james_nicoll

Bombs of the above design were injection molded of polystyrene by Columbia Plastics Ltd., Vancouver, B.C., and were available for testing in May 1970.

To expedite the tests, 1-year- old Douglas fir seedlings were transplanted into 400 of the new bombs. These were loaded into the fertilizer hopper of a Cessna Agwagon B and dropped in May 1970. The test site was representative of logged and burned areas in the Coastal Mountains of British Columbia, that is, it was steep, rocky, and covered in brush and heavy volumes of logging debris. Only 31 percent penetrated the ground and of these, only 14 percent had survived at the end of the growing season.

It was observed that because these seedlings had been transplanted into the bombs rather than having been grown in the bombs the soil mass was loose in the container and the roots were loose in the soil. As a result many seedlings were plucked from the containers as the bombs were released into the slipstream of the aircraft. The results, therefore, did not represent the potential of the system. It was observed that [...]

The inside walls of the moulds were lined with polyethylene film (Saran Wrap) to eliminate adhesion between the soil and the wooden moulds. Stabilizers were constructed by cutting 2-in. diameter polyvinyl chloride pipe into 1 in. sections. Four fins cut Irom the bombs described earlier were cemented at each quadrant on the outside face of the sectioned pipe. Two plastic struts, 6 in.[...]

These experiments prove that not only is the planting of seedlings from aircraft technically possible but that the technique has inherent advantages in terms of the biological requirements of forest tree planting. For example, the splitting of plastic bombs on impact permits root-egress. [...]