Direct Seeding of Trees 



141 



Central States Forest Experiment Sta- 

 tion has shown the necessity for raising 

 each spot an inch or so above the sur- 

 rounding level to escape the lodging 

 of leaves and smothering of the young 

 plants. With spots properly located 

 away from the natural obstacles where 

 litter collects, this slight elevation 

 causes most leaves to slide off or be 

 carried on by the next gust of wind. 



Where screen covers are used, they 

 should be placed on the spots immedi- 

 ately as sown; delay of a few hours or 

 overnight may be too late. Though 

 they may be lifted anytime after ger- 

 mination is completed, screens usually 

 are left in place until fall or the follow- 

 ing spring. Leaving them through the 

 first summer is desirable in that they 

 cast a light shade which measurably 

 reduces soil temperatures and evapora- 

 tion, and thereby tends to increase 

 seedling growth. 



Nut seeds, such as walnuts or acorns, 

 produce a more robust seedling from 

 the start than smaller seeds like pine 

 or the yellow-poplar. Early mortality is 

 lower, and, consequently, fewer seeds 

 need to be sown. The usual practice 

 with good-quality nuts is to sow two to 

 the seed spot, placing them several 

 inches apart so that, if both grow, one 

 can be removed later without injuring 

 the other. In furrows, single nuts are 

 planted at intervals of 2 to 3 feet. 

 Depth of planting should be 1 to 2 

 inches, or about twice the thickness of 

 the seed. 



Inasmuch as nut seeds are especially 

 subject to rodent depredations, spring 

 seeding, with its much shorter period 

 of exposure, often is preferable to fall 

 seeding. However, nuts held over- 

 winter require careful storage. For 

 most species they should be stratified 

 in moist sand or peat moss either in 

 a refrigerated room or in an outdoor 

 pit on a well-drained site. Pits should 

 be deep enough to prevent solid, win- 

 ter-long freezing. Germination will 

 start in pits as soon as ground tempera- 

 tures begin to rise in March or early 

 April, at which time the nuts should 

 be removed and planted without de- 



lay. Acorns of the white oak group 

 require no afterripening and may be 

 held overwinter without stratification 

 in an unheated cave or humid, cold 

 room. 



The foregoing discussion has dealt 

 only with hand methods, sometimes 

 aided by common machines, such as 

 plows and mechanical seeders. Those 

 are the methods on which we can pass 

 some measure of judgment based on 

 results, but even here the background 

 of experiment and experience is too 

 scant to warrant final conclusions. Fur- 

 thermore, these methods have all em- 

 bodied the idea of spot or row seeding 

 often with more or less ground prepa- 

 ration. Broadcast seeding, after nu- 

 merous unsuccessful trials on the na- 

 tional forests 35 to 40 years ago, was 

 abandoned as a futile effort. 



NOW, HOWEVER, A NEW TECHNIQUE 



is stirring the imagination of many for- 

 esters seeding from airplanes. With 

 the great impetus given to aviation by 

 the war, and the increasing awareness 

 of our dwindling timber resource ac- 

 centuated by the war, it was natural 

 that the idea of rapid reforestation by 

 airplane should emerge and demand 

 trial. The airplane has been adapted 

 with phenomenal success to the dis- 

 persal of insecticides and fungicides 

 over field, orchard, and forest. It has 

 been used successfully in the West to 

 seed herbaceous species for watershed 

 protection after fires, to seed rice fields, 

 and has found some use in range re- 

 seeding. Why not use airplanes to 

 reseed the forest? 



Several tests of airplane seeding of 

 forest trees are now under way. One of 

 the first was 600 acres seeded in the 

 spring of 1946 by the Oregon State 

 Board of Forestry. The Crown Zeller- 

 bach Corporation in Oregon seeded 

 1,100 acres by air in 1947, and 2,600 

 acres more in 1948, the latter by heli- 

 copter. The Central States Forest Ex- 

 periment Station tried airplane seeding 

 of trees in 1948 on spoils left after 

 strip mining bituminous coal, and the 

 Northeastern Forest Experiment Sta- 



