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The longevity of a single 22.4 Mg * [ha.sup.-1] application of dolomitic limestone at four northern hardwood stands was evaluated over 30 years (1986-2016) to determine whether changes in soils, foliage, and tree growth were sustained on the unglaciated Allegheny Plateau in northern Pennsylvania, USA. In limed plots, soils, sampled to 45-55 cm depth, and sugar maple (Acer saccharum Marsh.) and black cherry (Prunus serotina Ehrh.) foliage had significantly (P [less than or equal to] 0.05) greater concentrations of calcium (Ca) and magnesium (Mg) through 2016 compared with samples from unlimed plots. Ca and Mg capitals (g * [m.sup.-2]) in the Oi through A horizons combined were greater on limed plots than unlimed plots, largely due to increases in the thickness and nutrient concentration in the A horizon. Over 30 years, sugar maple basal area increment ([cm.sup.2] * [year.sup.-1] BAINC) was greater in limed plots (30.6 [cm.sup.2] * [year.sup.-1] vs unlimed 13.3), American beech (Fagus grandifolia Ehrh.) BAINC was unaffected by lime application, and black cherry BAINC was reduced in limed plots compared with unlimed plots. The sustained effect of this one-time lime treatment shows the strong role of efficient nutrient cycling in forests and suggests that the benefits over a substantial portion of a stand rotation may increase the feasibility of operational liming. Key words: forest liming, base cations, exchangeable calcium (Ca) and magnesium (Mg), percent carbon (C) and nitrogen (N), basal area increment, sugar maple, American beech, black cherry. La longevite d'une application unique de 22,4 Mg * [ha.sup.-1] de calcaire dolomitique dans quatre peuplements de feuillus nordiques situes dans la partie non glaciere du plateau des Alleghany dans le nord de la Pennsylvanie, aux Etats-Unis, a ete evaluee sur une periode de 30 ans (1986-2016) pour determiner si les changements dans le sol, le feuillage et la croissance des arbres ont persiste. Dans les parcelles qui avaient ete chaulees, les sols echantillonnes jusqu'a une profondeur de 45-55 cm, ainsi que le feuillage de l'erable a sucre (Acer saccharum Marsh.) et du cerisier tardif (Prunus serotina Ehrh.), avaient des concentrations de calcium (Ca) et de magnesium (Mg) significativement plus elevees (P [less than or equal to] 0,05) jusqu'en 2016 comparativement aux echantillons provenant de parcelles non chaulees. Les capitaux en Ca et Mg (g * [m.sup.-2]) dans les horizons Oi a A combines etaient plus eleves dans les parcelles chaulees que dans les parcelles non chaulees, surtout a cause de l'augmentation de l'epaisseur et de la concentration des nutriments dans l'horizon A. Sur 30 ans, l'accroissement de la surface terriere (AST [cm.sup.2] * [an.sup.-1]) de l'erable a sucre etait plus eleve dans les parcelles chaulees (30,6 contre 13,3 [cm.sup.2] * [an.sup.-1] dans les parelles non chaulees). L'application de chaux n'a pas eu d'effet sur l'AST du hetre d'Amerique (Fagus grandifolia Ehrh.) et a reduit l'AST du cerisier tardif dans les parcelles chaulees comparativement aux parcelles non chaulees. L'effet persistant de cette application unique de chaux illustre le role majeur du recyclage efficace des nutriments dans les forets et indique que les benefices qui perdurent pendant une partie importante de la periode de revolution d'un peuplement peuvent augmenter la faisabilite du chaulage operationnel. [Traduit par la Redaction] Mots-cles : chaulage en foret, cations basiques, calcium (Ca) et magnesium (Mg) echangeables, pourcentage de carbone (C) et d'azote (N), accroissement de la surface terriere, erable a sucre, hetre d'Amerique, cerisier tardif., Introduction Forest liming is used to alter soil acidity, counter effects of long-term acidic inputs, and improve the growth and health of trees (Long et al. 2011; Court et al. [...]

Liming, the application of carbonate materials (e.g., CaC[O.sub.3], CaMg[(C[O.sub.3]).sub.2]) to soils and surface waters, has been used extensively in Europe, and to a lesser extent in Canada and the United States, to mitigate the effects of acid deposition on forest and aquatic ecosystems. This literature review was conducted to assess the effects of liming on ecologically and economically important sugar maple dominated ecosystems of northeastern North America, where it is increasingly used to treat sugar maple dieback. Potential direct and indirect effects were considered to determine whether the use of liming to revitalize these forests could negatively affect other ecological parameters, including those in adjacent aquatic habitats. Based on current scientific literature, it is not anticipated that liming at rates of 1-3 t [ha.sup.-1] would have major detrimental effects on these ecosystems. However, liming could have negative effects on northern hardwood forests with regard to earthworm invasions. The choice of liming as a mitigation tool should be made not only after weighing the potentially negative effects against the benefits of restoring sugar maple dominated stands in poorly buffered soils, but also after considering ecological components that could be lost or never recovered if an acidified forest ecosystem is not limed. Key words: acidification, acid rain, mitigation, liming, sugar maple, restoration, ecosystem, forest, aquatic habitat. Le chaulage, l'application de materiel carbonate (par exemple: CaC[O.sub.3], CaMg[(C[O.sub.3]).sub.2]) sur les sols et les eaux de surface, a ete largement utilise en Europe, et dans une moindre mesure au Canada et aux Etats-Unis, afin d'attenuer les effets des depots acides sur les ecosystemes forestiers et aquatiques. Cette revue de litterature a ete effectuee afin d'evaluer les effets du chaulage sur les ecosystemes forestiers domines par l'erable a sucre, qui sont importants au plan ecologique et economique dans le nord-est de l'Amerique du Nord, dans lesquels il est de plus en plus utilise pour traiter le deperissement de l'erable a sucre. Les effets potentiels directs et indirects ont ete consideres afin de determiner si l'utilisation du chaulage pour revitaliser ces forets pourrait avoir des effets negatifs sur d'autres composantes ecologiques, incluant celles des habitats aquatiques situes a proximite. Sur la base de la litterature scientifique actuelle, il n'est pas prevu que le chaulage a des taux de 1 a 3 t [ha.sup.- 1] ait des effets nefastes importants sur ces ecosystemes. Cependant, les erablieres chaulees pourraient etre sujettes aux effets negatifs lies a l'invasion de vers de terre. La decision finale d'utiliser le chaulage comme outil de mitigation doit non seulement tenir compte des effets potentiellement positifs et negatifs de ce traitement dans les erablieres situees sur des sols a faible pouvoir tampon, mais aussi des composantes ecologiques qui pourraient etre perdues ou ne jamais etre recuperees si un ecosysteme forestier acidifie n'est pas chaule. Mots-cles: acidification, pluie acide, mitigation, chaulage, erable a sucre, restauration, foret, habitat aquatique, ecosysteme., 1. Acid deposition and the need for liming Acid deposition (acid rain) emerged as one of the most publicly visible environmental issues during the 1970s and 1980s (Driscoll et al. [...]

In Pennsylvania, two hypotheses compete to explain the chronic oak (Quercus spp.) regeneration problem: excessive deer browsing and soil cation depletion. We tested these hypotheses by evaluating the effect of forest liming and deer exclosure fencing on northern red oak (Quercus rubra L.) seedling growth and nutrition in five oak shelterwood stands in Pennsylvania over 6 years. In each stand, four planting plots were located inside a 2.4 m high woven wire fence and another four were established outside the fence. About 225 northern red oak acorns were planted in each plot in spring 2004. Dolomitic limestone was applied to randomly selected plots at rates of 0, 4.5, 9.0, and 13.5 Mg * [ha.sup.-1] during May 2004. There were no statistically significant (P ≤ 0.05) growth responses to lime applications. The only significant growth responses resulted from the fence versus no-fence treatment. A significant (P < 0.003) fence x year interaction for seedling height and root collar diameter indicates differential impacts of deer browsing. By 2009, seedlings inside fences averaged 32 cm tall, while seedlings outside the fences averaged 17 cm. Similarly, root collar diameter averaged 6.6 mm outside the fences and 9.1 mm inside fences. Resume: En Pennsylvanie, deux hypotheses s'affrontent pour expliquer le probleme chronique de regeneration du chene (Quercus spp.): le broutement excessif du chevreuil et l'epuisement des cations du sol. Nous avons teste ces hypotheses en evaluant l'effet apres six ans du chaulage en foret et de l'utilisation de clotures pour exclure le chevreuil sur la nutrition et la croissance de semis de chene rouge (Quercus rubra L.) dans cinq peuplements soumis a une coupe progressive en Pennsylvanie. Dans chaque peuplement, quatre parcelles de plantation etaient situees a l'interieur d'une cloture grillagee de 2,4 m de haut et quatre autres etaient etablies a l'exterieur de la cloture. Environ 225 glands de chene rouge ont ete plantes dans chaque parcelle au printemps 2004. De la chaux dolomitique a ete appliquee dans des parcelles choisies au hasard a des taux de 0, 4,5, 9,0 et 13,5 Mg * [ha.sup.-1] durant le mois de mai 2004. Les applications de chaux n'ont eu aucun effet signifi-catif (P ≤ 0,05) sur la croissance. La seule reaction significative de la croissance etait associee au traitement d'exclusion. Une interaction significative (P < 0,003) entre le traitement d'exclusion et l'annee dans le cas du diametre au collet et de la hauteur des semis indique que l'impact du broutement des chevreuils varie. En 2009, les semis avaient une hauteur moyenne de 32 cm a l'interieur des exclos tandis qu'ils n'avaient en moyenne que 17 cm a l'exterieur. De meme, le diametre au collet etait en moyenne de 6,6 mm a l'exterieur des exclos et de 9,1 mm a l'interieur. [Traduit par la Redaction], Introduction Regenerating oak (Quercus spp.) forests has been a persistent problem in Pennsylvania and other parts of the central hardwood region of eastern North America (Moser et al. 2006; McWilliams [...]

Oak dominance is declining in the central hardwoods region, as canopy oaks are being replaced by shade-tolerant trees that are abundant in the understory of mature stands. Although prescribed fire can reduce understory density, oak seedlings often fail to show increased vigor after fire, as the canopy remains intact. In this study, we examine the response of tree regeneration to a sequence of repeated prescribed fires followed by canopy gap formation. We sampled advance regeneration (stems >30 cm tall) in 52 gaps formed by synchronous mortality of white oak (Quercus alba L.); 28 gaps were in three burned stands and 24 gaps were in three unburned stands. Five years after gap formation, unburned gaps were being filled by shade-tolerant saplings and poles and were heavily shaded (7% of full sun). By contrast, tolerant saplings had been virtually eliminated in the burned gaps, which averaged 19% of full sun. Larger oak and hickory regeneration was much more abundant in burned gaps, as was sassafras, while shade-tolerant stems were equally abundant in burned and unburned gaps. Our results suggest that the regeneration of oak, particularly that of white oak, may be improved with multiple prescribed fires followed by the creation of moderate-sized canopy gaps (200-400 [m.sup.2]). Resume: La dominance des chenes diminue dans la region centrale de la foret feuillue et son couvert est graduellement remplace par celui d'arbres tolerants a l'ombre qui sont abondants dans le sous-bois des forets matures. Bien que le brulage dirige puisse reduire la densite des arbres du sousbois, les semis de chene sont souvent incapables d'augmenter leur vigueur apres feu lorsque la canopee demeure intacte. Dans cette etude, nous evaluons la reaction de la regeneration des arbres a la suite de brulages diriges repetes qui ont precede la formation de trouees dans la canopee. Nous avons echantillonne la regeneration preetablie (plus de 30 cm de hauteur) dans 52 trouees formees par la mort synchrone de chenes blancs (Quercus alba L.). Vingthuit trouees etaient situees dans trois peuplements brules alors que 24 trouees etaient situees dans trois peuplements non brules. Cinq ans apres la formation des trouees, les trouees des peuplements non brules etaient occupees par des gaules et des perches d'especes tolerantes a l'ombre et etaient fortement ombragees (7 % de la pleine lumiere). A l'inverse, les gaules d'especes tolerantes a l'ombre avaient ete pratiquement eliminees des trouees des peuplements brules qui recevaient, en moyenne, 19 % de la pleine lumiere. Une regeneration de grande taille de chene et de caryer etait beaucoup plus abondante dans les trouees des peuplements brules, tout comme le sassafras, alors que les individus tolerants a l'ombre etaient aussi abondants dans les trouees des peuplements brules que non brules. Nos resultats indiquent que la regeneration du chene, particulierement celle du chene blanc, peut etre amelioree a l'aide de brulages diriges multiples, suivis par la creation de trouees de taille moderee (de 200 a 400 [m.sup.2]) dans la canopee. [Traduit par la Redaction], Introduction In addition to climate and landform, disturbance regime is a key factor in determining the structure, species composition, and dynamics of forest ecosystems. In many regions, altered disturbance regimes [...]

Sugar maple (Acer saccharum Marsh.) is a keystone species in the northern hardwood forest, and decline episodes have negatively affected the growth and health of sugar maple in portions of its range over the past 50+ years. Crown health, growth, survival, and flower and seed production of sugar maple were negatively affected by a widespread decline event in the mid-1980s on the unglaciated Allegheny Plateau in northern Pennsylvania. A long-term liming study was initiated in 1985 to evaluate responses to a one-time application of 22.4 Mg * [ha.sup.-1] of dolomitic limestone in four northern hardwood stands. Over the 23-year period ending in 2008, sugar maple basal area increment (BAINC) increased significantly (P ≤ 0.05) in limed plots from 1995 through 2008, whereas American beech (Fagus grandifolia Ehrh.) BAINC was unaffected. For black cherry (Prunus serotina Ehrh.), the third principal overstory species, BAINC and survival were reduced in limed plots compared with unlimed plots. Foliar Ca and Mg remained significantly higher in sugar maple foliage sampled 21 years after lime application, showing persistence of the lime effect. These results show long-term species-specific responses to lime application. L'erable a sucre (Acer saccharum Marshall) est une espece cle de la foret feuillue nordique et les episodes de deperissement ont eu un effet nefaste sur la croissance et la sante de cette essence dans certaines parties de son aire de repartition au cours des 50 dernieres annees et un peu plus. Un episode generalise de deperissement, survenu au milieu des annees 1980 sur le Plateau d'Alleghany qui a echappe a la glaciation dans le nord de la Pennsylvanie, a eu un effet nefaste sur la sante de la cime, la croissance, la survie ainsi que la production de fleurs et de graines de l'erable a sucre. Une experience de chaulage a ete initiee en 1985 pour evaluer la reponse a long-terme a une application unique de 22.4 Mg * [ha.sup.-1] de chaux dolomitique dans quatre peuplements de feuillus nordiques. Pendant la periode de 23 ans qui s'est terminee en 2008, l'accroissement en surface terriere de l'erable a sucre a significativement (P ≤ 0.05) augmente dans les parcelles chaulees tandis que celui du hetre d'Amerique (Fagus grandifolia Ehrh.) n'a pas ete affecte. Dans le cas du cerisier tardif (Prunus serotina Ehrh.), la troisieme espece en importance de l'etage dominant, le chaulage a reduit sa surface terriere et sa survie comparativement aux arbres dans les parcelles temoins. Le Ca et le Mg foliaires sont demeures significativement plus eleves dans le feuillage de l'erable a sucre echantillonne 21 ans apres l'application de chaux indiquant que la chaux avait un effet persistant. Ces resultats montrent que les reactions a l'application de chaux sont propres a chaque espece. [Traduit par la Redaction], Introduction Concern for the effects of acid deposition on forest soils has led to interest in forest liming as a remedial measure. The northeastern United States has received historically high [...]

Cleavitt et al. (2018, Can. J. For. Res. 48(1): 23-31, doi:10.1139/cjfr-2017-0233) report a lack of sugar maple (Acer saccharum Marsh.) regeneration in Hubbard Brook Experimental Forest (HBEF), Watershed 5 (W5), following whole-tree clearcut harvesting and purport that harvesting-induced soil calcium depletion contributed to regeneration failure of this species. In New England, clearcutting is a silvicultural strategy used to promote less tolerant species, especially birch (Betula spp.; Marquis (1969), Birch Symposium Proceedings, USDA Forest Service; Leak et al. (2014), doi:10.2737/NRS-GTR-132), which is just the outcome that the authors report. While this study reports an impressive, long-term data set, given broad interest in sugar maple and sustainability of forest management practices, we feel that it is critical to more fully explore the role of nutrition on sugar maple dynamics, both prior to and during the experiment, and to more fully review the scientific record on the role of whole-tree clearcutting in nutrient-induced sugar maple dynamics. Key words: sugar maple, whole-tree harvest, management implications, regeneration, calcium. Cleavitt et al. (2018, Can. J. For. Res. 48(1): 23-31, doi:10.1139/cjfr-2017-0233) indiquent qu'il y a un probleme de regeneration de l'erable a sucre (Acer saccharum Marsh.) a la foret experimentale de Hubbard Brook dans le bassin versant 5 a la suite d'une coupe a blanc par arbre entier et pretendent que l'appauvrissement du sol en calcium cause par la recolte a contribue a l'echec de la regeneration de cette espece. En Nouvelle-Angleterre, la coupe a blanc est une strategie sylvicole utilisee pour favoriser les especes moins tolerantes, particulierement le bouleau (Betula spp.; Marquis (1969), Birch Symposium Proceedings, USDA Forest Service; Leak et al. (2014), doi:10.2737/NRS-GTR-132), ce qui correspond justement au resultat que rapportent les auteurs. Alors que cette etude presente un ensemble impressionnant de donnees a long terme, etant donne qu'il y a un vaste interet pour l'erable a sucre et la durabilite des pratiques d'amenagement forestier, nous croyons qu'il est essentiel d'explorer davantage le role de la nutrition sur la dynamique de l'erable a sucre, tant avant que durant l'experience, et de revoir en profondeur les donnees scientifiques sur le role de la coupe a blanc par arbre entier sur la dynamique de l'erable a sucre engendree par les elements nutritifs. [Traduit par la Redaction] Mots-cles: erable a sucre, recolte par arbre entier, consequences de l'amenagement, regeneration, calcium., Cleavitt et al. (2018) report a lack of sugar maple (Acer saccharum Marsh.) regeneration in Hubbard Brook Experimental Forest (HBEF), Watershed 5 (W5), following whole-tree clearcut harvesting and purport that [...]

Cystic fibrosis (CF) is due to mutations in the CFTR gene and is characterized by hypersecretion of the proinflammatory chemokine IL-8 into the airway lumen. Consequently, this induces the highly inflammatory cellular phenotype typical of CF. Our initial studies revealed that IL-8 mRNA is relatively stable in CF cells compared with those that had been repaired with [WT]CFTR (wild-type CFTR). Relevantly, the 3'-UTR of IL-8 mRNA contains AU-rich sequences (AREs) that have been shown to mediate posttranscriptional regulation of proinflammatory genes upon binding to ARE-binding proteins including Tristetraprolin (TTP). We therefore hypothesized that very low endogenous levels of TTP in CF cells might be responsible for the relative stability of IL-8 mRNA. As predicted, increased expression of TTP in CF cells resulted in reduced stability of IL-8 mRNA. An in vitro analysis of IL-8 mRNA stability in CF cells also revealed a TTP-induced enhancement of deadenylation causing reduction of IL-8 mRNA stability. We conclude that enhanced stability of IL-8 mRNA in TTP-deficient CF lung epithelial cells serve to drive the proinflammatory cellular phenotype in the CF lung. cytokines; chemokines; inflammation; gene regulation

Abstract: Sugar maple (Acer saccharum Marsh.) decline has occurred throughout its range over the past 50 years, although decline symptoms are minimal where nutritional thresholds of Ca, Mg, and Mn [...]

Abstract: We used dendrochronology to examine the influence of past fires on oak and maple establishment. Six study units were located in southern Ohio, where organized fire control began in [...]

Abstract: Sugar maple (Acer saccharum Marsh.) decline disease on the Allegheny Plateau (region 1) resulted in high levels of mortality during the 1990s. Sugar maple was predisposed to decline because [...]

Ref.: Can. J. For. Res. 38: 1761-1774 (2008). On p. 1761, some extraneous text was inadvertently included in the Resume. The corrected version appears below. Le deperissement de l'erable a [...]