I concur when you aver! Gary
On Nov 14, 2009, at 10:00 PM, Bob <[email protected]> wrote: > Ed, Tim, Gary, Don, et al, > > White pines that rise significantly above the surrounding > canopy are at extra risk from wind events. So our mythical 300- > hundred footer would have had to be in an area that received plenty > of protection from the wind. Additionally, it would have needed to > be in an area that possesses the right kind of soil for tall white > pines (sand-silt), receives sufficient moisture, etc. But even if > these conditions were met, what would be the incentive for a pine to > continue growing to eventually reach such an improbable height? > Competition? White pines reach their greatest heights in stands > (with rare exceptions). So our mythical pine would have likely had > company. The 300-footer would have had 250-footer companions. The > scenario becomes wildly improbable. > > Bob > > > Sent from my iPhone > > On Nov 14, 2009, at 6:26 PM, "Edward Frank" <[email protected]> > wrote: > >> 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] > > -- > 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] -- 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]
