Sustainability is meeting the needs of the present generation without compromising the ability of future generations to meet their needs. Notice, however, that this definition focuses on needs and not on flourishing.

Because most people want to prosper and not just survive, discussions of sustainability often morph into discussions of “sustainable development.” Sustainable development refers to a positive rate of change in the quality of life, such as well-being, of people based on a system that permits this positive rate of change to be maintained for an indefinite period of time. In other words, sustainable development pursues growth that does not compromise the future.

Originally, discussions of sustainability surrounded the environment. As these discussions expanded, they naturally moved to include economics. Most recently, these environmental/economic discussions have begun to include a societal element. The best discussions of sustainability include the planet, the purse and people.

The municipal forest includes all urban trees on public lands as well as all trees along streets within the right-of-way. Municipal forests can be evaluated along planetary, financial and societal lines. For the following reasons, municipal forests should be considered as fundamental to all discussions of sustainable development.

• The municipal forest brings health to the environment. In addition to other well-known benefits, trees sequester carbon. Simultaneously, urban trees provide cooling, which together reduces urban heat islands. In terms of weather, trees provide a weather buffer for both hot and cold temperatures. Trees also reduce erosion and manage stormwater.

• The municipal forest pays financial dividends. Not only do trees aid in reducing heating and cooling expenses, trees also preserve the length of asphalt. Because of the health benefits for humanity, trees can reduce healthcare costs. In business terms, research shows that customers will drive further and spend more time and money in well-treed retail districts. In terms of home values, trees can factor five to 15 percent of home values.

• The municipal forest provides for societal well-being. Planting trees increases community involvement. People come out together to see their trees. Crime is, therefore, reduced in these communities with heightened natural and communal awareness. Additionally, not only is the environment improved with trees, an improved environment improves society. Studies have shown, for example, that hospital patients recover more quickly in rooms with windows facing trees. From a different angle, studies show that well-treed streets are safer because traffic slows compared with untreed streets.

The University of Scranton is a concrete example of this concept. The university has contributed to the sustainable development of its neighborhood with its Mulberry Street renovation. On the one hand, the varied treescape functions in stormwater and traffic management. On the other hand, Scranton’s Hill section will see long-term benefits from the university’s investment in the natural and aesthetic character of this central thoroughfare.

Joshua Arp is an ISA-certified Municipal Specialist, a Clarks Summit Tree Commissioner and an operator of a landscape maintenance business. He can be reached at