Combining the light-demanding Araucaria angustifolia with the shade-tolerant Cabralea canjerana: mixed plantations to produce tropical timber trees outside the Atlantic rainforest

Abstract

Many trees of high timber value require canopy cover to become established and at present, they are only harvested from native rainforests. Other species require high radiation to establish and can be planted in monospecific stands. The main question was if the canopy generated by a light demanding rainforest species could protect mid-successional timber species from high radiation and extreme temperatures. We evaluated the establishment of Cabralea canjerana under the canopy of Araucaria angustifolia stands. We related growth with the number of neighbors to determine the better positions to plant C. canjerana. In one stand, we measured environmental and physiological traits and we determined that seedling did not suffer light or water stress. C. canjerana plants establishment was successful in stands of different basal areas and trees reached the highest growth with up to two A. angustifolia neighbors within a 5m radius. Therefore, the number of neighbors is a tool to choose the planting location to convert even-aged to uneven-aged mixed stands. In this way, valuable native timber species that requires canopy protection during the first years can be planted outside the rainforest. This is the first report of an uneven-aged mixed plantation of two Atlantic Forest timber species.