Forecasting production in thinned clonal stands of Tectona grandis in Eastern Amazonia

Abstract

Aim of the study: We investigated the most suitable thinning ages and intensities to maximize productivity and minimize the rotation age of Tectona grandis clonal plantations in the Brazilian Eastern Amazon.
 Area of study: Capitão Poço, State of Pará, Eastern Amazonia, Brazil.
 Materials and methods: We used diameter, height, and volume data from 72 permanent plots measured on nine occasions. We determined the classification of forest sites using the generalized algebraic difference approach (GADA). Clutter’s segmented model was used to simulate different intensities of basal area reduction, determining the technical ages according to the projected increments.
 Main results: The polymorphic site curves generated by the GADA method revealed that there were sites with different productive characteristics. The Clutter model produced compatible projections of basal area and volume that followed the behavior of the productivity classes. The final production was maximized when three thinning intensities (basal area reductions) were applied: 1st thinning (50%), between the ages of 3.5 to 4.2 years; 2nd thinning (50%), between the ages of 6.1 to 7.3 years; and 3rd thinning (25%), between the ages of 10.6 to 12.8 years. Projected rotation ages ranged from 13.9 to 16.6 years earlier than seminal plantings. The simulations increased the net volume by 8.3%, on average, compared to no thinning.
 Research highlights: Simulations with three thinnings maximized production compared to the no thinning scenario. The time interval between thinnings was less than five years. The research results can help forest management decision-making and reveal production increases of T. grandis clonal stands in a shorter time.

The Effect of Age on the Evolution of the Stem Profile and Heartwood Proportion of Teak Clonal Trees in the Brazilian Amazon

“…It is possible that the favorable environmental conditions and the genetic material (clonal material, which tends to be more productive) in our study provided an accelerated growth rate for teak trees in terms of biomass production, which had positive reflections on the productivity of wood with bark. This fact was confirmed in [31], in which it was suggested that the final harvest in clonal teak plantations in the Brazilian Amazon should be carried out between 13.9 and 16.6 years at the sites with the highest and lowest productive capacities, respectively.…”

“…The seedlings were manually planted at the following spacings: 3.5 × 3.5 m, 3.75 × 3.75 m, and 4 × 4 m. For all stands, the following silvicultural techniques were performed using identical calendars: cleaning the area with a bulldozer, combating leaf-cutting ants with ant bait; liming with dolomitic limestone, applying 3 t ha −1 ; base fertilization, with application of 200 g plant −1 of NPK 8-28-16 and 100 g plant −1 of KCl, in the planting hole; weed control using crowning with the aid of a hoe, as well as mechanized and semi-mechanized weeding with a hydraulic tractor; coverage fertilization with application of 7 g plant −1 of boron and 100 g plant −1 of KCl; and artificial pruning with a saw and motor-pruner [30]. Systematic thinning was also performed at 4.5 (1st) and 8.5 (2nd) years, aiming to reduce the basal area by 50% for both thinning practices [30,31].…”