Radial Variation in Oven-Dry Density and Shrinkage of Pinus caribaea M. var. caribaea B&G Wood: Native vs. Plantation-Grown Trees

Abstract

Radial variations in oven-dry density and shrinkage were compared between older native forest (exceeding 60 years of age) and fast-growing plantation (approximately 40 years of age) wood of Cuban Pinus caribaea M. var. caribaea B&G. Native timber exhibited a 30.2% higher mean oven-dry density (0.935 g/cm³ vs. 0.718 g/cm³) due to greater age, slower growth, and a higher mature wood fraction. Intense resinification and localized compression wood (CW) near the pith uncharacteristically inflated juvenile wood density over mature zones in both populations. Volumetric, radial, and tangential shrinkages rose progressively from juvenile to mature wood zones, peaking in the high-density native timber due to a higher cell-wall fraction. Conversely, longitudinal shrinkage was 3.49% higher in the plantation category. Severe stem eccentricity in plantation trees induced massive CW formation. X-ray densitometry and scanning electron microscopy (SEM) confirmed that CW heavily altered earlywood tracheid anatomy, producing hyper-thickened cell walls, reduced lumens, and helical micro-cracks. These structural modifications compressed the latewood-to-earlywood density ratio and triggered chaotic, elevated transverse anisotropy values, which increased warping risks. While native forests yielded dense, dimensionally stable timber, fast-grown plantation wood exhibited reduced dimensional stability and lower density. This may limit its performance in high-value structural applications.