Those look like olive trees? Grasses and agaves -- a drought-tolerant alternative to lawn in hot, dry climates. Oehme Van Sweden drought tolerant demonstration garden with grasses and agave at Cornerstone.
In my yard: Cottinus coggygria ‘Royal Purple’ . considered a tree but I grow it as a shrub, whacking it back to the ground each spring to keep the height lower and make it bush out. easily grows tall in a season. glows purple with the sun behind it.