Litterfall and nutrient input in undisturbed and adjacent fire disturbed forests of the Gran Sabana, southern Venezuela
Litterfall and nutrient return were studied in a primary forest (tall forest), a slight fire-affected forest (medium forest with low abundance of charred residues) and a strong fire-affected forest (low forest with abundant burned trunks on the forest floor) in the Gran Sabana, Southern Venezuela. The purpose was to determine how old fire disturbances that affected the forest structure are affecting the return of organic matter and nutrients from the biomass to the soil surface. The results did not reveal significant differences (P>0.05) in annual litter production between tall forest (5.2Mg·ha-1·year-1) and medium forest (5.7Mg·ha-1·year-1), indicating that minor perturbations had not affected the canopy productivity. Annual litter production in low forest (3.9Mg·ha-1·year-1) was significantly lower than in tall and medium forests (P<0.05). The differences in the litter production of low forest compared to tall and medium forests were surprisingly small considering that low forest were largely degraded, with 74 and 79% less stem density, 91 and 90% less basal area, and 97 and 96% less aboveground biomass than tall and medium forests, respectively. This indicates that fire disturbances that considerably affected the structural attributes of the forests are not influencing substantially the canopy productivity. Inputs of nutrients were low in all the forest types with low rates of litterfall to the soil surface and low concentrations of nutrients in such litterfall. The annual input of N and P followed the same trend as the annual input of litterfall, while the annual inputs of Ca, K and Mg were very variable.
| Main Authors: | , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
ASOCIACIÓN INTERCIENCIA
2006
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| Online Access: | http://ve.scielo.org/scielo.php?script=sci_arttext&pid=S0378-18442006001200013 |
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