A. Sogatchev

Publications (8)3.41 Total impact

• Article: Above-ground biomass and structure of pristine Siberian Scots pine forests as controlled by competition and fire

  C. Wirth, E.-D. Schulze, W. Schulze, D. von Stünzner-Karbe, W. Ziegler, I. M. Miljukova, A. Sogatchev, A. B. Varlagin, M. Panvyorov, S. Grigoriev, W. Kusnetzova, M. Siry, G. Hardes, R. Zimmermann, N. N. Vygodskaya
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  ABSTRACT: The study presents a data set of above-ground biomass (AGB), structure, spacing and fire regime, for 24 stands of pristine Siberian Scots pine (Pinus sylvestris) forests with lichens (n = 20) or Vaccinium/mosses (n = 4) as ground cover, along four chronosequences. The stands of the “lichen” site type (LT) were stratified into three chronosequences according to stand density and fire history. Allometric equations were established from 90 sample trees for stem, coarse branch, fine branch, twig and needle biomass. The LT stands exhibited a low but sustained biomass accumulation until a stand age of 383 years. AGB reached only 6–10 kgdw m−2 after 200 years depending on stand density and fire history compared to 20 kgdw m−2 in the “Vaccinium” type (VT) stands. Leaf area index (LAI) in the LT stands remained at 0.5–1.5 and crown cover was 30–60%, whereas LAI reached 2.5 and crown cover was >100% in the VT stands. Although nearest-neighbour analyses suggested the existence of density-dependent mortality, fire impact turned out to have a much stronger effect on density dynamics. Fire scar dating and calculation of mean and initial fire return intervals revealed that within the LT stands differences in structure and biomass were related to the severity of fire regimes, which in turn was related to the degree of landscape fragmentation by wetlands. Self-thinning analysis was used to define the local carrying capacity for biomass. A series of undisturbed LT stands was used to characterise the upper self-thinning boundary. Stands that had experienced a moderate fire regime were positioned well below the self-thinning boundary in a distinct fire-thinning band of reduced major axis regression slope −0.26. We discuss how this downward shift resulted from alternating phases of density reduction by fire and subsequent regrowth. We conclude that biomass in Siberian Scots pine forests is strongly influenced by fire and that climate change will affect ecosystem functions predominantly via changes in fire regimes.
  Oecologia 09/1999; 121(1):66-80. · 3.41 Impact Factor
• Article: Above-ground biomass and structure of pristine Siberian Scots pine forests as controlled by competition and fire

  C. Wirth, E.D. Schulze, W. Schulze, D. von Stunzner-Karbe, W. Ziegler, I.M. Miljukova, A. Sogatchev, A.B. Varlagin, M. Panvyorov, S. Grigoriev, W. Kusnetzova, M. Siry, G. Hardes, R. Zimmermann, N.N. Vygodskaya
  [show abstract] [hide abstract]
  ABSTRACT: The study presents a data set of above-ground biomass (AGB), structure, spacing and fire regime, for 24 stands of pristine Siberian Scots pine (Pinus sylvestris) forests with lichens (n = 20) or Vaccinium/mosses (n = 4) as ground cover, along four chronosequences. The stands of the "lichen" site type (LT) were stratified into three chronosequences according to stand density and fire history. Allometric equations were established from 90 sample trees for stem, coarse branch, fine branch, twig and needle biomass. The LT stands exhibited a low but sustained biomass accumulation until a stand age of 383 years. AGE reached only 6-10 kg(dw) m(-2) after 200 years depending on stand density and fire history compared to 20 kg(dw) m(-2) in the "Vaccinium" type (VT) stands. Leaf area index (LAI) in the LT stands remained at 0.5-1.5 and crown cover was 30-60%, whereas LAI reached 2.5 and crown cover was > 100% in the VT stands. Although nearest-neighbour analyses suggested the existence of density-dependent mortal
  Oecologia. 01/1999; 121:66-80.
• Article: Aboveground biomass and nitrogen nutrition in a chronosequence of pristine Dahurian Larix stands in eastern Siberia

  E. Schulze, W. Schulze, F. Kelliher, N. Vygodskaya, W. Ziegler, K. Kobak, H. Koch, A. Arneth, W. Kusnetsova, A. Sogatchev, A. Issajev, G. Bauer, D. Hollinger
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  ABSTRACT: useable, but little data for early stages
  Canadian Journal of Forest Research. 01/1995; 25:943-960.
• Article: Aboveground biomass and nitrogen nutrition in a cronosequence of pristine Darhurian Larix stands in eastern Siberia

  E.D. Schulze, W. Schulze, F.M. Kelliher, N.N Vygodskaya, W. Ziegler, K.I. Kobak, H. Koch, A. Arneth, W.A. Kusnetsova, A. Sogatchev, A. Issajev, G. Bauer, D.Y. Hollinger
  Canadian Journal of Forestry. 01/1995; 25:943-960.
• Article: Carbon dioxide efflux density from the floor of a central Siberian pine forest

  F.M. Kelliher, J. Lloyd, A. Arneth, B. Lühker, J.N. Byers, T.M. McSeveny, I. Milukova, S. Grigoriev, M. Panfyorov, A. Sogatchev, A. Varlargin, W. Ziegler, G. Bauer, S.-C. Wong, E.-D. Schulze
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  ABSTRACT: Total and forest floor carbon dioxide flux densities (FCO2) and environmental variables were measured for 18 consecutive mid-summer days during July 1996 in a 215-year-old stand of Pinus sylvestris L. trees located 40 km southwest of the village of Zotino in central Siberia, Russia (61°N, 89°E, 160 m asl). Forest floor FCO2 was regulated by surface soil water content, related to the limited storage capacity of the sandy soil equivalent to only 4 mm water per 100 mm depth of soil. Following 12 mm rainfall, forest floor FCO2 increased by 52% to a maximum value of 4.1 μmol m−2 s−1. However, the rate had returned to the general lower level by the next day in response to rapid drying of the surface soil. There was little correspondence between forest floor FCO2 and the distributions of root and soil carbon or soil temperature. However, for soil samples returned to the laboratory, sieved to remove roots and re-watered, microbial respiration rate was positively and exponentially related to temperature. Measurements of forest floor FCO2 by eddy covariance were in good agreement with the chamber data during the daytime when the atmosphere was regularly mixed by turbulence. Micrometeorological flux measurements at the forest floor and above the trees showed how, on average, 77% of the carbon sequestered by tree canopy photosynthesis was lost to the atmosphere by root and soil microbial respiration during the observation period. On a daily basis, the boreal forest was generally a modest net sink (−75 mmol m−2 per day), but also a small carbon source on hot and dry days.
  Agricultural and Forest Meteorology.
• Article: Evaporation from a central Siberian pine forest

  F.M. Kelliher, J. Lloyd, A. Arneth, J.N. Byers, T.M. McSeveny, I. Milukova, S. Grigoriev, M. Panfyorov, A. Sogatchev, A. Varlargin, W. Ziegler, G. Bauer, E.-D. Schulze
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  ABSTRACT: Total forest evaporation, E, understorey evaporation, Eu, and environmental variables were measured for 18 consecutive mid-summer days during July 1996 in a 215-year-old stand of Pinus sylvestris L. trees located 40 km southwest of the village of Zotino in central siberia, Russia (61°N, 89°E, 160 m asl). Tree and lichen (Cladonia and Cladina spp.) understorey one-sided leaf and surface-area indices were 1.5 and 6.0, respectively. Daily E, measured by eddy covariance, was 0.8–2.3 mm day−1 which accounted for 15–67% of the available energy, Ra. Following 12 mm rainfall, daily E reached a maximum on the second day (the first clear day) but declined rapidly thereafter to reach minimum rates within one week. The sandy soil had a range of water content equivalent to only 4 mm water per 100 mm depth of soil. It was estimated that 38% of soil water was utilised before water deficit began to limit E. Eu, also measured by eddy covariance and by lysimeters, was 0.5 to 1.6 mm day−1 or 33–92% of E. Eu was proportional to Ra, but in response to soil drying, the slope of this linear relation declined by a factor of three to a minimum value only three days after the rainfall. Based on the measurements and climatological data, including average annual precipitation of 600 mm year−1 with half as rain during the nominal growing season (1 May to 30 September), water balance calculations suggested E was 265 mm per growing season.
  Journal of Hydrology.
• Article: Evaporation from an eastern Siberian larch forest

  F.M. Kelliher, D.Y. Hollinger, E.-D. Schulze, N.N. Vygodskaya, J.N. Byers, J.E. Hunt, T.M. McSeveny, I. Milukova, A. Sogatchev, A. Varlargin, W. Ziegler, A. Arneth, G. Bauer
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  ABSTRACT: Total forest evaporation (λE), understorey evaporation, and environmental variables were measured on nine summer days under different weather conditions in a 130-year-old stand of Larix gmelinii (Rupr.) Rupr. trees located 160 km south of Yakutsk in eastern Siberia, Russia (61°N, 128°E, 300m above sea-level (a.s.l.)). Tree and broad-leaved understorey vegetation one-sided leaf area indices were 1.5 and 1.0, respectively. Agreement of λE and sensible heat flux (H), both measured by eddy covariance, and the available energy (Ra) was generally good: (H + λE) = 0.83 Ra + 9 W m−2 with r2 = 0.92 for 364 half-hour periods and the mean ± 95% confidence limit was 129 ± 17 for (H + λE) and 144 ± 19 for Ra. Daily E was 1.6–2.2 min, less than half of the potential evaporation rate and accounting for 31–50% of Ra, with the lowest percentage on clear days. A perusal of the sparse literature revealed that average daily E of boreal coniferous forest during the tree growing season (1.9 mm day−1 for this study) is relatively conservative, suggesting that low evaporation rates are a feature of this biome's energy balance. Using the Penman-Monteith equation, the maximum bulk-surface conductance (Gsmax) was 10 mm s−1. E and Gs were regulated by irradiance, air saturation deficit, and surface soil water content during a week-long dry period following 20 mm rainfall. From lysimeter measurements, 50% of E emanated from the understorey at a rate proportional to Ra. Based on the measurements and published climatological data, including average annual precipitation equal to 213 mm, water balance calculations indicated growing season forest E equal to 169 mm, the occurrence of a late summer-autumn soil water deficit, and annual runoff of 44 mm by snowmelt.
  Agricultural and Forest Meteorology.
• Source

  Available from: nrs.fs.fed.us

  Article: Forest–atmosphere carbon dioxide exchange in eastern Siberia

  D.Y. Hollinger, F.M. Kelliher, E.-D. Schulze, G. Bauer, A. Arneth, J.N. Byers, J.E. Hunt, T.M. McSeveny, K.I. Kobak, I. Milukova, A. Sogatchev, F. Tatarinov, A. Varlargin, W. Ziegler, N.N. Vygodskaya
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  ABSTRACT: We investigated the daily exchange of CO2 between undisturbed Larix gmelinii (Rupr.) Rupr. forest and the atmosphere at a remote Siberian site during July and August of 1993. Our goal was to measure and partition total CO2 exchanges into aboveground and belowground components by measuring forest and understory eddy and storage fluxes and then to determine the relationships between the environmental factors and these observations of ecosystem metabolism. Maximum net CO2 uptake of the forest ecosystem was extremely low compared to the forests elsewhere, reaching a peak of only ∼5 μmol m−2 s−1 late in the morning. Net ecosystem CO2 uptake increased with increasing photosynthetically active photon flux density (PPFD) and decreased as the atmospheric water vapor saturation deficit (D) increased. Daytime ecosystem CO2 uptake increased immediately after rain and declined sharply after about six days of drought. Ecosystem respiration at night averaged ∼2.4 μmol m−2 s−1 with about 40% of this coming from the forest floor (roots and heterotrophs). The relationship between the understory eddy flux and soil temperature at 5 cm followed an Arrhenius model, increasing exponentially with temperature (Q10∼2.3) so that on hot summer afternoons the ecosystem became a source of CO2. Tree canopy CO2 exchange was calculated as the difference between above and below canopy eddy flux. Canopy uptake saturated at ∼6 μmol CO2 m−2 s−1 for a PPFD above 500 μmol m−2 s−1 and decreased with increasing D. The optimal stomatal control model of Mäkelä et al. (1996) was used as a `big leaf' canopy model with parameter values determined by the non-linear least squares. The model accurately simulated the response of the forest to light, saturation deficit and drought. The precision of the model was such that the daily pattern of residuals between modeled and measured forest exchange reproduced the component storage flux. The model and independent leaf-level measurements suggest that the marginal water cost of plant C gain in Larix gmelinii is more similar to values from deciduous or desert species than other boreal forests. During the middle of the summer, the L. gmelinii forest ecosystem is generally a net sink for CO2, storing ∼0.75 g C m−2 d−1.
  Agricultural and Forest Meteorology.