Ed: Another way to look at this idea, which I am sure you understand, is to talk about "the forest sucession." For those reading this and not familiar with the idea, forests go through stages of development, starting with the more intolerant pioneer species, and then over time having those replaced by trees which reproduce and grow better in the company and shade of other trees. and then finally being composed mostly of the species that are the most shade tolerant. Now this depends on the site. On some sites an oak forest will be climax, on others over time it will be replaced by sugar maple and beech, etc.
White pine forests on some sites are a more or less early stage in the forest sucession. On the abandoned farms in Nne England it is a pioneer species, and over time will be replaced by sugar maple and beech. It is the similar with tulioptree.. Of course natural events such as fire, outbreaks of disease, can remove climax species and return the forest to a composition more like the earlier or middle stages of the forest sucession. And, here is where I am going with this--many of the species that are a part of the earlier or middle stages of the forest sucession are the trees that grow the tallest--white pine, tuliptree, and some others. Hemlock can grow very tall, but is a climax species. But most of the early sucession trees grow taller than do the climax species. Analyzed this way, your idea is exactly right. And, if some isolated specimens, or patches of the earlier sucession species remain, they are not growing among their peers, encouraged by competition to grow as tall as possible. These "remnants" from an earlier stage of forest succession will often be emergents, and not grow so tall. White pine emergents are a familiar feature of the New England landscape today In some cases, most famously with the redwoods in CA, the climax forest is made up of the species that also grows the tallest. But, contrary to some opinions, redwood may not always be climax. Over a good part of its range it can over time, if the forest is undisturbed, be replaced by western hemlock. But I digress, as is my habit. --Gaines ------------------------------------------------------------------------------------------------ On 1/12/10, Edward Frank <[email protected]> wrote: > 3) The third idea was that the circumstances of how the growth of the grove > was initiated would play a role. There might be a difference in species > composition and competition between those groves started from smaller > openings within a forested setting, and those formed from a large scale > disturbance such as a major fire or large scale blow down. The part left > out of this idea was that the first generation after a large scale reset > perhaps could grow taller than subsequent generations of replacement trees. > This is similar to the second idea above, and both could work together. The > difference is that in the second idea the second generation shorter trees > may reflect an adaptive genetic component favoring longer lived trees, while > the third idea postulates that different initial growing conditions may be > reflected in different heights of trees. Again this is just speculation on > how things might work, rather than interpretation of data sets. > > I an case, whether the ideas are valid or not, they do provide a different > approach to the question. > > Ed Frank >
