Start them in pots until they're at least a foot tall, then put them in the yard. The other way is, of course, to go out and buy a young tree to plant. Plastic takes over 100 years to biodegrade, so the less plastic we throw out, the better. After using a plastic bag, wash it out with soapy water and let it dry. Save it for the next time you need to jot something down quickly.
Little kids seem to love to make one line on a piece of paper and then get a new one.
Many network printers print out title sheets with every printout, telling who printed it. Use these for kids' coloring paper. This is a good tip for two reasons. First, it takes a burst of electricity to start up a light bulb, so turning one on in room you're going to be in and out of during the next ten minutes wastes more electricity than leaving it on the whole time. The second reason is that it can shorten the life of your bulb because of that burst of energy.