Sirvi Autor "Butlers, Aldis" järgi

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Impact of drainage on soil CH4 and N2O fluxes in nutrient-rich hemiboreal peatland forests of Europe
(2026) Kamil-Sardar, Muhammad; Laiho, Raija; Jauhiainen, Jyrki; Butlers, Aldis; Schindler, Thomas; Vahter, Hanna; Čiuldienė, Dovilė; Vigricas, Egidijus; Teemusk, Alar; Kull, Ain; Lazdiņš, Andis; Haberl, Andreas; Bārdule, Arta; Līcīte, Ieva; Samariks, Valters; Mander, Ülo; Armolaitis, Kęstutis; Soosaar, Kaido
Background and aims Peatland forests play a significant, yet highly variable, role in atmospheric methane (CH4) and nitrous oxide (N2O) emissions. Drainage reduces CH4 but increases N2O fluxes from nutrient-rich soils, creating complex climate trade-offs. To refine regional climate strategies, a clearer understanding of soil fluxes and influencing factors across forest types in the hemiboreal zone is needed. Methods This study presents two years of soil flux and environmental data collected from 2020 to 2023 using manual chambers at 18 drained (DF) and 7 undrained (UF) sites, with different tree species, in Estonia, Latvia, and Lithuania. Results Soil water‑table depth was the primary control on annual CH4 exchange; DF sites acted as CH4 sinks (–4.6 kg ha–1 y–1), whereas UF sites were net sources (38.2 kg ha–1 y–1). In contrast, N2O emissions occurred at all sites, averaging 5.9 kg ha–1 y–1 in DF and 1.4 kg ha–1 y–1 in UF soils. Within DF sites, Myrtillus‑type pine stands exhibited the lowest N2O fluxes, while alder stands showed the highest, followed by birch- and spruce-dominated stands, reflecting differences in hydrology, pH, and C/N ratios of the soil. Conclusions Our findings reveal significantly lower CH4 and moderately higher N2O emissions from DF soils than the IPCC Tier 1 temperate zone emission factor (EF), which has thus far been used for the hemiboreal zone. This study can improve national GHG inventories using specific information. We recommend applying Baltic region-specific EFs, as the mean annual CH4 and N2O emissions showed no significant difference across the three countries.
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Reviews and syntheses: Greenhouse gas emissions from drained organic forest soils – synthesizing data for site-specific emission factors for boreal and cool temperate regions
(2023) Jauhiainen, Jyrki; Heikkinen, Juha; Clarke, Nicholas; He, Hongxing; Dalsgaard, Lise; Minkkinen, Kari; Ojanen, Paavo; Vesterdal, Lars; Alm, Jukka; Butlers, Aldis; Callesen, Ingeborg; Jordan, Sabine; Lohila, Annalea; Mander, Ülo; Óskarsson, Hlynur; Sigurdsson, Bjarni D.; Søgaard, Gunnhild; Soosaar, Kaido; Kasimir, Åsa; Bjarnadottir, Brynhildur; Lazdins, Andis; Laiho, Raija
We compiled published peer-reviewed CO2, CH4, and N2O data on managed drained organic forest soils in boreal and temperate zones to revisit the current Tier 1 default emission factors (EFs) provided in the IPCC (2014) Wetlands Supplement: to see whether their uncertainty may be reduced; to evaluate possibilities for breaking the broad categories used for the IPCC EFs into more site-type-specific ones; and to inspect the potential relevance of a number of environmental variables for predicting the annual soil greenhouse gas (GHG) balances, on which the EFs are based. Despite a considerable number of publications applicable for compiling EFs being added, only modest changes were found compared to the Tier 1 default EFs. However, the more specific site type categories generated in this study showed narrower confidence intervals compared to the default categories. Overall, the highest CO2 EFs were found for temperate afforested agricultural lands and boreal forestry-drained sites with very low tree stand productivity. The highest CH4 EFs in turn prevailed in boreal nutrient-poor forests with very low tree stand productivity and temperate forests irrespective of nutrient status, while the EFs for afforested sites were low or showed a sink function. The highest N2O EFs were found for afforested agricultural lands and forestry-drained nutrient-rich sites. The occasional wide confidence intervals could be mainly explained by single or a few highly deviating estimates rather than the broadness of the categories applied. Our EFs for the novel categories were further supported by the statistical models connecting the annual soil GHG balances to site-specific soil nutrient status indicators, tree stand characteristics, and temperature-associated weather and climate variables. The results of this synthesis have important implications for EF revisions and national emission reporting, e.g. by the use of different categories for afforested sites and forestry-drained sites, and more specific site productivity categories based on timber production potential.
listelement.badge.access-status Avatud juurdepääs ,
Reviews and syntheses: Greenhouse gas emissions from drained organic forest soils – synthesizing data for site-specific emission factors for boreal and cool temperate regions
(2023) Jauhiainen, Jyrki; Heikkinen, Juha; Clarke, Nicholas; He, Hongxing; Dalsgaard, Lise; Minkkinen, Kari; Ojanen, Paavo; Vesterdal, Lars; Alm, Jukka; Butlers, Aldis; Callesen, Ingeborg; Jordan, Sabine; Lohila, Annalea; Mander, Ülo; Óskarsson, Hlynur; Sigurdsson, Bjarni D.; Søgaard, Gunnhild; Soosaar, Kaido; Kasimir, Åsa; Bjarnadottir, Brynhildur; Lazdins, Andis; Laiho, Raija
We compiled published peer-reviewed CO2, CH4, and N2O data on managed drained organic forest soils in boreal and temperate zones to revisit the current Tier 1 default emission factors (EFs) provided in the IPCC (2014) Wetlands Supplement: to see whether their uncertainty may be reduced; to evaluate possibilities for breaking the broad categories used for the IPCC EFs into more site-type-specific ones; and to inspect the potential relevance of a number of environmental variables for predicting the annual soil greenhouse gas (GHG) balances, on which the EFs are based. Despite a considerable number of publications applicable for compiling EFs being added, only modest changes were found compared to the Tier 1 default EFs. However, the more specific site type categories generated in this study showed narrower confidence intervals compared to the default categories. Overall, the highest CO2 EFs were found for temperate afforested agricultural lands and boreal forestry-drained sites with very low tree stand productivity. The highest CH4 EFs in turn prevailed in boreal nutrient-poor forests with very low tree stand productivity and temperate forests irrespective of nutrient status, while the EFs for afforested sites were low or showed a sink function. The highest N2O EFs were found for afforested agricultural lands and forestry-drained nutrient-rich sites. The occasional wide confidence intervals could be mainly explained by single or a few highly deviating estimates rather than the broadness of the categories applied. Our EFs for the novel categories were further supported by the statistical models connecting the annual soil GHG balances to site-specific soil nutrient status indicators, tree stand characteristics, and temperature-associated weather and climate variables. The results of this synthesis have important implications for EF revisions and national emission reporting, e.g. by the use of different categories for afforested sites and forestry-drained sites, and more specific site productivity categories based on timber production potential.