Root biomass and distribution and their allometric relationships with total height in macauba palms of different ages

Root biomass estimates require species-specific calibration, particularly in palms with distinct below-ground structures. We quantified root distribution and below-ground dry mass in 18 macauba palms ( Acrocomia aculeata ) aged 3.0–16.4 years and fitted height-based allometric models. Monolith sampling covered three radial classes and seven soil layers to 2.20 m. Total below-ground dry mass ranged from 13.62 to 93.94 kg plant -1 across age means. The 0–20 cm layer contained the largest root fraction in three-year-old palms, whereas 60–100 cm predominated at 5.4 and 12.2–16.4 years. The saxophone stem represented 26.8–44.0% of below-ground dry mass. Height-based models estimated root dry mass and total below-ground dry mass with relative RMSEs of 19.78% and 17.49%, respectively. These findings extend root distribution information to mature macauba and provide complementary estimates for root studies and below-ground biomass inventories within the calibration range.