Demography and biomass change in monodominant and mixed old-growth forest of the Congo

Mbau forest covers much of the Congo, and shifts in its composition could have a large impact on the African tropics. The Ituri forest in east Congo is near a boundary between the monodominant mbau type and non-mbau mixed forest, and two 20-ha censuses of trees ≥ 1 cm diameter were carried out over 12 y to monitor forest change. Based on published diameter allometry, mbau forest had 535 Mg ha−1 biomass above ground and gained 1.1 Mg ha−1 y−1. Mixed forest had 399 Mg ha−1 and gained 3 Mg ha−1 y−1. The mbau tree (Gilbertiodendron dewevrei) increased its share of biomass from 4.1% to 4.4% in mixed forest; other common species also increased. Sapling density declined at both sites, likely because increased biomass meant shadier understorey, but the mbau tree increased in sapling density, suggesting it will become more important in the future. Tree mortality and growth rates were low relative to other tropical forests, especially in the mbau plots. Shifting toward G. dewevrei would represent a large gain in carbon in the mixed forest, but mbau is presently more important as a high-carbon stock: biomass lost during forest harvest could not recuperate for centuries due to slow community dynamics.

Children’s Integration in Communities and Segregation From People of Differing Ages

This article reviews cultural differences in the extent of segregation of children from community life and their integration with people of differing ages, focusing especially on children’s engagement with older children or similar-age children. We highlight cultural differences in children’s everyday companionship with older children and with peers by discussing a study using naturalistic observations of young children’s days in four cultural communities. Young children were more often involved with older children (who were often related to them) among the Efe of the Ituri Forest of the Democratic Republic of Congo and in the Guatemalan Mayan town of San Pedro, whereas middle-class European American children from two regions in the United States were more frequently involved with children of similar ages (who were often unrelated to them). The mainstream research focus on similar-age (unrelated) peer involvements, often regarded as the “norm,” needs to be broadened to consider the various patterns of children’s social engagements worldwide, which often involve integration of children in broader communities, engaging with adults and children of all ages.