Planting a tree in honor of a loved one that has passed away can be a significant contribution for the future, and a place of remembrance for the family. Some forethought will need to go into this, and a variety of options are available. Some options exist today that allow you to bury the cremains with enriched potting soil and a sampling, and allow you to grow a tree near your home. Growing a tree from a seed can be challenging and novice gardeners can be more successful with a sapling. Consider these companies who offer such solutions:
Another solution would be to adopt a tree in a public place so that everyone would have the opportunity to watch it grow and enjoy it's shade in the future. Different communities offer programs like this, and the nearby City of Plano is one. You can find out more about their program by clicking here.