The Redwood Forest biome is a fairly flat biome with some slight low hills and large Redwood Trees growing around.
The Redwood Forest has many Redwood trees growing in it, some large enough to build a house into easily, Others only with a one block wide trunk and a 3x3 stump. There are smaller, low lying oak tree "shrubs" about 2 blocks high scattered around. Blue Orchids, Berry Bushes spawn in this biome and so do Snails.
Survival is easy with the amount of wood and shelter. Passive mobs do spawn within the forest. Most of these forests have many low hills inside the biome, this makes building large flat areas hard, and may also make them hard to navigate through at times. The sky is vanilla.
Before 1.10.2, the single redwood trees didn't exist and before 1.8, redwood trees were much duller and had a different shape.