Posted: Sun Feb 10, 2013 4:12 pm
by KoutaR

I agree that colder climate is a reason for the inferior growth rate of redwood in the UK. But as I said, I doubt the fog explanation. What would be the mechanism making fog so important? Fog is actually only a type of precipitation. Fog condenses on the leaves and drips down as liquid water. In addition, redwood can absorb a limited amount of water directly through leaves. The fog drip is very important in Californian summer as there is almost no rain, but why would fog be needed if there is plentiful summer rainfall like in western Scotland for example.

The claim, that fog is crucially important for redwood in all the climates, can be read from some sources, and it is possible that fog has an influence by reducing the atmospheric water stress, but I think the Rotorua example disproves it. Instead, I feel that it is rather a "romantic" idea: the tallest tree of the world needs the unique fog of its homeland and does not do well without.

But I am not a redwood specialist.