Relação entre os caracteres de crescimento e a produção de goma resina em Pinus elliottii var. elliottii Engelm

Abstract

The production of resin in Pinus elliottii var. elliottii is influenced by genetic and environmental factors. The determination of these most important factors affecting resin production will help guide appropriate silvicultural practices to facilitate an increase in resin production in commercial plantations. The aim of this study was to estimate the relationship between resin production and growth characteristics in forest stands to determine silvicultural practices that can contribute to an increase in resin production. Resin production and the average Diameter at Breast Height (DAP) of 63 stands of Pinus elliottii, covering 1,236 hectares in natural regeneration, were measured. The evaluated stands are located in the municipalities of Balneário Pinhal and São José do Norte, in the state of Rio Grande do Sul. The age of the assessed trees ranged from 14 to 26 years. Resin extraction followed traditional methods, using panels with a width of 20 cm and approximately 19 streaks per year. Resin was collected from October 2019 to August 2020. The data on resin production and average DAP (cm) were subjected to normality analysis and descriptive statistics. Subsequently, regression analysis and Pearson correlation analysis were applied to the evaluated characteristics using procedures in the Minitab and Excel software. The minimum and maximum values of average resin production were 1.53 to 5.35 kg per tree per year, respectively. There is a positive and significant correlation between the average values of resin production and average DAP, as well as between average resin production and the average age of trees in the stand, with values of 0.52 and 0.57, respectively. Simple linear regression was also significant for both considered characteristics against resin production with a p-value <0.05. The t-test also proved significant for both characteristics. The correlations between resin production, average DAP, and the average age of trees in the stand were moderate. Furthermore, only 31.9% of the variation in average DAP and 27.3% of the average age explain resin production. It is recommended to conduct additional studies involving genetic characterization of the population, measurement of crown dimensions, and stand density to obtain a more comprehensive and accurate understanding of the variables that can influence resin production in Pinus elliottii var. elliottii stands. The application of the study's results in defining silvicultural practices for managing pine stands for resin production should be done cautiously. However, this study serves as an indicator for future research and emphasizes the importance of obtaining more specific data to determine appropriate silvicultural practices in natural regeneration stands of Pinus elliottii.