The difference between them is the Pure Sine Wave inverter produces a better and cleaner current. They are also considerably more expensive. You might find it practical to get a small Pure Sine Wave inverter for any special need you may have, and also a larger Modified Sine Wave inverter for the rest of your applications.
Elm Trees can live over 100 years in their natural environment.
Birch trees live between 30-40 years, My favorite is the silver birch tree. Birch trees are not, in the long lived tree range. as are oak or giant redwoods etc , which may live for many hundreds of years, given ideal conditions.