Short lived peaks of stem methane emissions in temperate black alder forest - irrelevant for ecosystem methane budgets?

2021 ◽  
Author(s):  
Daniel Köhn ◽  
Anke Günther ◽  
Gerald Jurasinski
Keyword(s):  
Greenhouse Gas ◽  
Hydrological Regime ◽  
Alnus Glutinosa ◽  
Methane Emissions ◽  
High Variability ◽  
Incubation Experiment ◽  
Black Alder ◽  
Alder Forest ◽  
Methane Budget ◽  
Closed Chambers

<p>Tree stems can be a source of the greenhouse gas methane (CH<sub>4</sub>) and locally as regionally important to the overall GHG budget. Stem emissions even hold the potential of narrowing down knowledge gap in the global methane budget. However, assessments of the global importance of stem CH<sub>4</sub> emissions are complicated by a lack of research and high variability between individual ecosystems. Here, we determined the contribution of emissions from stems of mature black alder (<em>Alnus glutinosa</em> (L.) Gaertn.) to overall CH<sub>4</sub> exchange in two temperate peatlands. We measured emissions from stems and soils using closed chambers in a drained and an undrained alder forest over 2 years. Furthermore, we studied the importance of alder leaves as substrate for methanogenesis in an incubation experiment. Stem CH<sub>4</sub> emissions at the undrained alder forest were very variable in time and only persisted for a few weeks during the year. Generally the drained alder forest did not soil nor stem CH<sub>4</sub> emissions. Different upscaling approaches were assessed and all approaches showed that stem CH<sub>4</sub> emissions contributed less than 0.3 % to the total ecosystem CH<sub>4</sub> budget. However, stem CH<sub>4</sub> seem to depend strongly on the hydrological regime and therefore vary strongly between ecosystems. Hence, every ecosystem must be consdidered attentively with respect to their stem CH<sub>4</sub> emissions.</p>

scholarly journals Mature black alder shows intermittent events of high stem methane emissions

2020 ◽  
Author(s):  
Daniel Köhn ◽  
Anke Günther ◽  
Ines Schwabe ◽  
Gerald Jurasinski
Keyword(s):  
Greenhouse Gas ◽  
Alnus Glutinosa ◽  
Methane Emissions ◽  
High Variability ◽  
List Type ◽  
Relative Importance ◽  
Incubation Experiment ◽  
Black Alder ◽  
Alder Forest ◽  
Closed Chambers

SummaryTree stems can be a source of the greenhouse gas methane (CH4). However, assessments of the global importance are complicated by a lack of research and a high variability between ecosystems. Here, we determined the contribution of emissions from tree stems of mature black alder (Alnus glutinosa (L.) Gaertn.) to overall CH4 exchange in two temperate peatlands.We measured emissions from stems and soils using closed chambers in a drained and a wet alder forest over two years. Further, we studied the importance of alder leaves as substrate for methanogenesis in an incubation experiment.Stem CH4 emissions were shortlived and occurred only during times of inundation at the wet site. The drained site did not show stem emissions and the soil acted as a small CH4 sink. The contribution of stem emissions to the overall CH4 budget was below 0.3% in both sites.Our results show that also mature black alders intermittently can be a source of CH4. However, the low share of stem-mediated CH4 emissions in both forests may indicate that this pathway is only of minor relative importance in temperate peatlands.

scholarly journals Nitrogen mineralization and gaseous nitrogen losses from waterlogged and drained organic soils in a black alder (<i>Alnus glutinosa</i> (L.) Gaertn.) forest

2014 ◽  
Vol 11 (11) ◽  
pp. 2961-2976 ◽  
Author(s):  
T. Eickenscheidt ◽  
J. Heinichen ◽  
J. Augustin ◽  
A. Freibauer ◽  
M. Drösler
Keyword(s):  
Soil Moisture ◽  
Groundwater Level ◽  
Alnus Glutinosa ◽  
Organic Soils ◽  
Net N Mineralization ◽  
Incubation Experiment ◽  
Inorganic N ◽  
Black Alder ◽  
Net Nitrification ◽  
N2o Fluxes

Abstract. Black alder (Alnus glutinosa (L.) Gaertn.) forests on peat soils have been reported to be hotspots for high nitrous oxide (N2O) losses. High emissions may be attributed to alternating water tables of peatlands and to the incorporation of high amounts of easily decomposable nitrogen (N) into the ecosystem by symbiotic dinitrogen (N2)-fixation of alder trees. Our study addressed the question to what extent drainage enhances the emissions of N2O from black alder forests and how N turnover processes and physical factors influence the production of N2O and total denitrification. The study was conducted in a drained black alder forest with variable groundwater tables at a southern German fen peatland. Fluxes of N2O were measured using the closed chamber method at two drained sites (D-1 and D-2) and one undrained site (U). Inorganic N contents and net N mineralization rates (NNM) were determined. Additionally a laboratory incubation experiment was carried out to investigate greenhouse gas and N2 fluxes at different temperature and soil moisture conditions. Significantly different inorganic N contents and NNM rates were observed, which however did not result in significantly different N2O fluxes in the field but did in the laboratory experiment. N2O fluxes measured were low for all sites, with total annual emissions of 0.51 ± 0.07 (U), 0.97 ± 0.13 (D-1) and 0.93 ± 0.08 kg N2O–N ha−1 yr−1 (D-2). Only 37% of the spatiotemporal variation in field N2O fluxes could be explained by peat temperature and groundwater level, demonstrating the complex interlinking of the controlling factors for N2O emissions. However, temperature was one of the key variables of N2O fluxes in the incubation experiment conducted. Increasing soil moisture content was found to enhance total denitrification losses during the incubation experiment, whereas N2O fluxes remained constant. At the undrained site, permanently high groundwater level was found to prevent net nitrification, resulting in a limitation of available nitrate (NO3−) and negligible gaseous N losses. N2O flux rates that were up to four times higher were measured in the incubation experiment. They reveal the potential of high N2O losses under changing soil physical conditions at the drained alder sites. The high net nitrification rates observed and high NO3− contents bear the risk of considerable NO3− leaching at the drained sites.

scholarly journals Black Alder (Alnus glutinosa (L.) Gaertn.) on Compacted Skid Trails: A Trade-off between Greenhouse Gas Fluxes and Soil Structure Recovery?

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 726 ◽  
Author(s):  
Hannes Warlo ◽  
Klaus von Wilpert ◽  
Friederike Lang ◽  
Helmer Schack-Kirchner
Keyword(s):  
Greenhouse Gas ◽  
Soil Structure ◽  
Alnus Glutinosa ◽  
Soil Conditions ◽  
Trade Off ◽  
Soil Aeration ◽  
Black Alder ◽  
Beech Stand ◽  
Ch4 Uptake ◽  
Ghg Fluxes

The compaction of forest soils can deteriorate soil aeration, leading to decreased CH4 uptake and increased N2O efflux. Black alder (Alnus glutinosa) may accelerate soil structure regeneration as it can grow roots under anaerobic soil conditions. However, symbiotic nitrogen fixation by alder can have undesirable side-effects on greenhouse gas (GHG) fluxes. In this study, we evaluated the possible trade-off between alder-mediated structure recovery and GHG emissions. We compared two directly adjacent 15-year old beech (Fagus sylvatica) and alder stands (loamy texture, pH 5–6), including old planted skid trails. The last soil trafficking on the skid trails took place in 1999. GHG fluxes were measured over one year. Undisturbed plots with beech had a moderately higher total porosity and were lower in soil moisture and soil organic carbon than undisturbed alder plots. No differences in mineral nitrogen were found. N2O emissions in the undisturbed beech stand were 0.4 kg ha−1 y−1 and 3.1 kg ha−1 y−1 in the undisturbed alder stand. CH4 uptake was 4.0 kg ha−1 y−1 and 1.5 kg ha−1 y−1 under beech and alder, respectively. On the beech planted skid trail, topsoil compaction was still evident by reduced macro porosity and soil aeration; on the alder planted skid trail, soil structure of the uppermost soil layer was completely recovered. Skid trail N2O fluxes under beech were five times higher and CH4 oxidation was 0.6 times lower compared to the adjacent undisturbed beech stand. Under alder, no skid-trail-effects on GHG fluxes were evident. Multiple regression modelling revealed that N2O and CH4 emissions were mainly governed by soil aeration and soil temperature. Compared to beech, alder considerably increased net fluxes of GHG on undisturbed plots. However, for skid trails we suggest that black alder improves soil structure without deterioration of the stand’s greenhouse gas balance, when planted only on the compacted areas.

scholarly journals Gaseous nitrogen losses and mineral nitrogen transformation along a water table gradient in a black alder (<i>Alnus glutinosa</i> (L.) Gaertn.) forest on organic soils

2013 ◽  
Vol 10 (12) ◽  
pp. 19071-19107 ◽  
Author(s):  
T. Eickenscheidt ◽  
J. Heinichen ◽  
J. Augustin ◽  
A. Freibauer ◽  
M. Drösler
Keyword(s):  
Soil Moisture ◽  
Alnus Glutinosa ◽  
Organic Soils ◽  
Physical Factors ◽  
Net N Mineralization ◽  
Incubation Experiment ◽  
Inorganic N ◽  
Black Alder ◽  
Net Nitrification ◽  
N2o Fluxes

Abstract. Black alder (Alnus glutinosa (L.) Gaertn.) forests on peat soils have been reported to be hotspots for high nitrous oxide (N2O) losses. High emissions may be attributed to alternating water tables of peatlands and to the incorporation of high amounts of easily decomposable nitrogen (N) into the ecosystem by symbiotic dinitrogen (N2)-fixation of alder trees. Our study addressed the question to what extent drainage enhances the emissions of N2O from black alder forests and how N turnover processes and physical factors influence the production of N2O and total denitrification. The study was conducted in a drained black alder forest with variable groundwater tables at a southern German fen peatland. Fluxes of N2O were measured using the closed chamber method at two drained sites (D-1 and D-2) and one undrained site (U). Inorganic N contents and net N mineralization rates (NNM) were determined. Additionally a laboratory incubation experiment was carried out to investigate greenhouse gas and N2 fluxes at different temperature and soil moisture conditions. Significantly different inorganic N contents and NNM rates were observed which however did not result in significantly different N2O fluxes in the field, but in the laboratory experiment. Measured N2O fluxes were low for all sites, with total annual emissions of 0.51 ± 0.07 (U), 0.97 ± 0.13 (D-1) and 0.93 ± 0.08 kg N2O-N ha−1 yr−1 (D-2). Only 37% of the spatio-temporal variation in field N2O fluxes could be explained by peat temperature and groundwater level, demonstrating the complex interlinking of the controlling factors for N2O emissions. However, temperature was one of the key variables of N2O fluxes in the conducted incubation experiment. Increasing soil moisture content was found to enhance total denitrification losses during the incubation experiment, whereas N2O fluxes remained constant. At the undrained site, permanently high ground water level was found to prevent net nitrification, resulting in a limitation of available nitrate (NO3–) and negligible gaseous N losses. Up to four times higher N2O flux rates were measured in the incubation experiment. They reveal the potential of high N2O losses under changing soil physical conditions at the drained alder sites. The observed high net nitrification rates and high NO3– contents bear the risk of considerable NO3– leaching at the drained sites.

scholarly journals Methane emissions from Amazonian Rivers and their contribution to the global methane budget

2014 ◽  
Vol 20 (9) ◽  
pp. 2829-2840 ◽  
Author(s):  
Henrique O. Sawakuchi ◽  
David Bastviken ◽  
André O. Sawakuchi ◽  
Alex V. Krusche ◽  
Maria V. R. Ballester ◽  
...  
Keyword(s):  
Methane Emissions ◽  
Methane Budget

scholarly journals Glossiness Evaluation of Coated Wood Surfaces as Function of Varnish Type and Exposure to Different Conditions

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 558
Author(s):  
Emilia-Adela Salca ◽  
Tomasz Krystofiak ◽  
Barbara Lis ◽  
Salim Hiziroglu
Keyword(s):  
Artificial Aging ◽  
Chemical Resistance ◽  
Heat Exposure ◽  
Value Added ◽  
Alnus Glutinosa ◽  
Practical Applications ◽  
Black Alder ◽  
Structural Differences ◽  
Wood Surfaces ◽  
Water Borne

The objective of this study was to evaluate the glossiness of black alder wood (Alnus glutinosa L.) samples coated with two varnish types as a function of exposure to dry heat and artificial aging. The chemical resistance of the coated samples to cold liquids was also evaluated. Based on the findings in this work, it appears that the varnish types and their structural differences influenced the overall glossiness of the coated samples. The UV varnish exhibited higher gloss values than those coated with the water-borne product within the range of silky gloss and silky matte grades. The heat exposure influenced the surface glossiness of the UV-coated samples more than the samples coated with water-borne varnish. The overall gloss values of the samples decreased with the exposure time to artificial aging, resulting in no layer cracks. The cold household liquids left less visible traces on the surfaces and alcohol was found to be the strongest agent. This study could have practical applications in the furniture industry to produce value-added furniture units according to their specific conditions of indoor use.

scholarly journals Response of black alder (Alnus glutinosa (L.) Gaertn.) to selective thinning of various intensities

2020 ◽  
Vol 144 (7-8) ◽  
pp. 378-378
Author(s):  
Simon Lendvai ◽  
Jurij Diaci ◽  
Dušan Roženbergar
Keyword(s):  
Alnus Glutinosa ◽  
Black Alder

Područje poplavnih šuma crne johe (Alnus glutinosa (L.) Gaertn.) u Sloveniji čini samo 0,4 % (približno 4708 ha) ukupne površine šumskog zemljišta (Čater i sur., 2001.). Veći kompleks takvih sastojina u Sloveniji su Črni i Polanski Log, a istraživanje je provedeno na području potonjeg (slika 1). Kako čiste sastojine johe odlikuju brojne specifičnosti, potrebno im je prilagoditi šumskouzgojne postupke. Da bi se utvrdio odgovarajući intenzitet prorjede takvih sastojina, 1967. godine u Polanskom Logu postavljene su pokusne plohe. Od tada do 2018. godine na plohama je izvršeno pet do sedam mjerenja. Sva stabla na plohama su bila obrojčana. Izvršeno je mjerenje prsnih promjera i procjena sljedećih elemenata na stablima: pripadnost etaži, vitalnost, uzgojna perspektiva, uzgojna uloga, duljina krošnje i kvaliteta (tablica 3). Svaka ploha bila je podijeljena u tri polja (40 x 50 m) s različitim metodama rada: bez intervencije, umjereno i intenzivno prorjeđivanje. Uzgojni postupci koji su poduzeti tijekom praćenja pokusa prikazani su u tablici 2. Danas su te sastojine u zreloj fazi razvoja, stoga smo u ovom radu analizirali reakcije crne johe na različite intenzitete prorjeđivanja i dobivene rezultate usporedili s preporukama autora tradicionalnih uzgojnih modela i modela koji se temelje na situacijskoj njezi šuma. Ustanovili smo da se na plohama s intenzivnim prorjeđivanjem gustoća sastojine koja je u dobi između 50 i 70 godina i na kraju je ophodnje kreće od 295 do 690 kom/ha (slika 3), dok se na plohama bez intervencije ova vrijednost kreće u rasponu od 370 do 790 kom/ha. Drvne zalihe u istom su se razdoblju kretale u rasponu od 277 do 458 m<sup>3</sup>/ha na plohama s intenzivnim prorjeđivanjem, dok su na plohama bez intervencije bile veće, u rasponu od 309 do 516 m<sup>3</sup>/ha (slika 4). U to su se doba temeljnice nalazile u rasponu između 23 i 41 m<sup>2</sup>/ha na plohama s intenzivnim prorjeđivanjem, a na plohama bez intervencije u rasponu od 26 do čak 51 m<sup>2</sup>/ha (slika 5). Tijekom cijelog razdoblja praćenja ploha, stabla su, bez obzira na metodu rada, narasla za tri do četiri debljinska stupnja (slika 2). Na plohama s umjerenim prorjeđivanjem i onima bez intervencije, debljinski prirast stabala bio je skoro jednak (0,33 cm godišnje) (slika 6). Statistički je značajan veći debljinski prirast stabala na plohama s jako intenzivnim prorjeđivanjem (0,37 cm godišnje). Debljinski prirast dominantnih stabala bio je nešto veći, od 0,46 cm godišnje na plohama bez intervencije do 0,50 cm godišnje na plohama s jako intenzivnim prorjeđivanjem, ali statistički značajne razlike između metoda rada nisu utvrđene (slika 6). Međutim, otkrili smo da kod dominantnih stabala ne postoje statistički značajne razlike s obzirom na njihovu slojevitost, vitalnost, tendenciju, dužinu krošnje i kvalitete s obzirom na korištenu metodu rada. U usporedbi s uzgojnim modelima koji su se koristili za manji broj odabranih stabla, gustoća i temeljnica ispitivanih sastojina je znatno veća, a debljinski prirast manji. Autori tradicionalnih i modela s manjim brojem odabranih stabala zagovaraju rano prorjeđivanje takvih sastojina (tablica 1). Veće razlike nastaju u konačnom broju stabala po hektaru i u intenzitetu intervencije. Razlog malog debljinskog prirasta i razlike između metoda rada na našim plohama pripisali smo nedovoljnom intenzitetu i djelomično nedosljednoj provedbi postupka prorjeđivanja. Ipak, ukazala se potreba za intenzivnim prorjeđivanjem i pospješivanjem rasta stabala najvećeg prsnog promjera, vitalnosti i tendencije, lijepo oblikovane i duge krošnje (slika 7, slika 8).

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