There are many reasons to include trees in an urban landscape:

 

Trees help offset your carbon footprint

 

Find the value of your tree

 

Some basic information on pruning

 
This pamphlet is essential reading for anyone involved in construction around trees.
Tree Protection on Construction and Development Sites, A Best Management Practices Guidebook for the Pacific Northwest, 2009
 

The dangers of tree topping (and why you should be suspect of a company that offers this service)

 

Besides their obvious benefits like shade, bird habitat, and stormwater mitigation, trees can really change the feeling of a place, making it much more inviting and pleasant to be in as well as increasing property values. I recognize these benefits and strive to preserve and care for existing trees. When a tree just can’t be preserved and needs to be removed I donate funds so that two new trees can be planted in our National Forests through the Arbor Day Foundation. Or I will personally plant two trees per one removed on a homestead in the Skagit Valley North of Seattle.

 
Some more benefits of trees:

In the continental United States, carbon sequestration provided by urban trees alone is estimated to be about 25 million tons per year,1 which is equivalent to the carbon emitted by almost 18 million cars annually.2

Shade trees planted in parking lots reduce evaporative emissions of volatile organic compounds (VOCs)—precursors to ground-level ozone—from parked cars.3

In the Chicago area, urban trees filter an estimated 6,000 tons of air pollutants each year, providing air cleansing valued at $9.2 million.4

Once established, native plants can save time and money by reducing maintenance and resource requirements.5