Hi, my name is Blair Glenn. I am an ISA certified Arborist. The tree I am talking about here is the Liriodendron tulipifera, also referred to as the Tulip Tree or in some cases the Tulip Poplar.
This is a very fast growing tree. It is a great shade tree. It is typically from the East Coast. It grows wild in the United States and is commonly used as a hard wood tree for furniture production.
It is imported into California as a shade tree but unfortunately, there are some problems.
The tree was so popular when it first was introduced to our area that it was commonly used as a street tree. Through out San Jose, Campbell and many of the suburbs, there are literally thousands of these trees that have been planted.
And now for the problem, these little bumps you can see here on the twigs are actually insects. They are insect called Scale.
Scale can completely devastate a Tulip Poplar. They can cause branch die back, they can cause excessive amount of decline. They can cause dripping and they create an incredible mess.
And in large enough numbers, they can actually kill the trees. The tree in the center here is almost entirely dead and it is caused by Scale.
The Tulip Tree as I said before is used as a street tree and unfortunately, the insects caused the pitch from the trees to drip. The drip causes damage to cars. It also creates a very sticky environment on the sidewalks and on the streets. And can be very hazardous.
As you can see from this photo, this tree is about 50% gone. It is leafing out. It is surviving but slowly through the years, the canopy is going away.
Here is just another example, these trees are fairly tall. They are 50 to 60 feet tall. They should be full. They should be totally leaf out right now but they are almost gone.
It is really sad because a lot of our neighborhood’s environment and the beauty is derived from the trees and unfortunately when an entire neighborhood is comprised entirely of this Tulip Poplars, then the whole problem becomes very radical.
I am not advocate for monoculture where you have entire blocks of the same trees because when a problem does erupted such as scale, it affects everything. It affects an entire neighborhood.
These trees can get very large, they also can cause damage. Many of our streets are damage by the upheaval from the roots and the sheer expansion from the size of the trunk. If this tree continues to thrive, it is just going to be a few years before it outgrows its environment anyway.
And here is close up of these little creatures. They can be treated. It is extremely difficult because they have this little protective cases on their, the exterior sprays that are applied to the user are somewhat difficult.
You can put a chemical in the ground that is absorb through the tree as a systemic and that does have some effect. Some people are going so far is to inject the trees with the same kind of systemic and the insects are absorbing the chemicals through the twigs and that is actually causing them to decline.
All these things worked but they are very expensive. And in many cases, external spraying is also difficult on the streets.
Now, I have to be very careful because when I talk so negatively about the tree, it sounds like there is no hope. But on the positive side, I do see this tree in alternate environments at a little bit higher elevation or where it gets a little bit colder.
I have seen Tulip Trees growing in the Santa Cruz Mountains that show absolutely no sign of the scale at all. Occasionally, I see a Tulip Tree that is growing all by itself that is not as much of a target. When you have lots and lots of Tulip Trees are growing together, that seems to exasturbate the problem.
I really like the Tulip Tree. It is got a beautiful shady canopy. It is got some attractive flowers, it is great long tree. It does like a lot of water. Unfortunately, some of the effects from the trees, some of the problems from the tree, the insects are due to the fact that we imported a tree from an alternate environment that gets much colder even here, and it adopted and did qui
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