Collect seeds with your child, pointing out which tree they have come from. 
Point out how amazing it is that the 'pattern' for each huge tree lays in a tiny seed.
Plant the seeds in damp compost and put them outside for the Winter. Many tree seeds need frost to start them into growth.
In the spring, many of the seeds will have started to grow.
When the baby trees reach about 10 centimetres tall they need to be planted outside. Remember, many trees grow very tall. If you do not want to plant them in your garden, contact your local Wildlife Trust (number in the phonebook) and ask if there are any local planting schemes.
