CONTENTS. 



Page. 



Introduction 5 



Purpose and method of investigation 5 



Adaptability of the State to tree growth 6 



Topography 6 



Soil 6 



Climate 7 



Drainage 7 



Native timber 8 



Distribution 8 



Natural extension 8 



Condition 8 



Utilization 9 



Management of native groves 10 



Protection 10 



Fire 10 



Insects and fungi 11 



Reproduction 11 



Natural reproduction by seeds and sprouts 11 



Artificial reproduction by seeding and planting 12 



Improvement thinnings 12 



Harvesting the crop 13 



Planted timber 13 



Species 13 



Purpose of planting 14 



Probable causes of success or failure 14 



Planting and care of windbreaks 15 



Species to be used 15 



Seeds or seedlings 16 



Time for setting trees 16 



Methods of planting 17 



Spacing 17 



Distance and direction from dwellings and orchards 17" 



Diagram for proposed windbreak 



Care of young and old trees in the windbreak 



Tree planting for commercial purposes 



Location 



Species 



Planting 20 



Growth and probable returns 21 



ILLUSTRATION. 



Page. 



FIG. 1. Diagram for proposed windbreak for average soil and moisture condi- 

 tions in central Iowa 18 



P..IK, 



