Ed: I did a little on-line research and came across one interesting article that I could understand to allow me, or reminded me, that I could come at this logging effect on white pine genetics from a different angle, one I am embarrassed that I didn't think of before. It actually ties into something I learned from reading about provenance trials of Norway spruce years ago, and a conversation I had with a person in the UK who is very familiar with Norway spruce populations.
When I wrote my post about the idea that selective logging (maybe two or three times is what I had in mind) could have affected the genetic make up of the subsequent forest, I was of course thinking of a specific place. this could cause some genetic drift, but as you point out, not very substantial. What I am reminded of now is that different areas in the same area rather close to each other can have white pines of substantially different genetic make-up. I came across an article that talked about this in Ontario. One conclusion from this article was a bit like what I reported before about the Clover Run pines in WV--that is that when selecting seed to plant in a given area, it is not necessarily the seed from the same area that would be best. There is a very dramatic example of this in Scandinavia with Norway spruce, caused by having the area being repopulated after the most recent ice advance by Norway spruce migrating from two different directions. Of course after the most recent glaciations in North America, an uneven retreat of the ice may have resulted in an uneven repopulation by white pine of various areas. But in a way the study (which I admit I read only the abstract for) is surprising, given that white pine pollen is spread by the wind, which might suggest that populations over a wider area could be more homogeneous. With Norway spruce, a provenance trial done by Dr. John Genys many years ago seemed to suggest something similar with Norway spruce. Seed collected from areas near each other produced clearly different results. Of course, the seed could have been collected in different ways (which I won’t go into now), which perhaps could account for the differences. Also, the provenances of Norway spruce in Europe are somewhat muddied by having NS planted from seed collected in one area and then planted in another for hundreds of years. Anyway, here is what I think MAY be a possibility here. In the past there were specific areas that had especially tall white pines—tall because of a “superior” genetic strain, superior even to those growing in areas not that far away. Then as civilization/logging came, those populations were not selectively logged, but these stands of especially tall trees—and their specific collection/arrangement of genes—were entirely wiped out. All the pines were cut, and the land in that area did not grow back with white pine trees for one reason or another. There may have been some "superior" strains of white pine that simply became "extinct." Of course what I am talking about here would not be an effect from specificlly targeting areas with the tallest pines (as with specifically targeting the best trees to cut in a stand) and then cutting the pines and converting the areas to other uses. The process would be rather random, except to the degree that the best stands would be the most attractive to cut first, whether on the best sites or not. Of course, the richest sites would naturally have been converted to farming. From what you understand, can this make sense? Of course, although I am trying to support the idea that white pines taller than what we now see could have once existed, I am still “skeptical” about 250 foot white pines. I am just trying to explore all possibilities, all possible explanations. --Gaines McMartin --------------------------------------------------------- On 1/6/10, Edward Frank <[email protected]> wrote: > Gaines, > > Basically, No you are incorrect. In order to change the genetic footprint > of the species you would need to cut only those superior trees, kill all of > their offspring, and not cut any of the poorer quality trees, over the > course of tens of generations. Essentially all of the big trees in a stand > were cut, so there was no selection. The genetics of the big trees having > been there for hundreds of years would be represented in the smaller trees > that were too small to cut. Even after the initial trees were removed, > those trees with superior genetics would tend to out-compete those that were > the offspring of poorer trees and would dominate the second growth forest. > If you did this a hundred times you would not get a genetic drift, .unless > you were targeting a specific genetic definable trait while at the same time > leaving all of the other competing traits intact, People have suggested > this before, and the idea is simply wrong. You can't change the genetic > footprint by cutting all of the big pines, and it is unlikely that targeted > high grading would even have a noticeable effect without dozens of > generations of repetition. There are specific environmental effects that > can cause a genetic drift, but not generic logging operations. > > Ed Frank >
