Redwoods I know

I live in Berkeley, Ca. which part of the current range of the Coast Redwood ( Sequoia sempervirens). The current range is from just south of Big Sur, Ca. to just over the border into Oregon, from the coast to 60 km inland and from sea level to an elevation of 1 km. I've got one growing just 2 doors down from house.

In the distant past, before the beginning of the last Ice Age, the range was much larger. There are large stretches of the west coast of this continent the Coast Redwood should be growing. The 3 things that limit the redwood from growing are:

  1. Rainfall: The redwood needs a lot of rain to grow. Myers Flat, Ca. in Humboldt county, which is the heart of redwood county, gets 250 centimeters a year. There are many places on the west coast that get that much rain. Fork, Wa. gets 300 centimeters of rain a year.

  2. Temperature: The Coast Redwood likes a mild climate, not too hot and not too cold. Myers Flat does not get much over 90 in August and rarely gets down into 20's overnight during the winter.

  3. Soil: Andalouval soil is prefered but the redwood will grow and thrive in any sort of soil as long as there is good drainage. It really does not like a heavy clay soil.

Given all that, there is no reason that the Coast Redwood could not thrive all along the Pacific coast from Big Sur to the Olympic penisulal. It is my therory that the reason the redwoods don't grow any further north than Northern California is because of the geogorphy and the Ice Age.

During the last ice age the glaciers advanced down from the poles. The Cordilleran Ice Sheet covered the Puget Sound. The distance from Olympia, the appromate southern reach of the glacier, to the California border is about 570 Km. It is a safe assumption that the area near the glacier was very cold, too cold for redwoods.