Evaluate the other options: High temperatures are not characteristic of the tundra biome, so trees drying out due to heat is not a valid explanation. Additionally, the tundra does not receive excessive rainfall; it is actually one of the driest biomes. Lastly, while tundra soil may have some acidity, it supports plant life such as mosses, lichens, and shrubs, so this is not the primary reason for the absence of trees.