Reforestation - Tree Planting
| SILVICULTURE ||
Planting is only one component of a much larger process. Three to five years of care is required for a seedling to be considered "established." To obtain the highest possible percentage
survival of planted conservation seedlings, the following steps need to be followed:
Planning simply means, determining the objectives for the seedlings to be planted, and preparing a plan to plot out spacing between seedlings and between rows during planting.
Site preparation enhances the soil's ability to catch and store moisture, reduces grass and weed
competition, and prepares the soil for planting. (See silviculture)
Storage and Care of Seedlings
Storing for two weeks or less:
Storing for more than 2 weeks:
- Store bales in a cool, shaded place.
- Separate bales to avoid overheating and molding.
- Pour cold water into the open end of the bales often enough to keep seedling roots moist.
- Never store seedlings in water because roots will be damaged.
- Protect from freezing.
- Keep bales in cold storage at 3° C (36° F), or
- Put trees in a heeling-in trench.
- Trench should be dug in a shaded, protected place, adjusting the depth to fit the roots.
- Open bundles and spread seedlings in trench.
- Water the roots as trench is being refilled with soil.
- Water as often as necessary to keep soil moist, but avoid overwatering.
- A mulch placed on soil close to trees can help to hold moisture.
- After the trees have begun growing, it is best not to remove them from the heeling-in bed until the following spring.
Note: Open bales of seedlings shold never be left exposed to the sun and wind. During planting operations, only a few bundles of seedlings should be taken out at one time. The others should be kept covered, keeping them cool and moist until they are needed, taking care to avoid damaging the terminal buds.
Preparing Seedlings for Planting
BARE ROOT - Create a slurry by mixing a shovelful of soil, or two
tablespoons of polymer, in a five gallon bucket half-filled with water.
Place enough seedlings that can be planted in two hours into the bucket and submerge the roots completely in the slurry. Storing seedlings this way for more than two hours will often result in root death.
POTTED - Carefully remove the potting material, taking care not to break the root ball or to leave seedlings in sun or wind. Seedlings should only be removed from their containers shortly prior to planting.
Manual Tree Planting
Mechanical Tree Planting
Hand planting is more satisfactory in small areas, on steep terrain, and on extremely rough rock- or debris-covered land. Hand planting also is necessary where the size of the seedlings prevents proper planting by machine.
BARE ROOT - Dig a round hole one foot in diameter and place a small mound of soil in the
bottom of hole. Take the seedling from the slurry bucket and spread the out the roots using the mound as a root support. Pull loose soil back over roots, filling the hole half way. Lightly
tamp soil down or fill with water. Then, back fill the rest of the hole, tamp soil again or re-water. Do not compact the soil by tamping wet soil - it eliminates oxygen the roots need to survive.
Be sure the seedling root collar (where it was planted in nursery) is at the finished soil level. Watering is the best method to settle the soil, eliminate air pockets, and provide moisture to the root system.
POTTED - Follow the same planting instructions as for bare root, but do not disturb the roots. Make sure the root ball does not become exposed after final watering.
The "Pottiputki", a simple device of Finnish origin, speeds up manual planting operations.|
Mechanical planting usually is not warranted for less than 1,000 seedlings because of the time involved in acquiring, transporting and using the equipment.
Mechanical tree planters can speed seedling tree planting where several thousand trees are involved and where the terrain is not too steep nor too rough for mechanized equipment.
Many types of mechanical tree planters are available; they all consist primarily of a device pulled
behind a tractor that creates a slit in the soil. A seedling tree is placed in the slit and the packing
wheels on the planter close the slit and firm the soil around the seedling. In addition, some are
equipped with furrowing attachments to scalp part of the planting area, while more recent designs have spray attachments for applying herbicides to control unwanted vegetation.
Tree-planting machines are of three general types: The floating type is attached to a tractor by a three-point hitch so the entire machine can be raised from the ground by the hydraulic lift on the tractor. The semi-floating type has its front end carried by the tractor and its back end carried on wheels; it cannot be lifted by the tractor. The trailer type has all or nearly all its weight carried on its own wheels.
Planting speed varies with the ground conditions, the species and size of seedlings, and the experience and skill of the crew. Rates of 400 to 1,000 trees per hour are reported.
Most planting machines consist of a rolling coulter, a trencher, an operator's seat and packing wheels. These parts are attached to a sturdy frame, usually equipped with a three-point hitch for use on a tractor with a hydraulic lift unit.
The rolling coulter is a disc-like cutting wheel that cuts through the ground surface and severs old roots, trash and other debris. It also serves to automatically raise the trencher over buried rocks, logs, etc. It should cut at a depth slightly below the trencher point.
The trencher on many planters is essentially a moldboard plow with the moldboard cut away and
replaced by metal sides moving parallel with the landside. The trencher's purpose is to make an
opening in the soil sufficiently wide and deep to receive the roots of the seedling tree in a way that they are not twisted, L-shaped, or crowded into a single plane.
The front of the trencher is shaped so that it lifts the soil from the trench upward and to the side, where it remains until the trencher has passed. Then it is deposited back into the trench from above, falling downward among the roots of the tree being planted, carrying the roots downward while maintaining good distribution of the branch rootlets.
Packing wheels usually are two wheels following the trencher that are set on an angle to force the furrow to close around the seedling and to pack the soil around the tree. The weight of the operator normally provides the weight necessary for proper soil compaction.
Success in establishing a forest plantation is critical at four stages:
- Preparation of the site,
- selection and care of the planting stock,
- making the planting, and
- care of the seedlings after planting.
Failure to successfully complete any of these steps can cause seedlings to die or have limited growth.
In general, some form of site preparation will be needed for planting. It is usually needed in bottomlands and on good soils where there is a heavy continuous sod or dense weed and shrub growth. On cut-over timber or sprout-infested areas, site preparation is necessary and planting should not be considered until over-topping vegetation is controlled.
Control of competing trees, brush, grass and weeds makes planting easier and creates more favorable conditions for newly planted seedlings. Because of many problems associated with scalping and furrowing to control weeds, unwanted vegetation is often controlled with chemicals.
An erosion hazard is often created when trees are planted in rolling or hilly ground. Planting rows are likely to become waterways when slopes are greater than 5 percent. In these situations, contour planting may be necessary.
The direction of planting rows should be determined in advance. Chemicals may sometimes be used the fall before planting to eliminate grass competition in planting rows without disturbing the ground protection.
One key factor in a successful plantation is giving proper care to good quality planting stock. Stock quality should be judged mainly on the basis of size and balance. Both very large and very small trees are difficult to properly plant mechanically. Seedling stem diameter should be between 1/8 and 3/8 inches.
If the roots of the seedlings have not been pruned, this should be done before planting. In general,
pruning the seedling roots to a standard length of 8 inches from the root collar will make planting easier and increase survival rates. Slightly longer root lengths should be kept on hardwood seedlings with taproots, such as walnut and various oak. Pruning should be done with a sharp ax to avoid "peeling" small roots.
Best success is obtained when the seedlings are planted as soon as possible after arriving from the nursery. If planting will be delayed, the packing material around the roots should be kept moist and the seedlings should be stored in a cool, shady location or in cold storage at 33 to 40 degrees.
Roots of planting stock must be protected from drying or freezing. Stock packed tightly in rolls or bales for more than a week without moistening may be seriously injured from heating or drying.
Regardless of the method of planting used, the following points should be considered:
- Seedling roots must not be allowed to dry before or during plantings. All trees except the ones needed for a supply on the planter should be kept wrapped in a cool, moist condition in the shade of other trees or beneath a vehicle. If the roots of trees in a bundle are tangled together, each tree should be separated gently so that the small roots are not stripped. Trees on the planter should be covered with wet cloth or kept in water or a mud slurry in seedling racks.
- The roots of the seedling when planted must be in a natural, uncurled, untwisted position. It should be made sure that the furrow or hole is deep and large enough. Root pruning is better than planting L- or J-shaped roots.
- The seedling should be planted in an upright position at the same depth or only slightly deeper
than it was growing in the nursery (after the soil has settled, the root collar should be covered).
- The soil around the seedling after planting must be firm to prevent the roots from drying out.
Seedlings should resist gentle lifting pressure.
Seedlings should never be planted in frozen or snow-covered ground or on clay soils when the soil is too wet to pack properly. It is more desirable to keep stock in cold storage for as long as a month until moisture conditions improve than to plant in wet, muddy, heavy clay soils or in extremely dry soils.
A work crew of three usually is used in machine planting: a tractor operator, a tree planter and a tree packer who follows the machine to check the planting work and correct poorly planted seedlings.
Trees are taken from the seedling racks on the tree planter and held with the roots away. Single trees are then transferred to the planting hand and usually held between the forefinger and thumb at about root-collar depth in preparation for planting. Planting is done by placing the tree in the ground between the trencher blades, well forward of the soil that falls in the trench. The tree is held upright or leaned a little backward with the knuckles touching the ground. The operator follows through, holding the tree in position until the forward motion of the machine and soil falling back in the slit holds the tree in place.
Tractor speed affects quality of planting. It is important to have a tractor with enough power to pull steadily at slow speeds. Some factors that determine planting rates are soil quality and condition; presence of stumps, stones, etc.; size and condition of planting stock; and skills of the planter operator.
When the planting rate is too rapid, a number of trees will be planted shallow or flat. It is important that the speed of the planting machine be geared to the operator's ability to place the tree properly.
Proper spacing may be determined in a number of ways. Various marking devices attached to the
tractor or planter may be used to determine distance between rows (if the ground is soft, the tractor wheel prints can be used).
Spacing in the row may be marked by cross lines laid out with a cultivator shovel, or by the use of
bell devices on the planter or tractor wheels. Many persons are able to develop a tree-planting
rhythm that gives fairly accurate spacing.
Finally, each tree row should be walked to check for:
- Proper planting depth and root position
- Tree in a vertical position with the soil properly packed around the roots
- The planting furrow not filled with trash and debris.
Aerial Tree Planting
Aerial tree planting has been tried experimentally to reforest hard-to-reach wilderness areas. The results have been less than satisfactory.
A number of methods have been employed - from the dropping of seeds to specially-developed seedlings where the roots are encased in a biodegradeable "spike" which penetrates the soil when dropped from the air.
Both systems are fundamentally flawed; in both cases, little accuracy can be guaranteed which creates wasted resources. In short - even when a seed or seedling reaches the soil successfully, the survival percentages are low.
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