[Farael]

Not to mention that starting a forest-fire is a bit harder than

flaming-arrow POOF!!! fire.

Sure, there is the potential for a forest fire from things like a cigarette butt but it takes some specific circumstances (and some bad luck) for the fire to catch on and become a raging inferno.

For example, living trees are not very combustible... anyone who has tried breaking a branch off from a tree and tossing it into a camp-fire will see it. While trees can (and do) burn, it takes some serious heat to ignite them. In forest fires, often it's the fallen leaves that ignite first... and over the years a rather impressive amount of them may pile up, thus leading to enough fire to ignite trees, and then it spreads even more wildly. I don't know if the elves cleared the fallen leaves (after all Mallorn DID loose their leaves, but that happened during spring, when the flowers were blooming) or if perhaps they started smaller, controlled forest-fires (just like they do nowadays) to make sure that there never is enough debris left to start a real fire at an inopportune time.

Then there's the issue that, for the fire to be a viable militaristic alternative, they have to ensure that it actually catches on... which means, not only firing an arrow (or rather, a few hundred) or starting a few hundred fires, but also making sure that no-one is putting them away. That is hard to do in the middle of a battle, or with elven arrows whistling around you.

So, the way I see it, fire wasn't a viable alternative, since:
*They could probably not get close enough to start it
* If they managed to start a fire, they couldn't stay around to see if it caught on or not, as the elves were quite likely to show up (annoying elves)
*If they managed to start a fire, and then somehow it caught on, they still couldn't trust that it'd burn Lothlorien down. The spread of the fire depends on both the terrain... and wind.
*Finally, and perhaps most importantly, as it has been mentioned before, it is likely that some sort of "supernatural" (or rather, elven, who are VERY natural in Middle Earth) force was protecting Lothlorien.

Now, a dragon may have worked, as it could