NATURAL REGENERATION IN MIXED PLANTING FOR ECOLOGICAL RESTORATION IN THE COASTAL PLAIN OF PARANÁ STATE, BRAZIL

Pastures occupy approximately 20% of the Brazilian territory and a significant part of these areas are degraded and have legal environmental liabilities. Ecological restoration is necessary to remedy this liability. The objective of the present study was to determine the effectiveness of a forest restoration planting in an area previously used as buffalo pasture, through floristic and phytosociological parameters of natural regeneration. The study area was densely populated by invasive exotic grasses (Urochloa spp.) until 2006, when, after eliminating the grasses, six native tree species were planted at 2.5 × 1.6 m spacing. A total of 73 terrestrial plant species were found, the most important being Alchornea glandulosa Poepp. & Endl. - heliophilous, which showed high abundance in all strata. The restoration methodology employed was effective in triggering natural succession in the study area, resulting, after 12 years, in floristic and structural parameters consistent with the initial stage of development of the alluvial Dense Ombrophylous Forest. It is inferred that the well-preserved landscape in the region has been determinant in providing the propagules and dispersers that made the observed species richness possible, while the planting tends to have contributed with the control of grasses and with the recovery of the forest environment, facilitating the arrival and development of these propagules. Evidence of soil degradation by use as pasture was observed, and in former buffalo bathing areas neither restoration planting nor natural regeneration developed

REDUCING COMPETITION IN AGROFORESTRY BY PRUNING NATIVE TREES

ABSTRACT The degree to which pruning helps reestablish balance in agroforestry was assessed in a system established in São Carlos, São Paulo, Brazil, in 2008. Seven native tree species were planted at a density of 600 trees/ha in five strips of three rows each, and annual crops were cultivated in the 17-m crop strips between the tree strips. Competition was established after 35 months, decreasing the aboveground biomass production of corn planted close to the trees. An assessment of black oats in the dry season following tree pruning showed that the proximity of trees caused reductions in plant and panicle density, aboveground biomass production, number of grains per panicle and grain weight. Because pruning was not sufficient to maintain crop yields, tree thinning is recommended in order to minimize competition and restore conditions for adequate crop production

GROWTH OF NATIVE TREES IN TWO AGROFORESTRY SYSTEMS

ABSTRACT Agroforestry systems with eucalyptus prevail in Central and Southeast Brazil, and little information is available about systems using native trees. The aim of the present study was to evaluate the development of seven native tree species grown under two agroforestry systems. The experiment was conducted starting in 2007 in 12-hectare area in the municipality of São Carlos, São Paulo state, Brazil. The tree species planted in the two systems (a silvopastoral system and an agrisilvicultural system) were: 'capixingui' (Croton floribundus) and 'mutambo' (Guazuma ulmifolia) (tutors), 'jequitibá-branco' (Cariniana estrellensis), 'canafistula' (Peltophorum dubium) and 'ipê felpudo' (Zeyheria tuberculosa) (timber trees), and 'angico-branco' (Anadenanthera colubrina) and 'pau-jacaré' (Piptadenia gonoacantha) (N-fixing trees). Data were collected for 48 months. The results show differences among tree development, which was evaluated as growth in height and diameter, as well as sensitivity to insect and disease damage. The overall results show that the agrisilvicultural system allowed better tree development. The species with best performance in the two systems were capixingui, mutambo and canafístula. Ipê-felpudo and jequitibá-branco showed the worst results. The high variability among individuals of the same species indicates the possibility of high production advances with selective breeding of these species