Direct seeding to restore rainforest species: Microsite effects on the early establishment and growth of rainforest tree seedlings on degraded land in the wet tropics of Australia

Background

In Queensland, Australia, three degraded sites (a high elevation site, mid elevation site and low elevation site) that were dominated by non-native grass were studied. The study looked at how six different methods of sowing affected the establishment and growth of small and large seeds, as well as how it affected weeds growth and re-establishment. Before the sowing treatments were conducted, the weeds, since it often outcompetes seeds/seedlings, were removed using herbicides. The sowing treatments created microsites that either consisted of the seeds being buried beneath the soil or placed above the soil.

Conclusions & Takeaways

After 8 months of monitoring the seeds, the results showed that the seeds that were buried under the different conditions had a higher rate of seedling establishment than those seeds that were placed on top. Although seeds are not always naturally buried, seeds were buried in the experiments in order to protect them from extreme temperatures and predation; this may be one of the reasons why broadcast sowing was not successful. As for the weed re-establishment, it bounced back and was prevalent. However, lower rates of re-establishment occurred on the “furrow” sowing treatment.