Out of the two things mentioned by you, if one is done then the other can be obtained automatically as the result of the former.
Planting trees as much as we can, these can lead to having clean and fresh air (wind).
Oxygen is the most important thing for the life we humans need, and due to the pollution and other reasons we are facing problems like climate change, ozone depletion, and bad air. Due to this, we are facing many health disorders too. Hence one of the solutions to such problems is that we can increase planting the trees as much as we can, which reduces the pollution, gives us fresh air and oxygen and is really very helpful to us. Its like saving our environment.
Hence both things are very important in our life.