Shortening fire return interval predisposes west-central Canadian boreal peatlands to more rapid vegetation growth and transition to forest cover.

Climate change in northern latitudes is increasing the vulnerability of peatlands and the riparian transition zones between peatlands and upland forests (referred to as ecotones) to greater frequency of wildland fires. We examined early post-fire vegetation regeneration following the 2011 Utikuma complex fire (central Alberta, Canada). This study examined 779 peatlands and adjacent ecotones, covering an area of ~182 km2 . Based on the known regional fire history, peatlands that burned in 2011 were stratified into either long return interval (LRI) fire regimes of >80 years (i.e., no recorded prior fire history) or short fire return interval (SRI) of 55 years (i.e., within the boundary of a documented severe fire in 1956). Data from six multitemporal airborne lidar surveys were used to quantify trajectories of vegetation change for 8 years prior to and 8 years following the 2011 fire. To date, no studies have quantified the impacts of post-fire regeneration following short versus long return interval fires across this broad range of peatlands with variable environmental and post-fire successional trajectories. We found that SRI peatlands demonstrated more rapid vascular and shrub growth rates, especially in peatland centers, than LRI peatlands. Bogs and fens burned in 1956, and with little vascular vegetation (classified as "open peatlands") prior to the 2011 fire, experienced the greatest changes. These peatlands tended to transition to vascular/shrub forms following the SRI fire, while open LRI peatlands were not significantly different from pre-fire conditions. The results of this study suggest the emergence of a positive feedback, where areas experiencing SRI fires in southern boreal peatlands are expected to transition to forested vegetation forms. Along fen edges and within bog centers, SRI fires are expected to reduce local peatland groundwater moisture-holding capacity and promote favorable conditions for increased fire frequency and severity in the future.

Determining Incidence and Risk Factors of Pressure Injury After Orthopaedic Surgery in Children and Adolescents With Neuromuscular Complex Chronic Conditions.

BACKGROUND: Pressure injuries are serious yet often preventable alterations in skin integrity prevalent in orthopaedics, especially in pediatric patients with neuromuscular complex chronic conditions (NCCC). The aims of this study were to (1) estimate incidence of pressure injury in children with NCCC after orthopaedic surgery; (2) determine risk factors for pressure injury development; and (3) describe severity and location of pressure injuries. METHODS: Children and adolescents (<22 y old) with NCCC who underwent orthopaedic surgery at a single tertiary-care children's hospital between 2016 and 2020 were retrospectively identified. A matched case-control design was used to match patients who developed a pressure injury within 1.5 months after surgery to subjects who did not develop a pressure injury using a 1:1 matching based on neuromuscular diagnosis, age, sex, and type of surgery. Patient characteristics, comorbidities, pressure injury characteristics, and a pressure injury risk assessment score utilizing the Braden QD scale were compared across pressure injury groups. RESULTS: Of 564 children with NCCC who underwent orthopaedic surgery, 43 (7.6%) developed a postoperative pressure injury. Pressure injuries were primarily located on the heel, followed by sacral/groin/buttocks, then knee. The most common diagnosis was cerebral palsy with associated neuromuscular scoliosis, and hip reconstruction was the most common surgical procedure. The pressure injury cohort had significantly more patients who were non-ambulatory (GMFCS IV/V), with a seizure disorder, g-tube, nonverbal status, wheelchair usage, and had additional medical devices. Median Braden QD risk score was higher in the injury cohort and a cutoff ≥12 was optimal for predicting pressure injury development. CONCLUSIONS: Pressure injuries after orthopaedic surgery are not uncommon in children with NCCC. The entire care team should be aware of additional risk factors associated with pressure injury development, including the diagnosis of cerebral palsy with neuromuscular scoliosis, seizure disorder, nonverbal status, g-tube, and the presence of multiple medical devices. Implementation of evidence-based pressure injury prevention guidelines on identified high-risk children with NCCC may reduce pressure injury risk and improve the postoperative course. LEVEL OF EVIDENCE: Level III.

A Lightweight Leddar Optical Fusion Scanning System (FSS) for Canopy Foliage Monitoring.

A growing need for sampling environmental spaces in high detail is driving the rapid development of non-destructive three-dimensional (3D) sensing technologies. LiDAR sensors, capable of precise 3D measurement at various scales from indoor to landscape, still lack affordable and portable products for broad-scale and multi-temporal monitoring. This study aims to configure a compact and low-cost 3D fusion scanning system (FSS) with a multi-segment Leddar (light emitting diode detection and ranging, LeddarTech), a monocular camera, and rotational robotics to recover hemispherical, colored point clouds. This includes an entire framework of calibration and fusion algorithms utilizing Leddar depth measurements and image parallax information. The FSS was applied to scan a cottonwood (Populus spp.) stand repeatedly during autumnal leaf drop. Results show that the calibration error based on bundle adjustment is between 1 and 3 pixels. The FSS scans exhibit a similar canopy volume profile to the benchmarking terrestrial laser scans, with an r2 between 0.5 and 0.7 in varying stages of leaf cover. The 3D point distribution information from FSS also provides a valuable correction factor for the leaf area index (LAI) estimation. The consistency of corrected LAI measurement demonstrates the practical value of deploying FSS for canopy foliage monitoring.

Seismic line impacts on proximal boreal forest and wetland environments in Alberta.

Seismic lines are corridors cut through forest and wetland land covers for geophysical exploration of oil and gas deposits. Here we present a localised case study of the impacts of seismic lines on proximal boreal forest and wetland ecosystem vegetation structural characteristics. The study concentrates on a relatively undisturbed area of the Oil Sands Region of the Boreal zone in north central Alberta using airborne multi-spectral lidar and publically available geospatial data. The results of this study indicate that significant variations in adjacent forest/wetland edge vegetation structure occur proximal to 30 seismic lines identified within the study area. The variations observed in this area depend on the environmental characteristics of the seismic lines. Often taller trees and greater fractional cover extends to a distance of up to 55 m from the seismic line, especially in land covers adjacent to wider seismic lines. Random forest analysis of spatial correspondence between environmental and proximity-based variability associated with seismic lines indicates that distance, incident radiation and the potential for accumulation of surface water based on local geomorphology (inferred from topographic position) are the most important variables affecting height and fractional cover of proximal vegetation. Combined variables including distance from the seismic line, width of the seismic line, cardinal direction and incident radiation, topographic position and underlying surface geology may be used to predict spatial variability of vegetation height to an accuracy of 70% (adjusted (adj.) R2). From this research, we suggest continued sampling/testing of lidar/high resolution optical imagery and geospatial data to examine the impacts of seismic lines in other parts of the Oil Sands Region using the methods developed in this case study. Reclamation management plans for oil and gas exploration areas should focus on reclaiming wider seismic lines first as these have the greatest impact on proximal ecosystems.