Seeds are the offspring of adult parent trees. In a world without any seed dispersal (Box 1) mechanism in place, these seeds would fall right under the adult tree. In such a situation, the parent and the offspring would compete over the same resources such as soil nutrients and water; the parent would also intercept most of the sunlight, making germination difficult for the offspring. Additionally, these offspring would be susceptible to damage by the herbivores that target the parent or by the pathogens infecting the parent. Therefore, theoretically, greater the distance between the parent tree and the point of deposition of its seeds, the higher would be the chances of seed survival. While some tree species may not need any external vector for the dispersal of their propagules (autochory; eg. Delonix regia or gulmohar which has fruits that burst and release the seeds), others have developed different mechanisms for effecting their seed dispersal (see Box 2). For example, species may have their seeds dispersed by wind (anemochory; eg. Shorea robusta or sal which has light, winged seeds), or water (hydrochory; eg. Dalbergia sissoo or shisham).