Trees are great, until one falls on your house or car. Have you considered planting shrubs along with your next round of trees? Shrubs can be fast growing and long lived windbreaks which will shelter slower growing trees. They are also essential for creating "edge environments" which attract more wildlife than a stand of only trees. I totally agree with contacting your state forestry or conservation department. They will know what species will do best in your area and may know where you can get baby trees (really seedlings or small saplings) for a reasonable price. Everybody wants to plant the largest tree money can buy for the immediate impact but most often the smaller trees are a better buy. Small trees usually have a more complete root system and recover from transplant shock years earlier. Once recovered they grow quickly and often grow faster than transplanted large trees. They also withstand years of drought or flood better than larger trees with smaller root systems.