|Special Public Works Programmes - SPWP - Planting Trees - An Illustrated Technical Guide and Training Manual (ILO - UNDP, 1993, 190 p.)|
|5. Adapting planting techniques to different site conditions|
How to plant on "normal" sites has been described in the previous chapter, but the technique described has to be adapted to local conditions. It is always wise to consider local experience and to learn from previous mistakes and successes. Often the sites chosen for reforestation are those not suitable for agriculture - the difficult sites. They will require extra care. Below, some advice is given on how to adapt the general planting method to various site conditions.
On sites with light and soft soil where experience has shown that regeneration is easy, the less expensive bare-rooted plants can be used. Instead of actual holes simple slots in the ground suffice for planting small bare-rooted seedlings (i.e. shoots less than 25 cm). For containerized seedlings the planting holes do not need to be bigger than the container. One single worker may then complete the whole planting operation.
When little clearing of planting spots is needed or when clearing is carried out beforehand, an open-angle hoe can be used. The use of an open-angle hoe has proven to be very fast and effective. While it takes some training and practice, it permits workers to increase their productivity very significantly compared to other methods.
1. Hold the hoe in your right hand and take a number of seedlings in your left. Start with around 10.
Hold the seedling bunch with two fingers and take one seedling between your thumb on one side
and the index and middle finger on the other (see picture on opposite page).
2. Swing the hoe upwards and let the handle slide through your hand. Gloves should be worn
otherwise the handle might not glide well and you can burn your hand.
3. Thrust its blade into the ground by letting the hoe come down. The force comes from the hoe's
weight rather than from the worker's effort. Just before the edge of the blade hits the ground, let
the handle go, so the shock does not hit your hand.
4. Grab the hoe close to the blade, move it up and down and then outwards to open a triangular slot.
5. Place the seedling in the slot in front of the hoe's head with the root collar at the same level as the
surrounding soil surface or slightly deeper. Lift the hoe from the slot.
6. Push the soil around the seedling and firm soil carefully with your foot. Then move to the next
planting spot. As you get up from the last seedling planted, use the momentum of your whole
body to swing up the hoe and the work cycle starts again ...
Favourable sites Planting with an open angle hoe
1. Hold the hoe in your right arm and a few plants in your left
2. Lift the hoe with one hand
3. Thrust the blade into the ground
4. Open the hole by raising and twisting the handle
5. Insert the plant
6. Raise the hoe and firm soil around the seedling
- Use a hoe to clear a patch with a diameter of at least 1 metre around the planting hole. The grass has to be uprooted to reduce competition.
- Remove as many grass roots as possible from the soil before putting it back into the hole.
- Weed often. Use a hoe and uproot the grass around the seedling. The success of the plantation will depend on the subsequent weeding.
- Plant on mounds or ridges to improve drainage for the young plant.
- Plant at the end of the rainy season when the site has dried up sufficiently. This will give the seedlings time to become well established before the wet season starts.
Sites with high grass
Remove grassroots and weed often
Planting on ridges
Plant at the end of the rainy season
- Prepare micro catchments (as described in Technical sheet 2).
- On dry sites it is even more important than otherwise that planting is carried out at the right time, i.e. at the beginning of the rainy season. Prepare planting holes in advance in order to complete planting as quickly as possible.
- Use seedlings of best quality with a good root system.
- Use containerized seedlings if available. They generally survive better than bare-rooted seedlings.
- With tall broad-leaved species, young shoots and part of the foliage must be stripped off, as described in section 3.4.
- Make planting holes large and deep, 60 x 60 centimetre. A large planting hole with plenty of refilled soil will help root development and thereby increase the survival rate and growth.
- Pickaxe the bottom of the holes to make it easier for the roots to penetrate.
- Form a basin around the seedling to catch as much water as possible.
- Mulching with grass and leaves around the seedlings will reduce evaporation and prevent the surface soil from hardening.
Use containerized seedlings of best quality
Planting technique for dry sites
- Determine whether soil conservation measures such as bounds or contour ridges are necessary. If so, construct them as described in technical sheet 2.
- Use species with a deep, wide-spread root system and good initial growth.
- Restrict weeding to the area around the seedling.
- On severely degraded sites put a tablespoon of complete fertilizer at the bottom of the holes to provide a good start for the seedling.
- If stones are available, surround the plant with small stones.
- Avoid using vehicles that might damage the vegetation and the soil. Rainwater might otherwise wash away soil and cause erosion.
- Do not plant in a regular pattern, the seedlings should always be planted on the best available spot.
- When refilling the plant holes, remove all stones. Extra soil might be needed.
- On steep slopes a small horizontal platform has to be prepared where the planting hole will be dug.
- Work on a horizontal line to reduce physical effort.
Eroding slopes and rocky sites
Avoid using vehicles
One spoon fertilizer
Stones around seedling
Before starting planting on sand dunes, the moving surface must be stabilized. This can be done as follows:
- Drive wooden stakes into the sand and tie them together with branches. The fence should be about 0.5-1 metre high. The sand will pile up behind the fence. On the little hill formed a second fence can be built, and so on until it is impossible for the sand to blow over it.
- Cover the dune surface with a layer of branches, palm leaves or the like.
- Sow grass or plant bushes or trees to cover the ground and keep the sand in place. Local, fast-growing species with creeping roots should be used.
Since sand dunes are often found in areas with scarce or very unreliable rainfall, it is particularly important and difficult to pick the right moment to plant. On some sites irrigation from a local well or using a cistern truck or trailer may have to be provided for if the plantation is to succeed at all. The high cost of irrigation is only justified where the plantation protects such valuable assets as villages, roads or an oasis, and where other measures like protection from grazing and direct sowing are not effective.
- Plant seedlings in groups on the best sites and only where the snow disappears early in the spring. Over time the tree cover will the spread to areas between the groups of seedlings i.e. into the less favourable sites.
- Start planting as high up as possible on the slope to facilitate the natural generation further down in the valley.
Fence and cover dune surface
High altitudes with snow
Plant seedlings in groups
Common mistakes in planting on difficult sites
Local experience nor adequately considered. Contact local forest officers if available.
Starting on too large a scale, and not allowing time to learn by experience.