_Seed Studies._ Experiments in reforestation are grouped under seed studies, nursery studies, and sowing and planting. Considerable work has been done in developing the best methods of seed-extraction. Much valuable information has been gathered on the largest amount of seed that may be extracted from pine cones of different species per unit of time at different degrees of temperature; the maximum temperature which may be applied to seeds of different species without impairing their vitality; the germinating power of seed extracted at different temperatures; the comparative length of time required for the germination of seed extracted with or without artificial heat; and the most economical type of seed-extracting plant. Studies have been made upon the comparative germination of tree seeds in the field and the greenhouse. The ultimate success of the plantations being established on the National Forests in a large degree depends upon the character of the seed used. Hence studies are being conducted of the effect of altitude, soil, age of the tree, density of stand, insect damage and disease infection, and other factors that affect the mother tree, upon the character of the seed collected from those trees, and the growth and form of the resulting seedling. Also tests to show the effect of the source of seed on the form and growth of young seedlings have indicated very clearly that with all species the seed grown in the locality where the trees are to be planted give as a rule better results than seed imported from another region. _Nursery Studies._ Nursery studies endeavor to show the most efficient methods for growing young trees for field planting for each species of trees. It is of great importance to know how much seed to sow per foot in the nursery beds; what is the best time (spring or fall) for sowing; to what depth the seed should be covered in order to give the highest germination; whether better results are obtained by drill sowing or by broadcast sowing; the best methods of shading, fertilizing, watering, and cultivating the seed beds; the methods of securing the best root development of the young seedlings; the best time and method of transplanting from the nursery beds to the transplant beds; the best methods for retarding spring growth in seedlings to be used at high altitudes; and other problems of similar nature. _Forestation Experiments._ Experiments in forestation have, year after year, proven that planting is much safer than direct seeding and ultimately less expensive. For this reason a greater emphasis has been placed upon planting studies. These studies have attempted to show the best season for planting each species; the best methods of planting; the most advantageous classes of stock to use; and what the most suitable sites are for each species of tree.