Leibniz Centre for Agricultural Landscape Research

Transcription

1 Leibniz Centre for Agricultural Landscape Research Conversion of single-species pine forest stands to species-rich mixed decidous forests in north-eastern German lowlands simulation of effects on carbon budget Michael Janott, Hubert Jochheim, Martina Puhlmann, Uwe Heinrich

2 Context and motivation Project INKA BB (Innovation Network of Climate Change Adaptation Brandenburg Berlin) Climatic conditions affect stability of forest structures via promoting pathogen development extreme weather events like storm and drought

3 Uncertainties about future climate Future development of climate is uncertain, hence, unfavourable climatic condition can lead to decline of individual tree species Large areas of North-Eastern German lowlands are covered by single-layered pine forests

4 PROBLEM: Decline of pine can lead to forest decline on large areas SOLUTION: Conversion of dominating pine forests into climate adaptive species-rich mixed deciduous forests

5 Adaptivity Ability of ecosystems to organise themselves at varying environmental conditions without long-lasting successions, maintaining their system determining life functions Jenssen et al Crowe & Parker 2008: Using portfolio theory to guide reforestation and restoration under climate change scenarios." Climatic Change 89(3-4):

6 TASK: Quantification of effects of forest conversion on carbon and water balance in model region

7 understory overstory Management scenarios b us i ness as usual Climate adaptive Pine Douglas fir Oak Beech Lime Generation of scenarios: NEWAL-NET TP-B: Martin Jenssen Maintainance of current tree species distribution under consideration of rotation period Conversion to climate adaptive mixed deciduous forests under consideration of rotation period

8 Model region

9 Geo data Climate projections REMO (Jacob et al. 2005, 2006) N deposition (Gauger et al. 2008) Forest stands Forest survey map Forest inventory data base (LFE 2006) Management scenarios (Jenssen) BIOME-BGC (version ZALF) Relief DEM25 (LUA) Topography TK25 (BKG) Soil map BÜK300 (Bauriegel et al. 2001)

10 BIOME-BGC Biome-BGC (version 4.2) Source: Running et al., Thornton et al. 2002, Purpose: simulation of water, carbon, and nitrogen budgets of terrestrial biomes Scale biomes, regional global application Model developments at ZALF Higher tree species and site specifity Scale: forest ecosystems, site regional application

11 Carbon pools and fluxes of BIOME-BGC (vers. ZALF) GPP NPP NEP NBP atmospheric CO 2 exported wood photosynthesis growth respiration aboveground maintenance respiration root respiration heterotrophic respiration harvest photosynthates allocation leaves branch/stem leaf litterfall br/stem litterfall Multiple vegetation layers leaf litter br/st cwd litter layer coarseroot fine roots croot litterfall froot litterfall r cwd froot litter soil layer 1... n coarseroot croot litterfall r cwd Vertical root growth fine roots Phenology froot litterfall froot litter soil

12 Wood export plant resp. Carbon fluxes

13 total soil Litter + cwd Carbon stocks

14 Cumulated NBP

15 opt>bau.....opt<bau Cumulated NBP business as usual (bau) climate adaptive(opt) difference (opt-bau)

16 What is new in the research project INKA-BB? Development of BIOME-BGC (vers. ZALF) More elaborate model calibration

17 Decoupling of harvest and new planting harvest harvest planting planting planting planting Old: Harvest followed by planting of new layer automatically New: Decoupling of harvest and planting Understory layer benefits from removal of overstory layer

18 Decoupling of harvest and new planting harvest clearing planting 1 layer 0 layer 1 layer Litter and soil C become decomposted during deforested period and rise again after planting

19 Competition for light - soil cover fraction Soil cover fraction (scf) is direct light fraction absorbed by canopy scf = 1 exp k LAI first canopy layer second canopy layer soil surface Adding approach New approach scf cum i = MIN 1 ; 1 exp k l LAI l i l=1 scf cum i = 1 exp k l LAI l i l=1

20 Soil moisture stem increment leaf litterfall Mixed stand calibration at plot level for (Neuglobsow) Simulation of stem increment (left) and leaf litterfall (right) compared to measured data Simulation of volumetric soil water content compared to meaured data Thanks for data to Hubert Schulte- Bisping, Büsgen Institute

21 Regional level calibration of stem C with yield table Example birch (left) is good, lime (right) needs to be recalibrated Used parameters: C/N ratios of fresh leaves and leaves after retranslocation of N

22 Outlook Simulation setup almost finished Preliminary simulation results very soon Improve calibration Update regional data and use STARS climate scenarios Optional scenario: effect of a sudden pine decline in 2070 under bau and opt

23 Thank you for your attention. Picture taken from fsbio-hannover.de