Tree Height Limitations   edward coyle
  Jan 05, 2004 14:25 PST 

Hi Lee,

Forgive my ignorance, but I am trying to understand why, if the root
constriction idea is true then how is it we have several species(3-4) in
stands in the west which far exceed 200'. My understanding is that the
redwoods obtain a good deal of their moisture from roots within moss mats in
the canopy negating the need to pump it up 360' or so. I don't believe that
is the case for the other tall ones.

As a second part to this, why don't we have 260' white pines in the
Smokies? It is wet and rich, and there are valleys. Genetics?

I dare to have a third part, With the water need filled, why don't we have
400' redwoods? Do they grow above the upper limit for moss, or the fog

Sorry to ask so much, but you got me thinking.

Tree Height Limitations
   Jan 06, 2004 07:32 PST 

Let me answer two of your questions

It is true that canopy soils and leaf absorbtion of water are two methods to reduce water stress but there are always times during drought when the trees must use their full height to get their water. This is often when tops die back a few meters. The current limit of height is not a genetic one, it is an environmental one. During the mid 90s we saw many tall trees die back or grow slowly. The last few years have been kind, however, and we have seen some of these tall trees growing 20-30 cm in a year. The tallest trees are in Rockefeller Forest (86 trees over 107 m) which is an inland site that receives very little fog during the summer. The environment at the tops of these trees is very similar to the oak savannas growing on the nearby hills - HOT!