A redwood, like any plant, needs air, water, dirt, and not to be cut down!! (I’m not sure of the 4th need, maybe that’s actually it.)

Plants need air like people do, altho’ for exactly the opposite reason. The giant Sequoias of California need air to get carbon dioxide from, which is what allows them to live. They take the sunlight they get from their leaves, and mix or transform the carbon dioxide with the water it gets from the ground, and makes the chlorophyll it needs to live, and also gives off the oxygen that people and animals need to live. The animals then breathe the oxygen and give off carbon dioxide which trees use to live, etc.

I think the 4th need is sunlight. Which provides the energy for the plants and even animals to live.