Fire poses the greatest threat to the forests of Amazônia. The magnitude of this threat is amplified by three positive feedback loops that drive the expansion of forest fire in the region: (1) Fire promotes drought, and therefore more fire, by releasing smoke into the atmosphere, thus reducing rainfall. Fire-assisted conversion of forests to pastures may also promote drought by increasing albedo and decreasing water vapor flux to the atmosphere, further inhibiting rainfall. (2) Fire increases the susceptibility of forests to recurrent burning by killing trees, thereby allowing sunlight to penetrate the forest interior, and increasing the fuel load on the forest floor. (3) Finally, fires also self-perpetuate by burning agricultural and forestry systems, discouraging landholders from making those fire-sensitive investments in their land that would allow them to move beyond their dependence upon fire as a management tool.
Uptake of water by lateral roots of small trees in an Amazonian Tropical Forest
Uptake of water by lateral roots of small trees in an Amazonian Tropical Forest
A pulse chase technique was used to determine depth and breath of plant water uptake in an Amazonian evergreen forest. Two 2×2 m2 plots were irrigated with deuterated water. The deuterium pulse, measured as δD values of soil and plant sap water, was followed in the...