Tim, I always enjoy reading these historical accounts, whether they are deemed accurate or not. If you come across more, please post them to the list. I like the response regarding genetics as well. I must comment however when he talks about some variations have no specific benefit. Well - there might be some examples, but looking at things from the perspective of paleontology, there are very few genetic variations that do not have some adaptive purpose and if they have an adaptive purpose, then they are selected for or against. Things that might not have a "purpose," if I were to postulate that left or right handedness did not have a purpose, then the degree of variation between the two variable opposites tend to be minimal so that selection would not prefer one to the other.
Tree height has a very distinct purpose and is selected for dependant on the particular environmental conditions. Therefore the height parameter in one area of the range is different than in other areas of the range. Trees in that portion of the range fall within the heights genetically selected for in that region. In other cases the genes for a variety of different conditions are all present and environmental conditions turn one set of genes on and another off, dependant on conditions. An example is a fish in some Mexican caves. When found in darkness in the depths of the caves, they do not grow eyes, while the same species in surface pools do grow eyes. Parent that are eyeless will spawn eyed fish if moved to the light, and eyed parents will spawn eyeless fish if they are moved to the dark. I don't believe that there is enough variation in genetic height potential to grow a 300 foot tall tree in New England. The other consideration is one of environmental conditions. Overall tree heights seem to correlate with latitude, taller trees are more southerly and shorter trees are found more northerly. I wonder also about weather conditions. The tops of many of the taller trees do not seem to be stopped by reaching a growth limit, but rather a point at which the rate of breakage under the weather/climatic conditions equal the rate of growth. This is especially true once the trees emerge from the generalized canopy height. So perhaps tree height is not only limited by their own genetics, but limited indirectly by the genetics of the trees with which they share the forest. A tree growing among taller species may grow higher than a tree growing among shorter species. Anybody have any comments? [If so maybe we should start a new subject] Ed Frank Check out my new Blog: http://nature-web-network.blogspot.com/ (and click on some of the ads) -- Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected]
