Using forest inventory data from 6457 trees collected from 128 sites we make the first nationwide assessment of tree number density and woody structure for the lowland pine savanna woodlands of Belize. We analyse tree diameters and tree height distributions to quantify the structural differences observed between unprotected (here termed UPR) pine woodlands compared to pine woodlands that are protected and passively managed (termed PRPM), and others that are protected and actively managed for commercial pine extraction (termed PRAM). We find that the lowland pine woodlands of Belize can occasionally reach densities of up to 700 trees/Ha and with a biomass up to 100Mg/Ha locally, but that the tree density is often less than 300 trees/Ha. 95% of the trees surveyed were between 9–16m in height and more than half had diameters < 20cm, suggesting that many of these woodlands are dominated by juvenile individuals.

When our plot data is subdivided according to the type of protection and management applied, we find statistically significant differences in the tree diameter and total height distributions between the PRPM, PRAM and UPR types of woodlands (Kruskal Wallis ANOVA, P<0.001). The PRPM areas are found to have the highest diversity of tree diameters (RCV = 0.9), and the largest number of bigger trees [dbh (≥40cm) ≈ 10 trees ha^-1], while UPR areas are found to have the least variability in tree diameter (RCV = 0.6), and fewest big trees [dbh (≥40cm) ≈ 0.7 trees ha^-1]. These results provide the first published data to suggest that different structures may develop within these pine savanna woodlands depending on the type of woodland management that is applied (e.g. active management for extraction, compared with passive management for biodiversity conservation), and that a different structure is observed in those pine woodlands that have no form of protection.