What is Environment?

When reading 'Land and Environmental Art',1983, Phaidon; I was interested in this passage from Kenneth Friedman - Words on the Environment.

"What is the environment? What does the word environment mean?

Webster's Collegiate Dictionary (1943) defines the word environment - 1. act of environing; state of being environed. 2. that which environs; surrounding; specifically the aggregate of all the external conditions and influences affecting the life and development of an organism, etc; human behaviour, society, etc. The word environment is related to the sense of surrounding or of overall placement and situation.

(1969) 2a. the complex of climatic, edaphic and biotic factors that act upon an organism or an ecological community and ultimately determine its form and survival. 2b. the aggregate of social and cultural conditions that influence the life of an individual or community.

With the growth of concern for the biosphere as a political issue of the movements identified with 'ecology and environmental activism', the term began to be inappropriately and almost exclusively applied to 'nature'. This misunderstanding bound up in media-influenced slippage of meaning should be evident in the fact that it is the total environment (social, political, economic, cultural and natural) that affects our relationship to 'nature and ecology', as it has come to be understood. Given that human beings and their culture are in the largest scale of description simply a form of life moving about and acting on the surface of the planet, the drilling of an oil company is as much a part of the 'environment' as a tree.
It is the decisions that human societies make that control their uses of nature and of the planet."

My Greenbelt Project has brought up many questions and contradictions, I think this is common in life in general. I have observed the time and effort required by volunteers to 'tree plant' a site; and at the same time the speed at which bulldozers can remove mature vegetation. Yet we all need homes to live in, decisions of where and how need to be made.
Works developing from the Greenbelt Project reflect on my observations, exploring the role humans play in shaping their surrounding environment. I am interested in where a balance may lie, what is the middle ground? Is the middle ground anywhere near sustainability? We all have a part to play and I imagine contradictions to deal with.