3.4. Balance of soil nutrient reserves and aboveground nutrient export
Table 5 presents the potential exports of nutrients contained in stems þ bark based on a harvest yield of 100 Mg ha1, compared to the nutrient reserves in the soil (Mg ha1). Nutrient uptake by species show large differences among species, the following species are the ones that by far export more quantities of nutrients: T amazonia (N and P), V. guatemalensis (K and Mg), H. achornoides and G. arborea (Ca). On the other hand the species that export less quantities of nutrients are: P. caribaea (N, K, Ca, Mg), V. ferrugenia (P) and T. amazonia (Mg). Variation in the stability index shows a wide range of values, from 100% (extremely unstable).
3.5. Carbon content in aboveground tree compartments
Table 4 shows the means multiple comparisons for aboveground biomass C content according to tree compartments and species On the average for all the species C content follows the pattern: Stems > Branches > Foliage > Bark. The conifer by far is the species with the highest values of C content in all compartments surpassing the 50% except for foliage (49.6%). All the broadleaf species have average C values minor than 50%. The smallest C values are V. guatemalensis for foliage (41%) and T. amazonia for bark (40.2%). On the average, C content for all the broadleaf species shows similar values for branches (47.9%) and stems (48.6%), although there are statistical significant differences among the species.
3.4. Balance of soil nutrient reserves and aboveground nutrient exportTable 5 presents the potential exports of nutrients contained in stems þ bark based on a harvest yield of 100 Mg ha1, compared to the nutrient reserves in the soil (Mg ha1). Nutrient uptake by species show large differences among species, the following species are the ones that by far export more quantities of nutrients: T amazonia (N and P), V. guatemalensis (K and Mg), H. achornoides and G. arborea (Ca). On the other hand the species that export less quantities of nutrients are: P. caribaea (N, K, Ca, Mg), V. ferrugenia (P) and T. amazonia (Mg). Variation in the stability index shows a wide range of values, from <1.5 to >100% (extremely unstable).3.5. Carbon content in aboveground tree compartmentsTable 4 shows the means multiple comparisons for aboveground biomass C content according to tree compartments and species On the average for all the species C content follows the pattern: Stems > Branches > Foliage > Bark. The conifer by far is the species with the highest values of C content in all compartments surpassing the 50% except for foliage (49.6%). All the broadleaf species have average C values minor than 50%. The smallest C values are V. guatemalensis for foliage (41%) and T. amazonia for bark (40.2%). On the average, C content for all the broadleaf species shows similar values for branches (47.9%) and stems (48.6%), although there are statistical significant differences among the species.
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