Is Light and Gravity the Sole Influence on Tree Branch Growth?

[thedore]

I've had some arguments after I assumed ( perhaps wrongly) that electric fields were responsible for the direction that branches grow in. In any case my inquires on this all result in the same answers. That the direction of growth is determined by light and gravity. Do all you agree with this? To me it seems impossible. Branches have a fine structure and they always know how to avoid other branches close by. In some cases two trees will branch out away from each other but will not send branches toward the other tree. Also branches will develop so that they never touch each other. I think there has to be some other force that enters into this. Any commits?

 

[cesiumfrog]

I've had some arguments after I assumed ( perhaps wrongly) that electric fields were responsible for the direction that branches grow in. In any case my inquires on this all result in the same answers. That the direction of growth is determined by light and gravity. Do all you agree with this? To me it seems impossible. Branches have a fine structure and they always know how to avoid other branches close by. In some cases two trees will branch out away from each other but will not send branches toward the other tree. Also branches will develop so that they never touch each other. I think there has to be some other force that enters into this. Any commits?

Gravity and the direction of light (which is a kind of disturbance to the electric field) do affect the directions that branches grow in, anybody can verify this with a pot plant. (Unless you live somewhere like the ACT, best not that kind of pot plant..) So it's hardly surprising that branches avoid growing into the shadow of nearby trees.

Now sure, plants do communicate in some ways (chemicals from one stressed plant can induce a nearby one to grow thicker bark), but that doesn't seem necessary here. The above paragraph isn't contradicted by the fact that branches also obviously have fine structure, and various features determined by their genetics. Also, if you really believe "branches will [..] never touch each other" go listen for the squeaking (in a bush of eucalypts) on a moderately windy day.

 

[thedore]

I live in New England.