Something like the above (Natural Springs by Ellie Cooper) - either where the water originates from atop the tree through regular rainfall, or is directed up and into the tree via the spring (or some other source) below - somehow. I'd ideally like these to be created naturally, but man-made alterations are also possible if that would make them work when they otherwise wouldn't. It doesn't need to be a global phenomenon either, it could be local to a certain area of an otherwise Earth-like planet.
No, at least not with classical trees. A tree can be defined as
a woody perennial plant, typically having a single stem or trunk growing to a considerable height and bearing lateral branches at some distance from the ground.
Branches with leaves can't be dense enough to hold water, as this would defeat the purpose of the leaves on the trees. A leaf converts sunlight to usable energy and if it's packed tight enough to hold water, it wouldn't get sun. Furthermore, a leaves are designed to let water drip through to the trees root system below.
If you want something like on the image, I would suggest going with massive fungus which can be "waterproof" and don't undergo photosynthesis.
Of course there can!
Unless you're looking for a biologically true answer,1 in which case they can't because, looking around the Earth, there aren't any. BUT! I happen to know
Mephistopheles a particular mad scientist2 who thinks that with some suspension-of-disbelief gene splicing and some particularly unnatural "stuff," you might achieve your evil plan goals with the following ideas:
The tree is massive and grows a natural bowl surrounded by a leaf barrier. The leaf barrier is meant to slow the wind to minimize evaporation of the accumulated water.
One value of the water may be to foster the growth of bacteria, plant life, or animal life, that leaves behind a nutrient the tree needs in quantities it can't get through the soil. This could be a naturally-forming tree version of soil inoculant.
Another value to the water would be that the tree is a massive water-stealer, in which case everything under the tree is a desert.
One method of filling the bowl would be rain... but that's often capricious and, despite what our mad scientist just suggested, sunlight is going to evaporate the water pretty quickly no matter how deep it is. Therefore, I'm voting that the tree is capable of some world class transpiration. Transpiration is the process by which plants move water from the soil to where they need it. Some of it is used during the photosynthesis process - the excess is expired through the leaves (not unlike sweating, but in a much finer process that's a lot more atmospheric than it is fluid). But, your tree is BIG! And that means the process shifts from atmospheric to fluidic. Since plants do this today, yours simply need to do it on a larger scale with greater efficiency.
- What this really means is that your trees can only form along underground rivers or over large aquifers. They need a large source of underground water. Soggy soil isn't enough.
Finally, you might want to think through the waterfall concept. Consider the laws of thermodynamics, which basically say that if you've been
suckeredconvinced to buy something that produces more energy than goes into it, somebody's probably stealing your identity along with your money. In other words, a tree large enough to form a waterfall worth looking at would need a MASSIVE water source to justify the amount of waste water dumped on the ground below. Therefore, you might consider virga.
Virga is that streak of cloud you see that kinda looks like rain falling to the ground — but nothing actually hits the ground due to evaporation or sublimation. Basically, there isn't enough liquid water to survive the trip. If your trees resulted in virga (which, IMO, would be massively cool, the mad scientist likes it, too), they would be more believable since the massive water source need not be so massive.
And for the record, my mad scientist friend loves this idea because basically it's the most beautiful and amazing thing on the planet — and nothing and no one can live near them because it's a honking desert underneath them. See footnote #2.
1 And, frankly, if you really are looking for an answer to your "can this fantasy idea happen in real life?" question then you're kinda in the wrong place... with the exception of our Anatomically Correct series, but that has rules. Remember, this is a place where you, the creator of a fictional world, seeks help to create that world's rules and expression. Thus, if you're asking, "My wife wants one of these in the back yard, how can I get one?" the only answer is "concrete is your friend!" But if you're asking, "how to I get these into my world in a believable manner?" Read on.
In terms of physical possibility, I think that picture is honestly a bit of a stretch, just because water is so heavy that I doubt any amount of wood would be able to hold that much of it up. But if the trees are a bit smaller, or the planet has a lower gravity, or these trees are made of something much stronger than wood, then sure, why not?
The real question is an ecological one: why would something like that exist? Here's my offering:
Suppose there is a region of your world that consists of a very nutrient poor desert. It would be very hard for plants to grow there, except for a lucky geological coincidence: underneath the surface is an artesian aquifer, meaning that if you dig down far enough not only will you find ground water, but it's under pressure, so if you dig a hole the water will come up to the surface, forming an artesian well.
A tree with a deep enough root system can reach the water, but why would it channel the water up into its canopy instead of just growing its roots down into the aquifer?
Well, earlier I mentioned that this desert is very nutrient-poor, and trees need nutrients to grow. One excellent source of nutrients is bird poop. How can a tree attract birds to a desert? By growing a bird bath!
So imagine some kind of migratory flamingo-like bird. They eat plenty of food in the fertile regions of the planet, but then when it's breeding season they fly into the desert to mate and lay their eggs in the tree-tops, where they're safe from predators. The trees provide nesting sites and large, shallow pools of water for them to drink and perform their flamingo-like mating rituals, and while they're there they poop out all the nutrients they've eaten elsewhere, fertilising the trees. It's a reasonably plausible symbiotic relationship.
Of course, the pressure in the aquifer will vary quite a bit, and perhaps after the rains there will be so much water that it spills constantly out of the canopies, and the scene will look not unlike the picture you posted.
Edited to add: from a video link in LazyReader's answer I discovered that this is actually somewhat biologically plausible. Apparently there is a very old tree in Montenegro which has a hollow trunk and sits on an aquifer that, after several days of rain, has enough pressure to force it up through the trunk. Here's a couple of screen grabs:
One can just about imagine that under the right conditions, evolution might start to take advantage of this effect.
There is another video here with a little more information about this tree.
Perhaps giant fungal organisms? Mushrooms are effectively > 80% water, so with a little stretching of the genealogy one could imagine giant mushroom-like organisms that sponge up large quantities of fluid from nearby (or underground) sources. It could then continuously eject the excess from atop its structure via large pores, or perhaps on cycle (weather / solar cycles) open up its pores and eject mass quantities of fluids. Fungal organisms have been observed to use water to eject / propagate its spore content here on earth...
From a certain point of view, such things already exist, they're waterfalls found on buttes called Tepuis:
A tepui /ˈtɛpwi/, or tepuy (Spanish: [teˈpuj]), is a table-top mountain or mesa found in the Guiana Highlands of South America, especially in Venezuela and western Guyana. The word tepui means "house of the gods" in the native tongue of the Pemon, the indigenous people who inhabit the Gran Sabana.
Tepuis tend to be found as isolated entities rather than in connected ranges, which makes them the host of a unique array of endemic plant and animal species. Some of the most outstanding tepuis are Auyantepui, Autana, Neblina, and Mount Roraima. They are typically composed of sheer blocks of Precambrian quartz arenite sandstone that rise abruptly from the jungle, giving rise to spectacular natural scenery. Auyantepui is the source of Angel Falls, the world's tallest waterfall. (source, emphasis mine)
The change for your world is that the water pressure forces the water up through the non-homogeneous trunk of a tree rather than through the non-homogeneous rock of the tepui. And there's an example of this after the image.
Now for the example of water forced up through the trunk. If you're looking solely at a tree, consider the following two YouTube videos. The first is a tree with a waterfall that occurs only when it rains. The second is more on point where heavy water saturation in the local area appears to push water up through the trunk to create a waterfall... something like what you're looking for.
Hyathodes are pores on leaves of certain plants. When root pressure is great enough, excess water escapes thru the leave pores and dribbles out. This is called guttation. I think it is kind of an escape hatch so the excess water does not damage the plant.
If there were serious root pressure (for example a dry adapted tree during a wet time of year) I could imagine enough water coming up from the roots and out thru the leaves to accumulate.
Better though is a tree that did this on purpose. Consider the aphid. It drinks great quantities of tree sap and poops most of it out. Tree sap is protein poor and the aphid must process a lot of it to the the protein it needs, throwing out the rest. So too these trees. They process great quantities of water, retaining the nitrogen, phosphorus and iron they need and throwing out the rest as a cascade off the leaves.
One humid morning in real life I witnessed a situation where it was raining under the trees. The air was warm and moist and the leaves of the tree were apparently cool. Water was condensing on the leaves and falling to the ground like a gentle shower. Your tree could condense moisture from the air and funnel it to a specific path within the structure of the tree and let it fall to the ground in a stream. This would be dependent upon a constant supply of warm humid air moving past your tree.
It's possible, you just need Giant trees, why normal trees won't work? Because water won't accumulate in a pond, it will simply fall off the leaves.
But giant trees have a problem with gravity, the taller the tree the harder it is to pull water from the ground up to the leaves, but giant trees have evolved a rain chamber that gaters water from the rain to overcome this obstacle.
Take a look at Cushion Plants.
They are very low-growing here on Earth, but they are a true woody plant with leaves, rather than a moss or grass (which they do resemble). Their canopy is extremely tight - not watertight - but they also form mats underneath the growing canopy to conserve their dead leaves as insulation and compost.
You could imagine some sort of large-trunked version with a similar canopy, where the under-layers and branches form a dense, spongy 'aquifer' that can hold water. It would probably mean that the waterfalls would come out of the sides of the canopy, rather than flowing out of a 'bowl', and they wouldn't easily form permanent 'lakes' on top, but it seems at least plausible.
Generally speaking, a tree's roots extend as far as its branches extend. If the branches caught and retained water like the image, then the soil around the root system would dry out and the tree wouldn't live very long. I suppose the tree could evolve some way to absorb water through the canopy instead of the roots, but that's a distinct enough change that you it might not be classified as a "tree" any more.
Also, water will reduce the amount of light that reaches the tree's leaves. Water is generally a bit murky, but even crystal-clear water will have some portion of the sunlight reflect off the surface. This reduces the plant's ability to photosynthesize and would be a significant evolutionary disadvantage.
But let's forget about all that for now. Pretend you have a magic tree with roots that extend to an aquifer and that doesn't need sunlight at all. You still won't get something like you see in the image, at least not for very long. Take the small tree-pool on the left as an example. Based on the height of the woman standing near it (let's assume she's 1.7m tall), the tree-bowl appears to be ~1.5m deep and ~4.3m across. That's roughly equivalent to a medium-sized above-ground swimming pool. Given the rate that the water is flowing out of that tree, a completely full tree bowl would drain in no more than a couple of hours. The square-cube law says the larger trees could drain for longer, but likely not more than a day or so. You could see a spectacular sight like the image immediately after a large rainstorm, but they would quickly empty and you'd lose the waterfall effect.
The small tree next to the woman subtly reveals the only way you could get a scene that looks remotely like that image. That tree's bowl is slanted at a rather sharp angle, and there's water visible at least halfway up the bowl. This implies that the tree isn't holding or storing any meaningful quantity of water. The water is coming from somewhere else and the tree is simply funneling it into a waterfall shape. Some of the smaller trees in the foreground are dumping water at rates that are low enough that they could conceivably be fed by an underground spring and up through a hollow trunk.
The large trees in the background would almost certainly be an impossibility in the natural world. The amount of energy needed to push water that high combined with the sheer volume of water coming off those trees means that the source water is under an unnatural amount of consistent pressure (geysers build up pressure and then spray in a burst, not a continuous flow). Even if that pressure didn't blow a big hole in the rock, there's no way a young plant would be able to take root and survive while being blasted by a fire hose.
If you want to replicate this sort of visual experience in your Earth-like world, your more realistic option is for these "trees" to actually be rock/mineral formations. The tree-like appearance is due to the various mosses and plants that grow on top of them. This entire area was originally an underground cavern. Springs ran through the cavern, eroding away the softer rocks and leaving behind stronger ones. The cavern roof eventually collapsed, which is why you can see through to the sky. The large "trees" in the background are pillars of erosion-resistant stone topped by a chunk of what was previously the ground that sat atop the cavern. The smaller "trees" in the foreground are concentrated mineral deposits that accumulate around the openings where the spring's water exits the bedrock. An arrangement like that would get you 75% of the way there. You'd still have to figure out how to push significant volumes of water up to the top of the larger "trees", and I highly suspect you'll need artificial assistance for that. Perhaps your inhabitants liked the visual effect of the smaller structures and wanted to replicate them on a larger scale.
The trees grow over geysers which push the water up inside the trunk. The reason for them to grow over a geyser which pushes hot water up their trunks is that there are minerals in the water they need. The minerals in this high concentration can only be found in water from the depths of the earth's interior. These minerals also contribute to the stability of the trunks so that they can withstand the pressure and heat. In the treetop there is a basin in which the water is filtered by e.g. roots. The filtered water flows down in the form of waterfalls on the sides of the treetops.
Because the trees filter the water so well, the thermal pools under the trees are a popular travel destination. Nowhere else can you find cleaner water.
Didn't do the math about weight or anything. I just tried to find a reason why there would be water in the treetops.
Giant redwoods have quite interesting canopy ecosystems. See https://www.savetheredwoods.org/grant/sponge-like-mats-make-good-habitat-in-redwood-canopies-wandering-salamanders-benefit/
Notably, they are big enough that they can support soil formation. Scaled up you could have enough soil to have pools, and when the pools overflow, waterfalls. However, you're unlikely to get these at the edges of a tree like in the picture, simply because the whole top of the tree would need to be a pool, or the pool would need to form at the edge.
Basically, yes you could conjure up an ecosystem of very large, fairly densely packed trees that have behaviour like this.
Actually the structure on picture could have a non-tree explanation.
They're mineral deposits from the water, created on contact with air.
Somewhere deep there is a reservoir of water with high mineral compound, like quick setting concrete, that solidifies on contact with air. These are pushed up through the cracks and erupt as geysers. But because of the mineral buildup, you end up with mushroom like structures, as falling water deposits the minerals on edge of the structure.
The result is a very large stone structure like in the picture, with green fungus growth.
Yes, you have them in real life
Many plants have drip tips which is a heavy-precipitation adaptation to allow water to flow off of their leaves. This creates small waterfalls. Provided the scale of your setting is small enough (e.g. humanoid characters somewhere between 1mm - 10 cm in height) leaf-based waterfalls will be almost an inevitability.
The Traveller's Palm is known for its ability to trap water in the base of its leaves.
Another plant whose geometry leads to trapping water is Aloe Vera and similar plants.
Aloe Vera lives in a dry climate, and I would speculate that it could evolve to catch moisture in its leaves and funnel down to the centre where water could be absorbed. It's going to be tough to get enough water to be of any real advantage to a tree though. I would suggest heavy rainfall only about once a month would be the most conducive to developing a large plant with this characteristic. Of course, when the rains do come any excess will cascade off the leaves.
Aloe vera has a short stem, as do many arid plants, as it doesn't compete for light with its neighbours. There are plants in arid zones with tall stems. For example palms have a taller stem so it might be easier for a palm to evolve into a tree with a water trapping ability than Aloe Vera.
I can't imagine the diameter exceeding 10m though. Some of the trees in the painting look over 100m in diameter, bigger than any natural trees, and that's a separate issue.