Minecraft wiki entry for Old_Growth_Taiga, associated text: The old growth spruce taiga variant resembles the regular old growth taiga at first glance, with the main difference being the shape of the giant trees. The giant trees in old growth spruce taigas have leaves surrounding much more of the tree trunk, the larger amounts of leaves increase the chances of saplings dropping when these trees are cut down, leading to easier sustainability. This variant is also slightly colder than the regular biome, which means that snowfall starts at layer 160 instead of layer 200.