THE JOB OF PLANTING TREES: A SURVEY

PHILIP C. WAKELEY, G. WILLARD JONES.

The planting of forests has been going on for a long time in Europe, India, South Africa, Australia, and New Zealand. In the United States, the first few scattered plantations were started 60 to 70 years ago in New England, New York, and Pennsylvania. The first large plantings date from about 1900, but for a generation thereafter planting went slowly. By the end of 1934, the total planted area was only about 2 1/3 million acres.

The establishment of the Tennessee Valley Authority, the Prairie States Forestry Project, and the Soil Conservation Service and the expansion of the national forest and State nursery and planting programs extended public and farm planting from 1935 on, except during the war years.

By the end of 1948, nearly 5 million acres had been planted successfully in the United States-46 percent of it by farmers and private landowners, 7 percent by industrial organizations, 19 percent by States, counties, and municipalities, and 28 percent by Federal agencies. Planting has been most extensive in the Lake States, the South, New York, Nebraska, Pennsylvania, Iowa, and Kansas. Only Rhode Island, Delaware, Arizona, Nevada, and Wyoming which are either small or relatively dry-climate States report fewer than 10,000 acres each as successfully planted. In 1948 the demand on State and industrial nurseries exceeded all records.

Many individuals have been working on seed, nursery, and planting problems: T. E. Maki, a forester, perfected a method of testing pine cones for ripeness by floating them in oil, thus saving thousands of dollars formerly wasted on immature cones. Raymond C. Rietz, a heating engineer, designed cone-drying kilns and worked out safe kiln schedules for extracting pine seed from the cones. Lela V. Barton, a botanist, made important discoveries having to do with storing tree seed and increasing and speeding up its germination in the nursery. S. A. Wilde, a soil scientist, developed special fertilizer and compost treatments for forest nurseries in the Lake States. Carl Hartley, a forest pathologist, developed methods for preventing nursery seedlings from damping-off. Joseph H. Stoeckeler, E. J. Eliason, and Floyd M. Cossitt, foresters, evolved a highly economical way to weed seedbeds of pine by spraying them with dry-cleaning fluid.

The planting bar most widely used in the South was designed by three foresters, a ranger, a tool-company official, and a boy in the Civilian Conservation Corps. Professional foresters, implement manufacturers, and State forestry and pulp-company technicians have developed practicable tree-planting machines. Hundreds of others also have made contributions.

The techniques of planting are still advancing rapidly. Today persons who want to grow trees have a better chance of success than ever before.

Successful planting depends on sound information, good judgment, and careful work. Indeed, a conspicuous aspect of planting in America has been the outstanding success of many beginners who have observed local conditions carefully, compared information and suggestions from several sources, and intelligently chosen methods to fit their particular needs.

A FUNDAMENTAL PRINCIPLE is that, on any given site, native species do better than those brought in from another country or region. When species are planted out of their natural range, they are more susceptible to disease, insects, and damage from frost and ice than are native species. Douglas-fir, when planted in northwestern Oregon where it is native, for example, attains 18 inches in diameter and 50 to 60 feet in height in 35 years. In the Lake States, it does not grow nearly so high.

Special purposes sometimes justify exceptions to the rule of native species.

Scotch pine, which is native to western Europe, can be planted confidently in Indiana or Ohio for Christmas trees, and white spruce makes a good ornamental or windbreak in North Dakota.

The species planted vary with regions. On the national forests, for example, slash and longleaf pines are most widely planted in the Gulf States; loblolly pine in the Central Atlantic Coast States; shortleaf pine in the Ozarks; red, white, and jack pines and white spruce in the Lake States and the Northeast; Douglas-fir, Port-Orford-cedar, and ponderosa pine in the Pacific Northwest; ponderosa pine and the western white pine in the Rocky Mountains; and ponderosa pine and Jeffrey pine in California. The same species are generally planted on similar State, municipal, and private lands.

In the Great Plains region, eastern redcedar and Rocky Mountain juniper are the favored conifers. The boxelder, green ash, American elm, hackberry, the black locust, Siberian elm, honey-locust, and catalpa are the most-favored hardwoods.

In the Northeast, eastern white pine and red pine are favored species, supplemented by some Scotch pine, Norway spruce, white spruce, and jack pine, and small quantities of European larch and several hardwoods.

People often ask why conifers are usually planted on worn-out and abandoned farm land that once supported fine hardwood forests. The answer is that cropping and fires have destroyed the humus that covered the old forest floor, lowered soil fertility and moisture-holding capacity, and compacted the subsoil. Hence, it is usually necessary to make the first crop conifers, which build up the soil until the native hardwoods gradually reestablish themselves, often from seeds brought in by birds, rodents, or the wind.

MOST PLANTATIONS are made with nursery-grown seedlings. The rapid first-year growth of southern pines makes it possible to use seedlings 10 to 15 months old and as they come from the beds in which they were sown. Hardwoods are also planted as 1-year-old seedlings, especially in the Central States and the Great Plains. Use of such young stock helps keep down the planting costs.

Jack pine 2 years in the nursery bed is favored in the Lake States and 2-year-old Douglas-fir and Port-Orford-cedar in Oregon.

Most other conifers are transplanted at least once before they leave the nursery. Transplanting is the most expensive of all nursery operations, but it greatly improves hardiness and root system of the seedling and thus gives it a better chance to survive when planted out.

The digging, packing, and transporting of wilding seedlings usually involves considerable expense, quite often more than the cost of an equal number of nursery-grown seedlings. The mortality sustained in transplanted wildings is quite frequently severe. For those reasons, we do not recommend the use of wildings for planting. Experience has proved that the premium stock produced under controlled nursery conditions to meet approved specifications is usually less expensive than seedlings secured from areas near to the plantation.

To give planted trees their best chance to live and grow, some kind of tilling is usually needed to remove sod and brush from the planting site.

The several kinds include scalping the spots at proper intervals with a mattock, plowing shallow furrows 6 to 8 feet apart, or using a heavy disk to eliminate brush and churn up and expose mineral soil. On the Great Plains, thorough summer fallowing of the soil has been found necessary before planting of shelterbelt trees. In planting for erosion control, gully banks must sometimes be plowed in, gully channels dammed, and slopes mulched. Open sand plains, however, and much of the cut-over longleaf pine lands require no preparation; on other longleaf pine lands a single burn a year before planting may be enough.

Tilling is important, particularly when planting wild lands in the north where the planting sites are usually overgrown with heavy sod and dense brush. By removing this vegetation, competition for the young trees for moisture, light, and soil nutrients is greatly reduced. The cost of preparing the site will vary with density of the vegetation and the kind of tilling that is done. For large plantations double-buster plows drawn by crawler-type tractors are frequently used. Furrows in which the trees are to be planted are plowed at intervals to give desired spacing of the trees. This type of site preparation is efficient and economical. Heavy tractor-drawn disks have proved to be effective in preparing difficult sites of heavy brush, but the cost is correspondingly greater. For small or wood-lot plantations, scalping spots with a mattock or grub hoe, although laborious, is more practical than plowing or disking because it does not require heavy and expensive equipment.

The most frequently used hand planting tool is probably the grub hoe or mattock. On some sites it is used to make a slit just large enough for the roots. Where transplants or especially well-rooted seedlings are used, however, it is usually better ( even though slower and more expensive) to dig a hole in which the roots can be well spread.

Throughout most of the South where the soil is sandy loam and relatively free from stones and where slit planting is successful, a planting bar with a 10-inch wedge-shaped blade is used for 1-year-old stock. The same is true for seedling stock in parts of the Lake States. Technique with these bars was brought to a high peak of efficiency by the Civilian Conservation Corps planting crews. Crack planting teams had no trouble in setting 300 trees a man-hour; even average crews set about 160 a man-hour. A man planting in holes with a mattock does well to plant 65 to 80 trees an hour.

Planting machines have now been improved and are in use to reduce costs, labor, and time. Two or three men (one on the tractor and one on the planter, or two alternating as planter and follow-up man to replant trees set too high) can set 1,250 to 1,750 trees an hour. Different machines have been developed for the sand plains of the Lake States and the bunchgrass-covered, shallow, sandy loams with stiff subsoils of the southern pine region. Some of the machines work well in fairly heavy brush. None has yet been adapted to hilly or rocky land, however, or to areas cluttered with logs and tops.

Machine planting is becoming popular in the Lake States region among farmers who have small fields which they desire to plant to a productive crop. The areas usually include worn-out fields that have been cropped for many years and require a minimum of tilling to place them in shape for planting trees. Planting by machine is a relatively simple operation. It involves making a deep narrow slit in the soil in which the tree is inserted as the machine moves forward. The opening is closed and the soil firmly packed around the roots of the tree by small rolling packing wheels, which follow closely behind the trencher.

How closely to space the trees depends on the purpose of the plantation. The closer the spacing, the more trees are needed to the acre and the more they cost to produce, transport, and plant. Closely spaced trees must be thinned early, or they will crowd each other severely and fall off in growth rate. These facts have led to the use of wide spacings, with trees 8, 10, 16, or even 20 feet apart each way. Trees so spaced reach merchantable size at the earliest possible age, although their quality and their total volume per acre in the early years are often low.