Each region has suites of vegetation that can tolerate the most difficult conditions: drought flood, sand, clay, sun, wind, sterility. Roots penetrate the ground, improving the drainage where the soil is water-logged, increasing water retention where the soil dries too quickly. Leaves convert soil minerals to organic matter—compost the ground, make it looser, richer, moister. Ultimately species that could have thrived in the original harsh conditions begin to grow in the protective shade of this nursery, and gradually a more permanent community replaces the pioneers. … The land will mature, become more productive and rich in its diversity.

This is not true of unnatural plantings. Merely decorative plants merely grow. In time they grow too big, or they die; then someone takes them out and redecorates with others. Nothing else happens. There is no evolution. There is no profit set aside for the future because, for all the money spent, there has been no investment in the land.