For instance, rather than burning your fallen tree leaves in the fall, allowing them to decompose to mulch and then nutrient rich soil, will reduce or eliminate your need to fertilize in the spring. The mulch will slow soil evaporation, reducing your irrigation needs. When the plants absorb the nutrients, they they'll be much stronger and better defend against pests, reducing your pesticide needs.
Did you ever wonder what happens to all those Christmas trees that get thrown away each year? Traditionally, most got thrown away each year along with all your gift wrappings. Now days there are many places where you can take your trees to be shredded and turned into mulch. Here's a great video showing the process and benefits of Christmas tree mulching.