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close this bookSpecial Public Works Programmes - SPWP - Planting Trees - An Illustrated Technical Guide and Training Manual (ILO - UNDP, 1993, 190 p.)
View the document(introduction...)
View the documentPreface
View the documentIntroduction
close this folder1. Planning a plantation
View the document(introduction...)
View the document1.1 What regeneration method to use?
View the document1.2 What species to establish?
View the document1.3 Whether to plant a single tree species or a mixture of several?
View the document1.4 What type of planting stock to use?
View the document1.5 What planting pattern to use and how many seedlings to plant?
View the document1.6 When to plant?
View the document1.7 How to protect the seedlings?
View the document1.8 The plantation plan
close this folder2. Preparing the planting site
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View the document2.1 Clearing vegetation
View the document2.2 Ground preparation
View the document2.3 Marking where to dig the holes
View the document2.4 Digging holes
View the document2.5 Soil and water conservation measures
close this folder3. Handling seedlings
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View the document3.1 Packing and transport of seedlings
View the document3.2 Storing seedlings
View the document3.3 Quality of seedlings and grading
View the document3.4 Stripping and trimming
View the document3.5 Transporting seedlings from the road to the planting site
close this folder4. Planting techniques
View the document(introduction...)
View the document4.1 Digging the holes
View the document4.2 On-site distribution of the seedlings
View the document4.3 Planting
View the document4.4 Use of fertilizers
close this folder5. Adapting planting techniques to different site conditions
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View the document5.1 Favourable sites
View the document5.2 Sites with high grass
View the document5.3 Waterlogged sites
View the document5.4 Dry sites
View the document5.5 Eroding slopes and rocky sites
View the document5.6 Steep slopes
View the document5.7 Sand dunes
View the document5.8 High altitudes with snow
close this folder6. Maintaining plantations
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View the document6.1 Weed control
View the document6.2 Protection from grazing
View the document6.3 Fire prevention
View the document6.4 Protection from insects, diseases and rodents
View the document6.5 Fertilizers
View the document6.6 Replacement planting
close this folder7. Planting trees outside woodlots and forests
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View the document7.1 Trees in crop and grazing land
View the document7.2 Alley cropping
View the document7.3 Intercropping in rotation
View the document7.4 Intercropping for tree planting
View the document7.5 Shelterbelts
View the document7.6 Road-sides and river-sides
View the document7.7 Homesteads and public places
close this folder8. Organizing the work
View the document(introduction...)
View the document8.1 Planning
View the document8.2 Workforce
View the document8.3 Labour requirements over the year
View the document8.4 Worknorms
View the document8.5 Coordinating the work
View the document8.6 Tools and equipment
View the document8.7 Supervision and control
View the document8.8 Records to keep
close this folder9. Working conditions
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View the document9.1 Hours of work and rest
View the document9.2 Nutrition and amenities
View the document9.3 Wage systems
View the document9.4 Training, job content and labour-management relations
View the document9.5 Safety
close this folderAppendices - Technical sheets
View the documentAppendix 1 - Surveying and mapping of large planting sites
View the documentAppendix 2 - Laying out and preparing soil and water conservation structures
View the documentAppendix 3 - Survival count
View the documentSome useful guides/handbooks
View the documentTitles in the series of training elements and technical guides for SPWP workers

7.5 Shelterbelts

Shelterbelts or windbreaks are strips of trees and other vegetation that reduce the force of the wind. They are very important in areas with frequent high winds and windblown sand. Often they consist of several rows of shrubs and trees of different heights.

Shelterbelts are most effective if they do not block the wind completely, like a wall, but force it to slow down. If the wind cannot pass through the shelterbelt at all, it will try to pass underneath it or over the obstacle. If it flows over the shelterbelt, it produces turbulence which is harmful for the crops behind the belt. If it goes underneath, the belt acts like a funnel and the wind becomes very strong. Therefore choose large trees for the centre row. On each side of this row plant one or two rows of smaller species. Outside these rows shrubs or other vegetation can be planted to make sure that the wind cannot pass underneath the belt. Plant the trees with close spacing, e.g. 1-2 m apart.

The trees need to be able to stand up to the wind and to have flexible branches and medium dense crowns. The crowns should be long and narrow rather than spreading (the Casuarina species, for example, forms ideal windbreaks). The species should preferably be able to provide by-products. A well chosen mix will not only provide shelter from the wind but will also yield fruits, firewood, etc. If Shelterbelts are planted across grass and cropland where animals are grazing, it will be advantageous to plant thorny shrubs along the edges so that the shelterbelts can provide protection from livestock, like a live fence.

The shelterbelts should be planted perpendicular (at a right angle) to the direction in which the wind usually blows. The length of the zone protected is about 10 times the height of the shelterbelts. If large areas are to be protected, parallel shelterbelts should be planted. The spacing between the shelterbelts should then be 10-20 times the height of the tree.


front view

side view one row of shrubs three rows of trees

Schematic representation

good shelter belt = moderately dense

shelterbelt too dense - causes turbulence