what should scientists consider when studying tree rings to understand the variation in the local climate?

The wider the ring, the more warm and wet the climate is, the thinner the rings, the more cold and dry the climate is.:)

phaneritic textures in which phaner means visible so phaneritic textures are standard of impertinent volcanic rocks. these rocks crystallized gradually under the surface of earth. when the magma cools deliberately then the ores have chance to develop and produce long crystals.