Sharing 65 years of forestry wisdom
Robert Gevers established a timber farm in the Vryheid district 65 years ago, and has been running it successfully ever since. In the early days, he planted mainly wattle, which was processed in his own sawmill and sold to the coal mining industry that was still active in northern Natal. He also supplied firewood that was in big demand in the days before the widespread use of electricity.
|Robert Gevers with his zero-till planting team.|
|Clearing away the trash layer.||Clearing a hole in the semi-moist soil layer, after two hits with the hoe.|
|Making a hole in the moist soil with the tool.||Ready to plant the seedling.|
|The seedling goes into the prepared hole.||Replacing the semi-moist soil.|
|Replacing the powdery soil, the trash and organic matter.||Tamping down.|
But as the years passed, the coal mines closed down and Robert started planting pine with the intention of producing structural timber. He started with a second hand frame saw purchased from Germany, and has built up a substantial sawmilling business. The roundwood is sourced from his own plantation, approximately 2 500 ha in extent, and from surrounding farmers.
Pine species planted on the farm are P. patula and P. eliottii. In recent years, he has been planting more P. eliottii, which grows better than the P. patula and is less vulnerable to fire. He also plants a little wattle.
He has had no major fires and has no fire insurance because his silviculture team keeps the plantations very clean. He is very strict about tree spacing, starting with 1 666 stems per ha and ending up with 400 sph. Silviculture and motor-manual harvesting are both own operations.
Robert is still very active in the business, which he runs with three of his four sons. Over the years, he has done a lot of experimenting with different silviculture methods, and he has now come up with what he maintains is the most effective pitting and planting system.
It is basically a 'zero-till' system that requires no ripping, no gel, no fertiliser and no water, and cuts conventional planting costs by 50%. The secret is that disturbance of the soil is minimal and the hole or pit is not exposed to the air for longer than a few seconds. A planting team of two can plant up to 500 seedlings a day, and survival rates are around 98%. Using this system, he can plant right through the summer, and doesn't worry if it gets hot and dry – it makes no difference to the seedlings.
He has been using this system for the past two years, and he says that after a year, the trees are already five metres high.
Robert is an innovative person who has put his ideas into play, developing products and practices that have made his company unique. He is constantly striving to improve his forestry practices and is always ready to share his results with other timber growers.
He is convinced that his zero-till pitting and planting system works wonders, and has written a detailed description of it for the benefit of SA Forestry magazine readers.
The zero-till seedling transplanting method
As part of the background to explaining the rationale of this seedling planting method and its benefits, it is necessary to look at the vertical soil profile typically encountered.
- Trash and organic matter: ± 30 mm
- Dry powdery layer of soil: ± 30 mm
- Semi-moist soil. This is a buffer layer that tends to dry out in severe droughts but will usually contain some moisture: ±70 mm
- Residually moist soil. Even in a severe drought, this layer will be moist, the moisture content being determined by the soil type: + 90 mm.
The planting method described here takes this profile into consideration and works with the natural state that is presented in order to deliver superior performance.
Tools and equipment required
Mr Gevers has developed two simple tools or aids to facilitate the implementation of his planting method at a commercially viable pace of around 250 seedlings per worker per day.
The soak tray is a tray some 100 mm deep and slightly larger (no more than 10 mm per side) than the standard polystyrene seedling tray and has two handles for carrying.
It could be made either as an injection moulded plastic or be fashioned out of sheet metal. It should be light but reasonably sturdy to satisfy the requirements of portability and the fact that it needs to survive transportation and handling.
This tool consists of a light hoe at one end and a pointed end on the other. One could almost think of it as a cricket stump with a hoe at the end where the bail would be placed and the pointy end that goes into the ground.
The diameter of the pointed end should closely match the size of the hole in the seedling tray. While the seedling tray is a slender pyramid, this tool can be round to form a cone. Again this should be light and sturdy.
The seedlings are transported to the site to be planted. At the site a tray of seedlings is placed in the soak tray containing water. A team of two workers, each equipped with a digging tool, carries the soak tray between them. They are allocated adjacent rows, sharing the seedlings.
- In the case of re-establishing an existing plantation, the workers plant a seedling in between the stumps left from the previous crop. There is zero mechanical preparation of the planting area, hence zero-tillage.
- In the case of virgin land being converted to plantation, a rope or chain can be used to space the seedlings.
- In both cases, the planting methodology is the same, with reference to the soil profile described on the previous page.
Clear away 30 mm trash layer
Using the hoe, clear away the trash over an area of 500 mm x 500 mm.
Clear away 30 mm powdery soil layer
Again using the hoe, clear away an area of about 400 mm x 40 mm.
Make a hole in the semi-moist layer
With the hoe, dig a hole – no more than two hits with the hoe should be required, in the semi-moist soil. It is now important to keep this soil separate and together in the area cleared in the point above.The idea is not to mix it with the dry, powdery soil as this will disproportionately dry out the soil that will be close to the seedling. Make a seedling hole in the residually moist layer. Using the pointy end of the tool, make a conical hole in the moist soil into which the seedling will be placed.
Planting the seedling
The seedling is now placed in the prepared hole and the soil set aside is now carefully replaced. Make sure that only the semi-moist soil is used. Attention to detail is crucial in this step. This process takes but a minute.
Tamping down the soil
The worker now uses his/her feet to tamp the soil down firmly. This can be done quite vigorously as the conical hole made in the moist layer will protect the seedling.
Return the dry soil
Finally, the dry soil and trash can be returned to create a buffer so that the moist soil is not in direct contact with the atmosphere.
Benefits of this method
There are many benefits of this planting method and they are listed below.
All the moisture that is already in situ is utilised, making watering unnecessary. The speed with which this is done and the fact that the moist soil is only in contact with the atmosphere for a very short while means that the moisture loss is minimised.
Some older methods called for holes to be dug on one day and then some time later, the planting team would then have arrived and filled the holes. This left enough time for the soil in the hole as well as that used to cover the plant to become bone dry, unless it had rained the day before.
With the zero-till method, one plants a totally wet plant in all conditions.
Planting in any conditions
This method has the advantage of being used in even hot and dry spells, making planning and co-ordination of the work force easier and independent of the prevailing weather conditions, even in times when there has been no rain for three weeks.
While the method is simple, however, attention needs to be given to the simple steps outlined above. Each worker should be able to plant between 200 and 250 seedlings per day.
The method does not use tractors or bulldozers – only trained workers and some supervision. It uses the minimum of water, thus obviating the need to transport large volumes of water. In fact, this method has an extremely small carbon footprint and if used on a large enough scale, will contribute significantly to the reduction in carbon dioxide emissions for this part of the forestry life cycle.
Mr Gevers has employed this planting method for two years now and the results can be seen in the quality of the stand and the survival rate of seedlings.
Published in April 2012