Direct Seeding of Trees 



or destruction by all the natural ob- 

 stacles to plant establishment than are 

 transplanted nursery stock. In the nurs- 

 ery, seeds and seedlings are given in- 

 tensive care and protection during the 

 highly vulnerable early growth period; 

 such care cannot practicably be given 

 in the field. 



The natural obstacles most likely to 

 interfere more in direct seeding than 

 in planting are the rodents and birds, 

 drought, competition or smothering by 

 the surrounding vegetation, injuriously 

 high surface-soil temperatures, frost 

 heaving, insect pests, as well as the 

 seedling diseases. 



Of these, rodent and bird depreda- 

 tions upon the seed, and direct-heat 

 injury from high soil temperatures are 

 problems practically unique to direct 

 seeding. Planters of nursery stock ordi- 

 narily escape them entirely, and nurs- 

 erymen can feasibly institute control 

 measures if required. In certain sec- 

 tions, throughout the Western States 

 particularly, seeding without some 

 form of rodent control generally is 

 futile; in other sections, notably the 

 southern Gulf Coast States, birds are 

 the major problem. 



Direct-heat injury and mortality 

 (independent of drought effects) may 

 occur among tender, newly germinated 

 seedlings if the surface-soil tempera- 

 ture rises above 120 F. Such tempera- 

 tures are not unusual on bare ground 

 in full sun; considerably higher tem- 

 peratures sometimes develop on black 

 soil surfaces or south-facing slopes. In 

 extreme cases, even transplanted nurs- 

 ery stock may be damaged. 



Both seedings and plantings are 

 affected by the other obstacles named, 

 but in general seedings are more sensi- 

 tive and more likely to fail as any 

 factor or condition becomes increas- 

 ingly unfavorable. Little trees starting 

 from seed in the field are more subject 

 to the damaging effects of drought, 

 root competition from other plants, 

 and frost heaving because of their less 

 well-developed root systems; they are 

 more subject to smothering by other 

 plants because of their handicap in 



height. Certain insect pests, like cut- 

 worms and white grubs, sometimes are 

 highly destructive to the tender young 

 plants but ordinarily do not seriously 

 damage the 1- or 2-year-old seedlings. 

 Likewise, serious damage from certain 

 of the diseases, notably damping-off, is 

 largely restricted to the period during 

 and immediately after germination. 



Other lesser disadvantages of direct 

 seeding as compared to planting are 

 that it requires a good deal more seed 

 per reforested acre seed that may 

 sometimes be difficult to obtain and 

 that it is a somewhat more painstaking 

 type of work, especially with small- 

 seeded species like most conifers, which 

 germinate poorly unless the depth of 

 coverage is carefully controlled. 



With recognition that direct field 

 seedings are inherently more sensitive 

 to adverse factors than plantings, the 

 art of successful seeding can be char- 

 acterized as, first, the discernment and 

 the utilization of the combinations of 

 species, site conditions, and the seasons 

 where natural obstacles to plant estab- 

 lishment are relatively few or present 

 in mild degree; and, second, applica- 

 tion of such treatments as are necessary 

 and economically feasible for lessening 

 the obstacles or modifying the factors 

 most likely to cause failure. 



SEVERAL PRINCIPLES AND METHODS : 

 Direct seeding generally should be 

 restricted to the more favorable sites. 

 These sites usually are characterized by 

 fairly deep, mellow, loamy, and well- 

 drained soils situated on lower slopes 

 and benches with northern or eastern 

 exposures, in coves, or on bottom lands. 

 Site selection is more important in 

 dry climates than in the moister ones. 

 In the Lake States, for instance, which 

 average rather dry among the forest 

 climates, direct seeding generally is an 

 uncertain undertaking except on the 

 lower lying parts of the areas known 

 as sand plains. Extensive acreages of 

 this formation are found in Wisconsin. 

 Seeding tests in the sand plains have 

 indicated good chances for success 

 where the ground-water table lies be- 



