ABSTRACT: Tree and liana (vine) measurements were collected in a logging concession at the Fazenda Rohsamar in the municipality of Jurena in northwestern Mato Grosso. Tree identification and diameter measurements were collected between July 31, 2003 and October 14, 2003 on 10-m x 1000-m transects and the liana measurements were collected between August 5, 2003 and October 14, 2003 on 10 2-m x 1000-m transects within a 1400 ha logging block ( Feldpauschh et al. 2006). Liana transects were nested within tree census transects to relate total species data to the tree inventory. The biomass of lianas was calculated using two different allometric equations derived for lianas in Amazonian forests ( Gerwing and Farias, 2000; Gerwing et al. 2004). Comma-separated data files of measurements of (1) tree species (diameter >10 cm), and forest characteristics, (2) measurements of liana diameter, forest characteristics, and calculated biomass, and (3) georeference points for the liana sampling transects are provided.Selective logging has become a dominant land-use in Brazilian Amazonia. Published data on forest biomass in southern Amazonia is sparse. As part of a larger study to evaluate the effect of reduced impact logging on carbon dynamics and nutrient stocks, forest structure, and forest regeneration potential, we conducted a pre-harvest campaign to estimate tree and liana biomass in a parcel of managed forest in northwestern Mato Grosso. Prior to logging in 2003, a scientific inventory was conducted in Block 5 of the logging concession(Figure 1). Tree characteristics for all trees and palms > 10 cm DBH was measured by stratified sampling across the block to account for differences in tree densities (trees/ha). Transects were located using a commercial timber inventory to identify tree trunks approximately 10 cm DBH, lower and upper canopy height, species, and location of all individuals to the nearest 10 cm on an x-y grid. Diameter of all liana stems were included if their ultimate rooting point before ascending into the canopy fell within the transect. Lianas that had been cut due to reduced impact logging practices were also measured. Distance along the transect was recorded for each stem.