Another reason that I like trees is that they invite a tactile relationship: they can be touched, leaned against and climbed up into. Flowers , by contrast, keep you at a distance: they are for watching, not touching.
But there is more to it than that.
Consider the song of the hototogisu ouside my window. It is beautiful, yet lacks individuality. All birds of the same species sing the same. So why do I find it beautiful?
One could say: things lacking individuality too can create their own kind of beauty, the beauty of ambience, a beauty that creates pleasure while staying in the background. We have the same phenomenon in the case of the sound of water: again a beauty that lacks individuality. The beauty of clouds and city crowds also belong in this category.
But this answer is insufficient. Apart from such ”pleasant” ambience, there is what could be called beauty in the strong sense, a beauty that grasps your attention. Instead of staying in the background, it jumps to the foreground, startling you, and making you catch your breath. The sound of hototogisu can startle you in that way. In fact, doesn’t it almost always? Doesn’t much of the beauty of this bird’s singing come from the surprise of broken silences, from the intervals in its singing?
In the same way, a flower or the sound of water too can be startlingly beautiful, if it appears in an unexpected place.
So a generalization: even things lacking individuality can be beautiful in the strong, attention-grabbing sense to the extent that they startle you. The element of surprise helps them catch attention and in that way makes up for their lack of individuality.
This is confirmed by the fact that things like trees that do posses individuality are themselves made up of unoriginal elements, just like a piece of music consists of unoriginal elements called tones.
What happens in the case of trees, and what creates the impression of individuality, is that the elemenent of surprise doesn’t cease with the first impression. As you look closer and trace the shape with you eye, the first surprise yields to the next. Tracing a shape means exactly this: to go from one surprise to the next. Thus the attention continues to be held in thrall. Here the sensation of fascination comes into play: the phenomenon when you ”never tire” of looking at a thing or ”can’t get enough” of it. You linger with it, unwilling to leave, thinking you would have liked to stay until you knew or understood the thing better.
This arrangement of elements into shapes that continually create surprises is the root of individuality and fascination. We can see the same in mathematics or in people whose acquaintance we make: fascination arises when we encounter a phenomenon in which not only the first, but also the subsequent, impressions startle us.
Flowers or birds may catch our attention, but they seldom hold it for long. They startle us once, but seldom leave any room for further surprises. They are ”flat”. Ambience, as in the case of water, is the only beauty they can aspire to in the long run. This ”flatness” is a quality they share with much human-made beauty, including architecture, ”good design”, fashion and commercials.
Therefore, I think it is possible to distinguish between three kinds of beauty (which sometimes overlap): the ambient, the startling and the fascinating. All inspire a sense of pleasure, but the ambient lacks intensity and the ability of catching attention. The startling kind of beauty captures attention, but only for a moment. Only fascinating beauty invites lasting attention, but this kind of beauty is only possible for things that create an impression of individuality.
This categorization can be applied to human-made objects as well. Restaurants and cafés may be good at ambience and background, but are usually not very interesting in themselves. Monuments can startle but quickly become boring. One tires quickly of even the most startling architecture. In general, it would seem that whatever is domesticated, designed or planned rarely inspires fascination. At most the beauty it inspires is of the startling or ambient kind.
The quality of fascination seems to require ”nature” or ”wilderness” in the sense of things being able to grow in an unplanned fashion, in their own way, without conscious control or design interfering too much. Human beings are fascinating since they contain "wilderness" in that sense. Urban environments that fascinate are usually areas that are neglected: ruins, abandoned buildings, slums, shanty towns, or tent villages in parks.
Flower gardens are domesticated, but in trees there is something that remind me of the wilderness.