138 



Yearbook of Agriculture 1949 



tween 2 and 5 feet from the soil sur- 

 face, but increasingly greater risks of 

 failure as the water table gets deeper. 



Besides good soil and moisture con- 

 ditions, sites favorable for seeding are 

 characterized by relatively thin and 

 open plant cover. This points to recent 

 burns on forest land and to recently 

 abandoned farm lands as being among 

 the most likely situations for satisfying 

 direct-seeding requirements. 



Seeding can be done any time that 

 field conditions permit from late fall 

 to early spring roughly October 

 through April in the North, with a 

 somewhat shorter spring season in the 

 South. Fall sowing generally is best 

 because it allows the seed to afterripen 

 naturally on the ground and germinate 

 as soon as the weather is favorable in 

 the spring. With spring sowing, seeds 

 that require afterripening must have 

 been previously stratified at near freez- 

 ing temperatures for one to three 

 months. When no positive rodent-con- 

 trol measures are planned, spring sow- 

 ing sometimes is advisable because of 

 the shorter period during which the 

 seeds are exposed to the foraging of 

 the animals. 



All experience indicates that direct 

 seeding with most species in the west- 

 ern forest regions is futile without some 

 form of rodent control. Effective con- 

 trol measures are of two types : Hard- 

 ware cloth covers placed over the seed- 

 ed spots, and poisoning the area before 

 seeding. 



Covers or "screens" of hardware 

 cloth (3 or 4 meshes to the inch) are 

 effective but relatively costly and in- 

 convenient. They are made usually in 

 a conical or dome shape to permit nest- 

 ing for carrying and storage. At pre- 

 war prices, covers 6 inches in diameter 

 could be made for about 4 cents each, 

 and with reasonable care were expect- 

 ed to serve about 10 seasons. Thus, 

 where seeding might be done year after 

 year, the prorated cost per spot for 

 screens could be reduced to less than 

 one-half cent. Even at that rate, the 

 cost runs around $5 an acre of 1,000 to 

 1,200 spots; to this must be added the 



labor cost of placing them on the spots, 

 lifting them later, and storage. Obvi- 

 ously, seeding with screens offers little 

 chance for reducing reforestation costs 

 below those that are needed for plant- 

 ing. Their use clearly is out of the 

 question for a private landowner with 

 a small, one-season job. 



The prepoisoning for rodents, be- 

 fore seeding, seems to offer the best 

 promise of effective control at reason- 

 able cost. Experimental trials of this 

 method, as developed at the Northern 

 Rocky Mountain Forest and Range Ex- 

 periment Station in cooperation with 

 the Fish and Wildlife Service, were in- 

 terrupted by the war and have not been 

 resumed there. However, the prepoi- 

 soning technique has been employed 

 successfully since the war in the Pacific 

 Northwest. 



The procedure at the Northern 

 Rocky Mountain Station was to place 

 about a tablespoon of poisoned bait 

 (hulled sunflower seed treated with 

 thallium sulfate) at 20-foot intervals 

 over the seeding area a week before 

 sowing the seed. Four experimental 

 field trials of 10 to 50 acres each were 

 made on cut-over and burned forest 

 land in the western white pine type, 

 seeding with western white pine. After 

 5 years, from 67 to 79 percent of the 

 seeded spots on these areas were 

 stocked. Subsequently a 97-acre tract 

 was seeded as a reforestation job by 

 GCG labor without the painstaking 

 care exercised in the earlier experi- 

 ments. After 5 years this tract showed 

 62 percent of its spots stocked. Some of 

 the spot failures here were attributed to 

 too-deep coverage of the seeds by care- 

 less workmen rather than to rodents. 

 Other tests showed that treating the 

 tree seeds with poison failed to give 

 adequate rodent control where the area 

 had not been prepoisoned. When pre- 

 poisoning was used, treating the seed 

 did not increase the stocking enough 

 to justify the added costs. 



Cost of the bait used in the prepoi- 

 soning was about 25 cents an acre, and 

 the labor required to spread it was 

 about 2 man-hours. 



