39 páginasPuerto Rico’s forests consist of young, secondary stands still recovering from a long history of island-wide deforestation that largely abated in the mid-20th century. Limited knowledge about growth rates of subtropical tree species in these forests makes it difficult to accurately predict forest yield, biomass accumulation, and carbon sequestration. This study presents mean annual increases (periodic annual increment) in tree diameter at breast height among trees measured by the forest inventories of Puerto Rico; this information is given for each forested life zone, by species, then by species and crown class, and by crown position class. Additionally, the study presents mean periodic annual increment values calculated for commercial species by tree class (growing stock and cull). From 1980 to 2008, mean diameter at breast height periodic annual increment was 0.35 cm/year for 4,026 trees remeasured by the forest inventory; growth rate averaged 0.20 cm/year in subtropical dry forests, 0.37 cm/year in subtropical moist forests, 0.36 cm/year in subtropical wet/rain forests, and 0.20 cm/year in lower montane forestsurl.ie/8bec