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Forest and water‐resources management in floodplains requires an understanding of the nature of drought specific to ecosystems there. The complex relationships among floodplain vegetation, topography and hydrology affect water availability. This paper investigated whether hydrological assumptions within meteorological drought indicators and ecophysiological assumptions within remote‐sensing drought indicators reflect drought deficits as they occur in floodplain forests. We compared the performance of widely used meteorological and remote‐sensing drought indicators in floodplain forests to tree‐ring validation using five species at three floodplains in eastern Texas, USA. We found that the water balance in the Standardized Precipitation Evapotranspiration Index and the water loss estimated by the Evaporative Stress Index were useful models of water deficits in floodplain forests at the site and sub‐site scales, respectively. Hydrological and stand conditions varied among sites enough to affect the specific patterns of tree‐species responded to drought. However, of the species we examined, tree rings in green ash were the most consistently affected by drought across floodplains and were the most closely correlated with both meteorological and remotely sensed drought indicators. Finally, drought effects varied by species and among and within floodplains, but generally, growth of trees in topographically drier sites was more closely correlated with drought indicators. [ABSTRACT FROM AUTHOR]

Vegetation canopy height mapping is vital for forest monitoring. However, the high cost and inefficiency of manual tree measurements, coupled with the irregular and limited local-scale acquisition of airborne LiDAR data, continue to impede its widespread application. The increasing availability of high spatial resolution imagery is creating opportunities to characterize forest attributes at finer resolutions over large regions. In this study, we investigate the synergy of airborne lidar and high spatial resolution USDA-NAIP imagery for detailed canopy height mapping using an image-to-image deep learning approach. Our main inputs were 1 m NAIP image patches which served as predictor layers and corresponding 1 m canopy height models derived from airborne lidar data, which served as output layers. We adapted a U-Net model architecture for canopy height regression, training and validating the models with 10,000 256-by-256 pixel image patches. We evaluated three settings for the U-Net encoder depth and used both 1 m and 2 m datasets to assess their impact on model performance. Canopy height predictions from the fitted models were highly correlated (R2 = 0.70 to 0.89), precise (MAE = 1.37–2.21 m), and virtually unbiased (Bias = −0.20–0.07 m) with respect to validation data. The trained models also performed adequately well on the independent test data (R2 = 0.62–0.78, MAE = 3.06–4.1 m). Models with higher encoder depths (3,4) and trained with 2 m data provide better predictions than models with encoder depth 2 and trained on 1 m data. Inter-comparisons with existing canopy height products also showed our canopy height map provided better agreement with reference airborne lidar canopy height estimates. This study shows the potential of developing regional canopy height products using airborne lidar and NAIP imagery to support forest productivity and carbon modeling at spatially detailed scales. The 30 m canopy height map generated over Texas holds promise in advancing economic and sustainable forest management goals and enhancing decision-making in natural resource management across the state. [ABSTRACT FROM AUTHOR]

Recent studies have highlighted the key role of tree microhabitats in forest habitat complexity and have suggested using them as surrogates for local taxonomic biodiversity. However, few practical guidelines have been published to help foresters in managing microhabitats at the stand scale. This paper provides scientific background information to help to develop such guidelines. We surveyed trees in nine long-unmanaged beech-fir forests to model tree microhabitat occurrence and diversity at the tree level. Data were upscaled to a size range of tree cluster, i.e., at the tree population scale, by aggregating observed values of microhabitat occurrence. Accumulation curves were used to estimate the minimum number of trees required to make all the microhabitat types available. Two managed forests were then studied to quantify management effects on microhabitats. Diameter at breast height (dbh) and tree species, respectively, explained 16 and 10 % of the variations in the number of microhabitat-bearing trees, and 21 and 10 % for the number of microhabitat types. Beech trees and firs with a dbh of less than dbh 50 and 65 cm, respectively, did not ensure the provision of all microhabitat types. At least 20 ha of unmanaged forest were necessary to conserve all the microhabitat types. Current management practices have reduced the number of microhabitat-bearing beeches both by reducing the number of very large trees (dbh > 67.5 cm) and by tree selection within mid-size diameters. For fir, only the logging of very large trees (dbh > 62.5 cm) negatively affected microhabitats. These figures may inspire guidelines for conservation-friendly forestry. [ABSTRACT FROM AUTHOR]

The article presents information on research papers related to wildlife habitat. The paper "Creation Times and Costs for Five Tree-based Wildlife Cavity Structures (California)," by Christopher R. Keyes, David A. Jaramillo and Branden M. Woolley determines the amount of time and costs spent to create five types of tree-derived wildlife cavity structures to assess the feasibility of incorporating this element of forest restoration into a framework of active forest management. The paper "Fire History Effects on Dakota Skipper Occurrence and Habitat (North Dakota)," by Robert K. Murphy, Andi S. Rogers and Larry Lystad explores the occurrence of Dakota skipper and its key habitat elements in relation to prescribed fire history at Lostwood National Wildlife Refuge, a mixed-grass prairie in northwestern North Dakota. The paper "Pastures for Upland Birds: Landowner Incentive Program Restores Native Species in Bermudagrass Pastures (Texas)," by Matt Wagner, Fred Smeins and Brian Hays finds cost-effective strategies for establishing and managing native grasses and forbs in Bermudagrass pastures.

Visitation counts are the measures most widely used by park managers to demonstrate accountability and good stewardship of the public resources that legislatures invest in parks. Ostensibly, counting visitors may appear to be a simple task, but experienced park managers are aware that it is a complicated and difficult challenge with three dimensions: human, logistical, and technical. Part of the challenge has a human dimension in that pressure to demonstrate accountability may tempt managers to inflate visitation counts. However, much of the challenge is logistical and technical. The logistical dimension relates to the placement and maintenance of traffic axle counters, while the technical dimension refers to transposing axle counts into visitor numbers. In addition to providing an overview of the roles of the three dimensions, this paper describes a procedure implemented in Texas State Parks for addressing the technical dimension. To transpose raw axle count numbers into visitation estimates, two parameters have to be calculated: (i) the proportion of axles attributable to visitors, as opposed to officials, vendors, or visitors re-entering the park on the same day (parameter A); and (ii) the average number of visitors per axle (parameter B). A study was conducted for a 12-month period in 92 Texas state parks, during which time observers recorded the data relating to parameters A and B. As a result of the study, these empirically derived parameters could be used by each park site to transpose its axle counts to visitation estimates. Two major findings emerged from the study. First, the parameter estimates varied widely among the 92 parks, whereas the Texas Parks and Wildlife Department (TPWD) traditionally had used a single value system-wide for each parameter. The range for parameter A was 29% to 99%, while for parameter B the values ranged from 0.65 to 2.60. Second, the empirical values were substantially lower than those which traditionally had been used by the agency. Empirical verification of the parameter values used in visitor estimation formulas can improve the accuracy of patron counts and subsequently increase an agency's credibility in the eyes of legislators. [ABSTRACT FROM AUTHOR]

Despite his marked intellectual indebtedness to Coulter and his mentor's massive 588-page tome, Bray's scholarship dovetailed with that of his classmate and later University of Chicago ecologist Henry Chandler Cowles; the latter's pathbreaking research on habitat succession in the Indiana Dunes near Chicago sparked concerted efforts to protect this imperiled plant community.11 As Bray noted about his own work, it too focused on "the study of plants in their natural environments", that is, in their ecological relationships.12 The organizational structure of Bray's dissertation reflected its innovative methodology. 48 Bray, " I The Timber of the Edwards Plateau i , 25; making extensive use of Bray's foundational report is Lisa O'Donnell, I Historical Ecology of the Texas Hill Country i (Austin: City of Austin, Wildland Conservation Division, 2019), < http://www.austintexas.gov/edims/document.cfm?id=321715 > [Accessed Feb. 9, 2021]. 61 Bray, "The Timber of the Edwards Plateau", 29. 62 Rodgers, I Bernhard Eduard Fernow i , 482-485; Frank N. Edgerton, I A Centennial History of Ecological Society of America i (Boca Raton, Fla.: CRC Press/Taylor & Francis Group, 2015), 1-28. 63 Faust, "William L. Bray"; Anders S. Saustrup, "Bray, William L." I The Handbook of Texas Online i , < https://www.tshaonline.org/handbook/entries/bray-william-l > [Accessed Dec. 22, 2020]. Graph: Ecologist William L. Bray (1865-1953) was an expert on the vegetation of western Texas and one of the state's first conservationists; he taught at the University of Texas and Syracuse University. [Extracted from the article]

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Background: Ecologists continue to investigate the factors that potentially affect the pattern and magnitude of tree damage during catastrophic windstorms in forests. However, there still is a paucity of research on which trees are more vulnerable to direct damage by winds rather than being knocked down by the fall of another tree. We evaluated this question in a mixed hardwood–softwood forest within the Big Thicket National Preserve (BTNP) of southeast Texas, USA, which was substantially impacted by Hurricane Rita in September 2005. Results: We showed that multiple factors, including tree height, shade-tolerance, height-to-diameter ratio, and neighborhood density (i.e., pre-Rita stem distribution) significantly explained the susceptibility of trees to direct storm damage. We also found that no single factor had pervasive importance over the others and, instead, that all factors were tightly intertwined in a complex way, such that they often complemented each other, and that they contributed simultaneously to the overall susceptibility to and patterns of windstorm damage in the BTNP. Conclusions: Directly damaged trees greatly influence the forest by causing secondary damage to other trees. We propose that directly and indirectly damaged (or susceptible) trees should be considered separately when assessing or predicting the impact of windstorms on a forest ecosystem; to better predict the pathways of community structure reorganization and guide forest management and conservation practices. Forest managers are recommended to adopt a holistic view that considers and combines various components of the forest ecosystem when establishing strategies for mitigating the impact of catastrophic winds. [ABSTRACT FROM AUTHOR]