Diarylheptanoids from Alnus incana

This study aims to derive individual tree allometric equations for the above- and belowground biomass components of grey and common alder based on data sets obtained in Latvia. The species aboveground biomass data consisted of 81 trees collected in 27 forest stands. The belowground biomass data were obtained from 27 common alder and 28 grey alder trees sampled throughout Latvia. For grey and common alder, the root-to-shoot ratio decreased with increasing tree dimensions. Our analysis revealed that biomass functions currently used in the national forest inventory overestimate grey alder and underestimate common alder biomass stocks in Latvia. Our findings indicate that the existing local aboveground biomass equation has an overall satisfactory predictive ability compared to the derived equations in this study. The equations from southern Sweden underestimate biomass for mature trees and overestimate small tree biomass, suggesting that even in the hemiboreal region, the grey and common alder populations could have a different distribution of biomass allocated to various components. Model examinations indicated that the derived allometric functions for grey and common alder were unbiased and performed well within the data range and are the best available to substantially improve national estimates of carbon sequestration and biomass resources in Latvia.

The objective was to determine stem volume models for grey and common alders and, based on the models, stand volume for naturally regenerated grey and common alder stands was summarized. Basic density for grey and common alders and mean annual growth for stands was estimated. Net volume accretion data were collected from 24 stands of grey alder (Alnus incana (L.) Moench) and 31 stands of common alder (Alnus glutinosa (L.) Gaertner) in Sweden. The stands ranged in latitude from 58 to 64° N and from 56 to 62° N for grey and common alder, respectively. The mean age of grey and common alder stands was 41 years and 48 years, respectively, the mean stand density 1726 stems ha−1 and 1078 stems ha−1, and the mean diameter at breast height (over bark) was 20 cm and 21 cm. Stem volume equations were developed for grey and common alders. The adopted model for grey alder was based on diameter at breast height and height. For common alder, crown height was added to diameter and height. Mean standing volume (over bark) for grey and common alder stands was 428 and 374 m3 ha−1. Mean annual growth for grey and common alder stands was 12.0 m3 and 8.4 m3 a−1 ha−1, respectively. Basic density (under bark), for grey and common alder stems was 359 and 427 kg m−3, respectively. The basic density (under bark) for the lowest twigs in the crown and in the lateral part of the crown was 415 and 421 kg m−3 for grey alder and 423 and 423 kg m−3 for common alder.

Species-specific basic density (BD) data are necessary to improve the indirect methods of biomass determination. The density of tree components (e.g., bark, branches, roots) is studied much less than that of stem wood. Nevertheless, ignoring the specific BD values of these components in biomass calculations can lead to errors. The study aims to investigate BD variation of aboveground and belowground tree components by studying a total of 162 gray alder (Alnus incana (L.) Moench) and common alder (Alnus glutinosa (L.) Gaertn.) trees. From them, 55 stumps were excavated to determine the BD of the belowground components. Our findings reveal that the volume-weighted BD of the stem (wood and bark) and the branch density of common alder are higher compared to gray alder. Both species have similar bark density, while the BD of belowground components is higher for gray alder. The stem wood density of both species increases upward from the stump to the top. Compared to gray alders, the stems of common alders have more distinct radial within-stem density variation. According to our results, the application of default Alnus spp. wood density values recommended in the IPCC guidelines for the calculation of total biomass and carbon stock is likely causing overestimation. The BD values obtained in our study on alders’ biomass components will allow for more accurate appraisals of total biomass and carbon stock for gray and common alder forests.

Spring and early summer flood is one of the main factors affecting the dynamics of black ash (Fraxinus nigra Marsh.) stands growing on lake floodplains in the boreal forest. The effect of flooding on the vegetation was studied in five stands on the shore of Lake Duparquet in Abitibi, northwestern Quebec. Divisive hierarchical classification analysis (Twinspan) revealed the existence of four different vegetation types: (i) black ash – speckled alder (Alnus rugosa) – bog willow (Salix pedicellaris), (ii) black ash – balsam poplar (Populus balsamifera) – ostrich fern (Matteuccia struthiopteris), (iii) black ash – pussy willow (Salix discolor) – sensitive fern (Onoclea sensibilis), and (iv) black ash – speckled alder – sensitive fern. Detrended correspondance analysis (Decorana) shows that elevation and drainage are the main factors affecting plant distribution and dynamics. Geomorphology also plays a major role in the way each stand responds to flooding. For each of the vegetation types studied, black ash shows a particular regeneration pattern and sexual regeneration tends to become less frequent with increasing exposure to flooding. Finally, the strong sexual regeneration and the youth of the populations found in the most elevated sites could be related to a possible alteration of the flood regime. Key words: Fraxinus nigra Marsh., flooding, boreal forest, floodplain, ecological gradiant, regeneration.

Growth and carbon capture of grey alder (Alnus incana (L.) Moench.) under north European conditions – Estimates based on reported research

Field-grown trees of Alnus incana (L.) Moench, Alnus glutinosa (L.) Geartner and Betula pendula Roth displayed pronounced differences in responses of light-saturated net photosynthesis (Asat ) to herbivory by the alder beetle (Agelastica alni L., Galerucinae), a specialized insect which primarily defoliates alders. We found that photosynthetic rates of grazed leaves increased following herbivory in Alnus but not in Betula. Area- and mass-based Asat of grazed leaves declined linearly with increasing amount of leaf perforation in B. pendula, by as much as 57%. By contrast Alnus glutinosa and Alnus incana increased area-based rates of Asat by 10-50% at all levels of leaf grazing. Given increased Asat in the remaining portion of grazed leaves, a net reduction in photosynthesis per leaf occurred only when the proportion of leaf area grazed exceeded 40% for Alnus incana and 23% for Alnus glutinosa. Since vein perforation by Agelastica alni was observed much more frequently in leaves of Betula than in Alnus, we hypothesized that declining Asat in herbivorized Betula was related to this disruption of water transport. A field experiment with artificial leaf perforation demonstrated a greater decline in Asat in vein-perforated Betula leaves than perforated leaves with midrib veins intact. However, regardless of leaf perforation regime, birch never showed post-perforation increases in Asat . In all species, rates of transpiration of grazed leaves linearly increased and water-use efficiency decreased with increased amount of leaf perforation. In grazed Alnus incana leaves, increasing leaf area consumption by Agelastica alni resulted in an increase of total phenols, a reduction in starch content and no changes in nitrogen concentration in the remaining portion. The increase in photosynthesis in Alnus incana might be related to declining leaf starch concentration or increasing stomatal conductance, but was unrelated to leaf nitrogen concentration. These gas exchange and leaf chemistry measurements suggest that in contrast to B. pendula, Alnus incana and Alnus glutinosa, which are the major host species for Agelastica alni, possess leaf-level physiological adaptations and defence mechanisms which can attenuate negative effects of herbivory by the alder leaf-beetle.

Surface waters in forested watersheds in the Adirondack Mountains and northern New York State are susceptible to nitrogen (N) saturation. Atmospheric deposition of N to watersheds in this region has been measured but the extent of internal N inputs from symbiotic N2 fixation in alder-dominated wetlands is not known. We estimated N2 fixation by speckled alder in these wetlands by the 15N natural abundance method and by acetylene reduction using a flow-through system. Foliar N derived from fixation (%Ndfa) was estimated for five wetlands. The δ15N of speckled alder foliage from four of the five sites did not differ significantly (P≤0.05) from that of nodulated speckled alders grown in N-free water culture (-1.2±0.1‰). Estimates from the 15N natural abundance method indicated that alders at these sites derive 85-100% of their foliar N from N2 fixation. At one of the sites, we also measured biomass and N content and estimated that the alder foliage contained 43kg N ha-1 of fixed N in 1997. This estimate was based on a foliar N content of 55.4±7kg N ha-1 (mean±SE), 86±4%Ndfa, and an assumption that 10% of foliar N was derived from reserves in woody tissues. At this site, we further estimated via acetylene reduction that 37±10kg N ha-1 was fixed by speckled alders in 1998. This estimate used the theoretical 4:1 C2H2 reduction to N2 fixation ratio and assumed no night-time fixation late in the season. Nitrogen inputs in wet and dry deposition at this site are approximately 8 kg N ha-1 year-1. We conclude that speckled alder in wetlands of northern New York State relies heavily on N2 fixation to meet N demands, and symbiotic N2 fixation in speckled alders adds substantial amounts of N to alder-dominated wetlands in the Adirondack Mountains. These additions may be important for watershed N budgets, where alder-dominated wetlands occupy a large proportion of watershed area.

INTRODUCTION. Flavonoids contained in many plant species inhibit the induction of cytokines and arachidonic acid metabolites, which are tissue mediators of inflammation, thus exhibiting an anti-inflammatory effect. The leaves of black and gray alder contain flavonoids, phenolic carboxylic acids, tannins and can be considered as a new type of herbal medicinal raw materials.AIM. Evaluation of the anti-inflammatory effect of decoctions and gels containing the sum of biologically active substances of black alder (Alnus glutinosa (L.) Gaertn.) and gray alder (Alnus incana (L.) Moench.) leaves on laboratory animals using various models of inflammation.MATERIALS AND METHODS. The anti-inflammatory activity of aqueous extracts of black alder and grey alder leaves, as well as gels containing their alcoholic extracts, was studied in models of generalized and local inflammation induced by the administration of a 1% λ-carrageenan solution to Wistar rats (female and male). The anti-inflammatory effect in generalized inflammation was assessed by blood biochemical parameters (C-reactive protein, alanine aminotransferase, aspartate aminotransferase, γ-glutamate transferase), in case of local inflammation — by changes in the volume and mass of rat paws.RESULTS. On the model of generalized carrageenan inflammation, the effectiveness of aqueous extracts of black and gray alder leaves was evaluated on days 4 and 7. It was found that introducing aqueous extracts determines a statistically significant decrease in the specific inflammation indicator — level of C-reactive protein in animals receiving an infusion of black alder and grey alder leaves of intragastric introduction. Using models of local carrageenan inflammation, it was established that under the influence of infusions and gels containing biologically active substances of black and gray alder leaves, there was a statistically significant decrease in the increase in weight and paw diameters compared to control groups. The edema inhibition index (calculated by weight) for the gel containing black alder leaf tincture based on 60% ethyl alcohol was the highest and amounted to 57.95% in females and 56.53% in males, for the gel containing grey alder leaf tincture based on 70% ethyl alcohol — 56.78% in males, 52.02% in females.CONCLUSIONS. It has been proven the anti-inflammatory activity of aqueous and alcoholic extracts from black alder and gray alder leaves in models of generalized and local inflammation. Dosage forms (gels) containing alcohol extracts from the leaves of black alder and gray alder also have an anti-inflammatory effect in conditions of induced local inflammation. Also it has been proven the anti-inflammatory effect of biologically active substances of black alder and gray alder on laboratory animals using models of generalized and local inflammation.

The aim of the present work was to investigate the nutrient (N,P,K) allocation and accumulation in grey alder (Alnus incana (L.) Moench) and hybrid alder (Alnus incana (L.) Moench x Alnus glutinosa (L.) Gaertn.) plantations growing on former agricultural land and to estimate the above-ground biomass production during 4 years after establishment. In August of the 4th year, when leaf mass was at its maximum, the amount of nitrogen accumulated in above-ground biomass of grey alder stand was 142.0 kg ha–1, the amount of phosphorus 16.3 kg ha–1 and the amount of potassium 49.5 kg ha–1. The amount of nitrogen accumulated in a hybrid alder stand totalled 76.8 kg ha–1, that of phosphorus 6.2 kg ha–1 and that of potassium 28.2 kg ha–1. The smaller amounts of N,P and K bound in the hybrid alder plantation are related to the smaller biomass of the stand. Still, the amounts of N,P and K consumed for the production of one ton of biomass were similar in the case of up to 4-year-old grey alder and hybrid alder stands. In the 4th year, the amount of nutrients consumed in one ton of biomass produced were: 16.0 kg N, 1.6 kg P and 5.4 kg K for grey alder and 14.6 kg N, 1.1 kg P and 5.2 kg K for hybrid alder. In the 4th year the total above-ground biomass (dry mass) of grey alder (15750 plants ha–1) amounted to 12.3 t ha–1, current annual increment being 6.7 t ha–1. In hybrid alder stands (6700 plants ha–1), the respective figures were 6.1 t ha–1 and 4.5 t ha–1. Comparison of the production capacity on the basis of mean stem mass in the 4th year revealed that the stem mass of grey alder exceeded that of hybrid alder (0.64 kg and 0.58 kg, respectively). Grey alder outpaced hybrid alder in height growth; in the 4th year after establishment, the mean height of the grey alder stand was 4.6 ± 0.9 m and that of the hybrid alder plantation 3.5 ± 0.9 m.

Halli lepa, hübriidlepa ja arukase biomassi produktsioon endistel põllumaadel The present study is based on four experimental sites, located in Southern-Estonia: hybrid alder and grey alder plantations located in Põlva county, and two sample plots of silver birch, located in Tartu county. The stand characteristics, above-ground biomass and current annual production (CAP) were estimated in order to evaluate production capacity of different tree species growing on abandoned agricultural lands. Due to fast growth and high biomass production capacity the most promising tree species for short-rotation forestry in Estonia is grey alder. The stem mass in the 13-years-old grey alder and hybrid alder stand was 63.4 t ha-1 and 40.0 t ha-1, respectively. However, the different biomass production is mainly affected by stand densities, 6170 trees per ha and 4080 trees per ha, respectively. During ageing, the differences between the alder stands diminish. At the age of 14, mean height and diameter at breast height were practically equal. Also the mean stem mass in the older, 13-year old stand, is almost equal: 10.3 kg in grey alder stand and 9.8 kg in hybrid alder stand. At a younger age, the mean stem mass was higher in grey alder stand, but later, at the age of 13, the mean stem mass has become almost the same (10.3 kg in grey alder stand and 9.8 kg in hybrid alder stand). The rotation period for hybrid alder is longer than for grey alder and bulk maturity will occur later. Silver birch is also a highly productive tree species and has a prospect for short-rotation forestry. The mean stem mass and annual current increment of 8-year-old silver birch stand was in same the magnitude as in the grey alder stand. Although the average stand diameter and height were lower in the silver birch stand than in the grey alder stand, it is compensated by the higher wood density of birch wood. The number of trees has affected silver birch stand production, the above-ground biomass in the very high density birch stand (35 600 trees per ha) was significantly lower than in the sparse stand (11 600 trees per ha), 22.8 t ha-1 and 31.2 t ha-1, respectively.

The leaf extract of Alnus rugosa (AR) together with the isolated compound baicalein 5,6-dimethyl ether (BME) were investigated for their antioxidant, radical scavenging, antiaging, and neuroprotective properties using the Caenorhabditis elegans model. The stress resistance and antiaging potential of AR and BME were assessed in wild-type N2 and transgenic C. elegans strains CF1553, TJ356, and BA17. Transgenic CL4176 expressing the human amyloid-beta peptide (Aβ) was used as a model for Aβ toxicity, whereas transgenic AM141 expressing polyQ aggregates was employed as a model for Huntington's disease. An in silico molecular docking study using Discovery Studio 4.5 was performed to elucidate the putative binding mode of BME to the active sites of Daf-2 protein, involved in longevity and oxidative stress resistance in C. elegans. BME and AR significantly delayed the appearance of oxidative stress markers in wild-type N2 and transgenic strains TJ356 and CF1553, affecting the DAF-16/FOXO transcription factor subcellular distribution and inducing expression of the sod-3 antioxidative gene. Pretreatment with AR significantly reduced the aging marker lipofuscin accumulation in BA17 worms, its effect was greater than that of epigallocatechin gallate, suggesting a potential antiaging effect. Neuroprotective effects of AR and BME were confirmed in AM141 transgenic worms, inducing a significant reduction in the score of polyQ40::GFP aggregates. Moreover, BME (25 µg/mL) resulted in a significant delay in Aβ-induced paralysis in CL4176 worms. In silico molecular modeling revealed that BME exhibited good fitting scores within the active sites of the Daf-2 protein. AR and BME exert beneficial effects in the modulation of age-related markers and attenuation of neurotoxicity in neurodegenerative disorders. Hence, AR and BME could be recognized as promising antioxidant and neuroprotective natural drug candidates that could be included in neuro-nutraceuticals.

Summary 1. We investigated the population dynamics of the keystone symbiotic N‐fixing species Alnus tenuifolia (thinleaf alder) and the patterns of primary succession on the Tanana River floodplains of interior Alaska, USA. The goals of this study were to characterize (i) the variation in the population structure of thinleaf alder and its influence on ecosystem function; (ii) the role of a fungal disease outbreak in driving the population dynamics of thinleaf alder; (iii) the patterns of landscape‐scale thinleaf alder recruitment; and (iv) the variation in successional pathways across the landscape. 2. Soil N concentrations and pools increased tenfold with thinleaf alder stand age due to the accumulation of N‐rich organic material. Alder stem density varied threefold among early successional stands, and was directly related to soil N. 3. The current outbreak of a fungal disease caused widespread branch dieback and mortality of alder. Young stems were disproportionately susceptible to disease‐induced mortality. Overall disease incidence and mortality of young stems were positively related to alder stem density. 4. Thinleaf alder age structures revealed that landscape‐scale recruitment was pulsed over time. 5. Multiple pathways of primary succession were found using indirect gradient analysis and associated environmental characteristics were described. 6. Synthesis. The population dynamics of thinleaf alder and the inter‐relationship with disease‐driven disturbance can strongly influence soil N accumulation and ecosystem function in primary succession on an active glacial floodplain. The temporal pattern of thinleaf alder recruitment across the landscape appears to reflect the influence of the hydrologic regime on silt bar development and alder dispersal limitation and population dynamics. Differential life history traits explain the predominant successional pathway, but an alternative successional pathway suggests this pattern can be altered by stochastic events, disturbance, environmental variation or other factors.

With the objective of understanding how vegetation was structured in four Larix laricina (Du Roi) K. Koch dominated wetlands in north-western Quebec, 186 point-centred quarters were sampled in four stands. For each point, both biotic and abiotic variables were collected and species cover was recorded. Divisive hierarchical classification analysis (Twinspan) identified nine vegetation clusters: i) Larix laricina & Spiraea alba, ii) Larix laricina & Kalmia angustifolia, iii) Larix laricina, Picea mariana & Alnus rugosa, iv) Larix laricina & Betula pumila, v) Thuja occidentalis & Trientalis borealis, vi) Abies balsamea & Betula papyrifera, vii) Fraxinus nigra & Onoclea sensibilis, viii) Alnus rugosa, and ix) Eleocharis smallii. Results of the canonical correspondence analyses indicated that the distribution of these clusters was mainly related to (i) distance from shore, (ii) shade (canopy cover), (iii) substrate nitrate concentration (in relation to the abundance of Kalmia angustifolia and Alnus rugosa), (iv) substrate pH (in relation to the abundance of Sphagnum spp.), and (v) substrate conductivity. Several characteristics of the water table also affected species distribution, including pH, depth, and carbon concentration. Further studies should address the effect of the presence of Kalmia angustifolia and Alnus rugosa on larch growth.Key words: larch, wetland, vegetation analysis, flooding, boreal forest.

With the objective of understanding how vegetation was structured in four Larix laricina (Du Roi) K. Koch dominated wetlands in north-western Quebec, 186 point-centred quarters were sampled in four stands. For each point, both biotic and abiotic variables were collected and species cover was recorded. Divisive hierarchical classification analysis (Twinspan) identified nine vegetation clusters: i) Larix laricina & Spiraea alba, ii) Larix laricina & Kalmia angustifolia, iii) Larix laricina, Picea mariana & Alnus rugosa, iv) Larix laricina & Betula pumila, v) Thuja occidentalis & Trientalis borealis, vi) Abies balsamea & Betula papyrifera, vii) Fraxinus nigra & Onoclea sensibilis, viii) Alnus rugosa, and ix) Eleocharis smallii. Results of the canonical correspondence analyses indicated that the dis - tribution of these clusters was mainly related to ( i) distance from shore, (ii) shade (canopy cover), (iii) substrate nitrate concentration (in relation to the abundance of Kalmia angustifolia and Alnus rugosa), (iv) substrate pH (in relation to the abundance of Sphagnum spp.), and (v) substrate conductivity. Several characteristics of the water table also affected species distribution, including pH, depth, and carbon concentration. Further studies should address the effect of the presence of Kalmia angustifolia and Alnus rugosa on larch growth.

Symbiont nitrogenase, alder growth, and soil nitrate response to phosphorus addition in alder ( Alnus incana ssp. rugosa) wetlands of the Adirondack Mountains, New York State, USA