Cork Oak

The bark actually looks like cork.

This is a tree that takes some time to impress. Bloom is uninteresting. Foliage is no more distinctive than that of coast live oak. Instead, the most spectacular characteristic of cork oak, Quercus suber, is the boldly striated and uniquely spongy texture of its mature bark. Such bark takes a few years to develop, but gets so thick that it seems significantly older.

As its name implies, cork oak had historically been the exclusive source of bark for corks and cork products. As modern and more practical materials diminished demand for such bark, cork oak became more popular as an evergreen shade tree. It is quite happy within the arid chaparral climates of California. In fact, it behaves much like native oak species.

Mature cork oak trees generally stay less than forty feet tall, even if their trunks are wider than three feet with their unusually thick bark. Without excessive irrigation, their roots are notably complaisant. Low branches are more visibly sculptural than high branches. With pruning for adequate clearance though, trees with high branches are striking street trees. Foliar and floral debris is quite messy during spring bloom.

Black Oak

Not many native deciduous trees turn orange or brownish red in autumn like California black oak can.

Though native mostly to the Sierra Nevada and Coast Ranges between San Francisco and Oregon, California black oak, Quercus kelloggii, also inhabits isolated colonies in lower mountains as far north as the southern half of the Oregon Coast, and as far south as San Diego County. It actually occupies more area than any other hardwood tree in California. Wild trees competing in forests can get more than a hundred feet tall and live for five centuries. Well exposed urban trees may take their first century to eventually get about half as tall with trunks as wide as four feet.

Even while young, California black oak is a distinguished tree, with a broadly rounded canopy and elegantly arching limbs. The smooth silvery bark of young trees eventually becomes dark and uniformly checked with maturity. The distinctive deeply lobed leaves are about five inches long, and turn gold, soft orange or even brownish red before falling in autumn.

Tanoak

Tanoak is rare within refined landscapes.

Its plump and inch-long acorns are misleading. Tanoak, Notholithocarpus densiflorus, is not actually an oak. Otherwise, it would be a species of Quercus. Regardless, its wood is potentially as practical for furniture and flooring as wood of other oaks. It also works very well as firewood. Historically, tanoak bark was useful for tanning leather, hence its name.

Although native and somewhat common in some coastal forests, tanoak is almost never a choice for intentional planting. Those that inhabit home gardens likely either grew from acorns, or were there prior to development of the landscapes. Young trees can grow fast to more than forty feet tall, typically with conical form. Mature trees might get twice as tall.

Tall trunks of tanoak are elegantly upright, and eventually develop lofty branch structure. Their gray or brownish bark is handsomely furrowed. The somewhat leathery evergreen foliage produces potentially objectionable tomentum. The dentate leaves are two to four inches long. Sadly, tanoak is very susceptible to Sudden Oak Death Syndrome (SODS).

Six on Saturday: Native Range?

Valley oak, Quercus lobata, and Coast live oak, Quercus agrifolia, which I featured here last week, are the two formerly prominent native oaks of the Santa Clara Valley. I do not know if valley oak is native to the Santa Cruz Mountains above the Santa Clara Valley. It should be; and I should know for certain. However, I am not convinced. It is a chaparral species, not a forest species. The several old specimens in the Santa Cruz Mountains are on roadsides and in other situations where they seem to have been planted intentionally. Yet, this region developed mostly after the Great Earthquake of 1906, and not much was here prior to that, but some of the valley oaks seem to be a few centuries old.

1. A different perspective of the same valley oak from last Saturday conceals major storm damage that is otherwise so prominent. This really is a grand tree, in a perfect situation.

2. Although this is not a good picture, and does not seem to show much, it demonstrates how this tree is squarely centered within this view from the old depot baggage platform.

3. From the opposite side, the trunk obscures the baggage platform. Was it planted there intentionally? If so, why was it not centered on the window or doorway of the old depot?

4. It is just coincidence that the tree is situated so ideally on the edge of an area that was formerly used for parking? It was already old when cars still had horses in front of them.

5. Valley oak is such a grand tree. As big and sculptural as this specimen is, it is perhaps a century or so younger than the other tree. It was still quite small and shrubby in 1906.

6. Even the leaves are distinguished. The leaves of the trees in my former neighborhood had rounder lobes and sinuses. I do not know if such traits are environmental or genetic.

This is the link for Six on Saturday, for anyone else who would like to participate:

Valley Oak

Valley oak is the grandest of oaks.

From the north end of the Sacramento Valley to the San Fernando Valley, the valley oak, Quercus lobata, is among the most familiar and distinctive of native oaks. It is the largest oak of North America, reaching more than a hundred feet tall with trunks as wide as ten feet, which is why it is rare in urban gardens. The hundred fifty foot tall ‘Henley Oak’ of Covelo is the tallest hardwood tree in North America. The oldest trees are about six centuries old.

The two or three inch long leaves have deep and round lobes. The foliage turns only dingy yellow and then brown in autumn, and can be messy as it continues to fall through early winter, particularly since the trees have such big canopies. The gnarly limbs are strikingly sculptural while bare through the rest of winter. The gray bark is evenly furrowed.

Incidentally, Oakland, Thousand Oaks, Paso Robles and various other communities within their range are named for valley oaks. (‘Roble’ is the Spanish name.)

Valley Oak

Valley oak is also known as ‘roble’.

From the north end of the Sacramento Valley to the San Fernando Valley, the valley oak, Quercus lobata, is among the most familiar and distinctive of native oaks. It is the largest oak of North America, reaching more than a hundred feet tall with trunks as wide as ten feet, which is why it is rare in urban gardens. The hundred fifty foot tall ‘Henley Oak’ of Covelo is the tallest hardwood tree in North America. The oldest trees are about six centuries old.

The two or three inch long leaves have deep and round lobes. The foliage turns only dingy yellow and then brown in autumn, and can be messy as it continues to fall through early winter, particularly since the trees have such big canopies. The gnarly limbs are strikingly sculptural while bare through the rest of winter. The gray bark is evenly furrowed.

Incidentally, Oakland, Thousand Oaks, Paso Robles and various other communities within their range are named for valley oaks. (‘Roble’ is the Spanish name.)

Valley Oak

Valley oak is the grandest oak.

From the northern end of the Sacramento Valley to Santa Catalina Island, valley oak, Quercus lobata, is as Californian as Valley Girl. It inhabits mixed riparian forests and low hillsides up to about 2,000 feet, but prefers alluvial valley meadows in between. Although unpopular for landscaping, it sometimes self sows into home gardens. New landscapes sometimes develop around old trees.

Valley oak is one of the biggest of oaks, and the tallest oak of North America. Mature trees can be more than a hundred feet tall, and several centuries old. Trunks may be more than ten feet wide. Such big trees make big messes of acorns and deciduous foliage, which shed for weeks. Unfortunately, old valley oaks within new landscapes are susceptible to spontaneous limb failure and rot.

Where space is sufficient, new valley oaks are for future generations. They develop their distinctively sculptural branch structure slowly through several decades. If irrigation is not excessive, roots are remarkably complaisant. The evenly furrowed gray bark is rustically distinguished. The elegantly lobed leaves are about three inches long and half as wide. Yellowish autumn color is subdued.

Six on Saturday: Getting There Is Half The Fun

The biggest valley oak in the Santa Clara Valley supposedly lives next door to where I lived in town. Well, that was too far to go to get the picture I needed for the garden column next week. Another lives on the other side of the tracks.

1. Roaring Camp Railroad is out back. The Depot is out of view to the right, on the other side of Zayante Creek. The big valley oak that I got a picture of is on the left, but does not look so big from here. A few ecosystems mix here, so ponderosa pines, Douglas firs and all the riparian trees mingle with the coast live oaks and redwoods. However, I doubt that valley oaks are native.

2. Rhody stayed home. These grates on the pedestrian catwalk on the bridge are not intended for small paws. Some of those trees down there are about thirty feet tall! Most are white alder.

3. Riparian trees are close enough for pictures from a pedestrian bridge just downstream. That foliage in the middle of this picture is a sycamore. However, the deteriorating bridge is closed.

4. Old valley oaks, which are native just a few miles away, seem to have been planted here; since they all are on roadsides or driveways. Whether native or introduced, they happily self sow.

5. Moss makes these sculptural limbs seem to be older than they are. This now massive valley oak was a shrubby young pup in photographs from the 1920s. It was likely planted after 1906.

6. Gnarly roots were exposed by erosion on an embankment between the big valley oak and the train tracks. I suspect that the tree was planted to shade the depot during the late afternoon.

This is the link for Six on Saturday, for anyone else who would like to participate:

https://thepropagatorblog.wordpress.com/2017/09/18/six-on-saturday-a-participant-guide/

Horridculture – Vandalism

This would have been an ideal time for a seasonal update on the little Memorial Tree in Felton Covered Bridge Park. Until recently, it had been healthier and growing more vigorously than it had since it was installed a few years ago. It had survived major accidental damage, and was just beginning to thrive. Sadly […]

https://feltonleague.com/2020/06/28/vandalism/

via Vandalism — Felton League

Pin Oak

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Pin oak is not drought tolerant.

There are several oaks, especially natives, that do not need much more water than they get from rain. Pin oak, Quercus palustris, is not one of them. It is naturally endemic to areas that are damp or swampy for part of the year. It is more tolerant than others are to lawn irrigation, but is also more sensitive to drought.

Compared to other oaks, pin oak grows fast while young. It can get two stories tall in about ten years. Then, it takes more than twice as long to double in size. Old trees do not get much more than fifty feet tall, with trunks nearly three feet wide.

The deciduous foliage turns as brown as a grocery bag in autumn, and may linger late into winter, or until it gets replaced by new foliage in spring. The distinctively deeply lobed leaves are about two to five inches long, and about two thirds as wide. Each leaf has five or seven lobes. Each lobe has five to seven teeth.