Why destroy Laketown's bridge?

[Ibrîniðilpathânezel]

After following this thread with a mixture of amusement and bemusement, I felt I had to toss in my two cents.

I've been an illustrator, and a fiction writer. And I have to say, it's often extremely difficult to put down on paper (or canvas) an image of what one sees in one's head. I suppose that if I had devoted more time to drawing than to writing, I would be better able to render the illustrations, but one does have to make choices. So I went looking, and came across this in Tolkien's letters (#27, to the Houghton Mifflin Company, from 1938, apparently in reference to a request for JRRT to supply drawings of hobbits for use in a future edition of TH):

I am afraid, if you will need drawings of hobbits in various attitudes, I must leave it in the hands of someone who can draw. My own pictures are an unsafe guide.

And, from letter 280 in November 1965:

I do not recollect when the rough sketch of the Death of Smaug was made; but I think it must have been before the first publication, and 1936 must be near the mark. I am in your hands, but I am still not very happy about the use of this scrawl as a cover. It seems too much in the modern mode in which those who can draw try to conceal it. But perhaps there is a distinction between their productions and one by a man who obviously cannot draw what he sees.

Between the two comments (and doubtless others, I was looking specifically for references to either Smaug or Lake Town), I think it's fairly safe to assume that Tolkien did not consider himself a very good artist, and that he had difficulty rendering accurately things that he imagined. It's a tough job. I do think that his art gives the reader a good feel for how he envisioned the things he created in his imagination, but they are more impressionistic than realistic, and I believe he acknowledged this. He also remarks in the first letter that his illustrations in which hobbits are shown are largely "general impressions," and that "the very ill-drawn one in Chapter XIX is a better guide," the "hobbit in the picture of the gold-hoard, Chapter XII, is of course (apart from being fat in the wrong places) enormously too large." Which it is, else Smaug is mighty small for a dragon. All of this, to me, points to one thing: don't use Tolkien's illustrations as hard evidence of how something looked; go with the written story.

That said, it seems to me that cutting the bridges when one is about to be assaulted by an enemy capable of a nasty aerial attack is rather puzzling -- wouldn't that be cutting off one's escape routes as well? But the passage davem quotes, which shows us Smaug's reaction to the cutting/destruction of the bridges, does seem to indicate that the dragon would have liked to have used some sort of ground (or bridge ) attack. Why this should be so... I certainly can't say, though Smaug does appear to use both methods, else he would not be ensconced in the Lonely Mountain, sitting pretty on his hoard with all the Dwarves driven away. Perhaps he had it in mind to frighten the folk of Lake Town, then set up residence in it until he had driven all the humans away. Or perhaps even his fiery attack is more effective on the ground, because of the closer range. I surely can't say, and it's been a while since my last reading of The Hobbit. But I would agree that it does seem rather a peculiar situation, especially on a cursory examination.