The former is especially interesting because it implies that crown shyness is an explicit strategy for resource management beyond just responding to the availability of light, since it presumably also improves the survivability of the species. The latter is interesting because it might be an adaptation to other environmental stresses like wind damage.

As always, more questions than answers :-)

[1] https://pubmed.ncbi.nlm.nih.gov/33713413/

[2] https://esj-journals.onlinelibrary.wiley.com/doi/10.1111/144...

It's also not universal, which is why it's increasingly believed to be some sort of stress response. One patch of trees in a forest may exhibit it while another patch of the exact same species a few hundred feet away might not. It might even be the case that this is an old adaptation that most trees are capable of but no longer need.

  * Species of Dryobalanops, including Dryobalanops lanceolata and Dryobalanops aromatica (kapur)
  * Some species of eucalypt
  * Pinus contorta or lodgepole pine
  * Avicennia germinans or black mangrove
  * Schefflera pittieri
  * Clusia alata
  * K. Paijmans observed crown shyness in a multi-species group of trees, comprising Celtis spinosa and Pterocymbium beccarii

It’s similar to the prisoner’s dilemma, with shyness being “cooperate” and non-shyness being “defect”. Groups of trees with cooperative strategies would do better collectively (and win out), even if a non-cooperative individual can beat a cooperative individual every time.

Veritasium had a great video on this very topic today, in fact: https://youtu.be/mScpHTIi-kM

As a tree you don’t want to get dwarfed, starved and die. But you also don’t want to kill your neighbors either since they could be providing a wind break and helping you survive. Essentially their evolution has taught them that sharing, within reason, is an optimal strategy than pure greed.

The book goes into much more detail. I’m paraphrasing.

Crown Shyness - https://news.ycombinator.com/item?id=33217484 - Oct 2022 (1 comment)

The mystery of tree 'crown shyness' - https://news.ycombinator.com/item?id=24431062 - Sept 2020 (1 comment)

Crown shyness - https://news.ycombinator.com/item?id=14998591 - Aug 2017 (36 comments)

I like robot and monk too. Her short “To teach, if fortunate” is also good. So much talent.

It’s in a similar box to Mushishi, which is a really laid back anime without any real antagonists. I’d recommend it to anyone who liked the Monk and Robot series.

https://youtu.be/pkQ50oXPQ4A?si=w8fXbrY4w5b3lddM

Where I live, in the moderately dense mixed second-growth forests of the North American northeast, I have to trust the mathematics since neither the sugar maples, elms (RIP), ash (RIP) and red oaks nor any of the abundant coniferous species that grow here demonstrate any kind of crown shyness. Maybe the aspens or birches do, I'll have to remember to check them after the leaves are out next June.

[1] https://www.youtube.com/watch?v=rHkdU105HNA

In an alternate universe we might see crown hyperaggression where trees are constantly fighting it out along their crown lines...

Limbs sliding back and forth would strip the tinder and create long smooth patches which would cool between cycles in the high winds. You might end up with a charred coating on the limbs and sawdust all over the ground, but I don't think you'd get flame.

You really need the spin of a bow drill to concentrate the kinetic energy in a small enough patch, and you need tinder nearby.

Trees also need to prevent infection from other trees, need to prevent damage from colliding from other trees, and mass damping doesn't work if trees are touching.

But they also want to be close in order to share nutrients through their roots.

There are many reasons why trees would want to do this, from an evolutionary standpoint.