How do tree roots know whether they should fuse with other roots or not? How do plant leaves know to grow opposite of other leaves? How do stripes form on a tiger? Chemical gradients.
> ... arises due to the interplay between differential diffusion (i.e., different values of diffusion coefficients) of chemical species and chemical reaction.
There’s an old bonsai trick to force a branch to appear by cutting or bruising the wood above the point so that the cells that differentiate into buds can no longer see the signal from the apical bud, which in species that have them, is telling the rest of the tree to give it all of the energy so it can outcompete other trees reaching for the canopy.
Meanwhile if you prune the apical bud to try to keep the tree small, it will just elect another leader and keep growing on a side branch.
I have a tree in my yard that got nibbled by insects when it was chest high. Killed the crown bud but not its two siblings. One of them won, then stood up straight and two years later you can barely tell.
This is fascinating. Where could I learn more about these sorts of bonsai techniques? Is there a book or website that you would particularly recommend? I’ve always been intrigued by bonsai but if you do a basic web search it’s just people selling trash.