Christopher ThurnherHubert Hasenauer

Institute of SilvicultureUniversity of Natural Resources and

Life Sciences, Vienna

Development and application of Biome-BGC in Austria

Introduction

• Methodological improvements

• Technical improvements

• Application cases

Methodological improvements

• Based on Biome-BGC 4.1.1. (Thornton 1998)• Dynamic mortality (Pietsch and Hasenauer,

2006)• Species specific parameterization for the main

central European tree species (Pietsch et al., 2005)

• Interventions (clear-cut, planting, thinning)• Simulation of flooding groundwater ascent

(Pietsch et al., 2003)

Methodological improvementsDynamic mortality

• Spinup-run is used for the self-initialization of Biome-BGC

• Systematically overestimation when comparing with virgin forests (Pietsch and Hasenauer 2006)

• Dynamic mortality model is introduced to address natural forest dynamics

• High mortality during senescence and regeneration

• Low mortality during optimum phase

Dynamic mortality (Pietsch and Hasenauer. 2006)

Dead Biomass

NPPNEE (C-Balance)

I: Optimum(C-Sink)

II: Breakdown(C-Source) III: Regeneration

(neutral)

SoilStem

Jahre

Koh

lens

toff

[t h

a-1 y

r-1 ]

-10,0-7,5-5,0-2,50,02,55,07,5

Simulation years

0

50

100

150

200

250

300 I II III I II III

Methodological improvementsSpecies-specific parameterization

• Original version had parameters for ENF, DBF• Species specific parameterization for the main

central European tree species was developed (Pietsch et al. 2005)– Norway spruce (Picea abies)– Beech (Fagus sylvatica)– Scots pine (Pinus sylvestris)– Stone pine (Pinus cembra)– Larch (Larix decidua)– Oak (Quercus robur/petraea)

Validation plots (Pietsch et al. 2005)

Methodological improvementsSpecies-specific parameterization

Predicted vs. observed stand volume (left hand graph) and 10-year volume increment (right hand graph) (Pietsch et al. 2005)

Methodological improvementsInterventions

• In Austria, the clear-cut system is widely used• BGC is capable of simulating clear-cut, planting

and thinning interventions• A typical BGC simulation consists of:

– Spinup / model self-initialization (pre-industrial CO2, N-Deposition)

– Historic land-use – several forest rotations – clear cuts/plantings (increase of CO2, N-Deposition)

– Management of current stand – thinning

Methodological improvementsInterventions

BGC simulation run (Petritsch et al. 2007)

Technical improvements

• XML file to control the simulation

• Graphical user interface (Windows only)

• Multithreaded– OpenMP included (shared-memory architecture)– On distributed-memory, we use scripts to partition the

simulation on different nodes

• Windows and Linux binary

Technical improvementsArchitecture

Batch BGC

· Command line executable for Windows and Linux· Can be executed by the GUI (Windows only)· Multithreaded

(C++)

Graphical user interface (GUI)(C#)

XML Input:

· Point list· Simulation control parameters· Meteorological parameters· Restart control parameters· Output control parameters

creates

input

Climate files (ASCII or binary)EPC files

input

refers runs

Technical improvementsGUI

Technical improvementsGUI vs. Command line executable

• Start simulation with the GUI

• Use the command line executable

Application casesClimate change impact on Picea abies

• Examination of climate change effects on Picea abies in Austria (Eastaugh et al. 2011)

• Definition of climate change regions• Usage of Biome-BGC as a diagnostic tool to

assess the forest response to climate change– Simulation with climate data from 1960 to 2008– Simulation with synthetic climate record (1960 only)

• Investigation of climatic and non-climatic influences on forest productivity

Application casesClimate change impact on Picea abies

Application casesBeech forest growth in eastern Austria

• Study area: Vienna and the Biosphere Reserve Vienna Woods• 1 x 1 km gridded simulation (845 grid points)• In total 180.000 ha• 60 % forested area in the Biosphere Reserve, mainly beech forests

Average temperature trend 1960 – 2009. (Pötzelsberger et al., 2013)

Average precipitation trend 1960 – 2009. (Pötzelsberger et al., 2013)

Biosphere Reserve Vienna Woods. (Pötzelsberger et al., 2013)

Application casesBeech forest growth in eastern Austria

• 2 different climate change scenarios:– A1B: high temperature and CO2

increase– B1: low temperature and CO2

increase• Both scenarios were

simulated without and with precipitation change (dry period in the summer)

Temperature and precipitation trends. (Pötzelsberger et al., 2013)

Application casesBeech forest growth in eastern Austria

Modelled annual GPP, NPP and NEE averaged over the 845 gird points; Simulations driven by the climate observations and two temperature scenarios (A1B, B1) and the combined temperature - precipitation scenarios. (Pötzelsberger et al., 2012)

Modelled standing tree volume per hectare averaged over the 845 gird points; Simulations driven by the climate observations and two temperature scenarios (A1B, B1) and the combined temperature - precipitation scenarios. (Pötzelsberger et al., 2012)

Application casesBeech forest growth in eastern Austria

Summary

• Methodological improvements to the simulation algorithm.– Species-specific parameterization– Dynamic mortality– Intervention

• Technical improvements to facilitate (GUI) and speed-up (multithreaded) the simulation runs.

• Application cases

References

Eastaugh, C.S., Pötzelsberger, E., Hasenauer, H., 2011. Assessing the impacts of climate change and nitrogen deposition on Norway spruce (Picea abies L. Karst) growth in Austria with BIOME-BGC. Tree Physiology 31, 262–274.

Petritsch, R., Hasenauer, H., & Pietsch, S. A. (2007). Incorporating forest growth response to thinning within biome-BGC. Forest Ecology and Management, 242, 324–336.

Pietsch, S. A., Hasenauer, H., & Thornton, P. E. (2005). BGC-model parameters for tree species growing in central European forests. Forest Ecology and Management, 211, 264–295.

Pietsch, S. A., & Hasenauer, H. (2006). Evaluating the self-initialization procedure for large-scale ecosystem models. Global Change Biology, 12(9), 1658–1669.

Pötzelsberger, E., Wolfslehner, B., Hasenauer, H., 2012. Beech forest growth in eastern Austria - state and prognosis for a changing climate, in: Pötzelsberger, E., Mäkelä, A., Mohren, G., Palahí, M., Tomé, M., Hasenauer, H. (Eds.), Modelling Forest Ecosystems - Concepts, Data and Application. Proceedings of the COST FP0603 Spring School, May 9th-13th. Kaprun, Austria.

Pötzelsberger, E., Wolfslehner, B., Hasenauer H. (2013). Does climate change influence the provision of ecosystem services in the and petri-urban beech forests near Vienna. In prep.

Thornton, P.E., 1998. Description of a numerical simulation model for predicting the dynamics of energy, water, carbon, and nitrogen in a terrestrial ecosystem. Ph.D. thesis, University of Montana, Missoula.