If you have ever heard someone say that palm trees are not trees at all, you might have given them a funny look and wondered what on Earth they were talking about. However, they would be absolutely correct. Are palm trees technically considered grass? Yes, they are!
Amazingly, palm trees are considered a kind of grass, and not a kind of tree. This is because they do not have some of the key characteristics that a tree must have, such as a trunk and bark. They also do not have a secondary growth stage, which trees have, and genetically speaking, they have very little in common with trees.
Why Isn’t A Palm Tree A Tree?
It might sound extraordinary to say that something that actually has the word tree in its name is not a tree, but it’s true. So, why is a palm tree not classified as a tree? There are a number of different reasons, which we will explore.
Reason One: Genetic Differences
Palm trees are not genetically similar to trees at all. They have more in common with a blade of the grass in your garden than they do with, for example, an oak tree. If you examine the DNA and the evolutionary process of a palm tree, you will see that they have very little in common with true trees.
Reason Two: They Have No Trunk
Palm trees might look like they have a trunk, but they don’t. The big, thick structure that supports their foliage and makes up most of their presence is actually just a stem made of fibrous tissues. It is sometimes known as the caliper, and it is not made of wood at all.
There is no such thing as “palm wood,” because the palm tree does not produce wood cells. We can make a wood-like material from palms, but it isn’t real wood.
Palm trees also have no bark, and will not form rings inside their trunks as they grow, so you can’t tell how old a palm tree is by looking at a cross-section of the trunk. True trees produce cambium, which is the layer of actively growing cells that are found between the bark of the tree and the old wood.
Trees grow outward, and new layers of cambium create rings. If you cut into a tree, you will be able to see these rings, and they can be used to estimate the age of the tree. However, if you cut into a palm tree, you will not find these rings at all. You will just find fibrous plant tissue.
The outside of the “trunk” is formed by overlapping leaves or at least the base of the leaves. The palm tree sheds its leaves when they die, but the base that attached them to the stem remains in place, and these hardened structures help to support the palm’s stem as it continues to grow and gain height.
The stem of a palm tree may serve the same purpose as a trunk and it might look like a trunk, but it isn’t!
Reason Three: Different Roots
Palm trees have a different root system from that of many trees. It tends to be much shallower and more fibrous. The roots spread out just below the surface of the soil, forming an underground base that can grow to be very wide eventually.
By contrast, most trees put down deep roots that anchor them and allow them to access nutrients and water far below the surface of the soil.
Reason Four: They Are Flexible
If you have ever watched a palm tree whipping about in a strong wind, you may have noticed that it is highly flexible and tends to bend when put under pressure. Compare this to the way that grass moves when it is caught in a gale.
Proper trees do not usually thrash around the way that palm trees do. Their structure is much less flexible, comprised of tough bark and wood, and while they may sway in a strong wind, they do not move nearly as much as a palm tree.
Palm trees are more flexible because the cells are more malleable. This means that palms can bend in strong winds – an advantage in coastal areas where severe storms and hurricanes are more likely.
However, palm trees are more vulnerable to being torn up by the wind, because their roots are shallow. This is especially true if the wind is accompanied by heavy rain, which will loosen the soil around the roots. While the palm’s trunk may be flexible enough not to snap, it is still vulnerable to being ripped out of the ground by a storm.
Reason Five: They Don’t Have A Secondary Growth Period
While this is not something that most people will notice or be aware of, this is another significant distinction between a palm tree and an ordinary tree.
A standard tree has a secondary growth phase, in which the functioning tissues within the tree get replaced by newly generated, younger cells. The tree can continue to grow for a long time, but its cells die and get changed.
However, palm trees don’t grow in this way. Their cells do not get replaced; they simply age and keep going. Individual cells may last for hundreds of years, depending on the age that the tree lives to.
Reason Six: They Are More Vulnerable To Damage/Disease
Unfortunately, one of the problems that palm trees suffer from is that they do not have a tree’s ability to heal. Conventional trees are able to “seal off” branches and damaged parts of their trunks. This cuts the injured or infected part off from the main system and stops the infection from spreading or too much sap from being lost.
Effectively, the tree is healing itself, and it can do this provided it has enough strength to make the seal and survive without the injured part. The damaged area may fall away or remain attached, but it is no longer affecting the tree’s system.
In contrast, palm trees cannot do this, and they are therefore far more vulnerable to death by injury or disease. A palm tree that gets damaged in strong winds is less likely to recover because it cannot seal off the injury.
Are Palms Really A Grass?
To be clear, palm trees are monocots, which puts them in the same division as grass. Grasses are actually in the Poaceae family, while palms are in the Arecaceae family. However, they are botanically grouped with grasses and they have a lot in common with grasses.
You might be wondering what a monocot is. These are plants that have fibrous stems and a single seed leaf. Their roots are very fibrous rather than using a tap root to anchor into the ground. Also, the plants do not have a vascular cambium (the system which produces wood cells on the inside and bark cells on the outside).
The leaves of monocots have parallel veins, rather than the netlike ones observed in dicots (the other classification). Grasses, lilies, palms, orchids, sedges, and bamboos are all examples of monocot plants.
Therefore, while palms may be in a different family, they are essentially a kind of grass and have much more in common with grasses than with trees.
Why Do We Call Them Trees?
So, why do we refer to palm trees as trees if this is not correct? Is this accidental?
Sometimes, the misnaming of something arises from confusion at the time when it was named. It’s perfectly possible that palm trees were accidentally misclassified because they do look a lot more like trees than grasses. However, it also makes sense to continue this usage, even if it is misleading from a scientific perspective.
The term “tree” is commonly used to denote something large and tall, with a strong central stem. It helps us divide plants up into rough size categories, which makes things much easier when we deal with the plants in any way.
It does not really make sense from the perspective of daily usage to refer to palm trees as grass. You can’t mow them. You won’t be planting them as a lawn. You aren’t going to pluck a stem to chew on.
When you want to interact with a palm tree, it is usually as you would interact with any kind of true tree. If you want to cut it, you’ll need similar tools. If you want to plant it, you’ll have to take its height into account.
Essentially, it makes sense to refer to palm trees as trees simply because it’s more convenient. The point of language is to be understood. If you start calling palm trees grass, you cause a lot of confusion.
Summary
Palm trees are in the same division as grass, and they have a lot in common with it. They do not belong to the Poaceae family like grasses do, but they are very similar in many ways, and it isn’t incorrect to say that a palm tree is essentially just a giant grass!