Jack, Ed, ENTS: A few more thoughts/responses about white pine growth/measurement:
As for the capability of people 200 years ago to measure the heights of standing trees—that is unquestioned. The main question is “did they?” Often the reports of these very tall trees came from loggers, who, although I have worked as a logger at various times in my life, and believe at its best it can be a noble profession, I have not seen them much interested in taking precise measurements of any trees before they cut them down, nor in measuring trees after, especially when the top of the tree shatters and it would have to be carefully reconstructed to get an accurate measurement. I would think that if some one with a “scientific” mind did careful measurements, these would have some down to us in a quite different way than in the style I have seen them, i.e. “early lumberman reported that….” etc. One thing I have seen in reports from early lumbermen of the trees they cut down, is a focus on data such as, “at a height of 120 feet the tree had a top diameter of 20 inches,” or some such thing. They report this way because they are interested in how many logs the tree has produced. So here is what MAY have led to some of these reports. If a gigantic white pine is 200 feet tall, and at a height of 160 feet still has a diameter of something like 20”, someone could read that report and say, “Oh at 160 feet the tree was still 2” in diameter, so then it must have been 250 feet tall. Yes, many younger white pines have a rather gradual taper. A tree 20” in diameter in a young forest can be 100’ tall. But with very old trees, the taper at the top can be very, very rapid. A very old white pine could have a diameter of 20” near the top, and be only 40 feet taller, or perhaps much less. As for amount of light required—the amount of crown exposure above adjacent trees—for white pines to make maximum growth: This is an important factor. Tree crowns are usually classified by foresters into basically 4 crown classes: dominant, co-dominant, intermediate, and suppressed. Added to this I believe should be “emergent.” A dominant crown has a good portion of its crown exposed above the surrounding trees, but this does not require that the crown be “emergent,” meaning far above the surrounding trees as many white pines in NE, especially on ridges where the hardwoods they are often mixed with, cannot really compete. The next crown class, the co-dominant, is a bit lower in relation to the surrounding trees. Here the crowns of a group of trees are more or less equal in height, but they do have good space between them, and they receive plenty of direct sunlight. An issue here is also grown length. A dominant crown will be somewhat longer—extend further down— than a co-dominant tree. The next crown class is the intermediate. Here the tree is closely pressed on all sides by other trees. In some cases the crown can be at nearly the same height or more usually somewhat lower than those of its competitors. The crown is narrow, and depending on the species and the kinds of trees it is competing with, it can be either rather short, or rather thin foliaged. White pines are classed as a moderately intolerant tree, meaning that they require more direct sunlight than a tolerant tree. This means that to grow well in height, a white pine needs to be in either a dominant or a strong co-dominant crown position. To grow well in diameter, it should be in a dominant crown position. Norway spruce is more tolerant than white pine, and therefore can grow better in an intermediate or marginal co-dominant crown position than white pine. White pines that are in an intermediate crown position, or perhaps also in a marginal co-dominant crown position, usually will lose vigor and be overtopped. Well, sorry, I see I am giving too much background here. The basic answer to the question about the amount of crown exposure a white pine needs to grow the tallest is dominant or strong co-dominant. Emergent crowns get so much light that a great deal of the growth energy of the trees goes into creating a very large spreading crown with heavy branches. White pines, and most other forest trees grow tallest when they are in competition with other trees as in the usual dominant or co-dominant positions. Finally, occasionally a white pine tree growing far above the surrounding trees did not in fact grow as an emergent tree, but grew in a forest with other trees in a dominant or co-dominant crown position, and then, either because the surrounding trees were removed, or died for some reason, this tree will stand in a very, very strong emergent position. That does not mean that it grew to its present height as an emergent. --Gaines McMartin
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