Step 5. Decision time
Decide establishment method, planting density and layout.
Establish trees by planting seedlings from nurseries or direct seeding or a combination of planting and direct seeding.
Trees can be planted directly into improved pasture sites provided grasses and weeds are controlled near the tree. Mechanical site preparation can improve the ease of planting and increase tree survival and growth on compacted or poorly drained sites.
Seedlings can be planted at wide (5 m) or narrow (as low as 2 m) spacings depending on the species and the purpose.
To reduce browsing impacts use tree guards and control pest animals. Planting trees at a higher density can leave enough trees for adequate stocking.
Direct seeding is cheaper than planting but may not achieve enough trees for an effective shelterbelt. An option is to direct seed understory species and plant overstorey species in the seeded row.
Factors consider when deciding the width of a shelterbelt:
- sufficient rows to avoid wind tunnels and to achieve a porosity of about 30%-50%
- fencing cost – doubling the width from 10 m to 20 m for 200 m long belt only increases fence length by 5%
- carbon sequestration – narrow belts (<40 m wide) sequester more carbon per unit area than wide belts because of the higher proportion of larger ‘edge’ trees
- habitat value increases with the mix of species, understory and width.