Establishment of Tree Seedlings in the Understory of Restoration Plantations: Natural Regeneration and Enrichment Plantings

Establishment of Tree Seedlings in the Understory of Restoration Plantations: Natural Regeneration and Enrichment Plantings

Background

This study investigates how seedling establishment is affected in the understory of restoration sites of different ages (10,22 and 55 year-old) within the Brazilian Atlantic Forest. It also assesses some of the environmental microsite conditions that influenced the stand dynamics process.

Research Goals & Methods

A seed addition experiment was performed on each of the study sites to test how different microsite conditions affect seedling establishment. Parameters of density, diversity, seedling emergence, survival and biomass were compared.

Conclusions & Takeaways

With respect to species diversity, the 55-year-old forest contained the highest number of species per plot, while the other two sites showed no difference in species number per restoration plot. Moreover, regenerating seedling density was highest in the oldest site, following by the 22-year-old forest, and the youngest site with the lowest seedling establishment density. Both results supported the author’s set out hypothesis based on the assumption of better microsite conditions for seedling establishment and higher seed deposition in older sites. Seedling emergence was similar among restoration sites, but survival differed and was lower at the oldest plantation, that can be explained by greater canopy openness in younger forest and higher pathogens incidence in older sites, which is favored by low sun radiation and high soil moisture conditions. Total biomass differed among sites and was higher in seedlings that grew in the youngest restoration plantation. The authors conclude indicating that understory of young restoration plantations provides suitable microsite conditions at the early establishment phases for enrichment planting. Additionally, older forest influence a greater species diversity and density due to the recruitment capacity. Finally, it was found that there is a positive correlation between canopy coverage and seedling mortality, and a negative correlation between canopy coverage and total dry biomass per seedling.

 

 

Reference: 

Bertacchi MIsabel F, Amazonas NT, Brancalion PHS, et al. Establishment of tree seedlings in the understory of restoration plantations: natural regeneration and enrichment plantings. Restoration Ecology. 2015;24:100–108. doi:10.1111/rec.12290.

Affiliation: 

  • Departamento de Ciências Biológicas, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, Brazil
  • Departamento de Engenharia Florestal, Universidade Federal do Mato Grosso, Cuiabá, Brazil
  • Departamento de Ciências Biológicas, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, Brazil