Alder Trees Research Articles

When a Palearctic bacterium meets a Nearctic insect vector: Genetic and ecological insights into the emergence of the grapevine Flavescence dorée epidemics in Europe.

Flavescence dorée (FD) is a European quarantine grapevine disease transmitted by the Deltocephalinae leafhopper Scaphoideus titanus. Whereas this vector had been introduced from North America, the possible European origin of FD phytoplasma needed to be challenged and correlated with ecological and genetic drivers of FD emergence. For that purpose, a survey of genetic diversity of these phytoplasmas in grapevines, S. titanus, black alders, alder leafhoppers and clematis were conducted in five European countries. Out of 132 map genotypes, only 11 were associated to FD outbreaks, three were detected in clematis, whereas 127 were detected in alder trees, alder leafhoppers or in grapevines out of FD outbreaks. Most of the alder trees were found infected, including 8% with FD genotypes M6, M38 and M50, also present in alders neighboring FD-free vineyards and vineyard-free areas. The Macropsinae Oncopsis alni could transmit genotypes unable to achieve transmission by S. titanus, while the Deltocephalinae Allygus spp. and Orientus ishidae transmitted M38 and M50 that proved to be compatible with S. titanus. Variability of vmpA and vmpB adhesin-like genes clearly discriminated 3 genetic clusters. Cluster Vmp-I grouped genotypes only transmitted by O. alni, while clusters Vmp-II and -III grouped genotypes transmitted by Deltocephalinae leafhoppers. Interestingly, adhesin repeated domains evolved independently in cluster Vmp-I, whereas in clusters Vmp-II and–III showed recent duplications. Latex beads coated with various ratio of VmpA of clusters II and I, showed that cluster II VmpA promoted enhanced adhesion to the Deltocephalinae Euscelidius variegatus epithelial cells and were better retained in both E. variegatus and S. titanus midguts. Our data demonstrate that most FD phytoplasmas are endemic to European alders. Their emergence as grapevine epidemic pathogens appeared restricted to some genetic variants pre-existing in alders, whose compatibility to S. titanus correlates with different vmp gene sequences and VmpA binding properties.

Aquatic and riparian ecosystem recovery from debris flows in two western Washington streams, USA.

An exceptionally powerful storm struck southwestern Washington in December 2007 causing large debris flows in two adjacent streams. The two affected streams had been studied prior to the storm, providing a rare opportunity to examine ecosystem recovery. We monitored the streams and their riparian zones for six years after the disturbances to determine whether recovery rates of biota, physical habitat, and water temperature differed, and if so, what factors affected resilience. Along both streams, the debris flows removed wide swaths of soil, rock, and coniferous riparian forests, widening the active channel and increasing solar exposure and summer water temperatures. Initially depauperate of vegetation, after four years red alder trees dominated the riparian plant communities. The warmer water, greater solar radiation, and unstable substrates likely contributed to variable benthic insect and tailed frog tadpole densities over time, although benthic insect communities became more similar after three years. The debris flows also decreased channel slopes and removed channel step barriers such that cutthroat trout were able to rapidly occupy habitats far upstream, but sculpins were slower to recolonize and both fish species exhibited some differences in recovery between the two streams. Crayfish were severely impacted by the debris flows; this may be due to attributes of their life history and the timing of the flows. Overall, we found that recolonizing aquatic species exhibited varying levels of resilience and recovery after the disturbances being related to the influence of physical habitat conditions, species dispersal ability, and the presence of nearby source populations.

Alnus glutinosa L. Gaertn. as potential tree for brackish and saline habitats

Over 800 million hectares of land worldwide are affected by salinity. Predicted scenarios of global climate change include a rise in sea level, which may severely affect coastal forest areas. Black alder (Alnus glutinosa) is a tree species known to tolerate heavily waterlogged soils, but its salt resistance is still unclear. The aim of our study was to assess A. glutinosa growth under soil salinity as a possible tree for wet, salt-affected sites in a changing coastal environment due to climate change. We hypothesised that: a) growth parameters are directly related to soil conditions; and b) salinity and waterlogging can limit black alder growth. For our research, we evaluated 9-11-year-old black alder plantations in Poland, one in a saline area and two reference sites on non-saline soils (one with higher moisture content). The growth of trees at each site was characterised by calculating the growth success, mean diameter at breast height, the mean height and the standard deviations from the means. We also calculated the distribution of diameters in each population, regression models for growth as the relationship between diameter and height, and coefficients of variance. The means between sites were compared by one-way ANOVA with Scheffe’s post-hoc comparisons. To characterise soil conditions we took soil samples for each site and compared their properties by the same statistical tests.Under saline conditions, black alder growth was limited in terms of height, diameter at breast height and growth success. Salinity also affected the trees’ variability, growth form and growth pattern. However, these effects were comparable to those observed in the non-saline waterlogged site. The models of growth described by regression demonstrated similar reduction of growth dynamics in these two sites. Moreover, the coefficients of variation in diameter and height of trees in these sites were similar and higher than in non-stressed site. In addition, at the saline and waterlogged sites black alder trees had relatively large number of root suckers, whereas in non-stressed site this was not the case. On the plantations in stressed environments there had been losses in the A. glutinosa stand, which had been spontaneously settled by other species of trees and shrubs, which increased species richness. Therefore, regarding climate change, in our opinion black alder can be considered as an option for planting in brackish coastal areas, where nature conservation and watershed management are at least as important as wood production.

Groundwater Level Fluctuations Affect the Mortality of Black Alder (Alnus glutinosa Gaertn.)

Since the 1990s, a decline of riparian black alder (Alnus glutinosa Gaertn.) has been observed over Europe. The fungus-like eukaryotic pathogen Phytophthora alni subsp. alni is thought to be a causal agent of this process; however, abiotic factors may also be involved. Previous studies suggest that climate conditions and, especially, depletion of groundwater level may be among the most important factors that trigger this phenomenon. We investigated the radial growth and wood vessel diameter of black alder trees of various vigour classes as well as their response to groundwater level changes to search for the link between soil water resources availability and mortality related to alder dieback. Samples were collected in the natural stand located near Sieraków village in the Kampinoski National Park, central Poland, in the area where alder dieback has been recently observed. Based on the crown defoliation level, three vigour classes (healthy, weakened, and dead trees) were distinguished. Cross sections were prepared with a sliding microtome, and Cell P image analysis software was used for the measurements. Tree-ring width (TRW) and vessel diameter (VD) were determined and correlated with the monthly values of precipitation and groundwater level. Alders of the analysed vigour classes exhibited similar patterns of TRW and VD changes over the analysis time. The narrowest tree rings were observed in weakened alders, while the largest vessels were noted in healthy trees. In the case of TRW and VD chronologies, the weakest, and hence insignificant, resemblance was found for healthy and dead trees. TRW and VD of the analysed alders were not correlated with the monthly sum of precipitation, but a negative influence of rainfall in April was observed. In turn, groundwater level had an impact on the radial growth and wood anatomical features of the analysed trees. A negative effect of the highest water table level was found for TRW of weakened and dead trees as well as for VD of healthy and weakened alders. The lowest groundwater level and the amplitude of the water table positively affected VD of the dead trees. Alder decline has a polyetiological nature, and groundwater level fluctuations are one of many factors contributing to disease development.

SLOPE STABILITY ANALYSIS CONSIDERING WEIGHT OF TREES AND ROOT REINFORCEMENT

We study the effect of roots of alder trees on soil reinforcement and slope stabilization. Two types of soil, i.e. Marl and Clayey soils and alders of three ages are considered. The slope stability is studied according to the tree indices based on tree age and soil type. The effect of root reinforcement on slope stability is considered by an additional cohesion. The stability analyses are carried out by the FEM. We perform parameter studies considering tree age, soil type and surcharge. The results indicate that soil type is effective on cohesion. The results also showed that with increasing age of trees from 7 to 15 years, the amount of additional root cohesion increased and with the increase of the age of trees to 20 years this amount slightly decreased. Also, with regard to a constant slope geometry, the type of soil and the uniform surcharge pressure, 7-year-old trees have shown better performance in slope stabilization. It has been observed that as the age of alder trees grows, although the amount of additional root cohesion increases, however, due to increased surcharge pressure, the overall slope stability factor decreases.

Leaf orientation measurement in a mixed hemiboreal broadleaf forest stand using terrestrial laser scanner

Orientation of leaves in a mature hemiboreal mixed broadleaf stand (the Jarvselja RAMI birch stand) was measured using the high-density point cloud of terrestrial laser scanner hits. Leaf normal distribution in the upper part of crowns of tall aspen and birch trees is almost spherical, and slightly planophile in the lower part of crowns. Leaves of alder trees are rather planophile in the upper part of crowns, and strongly planophile in the lower part of crowns. Lime and maple trees form the lower layer of trees in the stand. Their crowns are mainly in shade, and therefore, their leaf orientation is strongly planophile throughout the whole crown. Parameters of beta distribution and elliptical distribution are provided for the approximation of empirical distributions. The acquired information about leaf orientation can improve performance assessment of radiative transfer models.

Cytological characteristics of birch and alder pollen (different breeding forms) used in hybridization

Hybrids of some species of birch trees form completely sterile seeds (laboratory germination is zero in some hybrids, such as Karelian birch × Chinese white birch of inbred and outbred origin). It was noted analyzing the size distribution of birch pollen. Six size classes of pollen grains were identified, the modal values of which are arranged in increasing order as follows: 17 µm, 22 µm, 28 µm, 33 µm, 39 µm and 44 µm. The process of development of the male generative sphere proceeds without significant deviations in the studied black and gray alder trees. It ends with the formation of high-quality, aligned pollen. The obtained data indicate that one group of trees show normal formation of the reproductive sphere. It indicates the reasonableness of including them in the breeding process

Chemical profiles of birch and alder bark by ambient mass spectrometry

Desorption atmospheric pressure photoionization (DAPPI) is an ambient mass spectrometry (MS) technique that allows the analysis of both polar and nonpolar compounds directly from the surfaces of various sample types. Here, DAPPI was used to study the chemical profiles in different parts of birch and alder tree barks. Four distinct fractions of Betula pendula (silver birch) bark were collected from three different developmental stages of the stem, after which the chemical profiles of the different tissue types were measured. Of special interest were triterpenoids, a class of important defensive substances, which are found in the bark of the silver birch. Additionally, the chemical profiles of lenticels and the surrounding surfaces in the phellem of B. pendula (silver birch), Alnus glutinosa (black alder), and Alnus incana (gray alder) were screened with DAPPI. Another ambient MS technique, laser ablation atmospheric pressure photoionization (LAAPPI), was further used for the mass spectrometry imaging of lenticels on the B. pendula phellem. All the studied birch bark fractions showed individual chemical profiles in DAPPI. The mass spectra from the young apical stem and the transition zone resembled each other more than the mature stem. Instead, the phellem was found to contain a high amount of triterpenoids in all the developmental stages of the stem. The most intense peaks in the DAPPI mass spectra of the birch bark fractions were those of betulin and lupeol. Betulinic and betulonic acid peaks were intense as well, and these compounds were detected especially in the lenticels of the tree samples.Graphical abstract

Fungal Endophytes of Alnus incana ssp. rugosa and Alnus alnobetula ssp. crispa and Their Potential to Tolerate Heavy Metals and to Promote Plant Growth

Soil contamination by metals is of particular interest, given that their retention times within the profile can be indefinite. Thus, phytostabilization can be viewed as a means of limiting metal toxicity in soils. Due to their ability to grow on contaminated soils, alders have repeatedly been used as key species in phytostabilization efforts. Alder ability to grow on contaminated sites stems, in part, from its association with microbial endophytes. This work emphasizes the fungal endophytes populations associated with Alnus incana ssp. rugosa and Alnus alnobetula ssp. crispa (previously A. viridis ssp. crispa) under a phytostabilization angle. Fungal endophytes were isolated from alder trees that were growing on or near disturbed environments; their tolerances to Cu, Ni, Zn, and As, and acidic pH (4.3, 3, and 2) were subsequently assessed. Cryptosporiopsis spp. and Rhizoscyphus spp. were identified as fungal endophytes of Alnus for the first time. When used as inoculants for alder, some isolates promoted plant growth, while others apparently presented antagonistic relationships with the host plant. This study reports the first step in finding the right fungal endophytic partners for two species of alder used in phytostabilization of metal-contaminated mining sites.

The Origin, Succession, and Predicted Metabolism of Bacterial Communities Associated with Leaf Decomposition.

Intraspecific variation in plant nutrient and defensive traits can regulate ecosystem-level processes, such as decomposition and transformation of plant carbon and nutrients. Understanding the regulatory mechanisms of ecosystem functions at local scales may facilitate predictions of the resistance and resilience of these functions to change. We evaluated how riverine bacterial community assembly and predicted gene content corresponded to decomposition rates of green leaf inputs from red alder trees into rivers of Washington State, USA. Previously, we documented accelerated decomposition rates for leaves originating from trees growing adjacent to the site of decomposition versus more distant locales, suggesting that microbes have a "home-field advantage" in decomposing local leaves. Here, we identified repeatable stages of bacterial succession, each defined by dominant taxa with predicted gene content associated with metabolic pathways relevant to the leaf characteristics and course of decomposition. "Home" leaves contained bacterial communities with distinct functional capacities to degrade aromatic compounds. Given known spatial variation of alder aromatics, this finding helps explain locally accelerated decomposition. Bacterial decomposer communities adjust to intraspecific variation in leaves at spatial scales of less than a kilometer, providing a mechanism for rapid response to changes in resources such as range shifts among plant genotypes. Such rapid responses among bacterial communities in turn may maintain high rates of carbon and nutrient cycling through aquatic ecosystems.IMPORTANCE Community ecologists have traditionally treated individuals within a species as uniform, with individual-level biodiversity rarely considered as a regulator of community and ecosystem function. In our study system, we have documented clear evidence of within-species variation causing local ecosystem adaptation to fluxes across ecosystem boundaries. In this striking pattern of a "home-field advantage," leaves from individual trees tend to decompose most rapidly when immediately adjacent to their parent tree. Here, we merge community ecology experiments with microbiome approaches to describe how bacterial communities adjust to within-species variation in leaves over spatial scales of less than a kilometer. The results show that bacterial community compositional changes facilitate rapid ecosystem responses to environmental change, effectively maintaining high rates of carbon and nutrient cycling through ecosystems.

Carbon and sulfur isotopes in tree rings as a proxy for volcanic degassing

Abstract Trees are useful archives of past atmospheric conditions. They have most commonly been used to infer large-scale changes in climate, industrial pollution, and the magnitude and frequency of geological hazards. While geochemical changes in tree rings have been linked to localized anthropogenic smelter pollution, their potential to track geochemical changes in volcanic degassing has not yet been fully realized. Here, we applied a new proxy using sulfur and carbon isotopes in tree rings to examine fluctuations in gas emission at Turrialba volcano, Costa Rica. Since 2009, Turrialba has emitted a persistent gas plume and increasingly frequent explosions and ash eruptions as activity has accelerated. We collected cores from a species of alder tree, Alnus acuminata, at several locations surrounding the volcano. Biannual isotopic analysis of rings demonstrated a notable δ34S shift of –5.2‰ and a similarly sharp δ13C shift of +1.3‰ in trees downwind of the plume following the onset of strong degassing in 2009. We propose that these shifts in the isotopic values of the tree correspond to those of the volcanic SO2 and CO2, and in the case of the δ13C, an additional fractionation caused by leaf impairment from exposure to volcanic SO2. This new proxy can be applied to other volcanoes as a novel method of obtaining a temporal record of degassing, a crucial tool for volcano monitoring.

Colonisation by enchytraeids as a suitable indicator of successful biological reclamation of post-mining technosols using alders

Enchytraeids and earthworms were studied in a reclaimed sand mine, at a combustion waste disposal site and in natural forest stands in the Bieszczady Mountains. The study verifies the influence of three alder species (Alnus incana, A. viridis, A. glutinosa), reclaimed mine soil substrates (RMS) and combustion waste (CW) on annelid communities. Earthworms were absent in RMS and CW. Enchytraeid densities varied, from almost 2000 ind. m−2 (individuals per m2) to >9000 ind. m−2 in RMS and CW and to 30,000–60,000 ind. m−2 in natural forest soils. Soil properties strongly correlated with enchytraeid density were pH, silt content and organic carbon content. In total, eight genera and thirteen species were recorded. In combustion waste technosols, species tolerating dry conditions and high pH predominated (e.g. Henlea ventriculosa). In sand mine soils, species diversity was very low (Shannon index 0.16), but Hemifridericia bivesiculata was recorded, a species that was known within Europe only from Hungary. Alder trees, especially A. glutinosa, allowed enchytraeids to reach high population density. In soil afforested by A. glutinosa the succession stage was more advanced than in soil under A. incana because, in variants with A. glutinosa, more species classified as belonging to the transitional stage of succession (Fridericia spp.) or even preliminary climax stage of succession (Cognettia sphagnetorum), were recorded. In the variant with A. incana, Enchytraeus spp. predominated. These are considered pioneer species. The study of enchytraeids confirmed that alders should be recommended for biological reclamation.

AbruptAlnuspopulation decline at the end of the first millennium CE in Europe – The event ecology, possible causes and implications

The study, based on the examination of 70 published and unpublished pollen profiles from Poland and supplementary data from the surrounding regions, shows that an abrupt, episodic Alnus population decline at the end of the first millennium CE was a much more widespread event than has been previously reported, spanning large areas of the temperate and boreal zones in Europe. The data from Poland suggest that the decline was roughly synchronous and most likely occurred between the 9th and 10th centuries, with strong indications for the 10th century. The pollen data indicate that human impacts were not a major factor in the event. Instead, we hypothesize that one or a series of abrupt climatic shifts that caused floods and droughts at the end of the first millennium CE could have initiated this ecological disturbance, leading to a higher vulnerability of the alder trees to a pathogen outbreak. Following current observations of the decline of alder stands in Europe due to a Phytophthora outbreak, we suggest that a similar process may have occurred in the past. This study provides insight into long-term alder (mainly Alnus glutinosa) dynamics in a condition of climate change and illustrates its great resilience, enabling the natural, successful regeneration of alder stands after critical diebacks if environmental conditions improve. Our finding that the Alnus pollen decline reflects a roughly synchronous event indicates that the decline could be used as an over-regional chronostratigraphic marker for 800–1000 CE in pollen diagrams from a large part of the European Lowland.

Exposure to pollen allergens in allergic rhinitis expressed by diurnal variation of airborne tree pollen in urban and rural area.

Exposure to airborne pollen allergens results in allergic symptoms in subjects who are sensitized. The paper presents diurnal variation in the counts of airborne allergenic pollen of selected trees (Betula L., Alnus Mill., Corylus L., Fagus L. and Ulmus L.) in two localities differing in the degree of urbanization: the city of Szczecin (urban) and the village of Gudowo, West Pomerania in northwest Poland (rural) in the years 2012-2014. The measurements were made by the volumetric method using a Burkardtype sampler operating in a continuous mode. The greatest similarities in the beginning of the main pollen season between the two sites studied were observed for birch and elm trees, while in the length of the main pollen season, for birch and alder trees. Pollen counts of alder and hazel reached higher levels in the rural area, while the levels of ash tree pollen counts were higher in the urban area. The level of birch tree pollen counts was similar in the two sites studied. For the majority of taxons observed in the urban and rural areas the dynamics of hourly changes in tree pollen counts were similar. The pollination peak was noted in the daytime, usually in the afternoon. For ash and elm trees increased pollen counts were observed at nighttime, while the birch tree pollen counts were at a high level for most of the 24 h cycle. The knowledge of seasonal and diurnal variations in tree pollen counts is crucial for prevention in patients with allergic rhinitis, sensitized to tree pollen allergens.

Nitrogen-fixing red alder trees tap rock-derived nutrients

Symbiotic nitrogen (N)-fixing trees supply significant N inputs to forest ecosystems, leading to increased soil fertility, forest growth, and carbon storage. Rapid growth and stoichiometric constraints of N fixers also create high demands for rock-derived nutrients such as phosphorus (P), while excess fixed N can generate acidity and accelerate leaching of rock-derived nutrients such as calcium (Ca). This ability of N-fixing trees to accelerate cycles of Ca, P, and other rock-derived nutrients has fostered speculation of a direct link between N fixation and mineral weathering in terrestrial ecosystems. However, field evidence that N-fixing trees have enhanced access to rock-derived nutrients is lacking. Here we use strontium (Sr) isotopes as a tracer of nutrient sources in a mixed-species temperate rainforest to show that N-fixing trees access more rock-derived nutrients than nonfixing trees. The N-fixing tree red alder (Alnus rubra), on average, took up 8 to 18% more rock-derived Sr than five co-occurring nonfixing tree species, including two with high requirements for rock-derived nutrients. The increased access to rock-derived nutrients occurred despite spatial variation in community-wide Sr sources across the forest, and only N fixers had foliar Sr isotopes that differed significantly from soil exchangeable pools. We calculate that increased uptake of rock-derived nutrients by N-fixing alder requires a 64% increase in weathering supply of nutrients over nonfixing trees. These findings provide direct evidence that an N-fixing tree species can also accelerate nutrient inputs from rock weathering, thus increasing supplies of multiple nutrients that limit carbon uptake and storage in forest ecosystems.

Isolation and Screening of Antibiotics Producing Streptomyces spp from the Soil Collected around the Root of Alnus nepalensis from Godawari

Actinomycetes are considered as the most invaluable prokaryotes whose genome mining show a great number of putative secondary metabolite biosynthesis pathways as well as gene clusters ranging from 20 to 50 per genome. The genus Streptomyces has been explored for its ability to produce 60% antibiotics worldwide. Alnus nepalensis (Alder) has been found to harbor diverse Eubacteria in its rhizosphere. To evaluate the antibiotic production potential from Actinomycetes, we collected soil samples from rhizosphere (5-7 cm deep) of Alder tree. Primary screening was done by cross-streak method against Multidrug Resistant (MDR) such as Methicillin resistant Staphylococcus auereus (MRSA), Vancomycin resistant Enterococcus feacalis (VRE), Imepenem resistant Acinetobacterbaumannii, Vancomycin resistant Klebsiella pneumonia and Imepenem resistant E. coli as well as Non-MDRs (E. coli, Bacillus subtilis, Klebsiella pneumoniae, S. aeureu and Enterococcus feacalis). Extraction of antibiotics was done using rota-vapour from extract obtained by solid-substrate fermentation technique followed by solvent extraction. Secondary screening was done using well diffusion assay against MDRs. Among total of 40 isolates of Actinomycetes recovered, 14 showed remarkable zone of inhibition (ZOI) to various MDRs. NASA 303 showed 26 mm of ZOI against VRE, NASA 101 had ZOI of 34 mm against MRSA, NASA 319 had 33.7 mm ZOI against Imepenem resistant E. coli, NASA 306 had 36 mm of ZOI against Vancomycin resistant Klebsiella pneumoniae, and NASA 108 showed ZOI of 29.6 mm against Imepenem resistant E. faecalis. This investigation revealed that the Actinomycetes found in Rhizosphere of Alder tree had MDR killing potent antibiotics, which needs to be further explored.

The Pilgrim of Łódź

The Pilgrim of Łódź Erik Harper Klass (bio) From The Letters and Diacritics of East Central Europe: With Descriptions and Examples Ł Rachel says—said—the lowercase Polish ł looks like a funambulist, balance-pole angled exaggeratedly, tightrope invisible beneath the walker’s feet. Funambulist. Her word. But the pole is too short. The figure, somehow, too perpendicular (ł), too secure. She sees correction, balance. I see error, nullification. Its pronunciation, according to A New Polish Grammar 1 by Joseph Andrew Teslar, “should present no real difficulty to the English pupil . . . the majority of Poles nowadays pronounce this sound with the lips, exactly like the English w.”2 Useful drawings display the exact placement of the tongue. We practiced: ła-la—łu-lu—ło-lo—łe-le—łi-li . . . We’d refill our glasses with wódka and laugh nonsensically at our lips’ and tongues’ machinations. Łatwo, she said, her lips, tongue, perfect. It is easy. But I was a poor learner. Later, jetlagged, incoherent, I walked to her across the room, one foot directly in front of the other, my balance-pole angled exaggeratedly, tightrope invisible beneath my feet, and fell finally into the net of her arms. We should not be like this, here, she said, holding in her laughter, holding in her tears. She spun the spent cubes in her glass and looked around the room, looked into these hotel walls, as if she could see beyond them to the dark streets of Łódź. But by then we had to drink, we had no choice. Our dissolution had already begun. Further examples follow. ________ REYMONT, WŁADYSŁAW STANISŁAW (1867–1925), writer. “His first novels on wandering actors and the industrial life of Łódź3 were followed by a huge novel in four volumes, The Peasants (Chłopi). He earned the Nobel Prize for Literature in 1924.”4 In his name we find three Polish ł s. Exceptional. [End Page 174] ________ Machine guns again. Somewhere to the west, the Jewish quarter. Distant and echoing across the city. With a white cloth he wipes the dirt from the window above the sink and leans forward and to the left, toward the square, where there is red—everywhere, red. Hanging from open windows the new red banners billow, either by the wind, in slow, somber beats, or by occupants who lean out into the November air with outstretched arms and wave the banners as if they were long carpets being cleaned. Women wearing skirts that stretch only to their knees have tied pieces of red cloth in their hair, and men—the few men still around, mostly older men with canes and tall hats—have placed in their breast pockets folded red kerchiefs, little triangles of color that look astonishingly clean and new against the ragged cloth of their lapels. Children have been dressed in suits, ornamented with red armbands made from ribbons, and there, beneath his window, they run and shout and shoot fake guns made from tree branches. Their wooden clogs clomp on the street like horse hooves. Red—everywhere, red. He hears the distant cries of the trains, coming in from the east, heading west, packed, he knows, with German soldiers leaving the front. These are the homecomers. The idea of movement plays in his mind like a wish. He wonders what it must feel like to have somewhere to go after the war. He positions his glasses a little higher on his nose, turns his head, looks to his right. A uniformed German soldier with an empty holster walks to the north. The soldier does not wear a field hat and his dark hair whirls in the wind. He looks once over his shoulder, not with concern, but with something more like relief. This, he thinks, watching the soldier, is something he might use someday. The soldier’s eyes are as blue as the sparkling Vistula just barely visible beyond the old alder trees that line the strand. On the last day of the war a German soldier wends his way through these broken cobblestone streets beneath the roiling November sky, he walks in the direction of his love, a Jewish girl with auburn hair...

Tree species and soil substrate affect buffer capacity of anthroposols in afforested postmine sites in Poland

The study presents the influence of tree species and soil substrate on the buffer capacity of anthroposols at two afforested postmine sites (Piaseczno and Szczakowa) in southern Poland. These postmine areas were reforested with homogenous stands of tree species Scots pine (Pinus sylvestris L.), common birch (Betula pendula Roth), European larch (Larix decidua Mill.), European oak (Quercus robur L.), and black alder (Alnus glutinosa Gaertn.), growing on various parent materials (substrates): mixed Quaternary sands and Neogene clays, Neogene clays, Quaternary sands, Quaternary loamy sands, and loams. Samples were taken from the 0 to 5 cm and 5 to 30 cm mineral soil layers. Basic soil properties such as soil texture, total organic carbon content (TOC), hydrolytic acidity, cation exchange capacity (CEC), and base saturation (BS) were investigated. The buffer capacity of the studied soils were measured by the Arrhenius method, and buffer surface areas (alkaline surface area [sNaOH], acid surface area [sHCl], and total buffer area [stotal]) were calculated using the definite integral. The highest buffer ability (stotal) was seen in stands of alder tree on Neogene clays in the 0 to 5 cm layer and the lowest were noted under pine trees on Quaternary sands in the 5 to 30 cm layer. The examined soils were usually characterized by a higher buffer capacity in the alkaline range than in the acid range. The study showed that the buffer capacity of the surface layers was most affected by the tree species, whereas in the deeper soil layers the capacity was most affected by the soil substrate. Buffer capacity was related to organic matter content (especially TOC and total nitrogen [N] content), soil texture, and sorption properties such as CEC and BS.

Planting of alder trees at the edge of skid trails helps to stabilize forest topsoil structure against damage caused by heavy forestry machines

The regeneration and soil-mechanical reinforcement effect by the rooting system of grey alder (Alnus incana) were tested in an annually driven forest skid trail on a silty clay loam soil located in Southern Germany. One side of the skid trail was bordered by an eight-year-old alder plantation, on the other side, there were no trees. Soil physical properties (relative apparent gas diffusion coefficient (Ds/D0), bulk density and the coarse porosity) were measured in order to detect the effects on soil structure as well as on fine root densities, taken as a biological target variable.Values of soil physical parameters linked to the soil aeration status did not show significant differences between planted and unplanted wheel track; however, low values of bulk density measured on the laterally planted wheel track indicated significant improvements in the topsoil compared to the unplanted one. Also, values for fine root density were higher in these plots. Strong relationships between Ds/D0, bulk density and the coarse porosity with fine root densities were also found, which give evidence of their mutual effects, either amplifying each other or reciprocal. In the top soil, root density positively affects soil gas permeability, while in the deeper horizons fewer macropores are found, which are partially blocked by fine roots for gas exchange.In summary, the wheel track which is laterally planted with alder trees showed signs of an initial regeneration of soil structure as well as a reinforcement against further soil damage caused by annual wheeling.

Effects of red alder on growth of Douglas-fir and western redcedar in southwestern British Columbia

Red alder (Alnus rubra [Bong.]), is the most common broadleaf species in the Pacific Northwest, and is widely distributed as a component of mixed stands with conifers. It rapidly overtops associated juvenile conifers and is a strong competitor. However, red alder is also a symbiotic nitrogen fixer and can contribute to improvement in soil nitrogen, as well as serving other roles such as improving biodiversity and forest health.We examined data collected in mixed red alder-conifer plantations established between 1992 and 1999 to examine the effects of red alder on the growth of Douglas-fir (Pseudotsuga menziessi (Mirb.) Franco, Fd) and western redcedar (Thuja plicata Donn., Cw). Results suggest that densities of up to 400 alder trees per hectare may be acceptable and possibly desirable on nitrogen deficient sites. The growth of Fd may be enhanced when red alder density is relatively low at older ages. We found that the competitive effects of red alder on conifer growth were consistently lower than that of the conifers (Fd and Cw) while alder had stronger effects on light availability. The relationship between volume growth and competition indices varied between the two conifer species: (1) for Fd the highest correlations were obtained using a distance-dependent competition index based on the height differences, and (2) for Cw the highest correlations were with distance-independent Lorimer’s index. As also expected due to Cw’s greater shade tolerance, its volume growth showed less sensitivity to the presence of red alder than Fd.