Experimental approaches to select tree species for forest restoration: effects of light, water availability and interspecific competition in man-degraded areas

CROCE JOHANNA; BADANO ERNESTO; TRIGO CAROLINA; MARTÍNEZ-GÁLVEZ FERNANDA; TÁLAMO ANDRÉS

Journal of Forestry Research

Springer

Año: 2022 vol. 33 p. 1197 - 1207

1007-662X

Knowing what native trees can recruit in man-degraded areas allows selecting the best species to restore them but, as this information is not often available, experimentation is required before to start planting trees. This study is aimed in using ex situ experiments to make these decisions. As competition with r-strategist plants, excessive solar radiation and water shortage commonly impair tree recruitment in open habitats, our experiments focused on the interactions among these factors. The experiments were conducted with three pioneer trees from seasonally dry forest of northwest Argentina, including Anadenanthera colubrina, Ceiba chodatii and Jacaranda mimosifolia. Seeds of all species were sowed at two light levels (sunlight/shade), two rainfall levels (full/reduced rainfall) and two levels of interspecific competition (with/without competitor) in a tree nursery. Seedling emergence and survival were monitored during a year and the results indicated that species differentially responded in face of varying levels of light and water. Seedlings of Anadenanthera colubrina tolerated water shortage under elevated solar radiation, which are desirable features in forest restoration proposals. Instead, seedlings of Ceiba chodatii tolerated shade and drought, suggesting that they require shading for establishing in open areas. In opposition, Jacaranda mimosifolia seedlings neither tolerate full sunlight nor water shortage, suggesting that this species requires shading and regular watering if used in restoration practices. Irrespective of these effects of light and rainfall, survival of all species was reduced by interspecific competition. These results highlight the importance of experimentation for selecting the best tree species for forest restoration proposals, which can enhance the cost/benefit ratio of these actions.