Fascinating question!

Redwoods are considered some of the tallest trees in the world. According to the Redwood National Park, the tallest known redwood tree is 379 feet tall! These trees can grow really tall due to the large amounts of rain that falls in the California redwood region (60-140 inches per year), most of which falls during the winter months from November to April. And during the summer months, frequent fog cover further reduces evapotranspiration, or the loss of water from the tree leaves. The redwood region is also a temperate climate, with average temperatures between 45 and 61 degrees Fahrenheit, enabling year-long growth. The region also has rich, fertile soil from the river beds, providing lots of tree food in the form of nutrients. Redwoods also have two features which can be linked to the tall growth. Redwoods have burl sprouts, which is a hard conglomerate of several dormant buds (like a tree branch that has not started growing yet). These burls promote growth on the trees after the tree is injured by fire or breakage from wind. So even when the trees are damaged, they can readily begin new growth. Redwoods also have few natural enemies and grow as groves abundant with redwoods. That helps protect the redwoods from falling down during heavy winds, since all the redwoods growing together act as a built-in wind block.

All of these factors contribute to redwoods having the right conditions to grow really tall. A typical old growth redwood can be over 300 feet tall and up to 16-20 feet in diameter (the distance across the trunk). Most of the oldest redwoods were cut down during California's intense logging period in the 1800's, but some redwoods can live to 2,000 years. Most of the redwoods protected today are between 500-700 years old.