Mass deforestation across Africa is common, where every year hundreds of millions of trees are cleared to produce timber, firewood, charcoal and forests products for household and industrial use. This has largely contributed to environmental degradation, climate change and reduction of agricultural production. Reforestation is therefore, mandatory for sustainable supply of forest products, sustainable agriculture and biodiversity preservation. The government of Kenya has made it a policy to achieve 10% forest cover. Farm forestry and agro-forestry are being promoted by extension officers from department of forest services and ministry of agriculture. This calls for reforestation at the rate of 25 plants per acre.
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| Farm Forestry or agro-forestry |
Tree nursery establishment is the most important activity in preparation for reforestation. A nursery is a place where young plants are raised from under special care, in preparation for reforestation. A tree nursery is an ideal business venture for the youth in Africa, as people who want to plant trees find nursery establishment for individuals cumbersome and uneconomical resulting in poor adoption reforestation.
A nursery should be near a permanent water supply as plants need to be watered continuously. The soil should be fertile, deep and well drained while the site should be slightly sloppy to avoid standing water. The plants should be well protected from destruction by wind and animals. The site should be easy to access by foot or by vehicle. Collect seeds from healthy, good quality and high yielding mature plants .To test for viability place them in a container with water and the viable seeds will sink while the non-viable seeds will float then. Sort and remove broken, insect damaged seeds and dry them. Some hard seeds need treatment before sowing to ensure germination. Below are some of the seed treatment methods which can be used.
- Soaking-soak the seed in hot water and leave them to cool in the water for 24 hours. Leucaenia leucocephala . Caliandra callothysus, acacia menisci and wattle are examples of seeds which can be treated this way, However seeds with softer coats can be soaked in cold water for 24 hours.
- Burning- burning is an alternative method. Cover seeds with a thin layer of soil and a layer of dry grass on top. Set the grass on fire and let it burn which makes the seeds ready for planting.
- Mechanical breaking-seeds are treated by breaking their hard coat to speed up germination e.g. croton megalocarpus seeds.
Clear the nursery site, dig to remove weeds and make soil fine .The nursery bed dimensions should be 1 meter wide, 15cm raised and any required length. Support the sides of the nursery bed with logs of wood, timber or tree branches. Add manure or fertilizer and sand to the soil before sowing. Note; in dry areas sunken beds are recommended in order to conserve moisture.
There are three main methods of sowing seeds in the nursery in preparation for reforestation.
- Broadcasting
- Sowing in drills
- Sowing in holes
The seeds should be planted at a depth not more than twice its diameter. The bed should then be mulched and watered twice daily, morning and evening, during the dry season. After germination the mulch is removed and a shade is made over the bed. After the plants have produced the first two true leaves, they may be transferred to poly tubes where they can be cared for until they are ready for transplanting.
The plants may also be left to grow in the nursery bed until they are ready for transplanting. Root pruning should be done every 2 months while the plants are still in the nursery. The nursery bed should be kept free of weed plants, and the shade over the nursery bed should be removed 2 weeks before transplanting, in order to harden the plants for field conditions.
Trees are best planted at the beginning of long rains season, having prepared the planting holes in advance.
· Place the plants in the hole, and then remove the polythene tube without twisting the roots
· Firm up the soil around and water the plants
· Protect the plants from damage
· Weeding should be done to avoid competition for plants nutrients
Pruning is done at various stages as it has the following advantages:-
1) Encourages plants vertical growth suitable for production of timber and posts
2) Reduces knots on the plants for production of good quality timber
3) Encourages branching for shade trees
4) Reduces the harvesting height for fruit trees
