The Oak Woodlands span across the northern, central, and southern parts of California. Each region has variations that arise from the differing climate. Most of the Central Oak Woodlands and the Southern Oak Woodlands are now extinct, which is really very sad if you count the number of wildlife supported by even a single oak tree. A large number of insects, butterflies, small wildlife, and birds such as woodpeckers and hummingbirds are supported by a single oak and its plant community.
We focus here on the Central Oak Woodlands which consists of three different types of oak communities: the Oak Savannah, the Oak Thicket, and the Oak Forest. The Oak Savannah is mostly open land, where single oaks dot the hillsides with grasses and forbs covering the space between the oaks. Forbs are non-grass, mostly herbaceous flowering plants. The Oak Thickets are usually several oaks growing together with other trees such as Pines and Toyons. The thicket also supports shrubs and ground cover plants to create a small self-sustaining eco-system. Grasses and forbs cover the open spaces between the thickets. The last type of community is the Oak Forest which is usually a larger area with oaks, pines, other trees, tall and short shrubs, and undercover growth. Each of these communities grew from different climatic conditions and therefore the plants that evolved in each community are also different.
To understand the different plant communities of the Central Oak Woodlands, let us take a look at the different types of oak trees and their natural growth sites. The Valley oaks (Quercus lobata) grew in the moister arroyos and flat areas. These magnificent trees could live to 200 or even 300 years and need the moisture from the stream or the river to survive. The inland dry, low rolling hills were dotted with Blue oak (Quercus douglasii) and Interior live oak (Quercus wislizenii). The coastal hills were dominated by the Coast live oak (Quercus agrifolia). And it is the latter two regions that provide the needed plant communities for drought-tolerant home gardens.
The Northern Oak Woodlands are characterized by colder winters and here prosper the deciduous oaks such as the Garry oaks (Quercus garryana) and California black oaks (Quercus kelloggii). The Southern Oak Woodlands support the Engelmann oak (Quercus engelmannii), which is a threatened species due to habitat loss, and Coast live oaks. In the colder parts of the South, in the mid-mountain areas grow the California black oaks.
Evidence of the Valley oaks (Quercus lobata) communities vanished early when the San Joaquin valley was cleared for firewood and agriculture. Some of the Oak Woodland communities on hillsides still remain and provide an excellent choice of plants that can thrive on slopes and in dry shade conditions. This condition is often assumed to be a difficult one to satisfy with drought-tolerant plants. But nature has taken this problem in hand and evolved solutions over thousands of years. Even if your garden does not have the space for an Oak tree, you can use the tree’s plant community to create a water-wise garden.
If you live in a part of California that does not experience extreme weather such as snow and above 100F, and has an annual precipitation between 15 and 35 inches, then you can grow and support an oak tree with its plant and wildlife community on your property. We provide you with the guidelines necessary to start and sustain such an oak ecosystem. You can then sit back and enjoy the pleasure of watching wildlife from your window or patio, and know that you have recreated a small piece of California. . Click on this link here to go directly to our how-to-guide for starting an Oak ecosystem in your garden (TBD). Click on this link to look at the list of plants that belong to the Central Oak Woodland community.
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