The Double Tree of Casorzo
Between Casorzo and Grana in Piemonte, a region in northwest Italy, there is a cherry tree growing healthily on top of a mulberry tree with branches spreading over 5 meters long. This tree, or should I say, these trees, are known as the Double Tree of Casorzo (Bialbero de Casorzo in Italian) or the Grana Double Tree.
By Enrique Arayata
ISA Certified Arborist® OH-7252A
May 11, 2022
Today I want to talk about a rare and interesting sight: the Double Tree of Casorzo. Before anyone asks, no I am not referring to a DoubleTree hotel in Casorzo. Between Casorzo and Grana in Piemonte, a region in northwest Italy, there is a cherry tree growing healthily on top of a mulberry tree with branches spreading over 5 meters long. This tree, or should I say, these trees, are known as the Double Tree of Casorzo (Bialbero de Casorzo in Italian) or the Grana Double Tree.
Image © Alfio Cioffi
As you may already know, it is not common by any means to see a tree on top of another tree, but somehow, someway, this cherry tree managed to find its home on top of this mulberry tree. It is unclear how exactly this double tree grew to be, but one popular theory is that a bird dropped off a cherry tree seed on top of the mulberry tree. The cherry tree seed then spread its roots down through the hollow trunk of the mulberry tree and found a connection to the soil where it can absorb nutrients. The relationship between the two trees does not appear to be parasitic or harmful to one another. It is fascinating to see that the mulberry and cherry trees are able to share water, sunlight, soil nutrients, and most importantly space without outcompeting one another and growing just fine.
Plants growing non-parasitically on top of other plants are not uncommon and are known as epiphytes. Common examples of epiphytes include some species of ferns, orchids, and bromeliads, which can attach themselves to trees or other plants and absorb some nutrients from rain and air along with any other nearby debris or soil they can access; all while not harming its host. What makes the Double Tree of Casorzo unique is that most epiphytes either are small in size or have a short lifespan due to lack of space and humus. However, as you can see in the photo within this article, this cherry tree is quite tall and healthy!
I talked to ISA Certified Arborist Andy Bartram (Crew Production Manager, Russell Tree Experts) about these trees to get his thoughts and opinions. Without seeing the tree in person, he believes the bird seed theory is plausible and he’s interested to know what the cherry tree’s root system looks like. As mentioned earlier, the cherry tree’s roots could be spreading down through the hollow trunk of the mulberry tree to get its nutrients, but there is also a chance that some grafting between the cherry tree and the mulberry tree’s root system could be occurring. The cherry tree could also be receiving nutrients from any available rain and mulberry leaves. I asked Andy about the tree’s health and longevity. In terms of treatment, if the trees have been growing healthily without any human interference, then they should be left untouched. If needed, watering during dry periods or seasonal fertilization could also aid in their health and growth. On a final note, Andy was curious about the structural rigidity of the Double Tree of Casorzo. With the cherry tree’s root system being higher off the ground (or potentially grafted to the mulberry tree), it may pose a hazard during windy days for visitor safety. If so, the fence surrounding the trees is definitely necessary and may even need to be extended as the trees continue to grow.
So if you ever take a trip to Piemonte, Italy, visit this tree and feel free to share any photos or videos you take! This Double Tree of Casorzo is definitely something you do not see every day!
Enrique Arayata I Media Production Manager, Russell Tree Experts
Enrique is an ISA Certified Arborist® and FAA Certified Remote Pilot. In his free time, he enjoys working out, hanging out with his family and girlfriend, video production, photography, cars, technology, and cooking. Enrique has a BA in moving image production with a double minor in film studies and studio art specializing in photography from The Ohio State University, and an AA in web graphic design from DeVry University. His favorite tree is the Kwanzan cherry tree.
Planting Trees for a Purpose
I think we all can agree that our TREE FOR A TREE® program is an awesome idea for replacing the trees that we remove, but as I set in the office watching nature happen outside my window, I started thinking of other reasons to plant trees. Trees provide countless benefits to our environment as well as providing food and shelter for a number of living organisms. Anytime that I am walking through a property I cannot help but notice the birds enjoying all that the trees are providing for them. I decided to write about planting trees that provide shelter and food for birds throughout the year.
I think we all can agree that our TREE FOR A TREE® program is an awesome idea for replacing the trees that we remove, but as I set in the office watching nature happen outside my window, I started thinking of other reasons to plant trees. Trees provide countless benefits to our environment as well as providing food and shelter for a number of living organisms. Anytime that I am walking through a property I cannot help but notice the birds enjoying all that the trees are providing for them. I decided to write about planting trees that provide shelter and food for birds throughout the year.
Eastern Red Cedar
One of the first types of trees that I would consider would be conifers. Not only do they provide fruit and seed throughout the fall and into winter, but they also provide unmatched cover and nesting sites. The Eastern red cedar would be a favorite for our area as well as White pine and many Spruce species. If you plan to feed the birds, it is always a good idea to have conifers nearby to provide cover for the birds taking advantage of your feeders.
The next type that I would recommend planting for attracting and feeding birds would be a variety of fruit trees. Careful selection of varieties can provide fruit throughout the year. One favorite would be the Mulberry tree, but be careful with placement as the fruit can be rather messy. Other smaller trees would be Serviceberries, Flowering Dogwoods, and Crabapples which can provide fruit from the summer, (Serviceberry) to the fall, and even into the winter with many Crabapples.
Of the large native trees, there are a few that seem to attract a large variety of birds, including wild turkeys. Some would be the White oak, Wild black cherry, and the American beech. They provide nuts, fruit, and the Beech often provides hollow nesting sites as well, often used by Owls.
Virginia Creeper
There are also many vines that are very beneficial to birds. A couple of favorites are wild grape vines which are great for the fruit they provide and the shredding bark is great for nest building material. Another would be the Virginia Creeper vine that provides fruit that can last into winter and as a bonus has brilliant fall color.
One thing to keep in mind when planting to attract birds in our area is to try to use native plant material when possible. There is a large variety of native shrubs as well that are awesome plants with a lot of benefits for birds.
Another idea that I observed recently while visiting a client’s property was a technique they used to attract woodpeckers. They gathered large fallen branches from a wooded area on their property and leaned them against a tree outside their window where they hang their bird feeders. The woodpeckers would come to extract insects from the decaying branches.
In closing, I would like to mention a few quick reminders to keep in mind whenever planting trees and shrubs:
Always identify the root flare on your plant material prior to digging the hole as this will identify how deep to dig the hole.
Dig a broad shallow hole, no deeper than needed to place the root flare at the same height as the surrounding grade, and broad enough to allow proper root expansion.
Firmly backfill around the root ball and only stake when necessary to support the tree.
Water thoroughly and cover the excavated area and tree with 1-2 inches of mulch.
Also, here is a how-to video created by our team. Check it out!
Mike McKee | Regional Manager, Russell Tree Experts
Mike graduated from Hocking College in 1983 with a degree in Natural Resources specializing in urban tree care. He has been a certified arborist since 1991. Mike started his career in the private industry in 1985 before becoming a municipal arborist in1989. He retired after serving thirty years before joining us at Russell Tree Experts in Sept. of 2018. His love of trees has never waned since trying to climb up the ridges of the massive Cottonwood tree in front of his childhood home.
Fall Webworm In Full Effect
We’ve received a high volume of calls over the last couple of weeks about “bagworms” in client’s trees. In central Ohio, true bagworm feeds predominantly on evergreens - arborvitae, spruce, and junipers although some deciduous trees can be hosts as well. Generally, this
Fall Webworm vs. Bagworm
We’ve received a high volume of calls over the last couple of weeks about “bagworms” in client’s trees. In central Ohio, true bagworm feeds predominantly on evergreens - arborvitae, spruce, and junipers although some deciduous trees can be hosts as well. Generally, this feeding occurs late Spring through mid-Summer and by mid-August they have stopped feeding to go pupate and become a moth. So I initially was confused about this late population of “bagworm” that had taken central Ohio by surprise and was making my appointment schedule grow faster than kudzu.
After visiting with a few customers, I realized the real culprit of concern was actually, Fall Webworm - not Bagworm. It’s easy to understand why a lot of folks call this pest (which resembles a bunch of worms in a bag) bagworm. This article should clear this up. (For information on true bagworm see the postscript at the end of this post). For those of you reading this article, I hope you can help me to rise up and start a movement to correct this awful error in nomenclature. 😉
The Facts about Fall Webworm
Fall webworm on Bald cypress
Fall webworm is a native pest of shade trees and ornamentals and can appear early summer through early fall. It feeds on over 100 different species of trees commonly attacking hickory, walnut, elm, birch, cherry, and willow. In urban landscapes, I’ve observed it daily on oak, sweetgum, redbud, linden, mulberry, and crabapple.
Fall webworm gets most folks attention by the large unattractive webbed nests it makes at the ends of branches. In most cases, Fall webworm is most damaging to plants aesthetically, diminishing the beauty of its host plant. A large nest can contain dozens to hundreds of caterpillars and can measure up to 3 feet across. Even after caterpillars have left to pupate, empty webbed nests can persist for months containing dried up leaf fragments and lots of caterpillar feces.
A fall webworm feed generally lasts for 5 - 6 weeks before the caterpillar leaves its host plant to pupate in the soil. Fall webworm generally has 2 generations per year.
Fall Webworm Management
Because Fall webworm generally causes little to no harm to the overall health of established healthy trees, I generally do not recommend management for this pest. Ohio has dozens of natural predators that make a living on Fall webworm including several species of birds, parasitic wasps, and other beneficial insects and they can generally keep populations of Fall webworm in check without the help of human intervention.
Newly planted trees could be at risk of significant defoliation and heavy feeding could impact fruit or nut yield for crop trees. If management of Fall webworm does become necessary, nests can be pruned out and destroyed or insecticides can be sprayed to kill the caterpillars while they are feeding. The beneficial bacteria "Bt" (Bacillus thurngiensis) can also be used on young caterpillars. This is available at most high-end garden centers labeled as Dipel or Thuricide.
If spraying is your control method of choice, please note that product only needs to be applied directly to the nests (rather than the entire tree) to avoid damage to beneficial insects and other non-target organisms.
If you need assistance managing Fall webworm - we’re here to help.
And Now, Bagworms
Bagworm is a small caterpillar that uses silk and bits of foliage and bark from its host plant to make a small bag around its body to protect itself. Each bagworm has its own individual bag (which often resembles a small pine cone), rather than large webbed nests that protect entire communities of caterpillars like in the case of Fall webworm. Bagworms feed aggressively from late May through July and can quickly defoliate entire portions of trees and shrubs if left unchecked.
Bagworms can be removed from plants by hand and disposed of easily on small trees and shrubs. On larger plants, insecticide applications can be made effectively through June before bagworms have covered their bodies with their bag.
Thanks for reading!
TJ Nagel
ISA CERTFIED ARBORIST® OH-6298A