the tide goes in, the tide goes out. no one can explain it.

magnets, how do they work??

That's a great view to have from a house. You are fortunate. New brother-in-laws are pretty cool too.

Oh, the topic!
Leaf senescence - I'm diggin it.

It's something that I've wondered about. Ten trees of the same species in a row on the same block, but some give up their leaves very readily, others hang on to their dead leaves until spring for no obvious reason. Ah, the complicated majesty that is nature!

Brendan: Contact the Nature Conservancy of Washington and ask to talk to one of the scientists there. I know one there specifically who knows a great deal about tree leaf coloration.

#4

The aerospace engineer has a good environmental answer, since he knows about vortexes and laminar flow. The wind patterns (as well as sun) could make lots of interesting hot and cold spots on a group of trees that variagate patches of their leaves.

Alternatively, some type of genetic drift, where the plants simply spread the phenotypical response all over the place and if there is no selective pressure favoring one approach or the other. Well, there it is.

It has to do with genetic variation within species as well as light availability. Street lights affect the timing, for example.

The term "senescence" is an invalid hypothesis.

Google the term "complex adaptive systems" instead. Highly complex behavior can emerge from the interaction of simple rules. Ant colonies, for example.

Plants are the ultimate decentralized systems. There is no centralized intelligence there at all. Everything a plant does is hardcoded into its cellular structure. A plant acts the way it does because of embedded biomechanical processes.

Plants don't have brains because brains evolved to regulate movement, which plants don't do. There's a good reason why "movement", "motive", and "motor" have common linguistic roots. When you think of something, your brain is literally "grasping" it.

To understand why plants behave as they do, you need to unlearn being an animal. Cars may give rise to traffic jams, but traffic jams do not behave like cars do. For one thing, traffic jams grow in the direction of cars arriving and shrink in the direction of cars leaving. In other words, traffic jams "shit" cars.

Check out a book called "Turtles, Termites, and Traffic Jams" if you want to understand how leaves work.

In which we learn that Brendan is deeply uncomfortable with the possibility that an observed phenomenon might have many hypothesized causes, but no specific mechanism backed by experimental or other available evidence.

When a person in the reality-based community encounters such a phenomenon, he or she says "we don't really know the answer to this question," rather than speculating, or substituting the speculations of authority figures for truth.

@4
Same species, different varieties. Do you live on my block? We have the same thing — all Norway maples, but lots of subtle differences between the trees, including, height, shape, density, color, time of leafing out, fall color, etc.

Plants, just like humans, are not simply plants...they are collectives that house large, active, and influential microorganisms populations in and on their bodies and in their root zones. This combined collective organism has agency in and of itself. Remember what a perennial plant is doing in the fall, it is indeed reacting to the surrounding abiotic conditions, but the process, which includes the breakdown of chlorophyll and the movement of those breakdown products into the storage in the roots, is decided upon collectively by the tree and its collective microbial community. The reds and oranges we see are simply other light fixing pigments that are not as abundant as chlorophyll, the plant still breaks them down and uses them to survive the winter, but the pattern of breakdown, exactly how each tree and its microbes goes about it, is unique to each plant. The range of environmental conditions, temp, humidity, soil nutrients, whatever, sets the broad context for leaves to change, but trees and their microbe bros are not simply dumb reactants within that context, they choose how to react within their specific space

You can tell this is not a Mudede post because the author actually attempted to find an answer instead of just making up some bullshit one wrapped in psuedo-philosophical nonsense words that sound "deep" to morons, but are actually just meaningless.

I think it's fascinating that we have a planet in a narrow band around our star that appears optimal for life and the optimal area for vegetation is a narrow band around our planet, if I understand correctly.