Root biomass and biomass increment in a beech (Fagus sylvatica L.) stand in North-East France

This study is part of a larger project aimed at quantifying the biomass and biomass increment of an experimental beech stand aged 30 years, and compar ing the carbon sequestration in trees to carbon fluxes. The below ground pa rt of trees is expected to play an important role in carbon sequestration. A method has been developed to estimate the biomass and biomass increment o f coarse, small and fine roots of trees from root system excavations of sam pled trees of different crown classes. The biomass and biomass increment of broken root ends during excavation was estimated from the diameter of the roots at the broken points. Equations were then established relating the bi omass and biomass increment of the different root categories to tree DBH. T hese equations were then used to estimate the root biomass and biomass incr ement of the experimental stand from stem inventory, for the different root categories. Trees from dominant and codominant crown classes contribute fo r more than 80% to below ground biomass and biomass increment of the stand.