Variation and Genetic Control of the Heartwood, Sapwood, Bark, Wood Color Parameter, and Physical and Mechanical Properties of Dipteryx panamensis in Costa Rica

Abstract

The Dipteryx genus has a natural distribution throughout several tropical countries in Latin America. This taxon has several tree species, all recognized for their high-density wood. The objective of this research was to study the variation and genetic control of several wood properties, including bark, sapwood, heartwood, green density (GD), specific gravity (SG), moisture content in green condition (MC-G), and mechanical properties, in a Dipteryx panamensis provenance/progeny test at 8 years old. The results showed that bark varied little among families and provenances, but heartwood (diameter and percentage) showed high genetic variation. SG and MC-G showed significant variation between provenances and families, while GD showed little variation. Among the mechanical properties evaluated, the greatest genetic variation was observed in the MOR in bending and shear stress. Families from the Coope San Juan provenance registered the highest values in all wood properties investigated, and families from Puerto Viejo obtained the lowest. Family heritability and the coefficient of genetic variation exhibited high values in heartwood/sapwood and the MOR in bending (h2 > 0.9 and CV > 20%) and lower values in SG, MC-G, compression stress, and shear stress. D. panamensis wood properties have a high potential to be improved through breeding programs.

Características genéticas de las propiedades de la madera de 14 clones de Gmelina arborea Roxb. en el Pacífico Sur de Costa Rica

“…Regarding the physical properties of wood, it is well known that specific weight is one of the most important in terms of quality (Moya, 2004). However, there are few studies that relate this parameter to the genetic origin of trees in broadleaf species (Rodríguez-Pérez et al, 2022). Studies in tropical species report that specific weight decreases with stem height (Pande & Singh, 2005;Rodríguez-Pérez et al, 2022;Weber & Sotelo-Montes, 2008)), a situation that differs from this study where it was observed that values increase with stem height (Figure 3g).…”

“…Moya (2004) reported 50 to 70 % heartwood in 12-year-old trees, while in the present study, the percentage of heartwood remained between 40 and 50 % with early-aged clones (three years old). Thus, Moya and Tomazello (2007) demonstrated that cloned trees have a significant amount of heartwood at an early age and that, probably, at the end of the rotation, the percentage of heartwood is higher, since it increases with tree age (Rodríguez-Pérez et al, 2022).…”

“…Los estudios sobre clonación en melina se han enfocado principalmente en el análisis de las propiedades morfológicas de las especies (Li et al 2017) y no tanto en las propiedades de la madera (Rodríguez-Pérez et al, 2022). Por ejemplo, Hernández-Castro et al (2021b) evaluaron los coeficientes de variación genética, la heredabilidad y las correlaciones genéticas en las propiedades fenotípicas como diámetro, altura comercial, volumen comercial y calidad del fuste de clones de melina de 10, 22 y 34 meses de edad.…”

“…Entre algunos ejemplos se puede mencionar el estudio de mejoramiento genético de Ávila-Arias et al (2015) en el Pacífico Sur de Costa Rica, quienes registraron un diferencial de selección de 19.8 cm, 54 m 3 •árbol -1 y 54.4 % en el diámetro, volumen y calidad del fuste, respectivamente, de árboles plus de melina con respecto a la población base. En esta misma región, Pérez et al, 2022). For example, Hernández-Castro et al (2021b) evaluated the coefficients of genetic variation, heritability and genetic correlations in phenotypic properties such as diameter, commercial height, commercial volume and stem quality of 10-, 22-and 34-month-old melena clones.…”

Engineered Wood/Bamboo Laminated Composites for Outdoor Hydrophilic Platforms: Structural Design and Performance

“…9A, in which it can be seen that the shear strengths decreased from 25.62 GPa to 23.74 GPa with decreasing fluffed bamboo veneer content. However, these shear strengths are significantly higher than those obtained for Dipteryx panamensis in Costa Rica (19.3-19.6 GPa) [23]. Encouragingly, the shear strengths of all LC samples evaluated in this experiment were close to or greater than twice that required for high-class outdoor use, as stated in GB/T 30364-2013 for "bamboo scrimber flooring" (≥12 MPa).…”