This second edition reflects a marked change from the first edition. Both share the same basic goal – to describe how terrestrial vegetation affects weather and climate. The first edition embodied three overarching principles: enduring relevance; a desire not to write a modeling textbook; and application of scientific principles to improve the quality of our environment through landscape design and urban planning. Joseph Kittredge's book entitled Forest Influences, published in 1948, is an example of enduring relevance. The studies he presented and the units of measurement are dated, but the concepts of how forests affect the environment are as relevant today as they were six decades ago. Mathematical models and the numerical methods to represent physical, chemical, and biological processes can quickly become dated, and in the first edition I chose to include a limited number of mathematical equations only to illustrate basic concepts. Many of the principles of ecological climatology are applicable to the built environment. Changing land use, like global climate change, is a grand unplanned experiment with unknown social and environmental consequences. Unlike global change, land use occurs locally in our communities. It gives substance to environmental issues at spatial and temporal scales to which people can see and respond; we see these changes happen in our communities, often over a period of a few years.

This second edition strays somewhat from these guiding values. It contains many more mathematical equations, but only to illustrate concepts and not with the intent of describing the state-of-the-art in model development.