Upon receipt of seed (the same seed source guidelines apply as did for planting), seed must be stored in a cool, dry place and preferably in a sealed bag. Storage should be at temperatures ranging from 34 F to 36 F. Sow loblolly, shortleaf and slash pine in late winter or early spring. Longleaf pine should be sown in the fall or early spring. Rapid germination is important when seed is sown in the spring to reduce its exposure to predators and adverse weather conditions. If seed is in a dormant condition, cold stratification is required. Cold stratification serves as a substitute for the time that seed in a natural state lies on the forest floor during the winter. After stratification, seed is treated with a mixture of pesticides to protect it from birds, seed-eating mammals and insects. Seed application rates vary by species and the quality of the site.
The table below gives critical information on the seed and sowing rates for the major southern yellow pine species. These rates are average recommendations, and you can modify them to meet different stocking requirements and site conditions.
| Species | Seeds per pound1 | Sowing method | Sowing rate per acre | |
|---|---|---|---|---|
| -number- | -pounds-2 | |||
| Longleaf | 4,700 | Broadcast | 15,000 | 3.24 |
| Rows3 | 2,900 | 0.63 | ||
| Spots4 | 4,350 | 0.94 | ||
| Slash | 14,500 | Broadcast | 14,000 | 1.11 |
| Rows3 | 2,900 | 0.23 | ||
| Spots4 | 4,350 | 0.35 | ||
| Loblolly | 18,400 | Broadcast | 12,000 | 0.75 |
| Rows3 | 2,150 | 0.14 | ||
| Spots4 | 3,650 | 0.23 | ||
| Shortleaf | 48,000 | Broadcast | 20,000 | 0.48 |
| Rows3 | 4,350 | 0.10 | ||
| Spots4 | 5,800 | 0.14 | ||
1 Wakeley's averages.
2 Weights based on stratified repellent-treated seed that are 100 percent sound.
3 Rows 10 feet apart for all species. Spacing within rows, 1.5 feet for longleaf and slash, 2.0 feet for loblolly, and 1.0 feet for shortleaf.
4 Spots spaced 6 x 10 feet, 6 seed per spot for longleaf and slash, 5 per spot for loblolly, and 8 per spot for shortleaf.
You can sow pine seed aerially or on the ground by hand or machine. Aerial seeding of oak acorns usually results in poor survival unless you take subsequent measures to cover the seed with soil. Sowing rates are influenced by various factors, including condition of the site, quality of the seed, method of seed distribution, and number of trees desired. Sowing seed by hand requires fewer seed but requires more labor and more time. A helicopter can seed 2,000 acres per day, and aerial work is the only practical way to seed areas that are inaccessible or where debris restricts ground movement. Most timberland owners in the same general area can combine their work and employ aerial seeding services. Seed distribution from the air is referred to as broadcast work. Another form of broadcasting is ground distribution with a cyclone seeder. Depending on the site conditions, one person can cover 12 to 15 acres per day. These cyclone seeders are adjustable to accommodate various seed sizes and result in uniform seed distribution across the area. The other two forms of ground seeding are row seeding and spot seeding. Both of these methods require much less seed per acre than broadcasting. In row seeding, seeds are dropped 1 to 2 feet apart along parallel lines of travel across the area. This is slightly slower than broadcasting, since rows are usually 8 to 10 feet apart. If site conditions are unfavorable for survival, make your rows closer together to ensure better stocking on the area. You can use spot seeding for pine and oak regeneration. In pine seeding, a fire rake is often used to clear a spot on the ground, usually 1 to 2 feet in diameter, and 5 to 8 seeds are dropped in the clearing. These spots are normally on spacings of 8 by 8 feet, but you can reduce the spacing for areas with poor survival conditions. When spot seeding acorns, the rule of thumb is to allow 30 square feet per acorn or to sow about 1,500 acorns per acre. A spacing of 3 feet between acorns in the row and 10 feet between rows has shown good results. Since the acorn needs to be covered with soil, a metal bar or even a sharp stick should be used to make a hole in the ground for the acorn. For best results for most oaks, make holes consistently 2 inches deep. You might want to construct a hand device to make holes of consistent depths.
Evaluation of Seeding
Since many variables affect the success of direct seeding work, careful inventories are required to evaluate the results. As mentioned, too many or too few seedlings may result, and more than a casual stroll across the area is required to determine the amount and distribution of the seedlings present. At least one inventory is essential at the end of the first growing season following seeding. Depending on the results of this sampling, you might need a second inventory after the second or third growing season. Regardless of the number of sample plots used, remember to distribute the plots evenly across the entire area. Map out a grid system before sampling, and locate plots according to the grid system. Sample plots should be mil-acre (1/1000 of an acre) size for broadcast areas. This is a circular plot with a radius of 3 feet 8.7 inches, which can be measured using string from a center point or making a permanent plot by bending some stiff wire into a circle of the appropriate size. Twenty-five is the minimum number of plots for any seeded area. On large areas, one plot per acre has been used successfully. During the inventory, count the number of seedlings in each plot and record the data separately for each plot. To get the number of seedlings per acre on the area, a two-step procedure is involved:
- Get an average number of seedlings per plot by dividing the total number of counted seedlings by the total number of plots.
- Multiply the average number of seedlings per plot by 1,000 = average number of seedlings per acre.
To determine the stocking percentage divide the number of plots with at least one seedling by the total number of plots and multiply by one hundred.
A successful seeding operation is one that results in 1,000 to 3,000 seedlings per acre with 55 percent stocking rates. If the inventory indicates fewer than 1,000 seedlings per acre, or 55 percent stocking, wait until the end of the second growing season and take an intensive inventory before reseeding or planting. Areas with more than 2,500 seedlings per acre at the end of the first growing season should be resampled at the end of the third year to determine if a precommercial thin is necessary. Row seeding and spot seeding require different sampling approaches for best accuracy. The mil-acre method may be used with confidence if enough samples are taken.
Summary
If proper procedures are followed, 80 percent of direct seeding operations is considered successful. Obviously, however, direct seeding requires a great deal of background knowledge and training, for best results, consult a professional forester who has experience in this type of work.
