Nutrient stocks

Table S3 Comparison of the aerial biomass (dry matter) and nutrient stocks of trees of a cerra-do sensu stricto in Brasilia and an Amazonian seasonal varzea forest in Ilha de Marchantaria.

A comparison of these data with those of an Amazonian forest shows that the aerial biomass of the trees of a cerrado sensu stricto in central Brazil may be only 8 to 22% of that of an Amazonian forest, and the basal area only 10 to 26% (Table 5.3). This difference in biomass reflects directly on the nutrient pools in the biomass. A comparison of the data reported by Klinge et al. (1995) for the aboveground biomass and nutrient stock in two inundation forests in the Ilha de Marchantaria with the data for a cerrado sensu stricto from central Brazil (Silva 1990) illustrates how nutritionally poor the cerrado is in quantitative terms. The proportions of stock of essential nutrients in the tree biomass of cerrado are 7 to 16% for P, 1.7 to 4.6% for K, 0.83 to 3.09% for Ca, and 3.5 to 7.4% for Mg. Thus Ca, K, and Mg seem to be much more deficient in the cerrados than P. We have no corresponding data for the stock of nutrients in the root biomass of trees for comparison among the two ecosystems. This comparison is only illustrative of two specific sites. Estimates of aboveground biomass for the Amazonian forests may vary... 

Buschbacher, R., C. Uhl, and E. A. S. Serrao. 1988. "Abandoned pastures in eastern Amazonia K. Nutrient stocks in the soil and vegetation." Journal of Ecology 76 682-699. 

Russell (1987) examined whole ecosystem nutrients within a native forest, a 6-month pine plantation, a 9-5-year pine plantation, an 8.5-year Gmelina plantation, and a 1.5-year second generation pine plantation that was established on a previous 8.5-year Gmelina plantation. A synthesis of the changes in nutrient stocks during the course of plantation establishment and growth is presented... 

Fig. 7.1 Total nutrient stocks and in plant biomass plus soil in rain forest, newly planted Pinus caribaea (6 months old), P. caribaea, and Gmelina arborea plantations at the end of the first rotation (9.5 and 8.5 years old, respectively), and second rotation P. caribaea (1.5 years old) at Jari (Sanchez et al. 1985). H = harvest loss from trees taken when clearing the rain forest for the plantations L = leaching. Total nutrient stock is defined as the sum of all the nutrients in plant biomass (aboveground, litter, detritus, roots) plus total N, available P (extracted by the Mehlich method), and exchangeable K, Ca, and Mg in the top meter of the soil.

The Recovery of Biomass, Nutrient Stocks, and Deep Soil Functions in Secondary Forests... 

Much of what we know about the nutrient stocks of secondary forests is based on soil measurements made to depths of only 0.1 to 1.0 m (Uhl and Jordan, 1984, Buschbacher et al., 1988, Koutika et al. 1997, Neill et al. 1997). However, water balance studies and direct measurements of deep soil moisture and roots provide evidence that forests across much of seasonally dry Amazonia depend upon root systems that extend well beyond this conventional sampling depth to absorb water during the dry season (Nepstad et al. 1994, Jipp et al. 1998, Hodnett et al. 1997, Holscher et al. 1997). The occurrence of root systems extending to 18 m depth in Amazonian forests (Nepstad et al. 1994) demands a re-examination of our thinking about the nutrient stocks of these ecosystems, and the recovery of these nutrient stocks in secondary forests. If the rooting zone of Amazonian forests extends to several meters depth, instead of several centimeters depth, are these forests less vulnerable than previously believed to nutri-... 

Table 9.1 Total nutrient stocks in mature and secondary forest aboveground biomass and in the upper 20 cm (meant 1 SD)of Oxisol (Haplustox) soils within the Fazenda Vitoria, Paragominas, Brazil.

Pedersen, M. P., Duarte, C. M., and Cebrian, J. (1997a). Rates of changes in organic matter and nutrient stocks during seagrass Cymodocea nodosa colonization and stand development. Mar. Ecol. Prog. Ser. 159, 29-36. 

---