The twigs of the tree are considered to be the sense objects. By development of the different modes of nature we develop different senses, and by the senses we enjoy different varieties of sense objects. The tips of the branches are the senses — the ears, nose, eyes, etc. — which are attached to the enjoyment of different sense objects. The twigs are sound, form, touch, and so on — the sense objects. The subsidiary roots are attachments and aversions, which are byproducts of different varieties of suffering and sense enjoyment. The tendencies toward piety and impiety are considered to develop from these secondary roots, which spread in all directions. The real root is from Brahmaloka, and the other roots are in the human planetary systems. After one enjoys the results of virtuous activities in the upper planetary systems, he comes down to this earth and renews his karma, or fruitive activities for promotion. This planet of human beings is considered the field of activities