Check out THIS thread on this forum about giant sequoia. It is one of many.

Thanks Sam.

I don't know about Giant Sequoia (my Zone 7 climate is much too humid to even consider this species). Dawn Redwoods are hardy into coastal Maine in the East, BUT they don't take kindly to unseasonal cold (or even heat for that matter). They can take the cold within the dormant, cold season, but are less forgiving with the cold (or heat) when it occurs when new leaves are just emerging in the Spring. Being a species natively found only in central China in modern times (in ancient times, they WERE an American tree), they are not as forgiving to the crazy extremes of the North American climate..., which is MUCH more unpredictable (many areas of North America have hard frosts after periods of sustained heat). Asian climates at mid latitude are much more predictable (Winters are cold, Summers are hot and killing frosts, and heat waves, are held in check by the calendar.) I lost a tree a decade ago when the newly emerging leaves (in April) were met with a premature heat wave of temps in the 90's and high winds. Looked like someone took a blowtorch to it.

They grow in southwest British Columbia, Argentina, Australia, New Zealand, Scotland, and ????? They grow really fast in Scotland because of the amount of rain and the moderate weather. In Scotland, temperatures seldom stay really cold or really hot. We saw redwoods and sequoias at Scone (pronounced Scoon) Palace. I think they have Douglas Firs and Sitka Spruces, also.

Sequoia giganteum is limited in many parts of eastern North America due to excessively high summer heat and humidity (especially at night). Just as well, have no more room for trees that wanna be giants, LOL. Arbor, you tree is gorgeous, Happy Holidays!

Other than the heat of southeast NA and the cold of < zone 5a, it's Cercospora needle blight that limits Sequoiadendron in eastern NA. High dew points benefit the fungus but don't directly impact the tree....it's an indirect impact on the tree similar to what is seen in eastern NA with Diplodia tip blight and Dothistroma needle blight on hard pines from the west coast, Europe, and Asia.