Ask a child with paints to make a large picture of a city look ecological. Splotches of greenery will be added around the buildings, perhaps with some birds in spots. Similarly, have the child make a remote natural valley look lived in, and some charming awkward houses will be drawn in the picture, along with people and a street. Of course no one pretends that real ecology is represented in the first image, or serious design and planning in the second image. Rather this is art, which sometimes even appears on huge highway billboards or the sides of trucks as green marketing.

After introducing regions, land planning, and socioeconomic dimensions in previous chapters, we are now ready to focus on natural systems, especially ecology. This challenging central topic for understanding and planning urban regions is introduced along with greenspaces, where natural systems have the potential of thriving long term.

Five major topics, which progressively build on each other, are presented: (1) ecosystem, community, and population ecology; (2) freshwater and marine coast ecology; (3) earth and soil; (4) microclimate and air pollutants; (5) greenspaces. Important themes and overlaps among the topics will become evident. The first four, even the fifth, are key foundations and motifs throughout the book.

Natural systems are effectively a scientific way of saying nature (Chapter 1). Rather than presenting the science of natural systems in their separate disciplines of soil science, hydrology, meteorology/atmospheric science, ecology, etc., the salient principles are nicely integrated through the lens of ecology.