Lifespan of a dogwood tree

What are all the trees with peeling bark? Which one is the most beautiful? Please include pictures.

Those would be Eucalyptus trees and there are many varieties.

They are all over California. They were first brought here by Australians who came for the gold rush. But not necessarily for gold, to plant trees for the wood industry as they grow rather quickly.

Beyond the drive to change the landscape and provide firewood, Californians also planted eucalyptus (mainly blue gum) to serve as windbreaks.

The problem was that they really weren’t good for wood to build with. They twist while growing and as they dry after cutting, and their wood is filled with oils that are highly combustible

A big part of the debate over whether the trees should be allowed to persist here traces back to the East Bay firestorm of 1991, which left 25 people dead and thousands homeless. Vast swaths of eucalyptus burned.

Although that may be a myth used as a slander campaign because not all people find them beautiful

Eucalyptus, shreddy bark low on the trunk, smooth bark higher on the trunk, Mosswood Park, Oakland, CA



Eucalyptus: How California’s Most Hated Tree Took Root

Pt Reyes Light sheds light on eucalyptus myths and an arborist adds context

With unusual characteristics you can see (a profusion of flowers), smell (camphor-like aromatic leaves), and feel (soft-to-the-touch bark), the paperbark tree provides a banquet for the senses. Native to Eastern Australia, usually found along waterways and wetlands in its native habitats, the paperbark tree is one of more than 230 species in the Melaleuca genus. It is known for its spongy and paper-like bark, its prominent clusters of fluffy white flowers, and its scent-bearing leaves, which can be used to make tea tree oil.

While the branches of young paperbark trees can look willow-like and wispy, mature trees have an umbrella-like crown. When the paperbark tree blooms, the crown is covered with a cloud of puffy white flowers—which led to one of the tree’s popular names, “snow-in-summer.”

The paperbark tree is popular for use in Southern California landscaping and gardens, as it is both hardy and drought tolerant, but it will also grow well in wet areas where drainage is a problem. This fast-growing tree can reach a maximum height of about 30 feet and can be up to 20 feet wide, however most backyard paperbark trees or shrubs are much smaller.

Eucalyptus: How California’s Most Hated Tree Took Root

Reaching heights of more than 100 feet, the main kind of eucalyptus you’re likely to see here is Tasmanian blue gum, eucalyptus globulus. They feature sickle-shaped leaves hanging from high branches, and deciduous bark that is forever peeling from their shaggy trunks. Some people experience the smell of eucalyptus as medicinal; others say the trees just smell like California.

The trees are deciduous, shedding their bark every year. (Samantha Shanahan/KQED)

So how did eucalyptus trees get here?

“They came here as envelopes of seeds on boats coming to California in the 1850s,” explains Jared Farmer, author of “Trees In Paradise: A California History.”

During the Gold Rush, Australians were among the throngs flocking to a place where wood was in short supply.

“This was the era of wood power,” Farmer says. “Wood was used for almost everything. For energy, of course, but also for building every city, for moving things around, all the things where today we use concrete and plastic and steel.”

Besides the practical need to plant more trees, settlers who were used to dense forests also felt that the lack of trees in California’s grassy, marshy, scrubby landscape made it feel incomplete. So within a few years, nurseries in San Francisco were selling young eucalyptus grown from seed.

The trees grew remarkably quickly here, even in poor soil.

“In an average rainfall year here in California, these trees probably put on 4 to 6 feet in height and maybe, in their early growth years, a half-inch to an inch in diameter,” says Joe McBride, a UC Berkeley professor emeritus of landscape architecture and environmental planning.

Beyond the drive to change the landscape and provide firewood, Californians also planted eucalyptus (mainly blue gum) to serve as windbreaks.

Eucalyptus trees grow fast, sometimes putting on 4 to 6 feet in height in a single year. (Samantha Shanahan/KQED)

In fact, that was the original purpose of what’s now the largest, densest stand of blue gum eucalyptus in the world, on campus at Berkeley, says McBride. It was planted around 140 years ago to provide a windbreak for an old cinder running track — to keep its fine ashen gravel from blowing into athletes’ faces.

The trees’ success in California owed to a lack of enemies here. Because they were grown from seed, they hadn’t brought along any of the pests or pathogens (or koalas) they contend with back in Australia.

An early 20th century boom

Within a few decades of its arrival, many Californians grew disenchanted with eucalyptus. Blue gum proved terrible for woodworking — the wood often split and cracked, making it a poor choice for railroad ties. The trees also proved thirsty enough to drain nearby wells.

“If you go back to California farm journals of the 1870s, ’80s, ’90s, there’s just report after report of disappointment, like ‘these trees are no good,’ ” says Farmer, the historian.

But things changed in the early 20th century when U.S. Forest Service officials grew concerned about a looming timber famine. They feared forests in the eastern United States had been overexploited and wouldn’t grow back, and predicted the supply of hardwood would dwindle over the next 15 years.

The bark sheds often, peeling in large strips. (Samantha Shanahan/KQED)

Investors saw an opportunity: California had a tree capable of growing to full size within that time frame. If hardwood was about to be scarce, they reasoned, such trees could be in high demand and yield sizable returns within a few short years. (These people, Farmer says, were not reading blue gum’s lousy reviews in old farm reports. “And even if they did read them, maybe they wouldn’t care because they just wanted to make a buck; they were just flipping land.”)

This played out as a speculative frenzy — a bubble. Boosters began selling plantations dense with eucalyptus — hundreds of trees per acre. Farmer writes in his book that claims were made like: “Forests Grown While You Wait,” and “Absolute Security and Absolute Certainty.” In just a few years, millions of blue gums were planted from Southern California up to Mendocino.

The anticipated timber famine never came to pass. Forests further east proved more resilient than expected, and the need was offset by concrete, steel and imports, like mahogany. Ultimately, the thousands of acres of eucalyptus planted around California were not even worth cutting down. Much of what you see today is a century-old abandoned crop.

What’s fire got to do with it?

Eucalyptus trees have lovers and haters in California. A big part of the debate over whether the trees should be allowed to persist here traces back to the East Bay firestorm of 1991, which left 25 people dead and thousands homeless. Vast swaths of eucalyptus burned.

“People at the time, I don’t think, associated that with a planted plantation; it was just a eucalyptus forest,” says CalPoly botanist Jenn Yost. “And then when the fire came through — I mean that fire came through so fast and so hot and so many people lost their homes that it was a natural reaction to hate blue gums at that point.”

Because the trees shed so much bark, critics argue they worsen the fire hazard and should be cut down. Defenders point out California’s native plants also have a tendency to burn. Both say the science is on their side, but so far no landmark study has shut down the dispute.

That ongoing dispute is also politically entrenched. A few years ago, federal funding to cut down trees in the East Bay hills was rescinded, after protesters got naked and hugged the eucalyptus trees on campus at Cal.

To some, the scent of eucalyptus trees is simply the scent of California. (Samantha Shanahan/KQED)

Are they here to stay?

Blue gums can’t reproduce on their own just anywhere in California; Yost says they need year-round moisture. They’re able to regenerate in places like California’s coastal fog belt, but elsewhere “there are some plantations that don’t reproduce at all. When you go there, the trees are all in their rows, there’s few saplings anywhere to be seen, and those trees are just getting older.”

Not all non-native plants capable of reproducing on their own do it enough to have an ecological impact, Yost says.

“As soon as it starts outcompeting native species or fundamentally changing the environment so that native species can’t grow there, we would consider that an invasive species,” she says.

Blue gum is classified as a “moderate” invasive, putting it a tier below such uncharismatic weeds as yellow star-thistle and medusahead. McBride, the retired Berkeley professor, says “although there’s been marginal expansion of some eucalyptus stands, it’s really not well adapted for long-distance dispersal. It hasn’t really spread very much on its own.”

With an estimated 40,000 of eucalyptus planted across the state, the trees aren’t easy to get rid of. Slicing down a large blue gum near a building can require a crane, at an expense of thousands of dollars. And keeping them from resprouting can also be its own chore.

Long term, as the climate changes over the coming decades, it’s possible the aging eucalyptus groves that don’t get enough water to reproduce will begin to die.

Then again, if the state becomes hotter and drier, it may become the type of place where some Australian species are able to thrive.

Dogwood Bark Peeling Off: Fixing Tree Bark Flaking On Dogwood Trees

Dogwoods are native ornamental trees. Most flower and fruit, and have dazzling fall displays as the leaves change color. Peeling bark on dogwoods may be the result of serious disease or it could be a natural condition in some species. Knowing the species of your tree is crucial to deciding if a dogwood with peeling bark is in danger or if it is a normal occurrence.

Dogwood is both a native and introduced species across North America, especially the cooler climates. The plants may be trees or shrubs in form, but all of them offer extraordinary color and many of them flower. Many of the varieties are deciduous and provide a rich fall color display followed by bright green, yellow, coral and orange revealed stems. They are quite winter hardy but are sensitive to mechanical injury and a variety of pests and diseases. For this reason, the tree bark flaking on dogwood trees may be the result of a canker, borer, string trimmer or fungal disease, to name but a few.

When a Dogwood with Peeling Bark is Normal

The Kousa dogwood is an ornamental tree that is more cold tolerant than flowering dogwood. It has bark which peels off in irregular patches, revealing a mosaic of mottled colors underneath. The dogwood bark peeling off is part of this tree’s appeal, along with its winter interest and fall display of purple leaves.

Other times that peeling bark on dogwoods may be normal is when it occurs due to wild herbivores rubbing their antlers or standing on the trunk. Small rodents may also chew on trunks and cause sloughing bark. None of these conditions are good for the tree but would be categorized as wildlife problems and completely normal in certain regions.

Sunscald on young trees may also result in peeling bark. It is a good idea to site them where winter sun won’t be aggressive or paint the trunk with latex paint thinned with water. Drought conditions can cause cracked bark near the base. This condition is easily corrected by giving the plant supplemental moisture.

Dogwood Tree Bark is Peeling Due to Disease

Dogwood anthracnose is a common disease in the Cornus genus. It causes yellow leaves and twig dieback, as well as sunken discolored areas of tissue. These are common symptoms of branch and crown canker as well.

Basal trunk canker will cause splitting and some loss of bark. It also presents with lesions in the tree that weep sap and can seriously affect the health of the tree. It is best to consult an arborist for either of these diseases which cause peeling bark on dogwoods.

Pests that Cause Tree Bark Flaking on Dogwood

Dogwood bark peeling off may be the result of tiny insects that do more harm than good. The dogwood twig borer is a nasty pest that gets into the vascular tissue of the tree and undermines the tissue. It lives in the tree’s tissue and causes bark upheaval in infested locations. These invasive creatures may be difficult to detect until widespread damage is done because they hide away from investigative eyes inside the plant. Other borers, like the apple tree borer, also appear to favor Cornus trees and cause similar damage.

Scale insects in high concentration may make it appear that the dogwood bark is peeling. This is because when they mass on a stem, they seem like hard-bodied scabs which can be easily flicked off with a fingernail. They have the appearance of damaged bark but are actually insects subject to pesticides and manual removal.

Another factor is disease, and dogwoods are susceptible to many fungus diseases that are particularly prevalent in wet spring weather. These include botrytis, leaf spot and twig blight. Botrytis affects the bracts and some leaves, turning them black. This same disease affects peonies and tulips. Leaf spot is a similar-looking disease, identified by Dr. Pascal P. Pirone, emeritus plant pathologist of the New York Botanical Gardens. Twig blight affects the young twigs.

The solution is to apply protective sprays of fungicide such as benomyl. This should be applied now and repeated in another two weeks, depending on rainfall. However, plant pathologists point out that sprays should be considered preventive rather than cures. Spraying after the disease is detected means it may be too late for this season.

In addition, trees planted in an open lawn area are subject to injury, as when a homeowner bangs a tree trunk with the power mower. The thin-barked dogwoods are especially susceptible to such damage, and it invites two serious problems: borers and canker.

Borers are the larvae of a small moth, which lays its eggs in the trunk wounds. The larvae hatch and gouge out the trunk to feed. The insect may go undetected until it is almost too late. When borers are suspected, examine the trunk for the entry hole. Poke a wire up into the trunk to kill it and then seal the wound over. Canker appears first as a wilting at the treetop. It, too, is a fungus disease that eventually girdles the bark and kills the tree.

One way to prevent injuries from mowers is to place a wide mulch of bark chips or a light ground cover around the base of the dogwood. The centuries-old appeal of the native American dogwood endures. Nurserymen report that sales of the trees remain high and they are frequently asked to replace dead or dying dogwoods.

For many, this tree is the beloved symbol of springtime, and few ornamentals can rival the magnificent display. Layer upon layer of branches are covered with the beautiful blooms, either white or pink. One of the most famous dogwood collections is at Greenfield Hill, a suburb of Fairfield, where 5,000 trees line the village’s streets. Its dogwood festival opens Saturday and continues through May 15.

Greenfield Hill has a $7,000 annual budget to care for its dogwood trees. Lloyd Godfrey, a certified tree expert, cooperates with the village to provide this care.

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