Dynamics of the Lecythis idatimon Aubl. population in a 30-year period in a terra firme managed forest in the Brazilian Amazon

Abstract

The changes in growth rate of Lecythis idatimom Aubl. (Lecythidaceae) was evaluated during 30 years in a forest area in the Tapajos National Forest, municipality of Belterra, Para state, where a planned logging and silvicultural treatments were performed. Five treatments were considered: T1 - harvest of trees with DBH ≥ 45 cm; T2 - harvest of trees with DBH ≥ 55 cm + girdling of competing trees until reaching 20.8% of the original basal area; T3 - harvest of trees with DBH ≥ 55 cm + girdling of competing trees until reaching 27.6% of the original basal area; T4 - harvest of trees with DBH ≥ 55 cm + girdling of competing trees until reaching 53.2% of the original basal area; and T0 - unlogged forest. The periodic annual increment in diameter (IPADAP), density, mortality and recruitment of trees were evaluated. The influence of solar radiation on crowns, influence of the presence of climbers, and influence of forest growth phases on IPADAP were evaluated. Data were collected in 1983, 1987, 1989, 1995, 2003, 2008 and 2012, totaling 30 years of monitoring. The results showed that the growth of the Lecythis datimon Aubl. population is favored by canopy opening by logging or by silvicultural treatments. The solar radiation on crowns allows more increase in diameter of trees, mainly in the mature forest phase. But big canopy opening (such as reduction of 27.6 and 53.8% of basal area in the present study) are practices that ecologically and possibly economically could prejudice the conservation of this species as well as of other species populations. We recommend applying less intensive thinning with lower basal area reduction (19.1% in the present study).