Vulnerability of Amazon forests to storm-driven tree mortality

Tree mortality is a key driver of forest community composition and carbon dynamics. Strong winds associated with severe convective storms are dominant natural drivers of tree mortality in the Amazon. Why forests vary with respect to their vulnerability to wind events and how the predicted increase in storm events might affect forest ecosystems within the Amazon are not well understood. We found that windthrows are common in the Amazon region extending from northwest (Peru, Colombia, Venezuela, and west Brazil) to central Brazil, with the highest occurrence of windthrows in the northwest Amazon. More frequent winds, produced by more frequent severe convective systems, in combination with well-known processes that limit the anchoring of trees in the soil, help to explain the higher vulnerability of the northwest Amazon forests to winds. Projected increases in the frequency and intensity of convective storms in the Amazon have the potential to increase wind-related tree mortality. A forest demographic model calibrated for the northwestern and the central Amazon showed that northwestern forests are more resilient to increased wind-related tree mortality than forests in the central Amazon. Our study emphasizes the importance of including wind-related tree mortality in model simulations for reliable predictions of the future of tropical forests and their effects on the Earth' system

Windthrows Inventory Data Base (WInD) v1

<p>In total 1403 windthrow swere identified, of which 1343 were processed, identified, and Classify.</p&gt

Landscape-scale consequences of differential tree mortality from catastrophic wind disturbance in the Amazon.

Wind disturbance can create large forest blowdowns, which greatly reduces live biomass and adds uncertainty to the strength of the Amazon carbon sink. Observational studies from within the central Amazon have quantified blowdown size and estimated total mortality but have not determined which trees are most likely to die from a catastrophic wind disturbance. Also, the impact of spatial dependence upon tree mortality from wind disturbance has seldom been quantified, which is important because wind disturbance often kills clusters of trees due to large treefalls killing surrounding neighbors. We examine (1) the causes of differential mortality between adult trees from a 300-ha blowdown event in the Peruvian region of the northwestern Amazon, (2) how accounting for spatial dependence affects mortality predictions, and (3) how incorporating both differential mortality and spatial dependence affect the landscape level estimation of necromass produced from the blowdown. Standard regression and spatial regression models were used to estimate how stem diameter, wood density, elevation, and a satellite-derived disturbance metric influenced the probability of tree death from the blowdown event. The model parameters regarding tree characteristics, topography, and spatial autocorrelation of the field data were then used to determine the consequences of non-random mortality for landscape production of necromass through a simulation model. Tree mortality was highly non-random within the blowdown, where tree mortality rates were highest for trees that were large, had low wood density, and were located at high elevation. Of the differential mortality models, the non-spatial models overpredicted necromass, whereas the spatial model slightly underpredicted necromass. When parameterized from the same field data, the spatial regression model with differential mortality estimated only 7.5% more dead trees across the entire blowdown than the random mortality model, yet it estimated 51% greater necromass. We suggest that predictions of forest carbon loss from wind disturbance are sensitive to not only the underlying spatial dependence of observations, but also the biological differences between individuals that promote differential levels of mortality

SUPERVIVENCIA E INSECTOS PLAGA DE ESPECIES FORESTALES Y FRUTALES EN PUERTO ALMENDRA, REGIÓN LORETO, PERÚ

Survival and insect pests of forest and fruit species in Puerto Almendra, Loreto, Peru were evaluated. Seedlings and cuttings of 15 forest species and 04 fruit species were obtained from natural populations and home gardens; these were installed in plots of 25 x 25 m, 25 individuals per species. Spondias purpurea cuttings had the highest survival (84%), Spondias mombin and Spondias dulcis reached 36% and 24% respectively. Plants from botanical seeds with Very good survival (80‑100%) were Copaifera paupera, Dipteryx odorata, Carapa guianensis, Swietenia macrophylla, Hura crepitans, Chorisia integrifolia, S. mombin, Guazuma ulmifolia, Pleurothyrium parviflorum and Amburana cearensis. With Good survival (60‑79%) are Cedrelinga cateniformis, Cedrela odorata, Genipa americana. In the category Regular (40‑59%) are Caryodendron orinocense y Calycophyllum spruceanum. In the category Bad (< 40%) are Calophyllum brasiliense and Aniba rosaeodora. Insect damage on plants was thoroughly checked, 04 pests were recorded: Hypsipyla grandella on S. macrophylla, C. odorata, and G. ulmifolia with incidences between 100 and 84%; Parasaissetia nigra had incidence (88%) on G. ulmifolia; Apioscelis bulbosa was found on G. ulmifolia, C. integrifolia, S. purpurea and S. dulcis with incidences of 80, 56, 8 and 4%, respectively and Aphis gossypii was recorded on S. purpurea with 20% incidence. This research provides information oriented to the propagation, management, and conservation of forest and fruit species in the Peruvian Amazon.Se evaluó la supervivencia e insectos plaga de especies forestales y frutales en Puerto Almendra, Loreto, Perú. Se obtuvieron plántulas y estacas de 15 especies forestales y de 04 especies frutales, a partir de poblaciones naturales y huertos familiares; estas fueron instaladas en parcelas de 25 x 25 m, 25 individuos por especie. Las estacas de Spondias purpurea tuvieron mayor supervivencia (84%), Spondias mombin y Spondias dulcis alcanzaron 36% y 24% respectivamente. Las plantas provenientes de semillas botánicas con muy buena supervivencia (80‑100%) fueron Copaifera paupera, Dipteryx odorata, Carapa guianensis, Swietenia macrophylla, Hura crepitans, Chorisia integrifolia, Spondias mombin, Guazuma ulmifolia, Pleurothyrium parviflorum, Amburana cearensis. Con buena supervivencia (60‑79%) se encuentran Cedrelinga cateniformis, Cedrela odorata y Genipa americana. En la categorı́a regular (40‑59%) están Caryodendron orinocense y Calycophyllum spruceanum. En la categorı́a malo (<40%) Calophyllum brasiliense y Aniba rosaeodora. Se revisaron minuciosamente los daños de los insectos en las plantas, 04 plagas fueron registradas: Hypsipyla grandella en S. macrophylla, C. odorata y G. ulmifolia con incidencia de entre 100% y 84%; Parasaissetia nigra tuvo una incidencia de 88% en G. ulmifolia; Apioscelis bulbosa fue encontrada en G. ulmifolia, C. integrifolia, S. purpurea y S. dulcis con incidencias del 80, 56, 8 y 4% respectivamente y Aphis gossypii fue registrada en S. purpurea con 20% de incidencia. Esta investigación proporciona información orientada a la propagación, manejo y conservación de especies forestales y frutales de la Amazonı́a peruana

Landscape-scale consequences of differential tree mortality from catastrophic wind disturbance in the Amazon

Wind disturbance can create large forest blowdowns, which greatly reduces live biomass and adds uncertainty to the strength of the Amazon carbon sink. Observational studies from within the central Amazon have quantified blowdown size and estimated total mortality but have not determined which trees are most likely to die from a catastrophic wind disturbance. Also, the impact of spatial dependence upon tree mortality from wind disturbance has seldom been quantified, which is important because wind disturbance often kills clusters of trees due to large treefalls killing surrounding neighbors. We examine (1) the causes of differential mortality between adult trees from a 300-ha blowdown event in the Peruvian region of the northwestern Amazon, (2) how accounting for spatial dependence affects mortality predictions, and (3) how incorporating both differential mortality and spatial dependence affect the landscape level estimation of necromass produced from the blowdown. Standard regression and spatial regression models were used to estimate how stem diameter, wood density, elevation, and a satellite-derived disturbance metric influenced the probability of tree death from the blowdown event. The model parameters regarding tree characteristics, topography, and spatial autocorrelation of the field data were then used to determine the consequences of non-random mortality for landscape production of necromass through a simulation model. Tree mortality was highly non-random within the blowdown, where tree mortality rates were highest for trees that were large, had low wood density, and were located at high elevation. Of the differential mortality models, the non-spatial models overpredicted necromass, whereas the spatial model slightly underpredicted necromass. When parameterized from the same field data, the spatial regression model with differential mortality estimated only 7.5% more dead trees across the entire blowdown than the random mortality model, yet it estimated 51% greater necromass. We suggest that predictions of forest carbon loss from wind disturbance are sensitive to not only the underlying spatial dependence of observations, but also the biological differences between individuals that promote differential levels of mortality. © 2016 by the Ecological Society of America