There is, absurdly, a page of reviews of the ancient bristlecone pine forest on Yelp; this strikes me as substantially more bizarre than there being a review of a Burger King, even though one might reasonably note that at least the forest is something significant. There simply seems to be something funny (not exactly presumptuous, but that's in there too) about reviewing a visually somewhat unimpressive but simultaneously mind-boggling stand of squat trees (and then giving it fewer than five out of five stars! Though that is not the important part). "Being in the presence of a tree that was not only alive but had been alive for around two thousand years when Homer was in short pants was amazing, A+++ WOULD BE HUMBLED AGAIN." 
Perhaps posting to Yelp is really no stranger, or even no different, from enthusing about the place to one's friends, and certainly I've done that. But it seems—each seems!—a weirdly inadequate response; describing the experience as "peaceful" (though it is) is an inadequate response; describing it as surreal or unsettling (though it is) is an inadequate response.
Part of the effect is doubtless a product not just of the knowledge that these trees are extremely old, but also the environment in which one encounters them: a windy drive up a tall hill (they are, of course, in a pretty isolated area) to an exposed area where the trees, which are surprisingly short, and surprisingly bare, sit in inhospitable earth. Near the area where you park (where we parked, when I was there, something like five years ago now) there's a bunch of sagebrush—it's downhill from the road, the pine trees uphill. There appears to be nothing else in the area with the pines than pines; there are lots of small ones, no more than six inches tall, for instance, which are probably older than my grandparents. It's all very disconcerting and one doesn't know quite how to take it. It seems to call for something.
It gets worse: while on the one hand a clonal organism seems like cheating in the "oldest living creature" competition, the idea of this colony of aspens is distressing in its own way: a going concern for 80,000 years, occupying 43 hectares. 43 hectares of nothing but yourself—and there are apparently colonies in Utah of over 80 hectares—how oppressive! It must, one wants to say, be so boring. And then there's this:
If its postulated age is correct, the climate into which Pando was born was markedly different from that of today, and it may be as many as 10,000 years since Pando's last successful flowering.
One can hardly imagine.
 Relating the age of the trees to things like when Homer lived is one of those maneuvers that you need to engage in, which take one away from the thing itself, in order to enable it to have its proper effect. Analogy: Arthur Dent, on learning that the Earth has been destroyed, finds himself unable to react to that knowledge at all until he frames it in terms of the nonexistence of some fast-food chain or other. (I think that's it.)