Horn is a communications associate at Casey Trees, a nonprofit that works to make D.C. a little bit greener. The 26-year-old is tasked with getting that message out as Casey Trees tries to increase the District's tree canopy to 40 percent of the city by 2035.

Why more trees?

Trees have a slew of environmental, sociological and economical benefits. They clean our air. They mitigate storm water, which decreases pollution in our waterways. They reduce crime, statistically.

Wait, really?

Yes, really! If you live in an area that's green, that's lush, it encourages you to be outside. More people are outside, and more eyes deter crime. And businesses with trees outside of them have 12 percent more sales. Trees decrease your energy bills because of the shade, and they also block wind in the winter. They're aesthetically pleasing, too. We're a grassroots, community-driven organization, so we do a lot of community tree plantings.

How did we get to a point where we're lacking trees?

Since the '50s, we've had a pretty steady decline in tree canopy, mostly from natural causes. Trees die when they're old. Some are diseased. Like many other American cities, we were hit with Dutch elm disease, and a lot of the street trees died as a result. As the city continues to develop and areas are turned from green space into housing or commercial building, those trees are impacted. We have a tree canopy goal of 40 percent by 2035. Right now we're at 35 percent.

Are certain areas of D.C. more lacking than others?

Yes ?-- in fact we have a ward-by-ward map on our website. Wards 3 and 4, the upper Northwest, have a lot of tree coverage. Ward 6 and Capitol Hill and some parts of Southeast don't really have trees. And part of being downtown is all the development.