i have't a clue why sea island(s) are better.. WAG's would include cool moist breezes (off shore breezed at night) which add moisture and help the plant 'fight stress', or just general level of humidity (i am guessing high humidity would be good, but could lead to mold of some sort, but sea island would have breezier air, providing humidity with out 'stale air', and so plants grow (as result of humidity) but don't fall prey to mildew..)

the same might be true of egypt.. (breezes help 'settle' egypt.. they tend to be southernly.. so with sails, boats could go down stream, and current (of the nile would move them upstream)--so the country (the settled part!) became long and narrow along the nile, but with an easy way to travel, it became one community/country.

The shore(NJ)/the beach(NY)--what ever its called(in VA and Carolinas--is a still a popular summer getaway. Most of the east coast has a pattern of cool moist breezes at sunrise/sunset, that make wonderful places that don't require A/C to be comfortable. (maybe cotton likes the weather too?)


my other obsession