A student does an experiment for a science fair to study whether temperature affects the timing of a cricket’s chirps. The student keeps a cricket in an enclosed box that is heated to different temperatures each day for twelve days. The student records the cricket’s chirps by using a sound-activated microphone so the timing of the chirps can be measured. Which is the dependent variable in this experiment?

If at first there was only grass in the community, the organisms living there would not be very protected by the wind and you could say that the wind is strong. 
If, later, in that same community, there grows a thick forest, the trees would shelter the organisms from the wind organisms hiding behind or inside trees would be able to hide, the living factor wind had changed in that community as a result of the succession of vegetation.