| 摘要 |
Plastic bags are continuously formed and filled with sand, soil and gravel to fabricate flexible soft bricks of various shapes and configurations which may be laid on the ground to stabilize sand for growing vegetation or to prevent soil depletion due to water erosion or to grow vegetation in them. Protective housings made of plastic membrane material may be erected in dry or desert regions for growing trees and vegetation. The lower portion of the housing may be located below ground into a trench. Self operating knives are located in the housing to sever the plastic membrane material when the tree grown in the housing has reached a predetermined maturity. Tree planting bullets are provided to facilitate forestation by airplane to land inaccessible regions. The tree seedling is located in supported in an embryonic sack located in a depression formed in the rear portion of the bullet head.
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