I don't know of any studies showing specifically that bristlecone pines can't survive a year under thousands of feet of water, but I do know that evergreen trees don't survive well with their roots in soggy ground. Bristlecones like dry conditions -- that's why they do alright in the harsh, dry conditions 3-4,000 meters up in California's White Mountains.
Their location at such a high elevation is another killer for Flood claims. If someone claims that the White Mountains were there before Noah's Flood, then they have to explain where enough water came from to flood the earth deep enough to cover these mountains, which are up to 4,500 meters high. Same goes for the Andes, Himalayas and other high mountain ranges. The problem is that the oceans contain only enough water to flood the earth to about 2,500 meters, even if the globe were as smooth as a billiard ball. And even if one says, "God created the water", then you have to claim equally, "God made the water disappear". Since even the most rabid of JWs and Fundies don't claim that, but say that God used already-existing water, they have an insurmountable problem.
Alternatively, on occasion the WTS has claimed that all of today's high mountains were formed after the Flood. But that doesn't work either. The White Mountains are essentially thick piles of granite, and granite is notoriously resistant to erosion. It is simply not possible for the White Mountains to have eroded out of the granite substrate in 4,500 years. And even if there were massive amounts of post-Flood erosion going on, it would necessarily prevent the growth of any vegetation at all on the rapidly-eroding mountains, much less allow 4,700 or 9,000 years of growth of the bristlecone pines that has been documented.
As ususal, no matter which way you look at such evidence, believers in a global Flood are screwed.
AlanF