Modelling Wind Damage to Southeastern U.S. Trees: Effects of Wind Profile, Gaps, Neighborhood Interactions, and Wind Direction

Tree damage from a variety of types of wind events is widespread and of great ecological and economic importance. In terms of areas impacted, tropical storms have the most widespread effects on tropical and temperate forests, with southeastern U.S. forests particularly prone to tropical storm damage. This impact motivates attempts to understand the tree and forest characteristics that influence levels of damage. This study presents initial findings from a spatially explicit, individual-based mechanistic wind severity model, ForSTORM, parameterized from winching research on trees in southeastern U.S. This model allows independent control of six wind and neighborhood parameters likely to influence the patterns of wind damage, such as gap formation, the shape of the vertical wind profile, indirect damage, and support from neighbors. We arranged the subject trees in two virtual stands orientations with identical positions relative to each other, but with one virtual stand rotated 90 degrees from the other virtual stand – to explore the effect of wind coming from two alternative directions. The model reproduces several trends observed in field damage surveys, as well as analogous CWS models developed for other forests, and reveals unexpected insights. Wind profiles with higher extinction coefficients, or steeper decrease in wind speed from canopy top to lower levels, resulted in significantly higher critical wind speeds, thus reducing level of damage for a given wind speed. Three alternative formulations of wind profiles also led to significant differences in critical wind speed (CWS), although the effect of profile was less than effect of different extinction coefficients. The CWS differed little between the two alternative stand orientations. Support from neighboring trees resulted in significantly higher critical wind speeds, regardless of type of wind profile or spatial arrangement of trees. The presence or absence of gaps caused marginally significant different in CWS, while inclusion of indirect damage along with direct damage did not significantly change CWS from those caused by direct damage alone. Empirical research that could most benefit this modelling approach includes improving crown area measurement, refining drag coefficients, and development of a biomechanical framework for neighbor support.

How Hurricane Katrina influenced the design of hurricane protection and risk reduction systems and national approaches to risk and resilience. Part 2: Designing the Hurricane and Storm Damage Risk Reduction System and resulting long-term engineering guidance and practice changes

Following Hurricane Katrina, the US Army Corps of Engineers, supported in part by the risk and reliability analysis conducted by the Interagency Performance Evaluation Task Force (IPET), made a major shift from ‘protection’ to ‘risk reduction’ as the principal goal in flood mitigation. The mitigation of the flood risk in Southeast Louisiana was embodied in the design and construction of the ‘Hurricane and Storm Damage Risk Reduction System’, the post-Katrina initiative for New Orleans flood mitigation. It also spawned a major overhaul of many of the Corps of Engineers’ technical guidance and engineering practice documents, incorporating risk as a key measure in the planning and design processes. The criteria applied for the design of the HSDRRS are discussed, with summaries of the associated major changes in Corps engineering guidance and practice relevant to flood mitigation.

RAINFALL PATTERNS ASSOCIATED WITH RUNOFF AND EROSION LEVELS IN WEST-SIBERIAN CHERNOZEMS

Aims of the study are to identify: 1) the main regularities of surface runoff formation due to downpours and, 2) the extent of erosion processes on arable chernozems under conditions of dissected relief and extreme continental climate. Location and time of the study. Field observations were carried out in Kuznetsk depression and Near-Ob areas during 1968-1979 and 1984-1986 years correspondingly, in Near-Ob area from 1995 until now. Methodology. Summer precipitaion and its intensity were measured by using Hydrograph unit. Water infiltration in the field was studied by the method by Nesterov using a PVN-00 device. Main results. The influence of rainfall patterns and soil physical factors on the processes of soil erosion was studied in three large geomorphological regions in the South–South-East of Western Siberia. As regards climatic factors the data of meteorological stations were analyzed for historical rainfall patterns, including interannual variability and downpour recordings. Experimental data of water infiltration, runoff and soil loss were discussed for the main soils units: Greyzemic Phaeozems (Siltic), Luvic Chernozems (Siltic) and Haplic Chernozems (Siltic) with variable content of soil organic matter and erosion levels. Conclusions. In western Siberia, the greatest erosion hazard is represented by meltwater, not only by its total volume, but also by the speed of thaw. Heavy rains cause significant damage to agricultural land only locally, during early spring, when the soil is not protected by vegetation. In both cases, the permeability of the soils plays an important role in the resulting runoff volumes. The vulnerability to erosion in the studied area is as follows: Kuznetsk Basin> Predsalairie> Ob Region (no storm damage).

Valuing the Role of Mangroves in Storm Damage Reduction in Coastal Areas of Odisha

Mangroves help in building coastal resilience as effective natural safeguards against cyclones. The state of Odisha is the most cyclone prone region in the east coast of India and was endowed with nearly 500 km2 of mangroves until 1940s, which has now been reduced, through destruction, to 227 km2. This chapter attempts to value the storm protection provided by these remaining mangroves during the 1999 super cyclone and examines whether it is economically efficient to conserve these mangroves. During this storm, the storm protection value of mangroves was estimated to be USD 68,586 per km width and USD 4335 per ha of mangroves to all households living in the impact zone of the forest. To examine the question of conservation, these onetime values were annualized and the annual storm protection value of a mangrove hectare was found to be more than two times higher than the land price of cleared forests and more than twenty times higher than the annual return from alternative land uses, justifying mangrove conservation as a socially and financially viable policy and an economically efficient decision to build resilience.

Regional High-Resolution Benthic Habitat Data from Planet Dove Imagery for Conservation Decision-Making and Marine Planning

High-resolution benthic habitat data fill an important knowledge gap for many areas of the world and are essential for strategic marine conservation planning and implementing effective resource management. Many countries lack the resources and capacity to create these products, which has hindered the development of accurate ecological baselines for assessing protection needs for coastal and marine habitats and monitoring change to guide adaptive management actions. The PlanetScope (PS) Dove Classic SmallSat constellation delivers high-resolution imagery (4 m) and near-daily global coverage that facilitates the compilation of a cloud-free and optimal water column image composite of the Caribbean’s nearshore environment. These data were used to develop a first-of-its-kind regional thirteen-class benthic habitat map to 30 m water depth using an object-based image analysis (OBIA) approach. A total of 203,676 km2 of shallow benthic habitat across the Insular Caribbean was mapped, representing 5% coral reef, 43% seagrass, 15% hardbottom, and 37% other habitats. Results from a combined major class accuracy assessment yielded an overall accuracy of 80% with a standard error of less than 1% yielding a confidence interval of 78%–82%. Of the total area mapped, 15% of these habitats (31,311.7 km2) are within a marine protected or managed area. This information provides a baseline of ecological data for developing and executing more strategic conservation actions, including implementing more effective marine spatial plans, prioritizing and improving marine protected area design, monitoring condition and change for post-storm damage assessments, and providing more accurate habitat data for ecosystem service models.

Linear extension, skeletal density, and calcification rates of the blue coral Heliopora coerulea

The brooding reef-building octocoral Heliopora is widespread on Indo-West Pacific reefs and appears to be relatively resistant to thermal stress, which may enable it to persist locally while scleractinians diminish under Anthropocene conditions. However, basic physiological measurements of “blue corals” are lacking and prevent their inclusion in trait-based studies. We address this by quantifying rates (mean ± SE) of linear extension (0.86 ± 0.05 cm yr−1) and skeletal density (2.01 ± 0.06 g cm−3) to estimate calcification rates (0.87 ± 0.08 g cm−2 yr−1) for the small branching/columnar morphology of Heliopora coerulea. We postulate that H. coerulea may become an increasingly important reef-builder under ocean warming due to its relative resistance to thermal stress and high skeletal density that make colonies less vulnerable to storm damage under ocean acidification. Moreover, Heliopora corals are likely dispersal limited suggesting they may be an underappreciated genus for restoration of stress-tolerant reef-building capacity on degraded reefs.