Question
hi james,
we are about to plant 20 acres of land with christmas trees but there isnt much soil on the land as it was a landfill site up to a few years ago, what can you suggest please, and what is the best type to plant in this type of ground?
regards
frank

Answer
Hi Frank, I'm not going to be much help to you.  I'm in the United States and I'm not familiar with your climate, your soil type and "isn't much soil" doesn't give me much info.
Our state universities often have a "county agent" whose job is to assist farmers.  You need to try to find someone locally who does the same.  You may also need to have some surveys done on the soil type and depth before the expert can suggest the proper species.
I wish I could be more help, but you really need more local help to insure your financial success.  Jim