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Live shrubs in forest understories pose a challenge for mitigating wildfire risk with prescribed fire. Factors driving shrub consumption in prescribed fires are variable and difficult to explain. This study investigated spatial patterns and drivers of Sierra Nevada mixed-conifer forest shrub consumption in prescribed fires through analysis of high-resolution imagery taken before and after prescribed fire. We applied a spatially explicit, generalized additive model to assess tree cover and coarse woody material as potential drivers of shrub consumption. Shrub cover in two experimental stands prior to burning was 38% and 59% and was 36% and 45% one-year post-burn. In both stands shrub patch density increased, while area-weighted mean patch size and largest patch index decreased. Increased local percent cover of coarse woody material was associated with increased shrub consumption. These findings provide information for prescribed fire managers to help better anticipate shrub consumption and patchiness outcomes under similar conditions. Key words: high resolution imagery, Teakettle Experimental Forest, mixed- conifer, fire hazards, fuel treatments, coarse woody debris. Les arbustes vivants dans les sous-bois constituent un defi pour l'attenuation des risques d'incendie lors d'un brulage dirige. Les facteurs responsables de la combustion des arbustes lors des brulages diriges sont varies et difficiles a cerner. Cette etude se penche sur les patrons spatiaux et les facteurs determinants de la combustion des arbustes dans la foret mixte de coniferes de la Sierra Nevada lors de brulages diriges au moyen de l'analyse d'images a haute resolution prises avant et apres un brulage dirige. Nous avons applique un modele additif generalise, spatialement explicite, pour evaluer le couvert arborescent et le materiel ligneux grossier en tant que facteurs determinants potentiels de la combustion des arbustes. Le couvert arbustif dans deux peuplements experimentaux etait de 38 et 59 % avant le brulage et de 36 et 45 % un an apres le brulage. Dans les deux peuplements, la densite des ilots d'arbustes a augmente tandis que la taille moyenne des ilots ponderee par la superficie et l'indice des plus grands ilots ont diminue. L'augmentation locale du pourcentage de couverture du materiel ligneux grossier etait associee a l'augmentation de la combustion des arbustes. Ces resultats fournissent de l'information aux gestionnaires des brulages diriges pour les aider a mieux anticiper la combustion et la repartition en ilots des arbustes dans des conditions similaires. [Traduit par la Redaction] Mots-cles: imagerie a haute resolution, foret experimentale de Teakettle, coniferes mixtes, risque d'incendie, traitements des combustibles, debris ligneux grossiers., Introduction Shrubs are an essential ecosystem component of forested environments in the western United States and are important for wildlife, nutrient cycling, and biodiversity (Hunter 1990; North et al. 2016). [...]

Changing climatic conditions are increasing overstory tree mortality in forests globally. This restructuring of the distribution of biomass is making already flammable forests more combustible, posing a major challenge for managing the transition to a lower biomass state. In western US dry conifer forests, tree density resulting from over a century of fire‐exclusion practices has increased the risk of high‐severity wildfire and susceptibility to climate‐driven mortality. Reducing dead fuel loads will require new approaches to mitigate risk to the remaining live trees by preparing forests to withstand future wildfire. Here, we used data from the Teakettle Experimental Forest in California to evaluate different prescribed fire burn frequencies and their impact on accumulated dead fuels after a 4‐year drought. Increasing burn frequency could reduce surface fuel build‐up but comes with additional challenges that will require creativity and experimentation to overcome. [ABSTRACT FROM AUTHOR]

Background: Since 2010, all non‐VA hospitals performing cardiac surgeries and percutaneous interventions in Washington State have participated in the Cardiac Care Outcomes Assessment Program (COAP), a data‐driven, physician‐led collaborative quality improvement (QI) collaborative. Prior literature has demonstrated QI programs such as COAP can avert avoidable utilization such as hospital readmissions. However, it is unknown whether such improvements translate into economic benefits. Hypothesis: This study compared downstream healthcare costs between patients undergoing cardiac interventions for coronary artery disease (CAD) at hospitals that were and were not participating in COAP. Methods: Post hoc analysis of Medicare administrative and claims data examined 2.5 million randomly selected deidentified beneficiaries receiving a percutaneous coronary intervention or coronary artery bypass grafting between 2013 and 2020. Total costs were defined as all reimbursements paid by Medicare for up to 5 years following cardiac intervention. Because all non‐VA hospitals in Washington State participated in COAP, we compared respective groups of patients receiving intervention in Washington State with all non‐Washington states, adjusting for patient demographics and comorbidity. To model costs, we applied a multipart estimator, which distinguishes the impact of QI program participation due to survival and utilization while accounting for censoring. Results: Total 5‐year downstream costs were $3861 lower (95% confidence interval [CI] = $1794 to $5741) among patients receiving cardiac intervention at COAP‐exposed hospitals. Lower costs were largely driven by lower utilization during calendar quarters where death was not observed. Conclusions: Participation in this state‐wide cardiac quality improvement program was associated with economic benefits in patients receiving intervention for CAD. [ABSTRACT FROM AUTHOR]

Wildfires, insect outbreaks, and windstorms are increasingly common forest disturbances. Post-disturbance management often involves salvage logging, i.e., the felling and removal of the affected trees; however, this practice may represent an additional disturbance with effects on ecosystem processes and services. We developed a systematic map to provide an overview of the primary studies on this topic and created a database with information on the characteristics of the retrieved publications, including information on stands, disturbance, intervention, measured outcomes, and study design. Of 4341 retrieved publications, 90 were retained in the systematic map. These publications represented 49 studies, predominantly from North America and Europe. Salvage logging after wildfire was addressed more frequently than after insect outbreaks or windstorms. Most studies addressed logging after a single disturbance event, and replication of salvaged stands rarely exceeded 10. The most frequent response variables were tree regeneration, ground cover, and deadwood characteristics. This document aims to help managers find the most relevant primary studies on the ecological effects of salvage logging. It also aims to identify and discuss clusters and gaps in the body of evidence, relevant for scientists who aim to synthesize previous work or identify questions for future studies. Key words: salvage harvesting, sanitation logging, wildfire, insect outbreak, windthrow. Les feux de foret, les epidemies d'insectes et les tempetes de vent sont des perturbations forestieres de plus en plus frequentes. A la suite d'une perturbation, l'amenagement implique souvent une coupe de recuperation, c.-a-d., l'abattage et le prelevement des arbres endommages. Cependant, cette pratique peut constituer une perturbation additionnelle et avoir des effets sur les services et processus de l'ecosysteme. Nous avons developpe une carte systematique destinee a fournir un apercu des etudes originales sur ce sujet et cree une base de donnees contenant de l'information sur les caracteristiques des publications retenues, incluant des informations sur les peuplements, la perturbation, l'intervention, les resultats mesures et la methodologie de l'etude. Des 4341 publications trouvees, 90 ont ete retenues dans la carte systematique. Ces publications representaient 49 etudes menees principalement en Amerique du Nord et en Europe. La coupe de recuperation apres feu a ete etudiee plus frequemment qu'apres des epidemies d'insectes ou des tempetes de vent. La plupart des etudes portaient sur la coupe apres une seule perturbation et le nombre de repetitions de peuplements recuperes depassait rarement 10. Les variables reponse les plus frequentes etaient la regeneration de la strate arborescente, le couvert vegetal et les caracteristiques du bois mort. Ce document vise a aider les gestionnaires a trouver les etudes les plus pertinentes portant sur les effets ecologiques de la coupe de recuperation. Il vise aussi a identifier et examiner les points forts et les lacunes parmi l'ensemble des arguments pertinents pour les scientifiques qui cherchent a synthetiser les travaux anterieurs ou a identifier les sujets de futures etudes. [Traduit par la Redaction] Mots-cles : coupe de recuperation, coupe d'assainissement, feu de foret, epidemie d'insectes, chablis., Introduction Large, episodic, severe forest disturbances such as those caused by wildfires, insect outbreaks, and windstorms are part of the natural dynamics of forest ecosystems across the world (Noss et [...]

Fire suppression and past selective logging of large trees have fundamentally changed frequent-fire-adapted forests in California. The culmination of these changes produced forests that are vulnerable to catastrophic change by wildfire, drought, and bark beetles, with climate change exacerbating this vulnerability. Management options available to address this problem include mechanical treatments (Mech), prescribed fire (Fire), or combinations of these treatments (Mech + Fire). We quantify changes in forest structure and composition, fuel accumulation, modeled fire behavior, intertree competition, and economics from a 20-year forest restoration study in the northern Sierra Nevada. All three active treatments (Fire, Mech, Mech + Fire) produced forest conditions that were much more resistant to wildfire than the untreated control. The treatments that included prescribed fire (Fire, Mech + Fire) produced the lowest surface and duff fuel loads and the lowest modeled wildfire hazards. Mech produced low fire hazards beginning 7 years after the initial treatment and Mech + Fire had lower tree growth than controls. The only treatment that produced intertree competition somewhat similar to historical California mixed-conifer forests was Mech + Fire, indicating that stands under this treatment would likely be more resilient to enhanced forest stressors. While Fire reduced modeled wildfire hazard and reintroduced a fundamental ecosystem process, it was done at a net cost to the landowner. Using Mech that included mastication and restoration thinning resulted in positive revenues and was also relatively strong as an investment in reducing modeled wildfire hazard. The Mech + Fire treatment represents a compromise between the desire to sustain financial feasibility and the desire to reintroduce fire. One key component to long-term forest conservation will be continued treatments to maintain or improve the conditions from forest restoration. Many Indigenous people speak of "active stewardship" as one of the key principles in land management and this aligns well with the need for increased restoration in western US forests. If we do not use the knowledge from 20+ years of forest research and the much longer tradition of Indigenous cultural practices and knowledge, frequent-fire forests will continue to be degraded and lost. [ABSTRACT FROM AUTHOR]

Fire scar based studies have provided robust reconstructions of past fire regimes. The season in which a fire occurs can have considerable impacts to ecosystems but inference on seasonality from fire scars is relatively uncertain. This study examined patterns in the phenology of cambium formation and wounding responses in the five common mixed conifer tree species of the Sierra Nevada. The outer bark was shaved on 35 trees and individual locations within the shaved portions were wounded systematically by applying direct heat using a handheld torch. Most of the trees had not commenced annual ring development by the first burning treatment in late May. By the second treatment, scars were identified mostly within the early or middle earlywood, although variation was high compared with other treatment periods. By late October, all scars were recorded at the ring boundary. Although intra-ring scar positions generally followed a logical temporal pattern, there was high tree to tree variation such as Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) burned on 26 June induced scars in the early, mid, and late earlywood depending on the individual tree. This high variation makes it somewhat challenging to precisely assign past fire season to published fire history studies. Key words: cambium phenology, dendrochronology, fire regime, fire scar, fire seasonality. Les etudes basees sur les cicatrices de feu ont fourni des reconstitutions robustes des regimes des feux passes. La saison durant laquelle un feu survient peut avoir des impacts considerables sur les ecosystemes mais les deductions fondees sur la saisonnalite des cicatrices de feu sont relativement incertaines. Cette etude examine les patrons dans la phenologie de la formation du cambium et les reactions aux blessures chez cinq especes communes de coniferes melanges de la Sierra Nevada. L'ecorce externe a ete enlevee sur 35 arbres et plusieurs endroits distincts a l'interieur de la zone sans ecorce ont ete systematiquement blesses en y appliquant directement une source de chaleur a l'aide d'un chalumeau. Le developpement du cerne annuel n'avait pas debute chez la plupart des arbres lors du premier traitement a la fin du mois de mai. Lors du deuxieme traitement, des cicatrices ont ete identifiees surtout au debut ou au milieu de la zone de bois initial, mais il y avait beaucoup de variation comparativement aux autres periodes de traitement. Vers la fin du mois d'octobre, toutes les cicatrices ont ete observees a la limite du cerne annuel. Meme si la position a l'interieur du cerne annuel suivait generalement un patron temporel logique, il y avait une grande variation d'un arbre a l'autre de telle sorte que des cicatrices ont ete observees au debut, au milieu et a la fin de la zone de bois initial chez des douglas de Menzies brules le 26 juin. Cette grande variation constitue un defi de taille pour determiner precisement durant quelle saison dans le passe des feux sont survenus dans le cas d'etudes publiees au sujet de l'historique des feux. [Traduit par la Redaction] Mots-cles: phenologie du cambium, dendrochronologie, regime des feux, cicatrice de feu, saisonnalite des feux., Introduction Using dendrochronological techniques, tree-ring fire scars are dated with annual resolution and, with multiple fire-scarred samples collected across a given area, fire regime attributes such as frequency and spatial [...]