THG-Emissionen aus Waldökosystemen. Rainer Brumme Department of Soil Science of Tropical Ecosystems Göttingen, Germany

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1 THG-Emissionen aus Waldökosystemen Rainer Brumme Department of Soil Science of Tropical Ecosystems Göttingen, Germany

2 N 2 O Emissionen aus Waldökosystemen

3 Mean annual N 2 O fluxes in forest biomes 8 6 tropical biome temperate biome boreal biome [kg N ha-1 yr-1] mean annual air temperature [ C] Brumme et al., 25

4 Effects of trees on N 2 O emission 4 3 Temperatur e 15 C 1 µg N m -2 day Spruce Beech

5 Control on N 2 O emission [µg N m-2 d-1] High seasonal 2 emissions: 1 >6 C >1 mm precipitation monat -1 N2O Emission Solling, Beech Temperature [ C] 8% WFPS 6% WFPS 3% WFPS

6 Effects of forest harvesting on N 2 O emissions Soil temperature [ C] hpa Jan-94 Mar-94 May-94 8 stand gap 6 limed gap 4 Jul-94 Sep-94 Nov-94 b a µg N2O-N m -2 h Jan-94 Mar-94 May-94 Jul-94 Sep-94 Nov-94 2 c Jan-94 Mar-94 May-94 Jul-94 Sep-94 Nov-94 Brumme & Borken submitted

7 Impact of soil compaction during harvesting on N 2 O emissions

8 Impact of soil compaction during harvesting on N 2 O emissions (growing season) 12 x56 g N2O-N ha -1 7month x6 control compacted x21 x12 x27 sand silt sand silt clay spruce beech beech beech beech mm mm Teepe et al. SSSAJ 24

9 Effects of liming on N 2 O emission Reduction of N2O emission (%) Solling beech 3 (1982) Solling beech 1 (1975) Solling spruce 6 (1985) Lappwald beech 7.5 (1988) Lappwald spruce 43 Mg lime ha -1 (1988) Borken & Brumme S&M 1997

10 Impact of N-deposition on N 2 O emission Papen & Butterbach-Bahl 1999

11 Impact of Climate Change on N 2 O emission Temperature increase will prolong the period with high N 2 O fluxes, as long as low precipitation reduces this period. Brumme et al., 25

12 CH 4 Oxidation in Waldböden

13 Methane oxidation in Temperate forests 6 GW µg CH4 m -2 h Beech, Solling Spruce, Solling Soil depth [cm] Forest floor Mar May Jul Sep Nov Jan Mar Relativ e gas diffusifity Beech forest w ith m ul hum us on clayed soil (GW) Spruce forest w ith m oder hum us on silty soil (Solling) Beech forest w ith m oder hum us on silty soil (Solling) Brumme & Borken GBC 1999

14 Methane oxidation of 7 temperate forests 3, 2,5 y = 1.29x R 2 =.77 GW kg CH4 ha -1 a -1 2, 1,5 1,,5, Spruce Beech F1 Sp B1 LF Ha 3,5 4 4,5 5 5,5 ph (H 2 O) LB Brumme & Borken GBC 1999

15 Effects of forest harvesting and liming on CH 4 uptake Soil temperature [ C] hpa Jan-94 Mar-94 May-94 stand 8 gap 6 limed gap 4 Jul-94 Sep-94 Nov-94 b a µg CH4 m -2 h -1 2 Jan-94 Mar-94 May-94 Jul-94 Sep-94 Nov c Jan-94 Mar-94 May-94 Jul-94 Sep-94 Nov-94 Borken & Brumme submitted

16 Impact of soil compaction during harvesting on CH 4 uptake (growing season) g CH4-C ha -1 7month x12 control compacted x2 x6 x4 x3 sand silt sand silt clay spruce beech beech beech beech mm mm Teepe et al. unpublished

17 Effects of liming on CH 4 uptake Increase of CH4 uptake (%) Solling beech 3 (1982) Solling beech 1 (1975) Solling spruce 6 (1985) Lappwald beech 7.5 (1988) Lappwald spruce 43 Mg lime ha -1 (1988) Borken & Brumme S&M 1997

18 Difference in CH 4 uptake to respective control (%) a b c d e Effects of N- fertilisation on methane uptake -5 Figure Proportional deviations of N-treated plots to the control plot in CH 4 uptake in the spruce forest at Solling using automated chambers from August 1993 to December 1994 [a: (NH 4 ) 2 SO 4, b: NH 4 NO 3, c: NH 4 Cl, d: urea, e: NaNO 3 ]. All fertilized plots were treated four times with 3 kg N ha -1 on November 4 th 1993, on May 22 th 1994, on July 12 th 1994 and on September 14 th Difference in CH 4 uptake to respective control (%) a b c d e f g h Figure Proportional deviation of N-treated plots to the control plot in CH 4 uptake at Göttinger Wald measured from April 1994 to April 1995 (n=41) [a: (NH 4 ) 2 SO 4, b: (NH 4 ) 2 SO 4, c: NH 4 -acetate, d: urea, e: NH 4 Cl, f: NaNO 3, g: NH 4 NO 3, h: KNO 3 ]. Plot a received 12 kg N ha -1 as (NH 4 ) 2 SO 4 on June 1 th All other plots received 3 kg N ha -1 on June 1 th 1994, on August 4 th 1994, on November 28 th 1994 and on February 27 th Borken & Brumme submitted

19 Waldökosysteme als Kohlenstoffspeicher

20 Kohlenstoffspeicherung in den Waldböden von Deutschland (t C ha -1 a -1 )

21 Kohlenstoffspeicherung in Waldböden von Deutschland (BZE) 12 1 forest floor - 9 cm Mg C ha Mull Mull-Moder Moder Moder-Rohh. Rohhumus

22 Humusakkumulation im Moderhumus (Buche, Fichte, Solling) C (t ha -1 ) +999 kg C ha -1 yr kg N ha -1 yr kg C ha -1 yr kg N ha -1 yr beech spruce sampling year Meiwes et al., F&H, 22

23 Einfluß der Bewirtschaftung auf den Kohlenstoffvorrat Jandl et al. 27 (Geoderma)

24 Impact of land use change on the soil-c-stock Labiler Humus-Pool Matson et al. Science 1997 Physikalisch und chemisch geschützter Humus-Pool

25 Zusammenfassung / N 2 O Nur wenige Waldökosysteme emittieren mehr als 1 kg N 2 O-N ha -1 yr -1 Eine fehlende Bestockung und Kompaktierung hat eine deutliche Erhöhung der N 2 O Emissionen zur Folge Kalkungen reduzieren die N 2 O Emission Den größten Einfluss auf die N 2 O Emissionen aus N-gesättigten Wäldern haben Massnahmen, die die Sauerstoffzufuhr in den Boden verringern Zusammenfassung / CH 4 Eine hohe bodenbiologische Oxidation fördert die Oxidation von Methan Eine fehlende Bestockung und Kompaktierung verringert die Oxidation Kalkungen erhöhen die biologische Aktivität und fördern die Oxidation Der Einfluss von N-Depositionen ist widersprüchlich