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Nontuberculous mycobacteria (NTM) are opportunistic pathogens found in soil and water and are the sources of an increasing number of infections and illness (1,2). Multiple recent studies have recognized this [...]

Theoretical tree crop ideotypes have long and narrow live crowns with a high total leaf area. This crown form allows more efficient exploitation of site resources, in part by physically occupying less growing space per unit leaf area and by packing a greater number of trees into a given area. Genetic selection for crop ideotypes has been proposed as a strategy for maximizing productivity per unit area in stands managed under intensive silviculture. The primary objective of this study was to test the relationship between the relative growth performance of different families in a Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) progeny test and morphological crown attributes that conform to a theoretical crop ideotype. The overarching goal was to identify attributes conferring superior height and diameter growth on families and to facilitate the incorporation of these attributes and associated growth mechanisms into hybrid growth models for intensively managed plantations. Crown structural attributes were measured on destructively sampled trees and averaged for the entire crown and each third of live crown length among families. Multivariate analysis revealed that crown attributes averaged over the entire crown performed best for identifying families with different height and diameter growth, followed successively by the bottom, middle, and top crown third. Trees with relatively short branch lengths and steep branch angles tended to have higher total leaf area per unit crown length (TLACL), and this structural attribute showed a strong positive correlation with cumulative diameter growth. The ratio of crown width to crown length (CWL) was moderately and negatively correlated with cumulative height growth. The families displaying the most rapid diameter growth in this progeny test conformed to a theoretical crop ideotype, while those with the most rapid height growth displayed crown attributes with a less obvious relationship to the crop ideotype concept. TLACL implied one possible mechanism driving genetic gain in Douglas-fir families, given its high heritability and strongly positive correlation with growth performance. Incorporating TLACL as an explanatory variable in diameter growth models could at least partly represent different genetic levels. TLACL is less strongly correlated with height growth rate, so incorporating CWL may better represent genetic effects on height growth models. [ABSTRACT FROM AUTHOR]

Seed transfer zones ensure that germplasm selected for restoration is suitable and sustainable in diverse environments. In this study, seed zones were developed for mountain brome (Bromus carinatus Hook. & Arn.) in the Blue Mountains of northeastern Oregon and adjoining Washington. Plants from 148 Blue Mountain seed source locations were evaluated in common-garden studies at two contrasting test sites. Data on phenology, morphology, and production were collected over two growing seasons. Plant traits varied significantly and were frequently correlated with annual precipitation and annual maximum temperature at seed source locations (P < 0.05). Plants from warmer locations generally had higher dry matter production, longer leaves, wider crowns, denser foliage, and greater plant height than those from cooler locations. Regression models of environmental variables with the first two principal components (PC 1 and PC 2) explained 46% and 40% of the total variation, respectively. Maps of PC 1 and PC 2 generally corresponded to elevation, temperature, and precipitation gradients. The regression models developed from PC 1 and PC 2 and environmental variables were used to map seed transfer zones. These maps will be useful in selecting mountain brome seed sources for habitat restoration in the Blue Mountains. Key words: genecology, Bromus carinatus, seed zones, plant adaptation. Les zones de transfert des semences assurent qu'un germoplasme selectionne pour la restauration convient et demeure durable dans divers environnements. Dans cette etude, les auteurs ont developpe des zones d'ensemencement pour le brome (Bromus carinatus Hook. & Arn.) des Blue Mountains du nord-est de l'Oregon et de l'etat de Washington voisin. Dans des jardins communs situes sur deux sites fortement contrastes, ils ont evalue des plants provenant de 148 provenances de semences recoltees dans les Blue Mountains. Ils ont reuni les donnees sur la phenologie, la morphologie et la productivite au cours de deux saisons de croissance. Les caracteres des plantes varient significativement et montrent souvent des correlations avec la precipitation annuelle et les temperatures maximales annuelles prevalant sur les sites de provenance des semences. Les plantes venant des localites plus chaudes montrent generalement une productivite en matiere seche plus grande, des feuilles plus longues, des cimes plus larges, un feuillage plus dense et des plants plus hauts, que ceux provenant de localites plus froides. Les modeles de regression des variables environnementales portant sur les deux premieres composantes principales (PC 1 et PC 2) expliquent respectivement 46 % et 40 % de la variation totale. Les cartes des PC 1 et PC 2 correspondent generalement aux gradients d'elevation, de temperature et de precipitation. Les auteurs ont utilise; les modeles de regression developpes a partir des PC 1 et PC 2 avec les variables environnementales pour cartographier les zones de transfert des sources de semences destinees a la restauration des habitats dans les Blue Mountains. Mots-cles: genecologie, Bromus carinatus, zones des semences, adaptation vegetale. [Traduit par la Redaction], Introduction Native forest and rangeland plant communities are increasingly threatened by overgrazing (Belsky and Blumenthal 1997), uncharacteristic frequent wildfires (Hessburg et al. 2005), invasive weeds (Mack 1981; Keeley 2006), and [...]

Abstract: Genetic variation in fall cold damage in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) was measured by exposing excised branches of seedlings from 666 source locations grown in [...]

The convectively driven transport of soluble trace gases from the lower to the upper troposphere can occur on timescales of less than an hour, and recent studies suggest that microphysical scavenging is the dominant removal process of tropospheric ozone precursors. We examine the processes responsible for vertical transport, entrainment, and scavenging of soluble ozone precursors (formaldehyde and peroxides) for midlatitude convective storms sampled on 2 September 2013 during the Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) study. Cloud‐resolving simulations using the Weather Research and Forecasting with Chemistry model combined with aircraft measurements were performed to understand the effect of entrainment, scavenging efficiency (SE), and ice physics processes on these trace gases. Analysis of the observations revealed that the SEs of formaldehyde (43–53%) and hydrogen peroxide (~80–90%) were consistent between SEAC4RS storms and the severe convection observed during the Deep Convective Clouds and Chemistry Experiment (DC3) campaign. However, methyl hydrogen peroxide SE was generally smaller in the SEAC4RS storms (4%–27%) compared to DC3 convection. Predicted ice retention factors exhibit different values for some species compared to DC3, and we attribute these differences to variations in net precipitation production. The analyses show that much larger production of precipitation between condensation and freezing levels for DC3 severe convection compared to smaller SEAC4RS storms is largely responsible for the lower amount of soluble gases transported to colder temperatures, reducing the amount of soluble gases which eventually interact with cloud ice particles. Key Points: Formaldehyde and hydrogen peroxide scavenging efficiencies are consistent with literature, while methyl hydrogen peroxide is generally smallerHighly soluble hydrogen peroxide is mostly depleted between cloud base and the freezing level, that is, the warm region of the stormRetention of dissolved trace gases in frozen precipitation seems to be more important for moderately soluble trace gases [ABSTRACT FROM AUTHOR]