Volumetric growth of a new thinning methodology in Nothofagus forests under forest management in Southern Patagonia.

CELLINI, JUAN MANUEL; SOLER, ROSINA; LENCINAS, MARIA VANESSA; MARTÍNEZ PASTUR, GUILLERMO J.

Bucarest

Congreso; Forest Science for a Sustainable Forestry and Human Wellbeing in a Changing World (INCDS); 2018

Forest Science for a Sustainable Forestry and Human Wellbeing in a Changing World (INCDS)

The forests of Nothofagus form the entire timber resource for the sawmills in Tierra del Fuego, Argentina. Most of the studies on growth inforests of Nothofagus pumilio (lenga) in the region have focused on mature forests, being scarce in harvest forests and even less after the applicationof intermediate treatments. The establishment of permanent plots allows to know the evolution and response of trees to silvicultural interventions(e.g., growth and mortality) that affect their forest structure. The objectives of this work were to determine the differences in forest structure andgrowth of a young stand of N. pumilio in the Aguas Blancas experimental plot. The study forest was installed in 1967 and a thinning was carried outin 1985 using 2m width strips alternating crossed transversely (checkerboard), and later in 1999 a selective thinning was performed. In this workthree situations were compared: control thinning (CT, only thinning in 1985 n = 15432 ind / ha DBH = 4.2 cm), strong thinning (STT, thinned in 1985and 1999 n = 2933 ind / ha DBH = 6.8 cm) and soft thinning (ST, in 1985 and 1999 n = 6141 ind / has DBH = 6.9 cm) during the period 1999 - 2010.Simple and multiple ANOVAS were performed, and the means were separated by the Tukey test (p <0.05). This forest responded favorably to theapplication of different levels of thinning. The growth in individual volume for the year 1999 did not present differences for all treatments (0.0014m3.yr-1.), While in 2008 the differences were the most marked (CT 0.0017 m3.yr-1, ST 0.0039 m3 .year-1 and STT 0.0046 m3.year-1). An increase inthe annual individual growth in the treatments was observed until reaching a maximum of 6 years after the thinning, gradually decreasing untilreaching the initial values in the year 2010. In contrast, ST presented the greatest volumetric increases (13, 6m3 / ha.year) compared to the highestintensity (9.5m3 / ha.year). Silvicultural interventions improve individual growth levels, meeting the objectives of forest management.