Bristlecone Pines, have adapted the best root system for the environment they have to survive in. In order to maximize water uptake, the trees have a very branched shallow root system, usually only 2-7 inches below the soil's surface. The shallow root system allows for the tree to survive in the very rocky soil. The average precipitation per year in the White Mountains is less than 12 inches, and most of that is from snowfall, so the trees must be able to get as much water from the snow as soon as it starts to melt, and they do this by having a shallow branchy root system. The soil is derived from dolomite or limestone that is light in color, more than 50% rock, and allows for a large amount of water storage.(http://eol.org/pages/1034948/details)The incredibly extreme environment that these trees live in makes it very difficult for disease or rot causing fungi to live, this is good for the bristlecones, but it also means that they don't have any symbionce with michorizzae or nitrogen fixing bacteria, because it cannot survive in the harsh conditions of the White Mountains. This also means that there is no competition for the Bristlecones to get water or nutrients from the soil, so it is able to obtain them that way, just very very slowly. Which is why the Bristlecone Pines can grow so old. (http://www.pbs.org/wgbh/nova/methuselah/long2.html)
Cool root systems! But I am unclear on how a soil that is >50% rock can store a lot of water… usually one problem with rocky soils is that they drain quickly. Interesting that this plant does not have any mycorrhizae…. That is pretty unusual. Where did that information come from?
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