i feel exactly the same about nature. i feel a comfort and happiness from just being around it. i think it has to do with a transfer of energy.

everything has an ability to absorb and create energy. energy also interracts with us. i think when you smoke that since you're relaxed and calm and your senses are extremized, you can absorb and create more energy. and more energy brings more happiness. (tired, stressed people aren't usually that happy) so when you go outside into nature, you see the beauty of things, and you get a greater appreciation for nature, life and beauty, thus creating more positive energy in your life and balancing you out.

part of the reason they probably have marijuana use as a felony is to control us and keep us with the motivation to be productive for corporate america and get your happiness drained from you so you always have something harder to work for.