By gregladen on December 17, 2014. A new study has recently been published that looks at the ecology of bristlecone pine growth at Sheep Mountain, and the tree ring signal those trees produce, at high altitudes in the Southwestern US. This is important because tree rings are an often used proxyindicator for reconstructing past climates. Those who keep track of the paleoclimate research will recall, for example, that tree rings were one of the proxyindicators used by Michael Mann and his team in constructing the famous "Hockey Stick" graph showing a dramatic increase in the Earth's temperature since the onset of industrial times, when the instrumental record (of the last century plus) is put in context of previous centuries. Since then, tree rings have played an important role in past climate reconstruction.