Effect of thinning on Pinus pinea L. development and physico-chemical soil characteristics in northwestern Tunisia: modeling of radial growth under thinning intensity

Abstract

In this study, the potential beneficial impacts that the thinnings intensity on stand behavior and soil properties are also studied. This study was designed to test the hypothesis that thinning to various stand densities at young age enhance productivity of wood, cones and the physicochemical characteristics of the soil in Pinus pinea stands. We based our study on four thinning intensity (30, 40, 50 and 65%) in comparison with the control plot. The study was supplemented by a haracterization of radial growth of trees under the four thinning intensity. It was based on a complete randomized experimental field installed in 1994 in Tabarka forest, in Tunisia. For the radial growth analysis, three cores were taken from 125 trees at a rate of one tree per plot.The study showed that thinning has a significant effect on all dendrometric parameters. They revealed that a thinning intensity of 65% produces the best wood production (180.710 m 3 /ha), in annual growth in volume (4.634 m 3 /ha/year) and cone production (1211 cones/ha) compared to other thinning and control plot. Associated vegetation was also influenced by thinning intensities. The physicochemical characteristics of the soil were improved by thinning compared with the control. Significant radial growth thinning was recorde especially in a thinning of 65% intensity (increases of 3.5 to 6.1 mm/year) compared to the control (1.1 to 2 mm/year). A strong relationship between radial growth and age was recorded at Thinning 4 (R 2 = 0.923). These results can be used as an initial basis to refine silviculture of pinion pine in order to improve stand productivity in Tunisia in wood and especially in cones given their importance on the world market.

Climate change impacts on spatial distribution, tree-ring growth, and water use of stone pine (Pinus pinea L.) forests in the Mediterranean region and silvicultural practices to limit those impacts

“…Cherubini (1993) concluded that precipitation plays the most important role in tree-ring growth in Pinus pinea L. Calama et al (2019) detected a positive relationship between rainfall and growth, extending back to the precipitation of previous autumn and winter seasons. Similar findings have been reported in previous studies on dendroecological growth-climate relationships for the species (Mazza et al 2014, Natalini et al 2015, 2016, Jaouadi et al 2018. Total rainfall occurring during the period from October of the previous year to September of the current growth year as well as mean temperature in May and June, are the main climatic factors driving secondary growth in Pinus pinea (Calama et al 2019).…”

Growth response of seven multipurpose tree species to climatic factors: A case study from northwestern Himalayas, India

“…Tree growth has been known to be sensitive to rainfall (Grogan, Schulze 2012;Bauwe et al 2015;Natalini et al 2015), air temperature (Schweingruber 1996; Jump et al 2006;Savva et al 2006;Natalini et al 2015), wind (Urban et al 1994), solar cycles (Rigozo et al 2002;Šimůnek et al 2020) and air pollution (Putalová et al 2019;Mikulenka et al 2020;Sidor et al 2021). Similarly, the radial growth of trees could also be affected by biotic factors, such as game damage (Cukor et al 2019;Vacek et al 2020), silvicultural treatments (Pérez- de-Lis et al 2011;Remeš et al 2015;Jaouadi et al 2018) or fertilization (Ponton et al 2019;Vacek et al 2019;Gallo et al 2021). However, these variables impact species differently and the same species at different habitat (Dié et al 2015) depending on their environment.…”