Isotope studies have shown that almost all oceanic moisture falls as rain within the first 150 miles from any coast. All the rest of the rainfall on land is recycled water, evaporated from the land and the vegetation on it. Bare land such as sand or rock desert can only evaporate a small amount of the water before it runs off back to the sea. Farmland will hold a little, but the best reservoir is a forest.
A single oak tree may have ten to thirty acres of leaf surface, so forests are the best thing for ensuring that inland areas get rain. In fact, to destroy the Amazon forest, all we need to do is to chop down the first 200 miles, and we’re busy doing that now.