The key to successful planting is the ability of the root system of the newly planted seedling to begin quickly taking up water and nutrients. Plant seedlings in moist mineral soil where moisture is immediately available. Newly planted seedlings may be unable to take up moisture in dry soils or until drainage is achieved in flooded soils. If drainage does not occur until late March or April, use container-grown seedlings to extend the planting season.
Depending on the site, both hand and machine planting are efficient and reliable planting options. Large open tracts are more easily planted by machine; smaller or irregularly shaped tracts, sites with minimal site preparation, and rocky sites are more easily planted by hand.
Show planters the correct depth to plant seedlings. The depth will vary with soil-site conditions, but plant seedlings no deeper than the length of the dibble bar or planting foot on the machine. Shallow planting results in early seedling mortality, particularly during early spring and summer droughts. On many "old field" sites where the soil contains a dense traffic pan or hardpan near the surface, subsoiling breaks up the pan to permit deeper planting. Slash, loblolly, and shortleaf pine can be planted up to 2 to 3 inches above the root collar, provided the planting hole is deep enough to avoid root deformation. Improper planting, resulting in J-rooting or L-rooting, slows early seedling growth. In wet soils with a high water table, plant only to 1 inch above the root collar.
Longleaf pine requires special care in planting and great attention to planting depth. Plant longleaf seedlings so the bud is not buried or the root collar exposed. The large tap root and lateral root system of high quality longleaf seedlings require larger and deeper planting holes than other pines. Hand planters should use the large KBC dibble rather than the narrow OST dibble. Machine planting is preferred when possible.
Regardless of planting method, plant seedlings at the correct spacing and depth so that the roots are not deformed and the soil is firmly packed around the roots. This eliminates air pockets. Have a written contract that details all planting specifications, including transport and handling of seedlings, planting dates, packing, and conditions when planting is to be suspended (site too wet or dry, freezing weather, or summer-like conditions). The contract should provide for inspections during planting to insure that quality standards are met before payment is made. This is especially important when planting with assistance of cost-share programs.
Planting Conditions
Carefully check the site and environmental conditions at planting time. Planting on bright, sunny, windy days in dry soil can result in dead seedlings. Dry soil is difficult to pack around the seedling. When soils are too wet, especially clay soils, machine planting can result in soil compaction around the seedling and other site damage.
The best planting conditions are when temperatures are between 35 °F and 60 °F with relative humidity greater than 40 percent and wind speeds less than 10 mph. When air temperatures are in the 70's and low 80's with low humidity (less than 40 percent) and wind speeds of 10 mph or greater, plant cautiously, as seedlings can quickly dry out after planting. If the situation allows, delay planting until conditions improve, or plant in the afternoon hours when seedlings will be exposed to less environmental stress. If planting must continue under these conditions, have planters carry fewer seedlings in the field and take more care to prevent them from drying out. Do not plant in freezing weather or summer-like conditions when temperatures are below 32 °F or above 85 °F.
Container-Grown Seedlings
Seedlings produced in containers are becoming increasingly available. Their use was originally developed in the Scandinavian countries and Canada where operational planting of container-grown stock has long been common. Container-grown stock offers the advantage of extending the planting season over bareroot stock. Early season planting can begin in October, allowing seedlings to become established before freezing weather occurs. Planting can extend into late spring and even summer on sites that may be too wet to plant during the fall or winter with bareroot seedlings. The protected root systems of container-grown seedlings reduce seedling damage associated with the lifting, storage, and planting of bareroot seedlings.
Seedlings are best stored in their containers where they are protected from root damage and drying out. Protect them from freezing, as the root plugs can easily freeze. The limited soil volume of the container makes the seedlings susceptible to drying out in sunny and windy conditions. Store in partial shade, and water frequently to maintain adequate moisture throughout storage and planting.
Container-grown seedlings may be machine or hand planted, but whichever method is used, it is critical that the planting hole be deep enough so that the top of the root plug can be completely covered with soil. If the top of the root plug is not covered with soil, it will rapidly dry out, and the seedling will die. (This also reduces first heaving of fall-planted seedlings.) Take special care when planting container-grown longleaf pine seedlings. If planted too deep, the bud is covered; if planted too shallow, the root plug is exposed, which rapidly dries out the rooting media.
Evaluating Planted Stands
Survival and stocking are two important factors in evaluating the success of your planting effort. Survival is the number of planted seedlings alive at a given time. It is best estimated by establishing permanently marked plots soon after outplanting. Seedlings are then counted at the end of the first field season and compared to the initial number of seedlings in the plots. Ten to twenty well-distributed plots are usually sufficient for survival estimates.
Stocking represents the number and distribution of living seedlings over the plantation. This information is used to determine whether replanting a portion or the entire stand is necessary. A systematic sampling system is the best way to sample stocking. The number of live trees is counted in fixed-area plots, usually circular plots. These plots are uniformly spaced across the plantation. Plots of 1/50 acre to 1/100 acre in size are convenient. Larger plots are time and labor consuming, while the larger number of plots smaller than 1/100 acre required to give an accurate estimate may be prohibitive.
You need 40 to 60 plots to get accurate estimates of first year stocking, regardless of plantation size. Orient sample plots on lines that cross the planting rows throughout the entire plantation.
Replanting
If the survey reveals that at least 300 seedlings per acre are evenly distributed over the plantation at the end of the first growing season, replanting or interplanting the skips will not be necessary. If there are large areas with poor stocking, these areas can be replanted. Some additional site preparation may be required.
Avoid interplanting the skips within rows. Newly planted seedlings do not compete favorably with established 1-year-old seedlings. Interplants seldom add to the volume production at harvest, and the added investment for the seedlings and planting cost will not be recovered. If you attempt interplanting, plant no closer than 20 feet to an established seedling. Interplanting may be required in stands established under federal incentive programs to meet minimum stocking requirements. If so, spot herbicide treatments for weed control around the interplants may aid their survival and growth.
