Diametric structure and carbon stocks in commercially significant species were measured in a low hill forest in the district of El Tigre, Loreto, Peru. Forest census data from cutting plot (CP) 1 operational plan (OP) 1 were evaluated for commercial species. The species with the most trees in the area are Virola albidiflora, Otoba parvifolia, Albizia subdimidiata, Macrolobium acaciifolium and Cedrelinga cateniformis. The diameter classes of 50 cm to 60 cm (2.40 trees/ha), 60 cm to 70 cm (1.87 trees/ha) and 70 cm to 80 cm (2.99 trees/ha) show the highest values. The carbon stock is 36.86 tC/ha, or 30 284.46 tC. The highest concentrations of carbon stocks are found in the species Cedrelinga cateniformis (5.44 tC/ha), Virola albidiflora (3.08 tC/ha), Albizia subdimidiata (2.81 tC/ha), Otoba parvifolia (2.27 tC/ha) and Macrolobium acaciifolium (2.21 tC/ha). The diameter classes of 60 to 70 c...