongated covered halfway down by the cup.
The blue oak (Quercus douglasii) is another deciduous oak plentiful in our area. It typically has a single trunk and dark blue-green waxy leaves, which help it retain moisture. The bark appears shaggy as if a bobcat has used it as a scratching post. Acorns are one inch long and have a narrow base.
Coastal live oak (Quercus agrifolia) is our dominant evergreen variety. It has a distinctive bark resembling an elephant's skin which protects it from fire. The convex-shaped leaves have spiny edges and young coast live oaks are shrubby, adaptations that deter browsing animals. Acorns are slender and light reddish-brown.
Sympatric with coastal live oak is the canyon live oak (Quercus chrysolepis). The two are hard to tell apart because they grow in the same area and have similar spiny leaves. If you turn the leaf over and you find a soft yellow layer of fine hairs, it is a canyon live oak. The mature canyon oak is further distinguished by its much-branched trunk covered in scaly bark, gray with touches of red scattered throughout. Acorns are ovoid, born solitary or in pairs in a turban-like short cup of scales. After a fire, the canyon live oak regenerates by basal sprouting.
Since acorn production occurs in autumn, a walking tour below the oaks may yield an additional clue to your local oak varieties, that is, if the squirrels and jays haven't gotten to the acorns first! Those of you who have bemoaned your inability to grow trees from an acorn should not be discouraged. The average chance of an acorn becoming a full oak tree is 1 in 10,000.
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