Temperate agroforesty systems

Agroforestry system with poplarInfluence of agroforestry systems on microclimate and crop productionLeaf gas exchangeDetermination of growth and tree transpirationExperimental site near Forst (Brandenburg)

Agroforestry systems in form of planted hedgerows have a long-term tradition as land-use systems in various European landscapes, primary in Denmark, North Germany and England. Planting of trees and shrubs into agricultural systems have economical benefits as they provide timber and and fuelwood and other products. It is well recognized, that these shelterbelts enhance biodiversity and have positive effects on the ecosystem functioning. In those contemporary agroforestry systems, selection of tree species and their management are more economically oriented towards an optimizing biomass production, use and harvest, especially in short-rotation systems for bioenergy. Our research focus on the ecophysiology and stress physiology of poplars (Populus spec.), black locust (Robinia pseudoacacia), and  willows (Salix spec.). Aim is to determined the water consumption and nutrient efficiency of the trees in relation to biomass production. Photosynthesis and water fluxes are measured on the tree level and scaled-up to the stand level. The experimental are carried out at different sites in southern Brandenburg (NE Germany). 

The research is in cooperation with the University of Hohenheim and integrated in the agroforestry research activties at the BTU Cottbus-Senftenberg.

  • Modeling photosynthesis and carbon fluxes in agroforestry system

For a better understanding of biomass production of fast-growing trees in agroforestry systems more detailed ecophysiological informations and their annual carbon balances are required. Carbon gain by photosynthesis is a predominant factor for plant growth and to estimate biomass allocation at the tree, stand and landscape level. Hence, biochemical photosynthesis models are widely used to estimate diurnal and annual carbon uptake on the leaf level and scaling up to predict carbon fluxes on the canopy level. However, biochemical parameters are often difficult to determine under field conditions, and therefore we develop an empirical photosynthesis model based on gas exchange parameters and their dependence from microclimatic parameters, which can be easily obtained in the field. For up-scaling from leaf photosynthesis to annual tree carbon balance the structure of hedgerow, which is influencing the physiological functions and interactions must be taken into account. Our specific objectives are, therefore, to developed a leaf carbon model driven by light and modulated by temperature and air humidity. The seasonal variation of CO2 uptake and release can be then modeled and up-scaled to estimate the annual carbon fluxes of sun and shade leaves of black locust and poplars in agroforestry system.

Impressum               © Maik Veste 2017 - All rights reserved -  Last update  14May 2017