A plant can offer us cool shade in the scorching hot of summer with its leafy branches. Moreover plants help in bringing rain. Through a process called transpiration aerial parts of the plants lose water as vapor during photosynthesis. This water is then added to the moisture of the air making the air saturated faster and brings rain. So, the credit for the cool shade and the rains goes to the man who plants the tree. That is why the poet says that a tree planter actually plants ‘cool shade’ and ‘tender rain’.