They divided CWD into two categories: 2.5¯7.6 and 7.6 cm diameter (Kauffman and Kauffman). The forest floor component was composed of litter, small wood debris (<2.5 cm diameter), and rootmat. Rootmat contained a large amount of decomposing organic matter, as well as live roots, and was not as well developed as that in the Venezuelan Amazon reported by Kauffman et al. (1988).
 

Individual equations for each forest component were used for calculating the biomass (Table 2 and Table 3). Biomass of trees 5 cm dbh was calculated from equations based on dbh given by Higuchi et al. (1998) for Amazonian trees. Biomass of trees <5 cm dbh was calculated from equations based on dbh given by Hughes et al. (1999). Tree height was estimated from a regression equation with tree diameter as the independent variable. Data for the tree height model were collected from 129 trees in Rondônia. Diameter at breast height of the trees ranged from 1.5 to 238 cm.

 
Steps involved with the methodology
 

Biomass of CWD was calculated by using the methods of Van Wagner (1968). Transects to measure mass of CWD 7.6 cm in diameter were 15 m long. Pieces of CWD that were 2.5¯7.6 cm in diameter were measured along the central 5 m of the 15-m transect. Coarse woody debris was further separated into tree (dicot) wood or palm wood components. The 7.6-cm diameter class was also separated into sound or rotten classes following the methods of Kauffman et al. (1988) and Brown (1971).

One hundred samples for each size class of CWD were collected in forests near Jamari, Rondônia, to obtain an average wood density (sg=0.41 g cm-3 for CWD 2.5¯7.6 cm, 0.49 g cm-3 for sound wood, 0.34 g cm-3 for rotten wood, and 0.33 g cm-3 for palm wood 7.6 cm diameter). For the 2.5¯7.6 cm diameter classes, the diameter and angle off the horizontal of 65 individual pieces along a 100 m transect were measured to calculate the quadratic mean diameter and wood particle tilt (Brown and Roussopoulos, 1974). Thereafter, they only counted pieces that intersected the line, and they used density, quadratic mean diameter, and wood particle tilt variables to calculate biomass.

To calculate forest floor biomass, each sample was initially weighed in the field. Sub-samples were then oven-dried to determine the ratio of wet-to-dry weight. This ratio was then applied to the entire sample to convert from wet-to-dry weight.

To estimate biomass of basal leaf palms, the number of leaves of each individual palm encountered in the 2 m×10 m plot was counted and multiplied by a mean weight per leaf derived from a random sample of 30 basal leaves that had been oven-dried and weighed. Three equations were necessary to ascertain biomass of palms: biomass of Attlea sp. 1.78 m high was calculated with the model developed by Anderson (1983); biomass of other palm species 10 cm dbh was estimated with the model of Frangi and Lugo (1985); and biomass of palms <10 cm dbh was calculated by using a model developed specifically for this study.

Vine biomass estimates were calculated with the model given by Putz (1983). All seedlings (<1.37 m height) were counted in each of the 16 (1 m×1 m) plots per site. Seedling biomass was based on sub-sample of 50 randomly collected oven-dried seedlings from which an average weight per seedling had been determined.

Biomass of standing dead trees <10 cm dbh was calculated from an equation developed by Hughes et al. (1999). Biomass of standing dead trees 10 cm dbh was estimated by first calculating volume, then multiplying volume by the mean value of specific gravity of sound dead wood. Standing dead palm biomass was estimated from an equation developed for this study for palms <10 cm dbh and by multiplying volume by specific gravity (0.327 g cm-3) for palms 10 cm dbh.

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