2 weeks Ago
I recently received the following questions about plants. Q. Can you tell me what could have made lumps on the trunk of a tree my wife and I found in the Smokies? The lumps range from baseball-size to basketball-size.
It is her favorite tree and we hike to it a couple of times a year. A. The bumps, which are called burls, are irregular swellings on a tree usually caused by some type of stress that disrupts the tree’s growth.
According to Linda Lee, a botanist at the University of Georgia’s Savannah River Ecology Laboratory, burls can result from “a variety of causes, such as infections by viruses or fungi.” Burrowing insects or injury to a tree can also cause a burl to form. Many kinds of trees produce burls.
A burl is a living part of the tree, but it is growing in an abnormal manner. The swirling growth rings produce unusual configurations that are prized by woodworkers who make bowls or smaller objects, such as pens and letter openers, from the burl. Depending on the tree’s age and its size at the time growth was disrupted (which may have occurred years or even decades earlier) burls may reach diameters of more than 2 feet and can even be made into small tabletops.
Not surprisingly, the biggest burl ever recorded was from one of the largest trees in the world, a California coast redwood. According to Guinness World Records, the largest burl was more than 118 feet in circumference and nearly 30 feet tall. It was estimated to weigh more than half a million tons.
A bit heavy for a tabletop. Linda Lee says, “I think that if the process were well-understood burls would no doubt be cultured like pearls, because the wood inside is often beautiful.” Q.
We have some enormous Chinese wisteria vines in our yard in Aiken that produce beautiful purple flowers and large seed pods. I have read on the internet that wisteria seeds can be poisonous to a dog if it eats them. Is this true? A.
I asked Jason Norman, veterinarian at Hammond Hills Animal Hospital in North Augusta, South Carolina, what his experience had been. According to him, “A dog that eats wisteria seeds can develop progressive gastrointestinal and neurological symptoms that could be fatal.” The source of the problem is a toxin called lectin that becomes concentrated in the seeds within the pods.
The toxin in castor beans, the highly poisonous ricin, is a lectin that has been used in political assassinations. Norman says, “Lectin causes coagulation of the red blood cells, resulting in clots and stroke symptoms.” The symptoms increase with dose level.
In other words, the more seeds eaten, the more serious the complications. “The consumption of 3 seeds often causes symptoms. More than 5 are often fatal.
Wisteria and its seed pods do not taste bad, so many pets will readily consume them.” Fortunately, a dog that eats wisteria pods will show symptoms of distress, which can alert the owner to a problem. It can recover with proper treatment.
Wisteria seeds are also highly toxic to humans. Q. We have wisteria vines in our yard in Selma, Alabama.
When it turns cold in the fall, we hear a popping sound. What’s that all about? A. When the large, green, hanging pods of wisteria start drying out, they begin gradually to twist.
When they burst open, with a pop, they spray seeds several feet in various directions. This form of propagation disperses the seeds in a way different from, for example, plum trees and oaks. Plum seeds and acorns are transported away from the parent plant by wildlife.
In the United States, Chinese and Japanese wisteria are introduced species. Some people consider them magnificent yard plants. Others view them as invasive species that should be eliminated.
The Southeast is also home to a native species of wisteria with smaller vines and flowers half the size of the introduced species..
