REFORESTATION BY DIRECT SEEDING

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In this study, the researchers compared the rate of regrowth of the forest on unplanted control plots of land and directly seeded (not planted with young trees) plots of land. They found that the remaining forest around the plots of land filled in naturally more rapidly with the directly seeded plots. Planting trees increases the complexity of the habitat in that area which does a number of things to make it more favorable than just starting from a bare patch of ground. The plants provide more diverse habitats, increase shade, and also put down a layer of litter that will decompose and act as a source of nutrients. These things make it easier for the neighboring natural rainforest to regrow in the area by giving the seeds that enter the area a better chance for survival. Advantages to direct seeding versus nursery-grown seedlings is that though there is less of a definite survival rate, there are savings in cost and the seeds grown directly in the environment they will be living in may develop more “naturally and quickly.” However, the quality of the seeds used must be good in order to get a good germination rate.

Intercropping legume trees with native timber trees rapidly restores cover to eroded tropical pasture without fertilization
The land left after deforestation and use from agriculture is usually very infertile due to erosion and things like overgrazing. The researchers wanted to try reforesting these areas with commercially valuable trees and also including legume trees among them so that inorganic fertilizer wouldn’t be needed. This along with cover crops while the commercial trees were still small should allow a landowner to harvest multiple products. The species diversity also benefits the plants and animals of the rainforest.
As the trees grow up, the canopy closes and provides shade, reducing the amount of weeding needed. The more mature environment also attracted the necessary pollinators and seed dispersers. The other crops also help to create more litter and in turn more nutrients in the soil to help the trees grow faster. They actually found that their logging tree T. Amazonia grew 15% better in the presence of I. edulis than in the controls. The legume trees were meant to provide nitrogen, but phosphorous was also a limiting factor. 

References:
Engel, V.L., Parrotta, J.A., 2000. An evaluation of direct seeding for reforestation of degraded lands in central Sao Paulo state, Brazil. Forest Ecology and Management, 152, 169-209.
Pictures:
1. Picture from: http://www.uidaho.edu/aberdeen/cereals/growstage/510.htm