Hurricane Katrina's Carbon Footprint on U.S. Gulf Coast Forests

Abstract

Hurricane Katrina's impact on U.S. Gulf Coast forests was quantified by linking ecological field studies, Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS) image analyses, and empirically based models. Within areas affected by relatively constant wind speed, tree mortality and damage exhibited strong species-controlled gradients. Spatially explicit forest disturbance maps coupled with extrapolation models predicted mortality and severe structural damage to approximately 320 million large trees totaling 105 teragrams of carbon, representing 50 to 140% of the net annual U.S. forest tree carbon sink. Changes in disturbance regimes from increased storm activity expected under a warming climate will reduce forest biomass stocks, increase ecosystem respiration, and may represent an important positive feedback mechanism to elevated atmospheric carbon dioxide.

Widespread Amazon forest tree mortality from a single cross‐basin squall line event

“…[5] We employed a method similar to Chambers et al [2007] to investigate forest disturbance and tree mortality produced by this squall line. Landsat images from Brazil's National Institute for Space Research (INPE) covering the Manaus area (scene P231 R062, 3.4 × 10 4 Km 2 ) collected on 10 July 2001 (Landsat 7, L7, for calibration), 14 October 2004 (Landsat 5, L5, previous to disturbance) and 29 July 2005 (Landsat 5, for disturbance evaluation) were used in this work.…”

Mobilization and transport of coarse woody debris to the oceans triggered by an extreme tropical storm

“…It could also play an important role in the global carbon cycle if it delays the oxidation of organic material by sequestration in deep water or in sediment. The impact of tropical storms on forest vegetation has been shown to be significant, but it is not clear if the net effect is to release carbon to the atmosphere, through reduction of living biomass (Chambers et al 2007;Zeng et al 2009), or to trap carbon through burial of organic material in sediments, facilitated by transfer at high concentrations from the land surface to the oceans (Hilton et al 2008b). Depending on their relative magnitudes and timescales, the balance between these effects may determine whether increased storm frequency and intensity acts as a negative or a positive feedback in response to changing climate.…”

Effects of crop species richness on the community of soil nematodes in an experimental agro-ecosystem

“…The aboveground biomass loss (117 Mg•ha −1 ) in the Wenchuan fault zone was even higher than the biomass loss following hurricane Katrina (87 Mg•ha −1 ) [30]. Second, the influence of the earthquake declined rapidly with distance away from the fault zone, suggesting the entire impact area was relatively small when compared with other disturbances [4]. …”

“…This might because that the damaged trees were usually buried and demonstrated little NPV signal but more bare land signal. Therefore, instead of using NPV as a proxy for dead wood as has been done in other studies [4,13], here we used the difference in green vegetation before and after the earthquake event (ΔGV) as a measure of total wood loss in each pixel. Prior to calculating ΔGV, the GV values from all the images were shade-normalized to limit the effects of topography [22].…”

“…It can remove and bury trees by landslides and debris flows [2], a consequence more evident in mountainous areas [3]. Unlike other agents of disturbance such as wind [4], drought [5] and pest [6] that leave dead trees aboveground, earthquakes represent a form of damage to forests that usually results in the burial of uprooted trees.…”