Figure 9.9. Moisture content of
canopy organic matter (C-H) and the
forest floor H horizon (FF-H) at the
study area in Monteverde. Moisture
content, determined from 10-gm
samples taken from the top 10 cm of
soil, is expressed as (water content/
total wet weight). Asterisks (*)
represent a significant difference
(P < .05) between C-H and FF-H.
(From Bohlman etal. 1995)of the relative basal area (Table 9.3). A dominance-
diversity curve was computed at the species level by
ranking the relative basal area of all stems >10 cm for
trees in the subplots for which species were identi-
fied. Six species constituted more than 97% of the
percent basal area, illustrating the strong dominance
by relatively few species. A single dominant species,
Ocotea tonduzii, made up 23% of the total basal area,
and a single dominant family, Lauraceae, made up
31% of the total basal area (Table 9.3).
Comparison of Monteverde forest structure and compo-
sition with other forests. Tree densities we report fell
in the middle of the range of densities reported else-
where (Nadkarni et al. 1995; Table 9.4). Only one other
study (Edwards 1977) reported a higher total basal area
and species richness. Vegetation at the 1500 m site on
Volcan Barva, Costa Rica (Heaney and Proctor 1990),
about 40 km from our study area, presents the most
interesting comparison to our site due to its proximity
and similar elevation and rainfall. Stem density (trees
> 10 cm) at the two sites was nearly identical (55 3/ha^1
at Barva vs. 559/ha^1 at our site). However, basal area
at Barva was less than half that at our site (Table 9.4).
We identified nearly twice as many species at Monte-
verde compared to Barva. Our values come from a
larger area (3 vs. 1 ha). However, in the one hectare for
which identifications were determined for all stems
>10 cm at our site, the Monteverde forest was slightly
richer in species and families (39 families and 76 spe-
cies in Monteverde, compared to 34 families and 65
species at Barva). There were 28 families for trees
>10 cm DBH in common between the Monteverde and
Barva sites; 18 families occurred only at the Monte-
verede site, and seven families occurred only at the
Barva site (Nadkarni et al. 1995).316 Ecosystem Ecology and Forest Dynamics