A new way of carbon accounting emphasises the crucial role of sustainable timber use for successful carbon mitigation strategies

The roles of forest management and the use of timber for energy in the global carbon cycle are discussed. Recent studies assert that past forest management has been accelerating climate change, for example in Europe. In addition, the increasing tendency to burn timber is an international concern. Here, we show a new way of carbon accounting considering the use of timber as a carbon neutral transfer into a pool of products. This approach underlines the robust, positive carbon mitigation effects of sustainable timber harvesting. Applying this new perspective, sustainable timber use can be interpreted not as a removal but a prevention of carbon being converted within the cycle of growth and respiration. Identifying timber use as a prevention rather than a removal leads to the understanding of timber use as being no source of carbon emissions of forests but as a carbon neutral transfer to the product pool. Subsequently, used timber will then contribute to carbon emissions from the pool of forest products in the future. Therefore, timber use contributes to carbon mitigation by providing a substantial delay of emissions. In a second step, the carbon model is applied to results of a previous study in which different timber price scenarios were used to predict timber harvests in Bavarian forests (Germany). Thus, the influence of the economic dimension “timber price” on the ecological dimension carbon sequestration was derived. It also shows that these effects are stable, even if an increasing tendency of burning timber products for producing energy is simulated. Linking an economic optimization to a biophysical model for carbon mitigation shows how the impact of management decisions on the environment can be derived. Overall, a sustainably managed system of forests and forest products contributes to carbon mitigation in a positive, stable way, even if the prices for (energy) wood rise substantially.     

Combinatorics of aliphatic amino acids

This study combines biology and mathematics, showing that a relatively simple question from molecular biology can lead to complicated mathematics. The question is how to calculate the number of theoretically possible aliphatic amino acids as a function of the number of carbon atoms in the side chain. The presented calculation is based on earlier results from theoretical chemistry concerning alkyl compounds. Mathematical properties of this number series are highlighted. We discuss which of the theoretically possible structures really occur in living organisms, such as leucine and isoleucine with a chain length of four. This is done both for a strict definition of aliphatic amino acids only involving carbon and hydrogen atoms in their side chain and for a less strict definition allowing sulphur, nitrogen and oxygen atoms. While the main focus is on proteinogenic amino acids, we also give several examples of non-proteinogenic aliphatic amino acids, playing a role, for instance, in signalling. The results are in agreement with a general phenomenon found in biology: Usually, only a small number of molecules are chosen as building blocks to assemble an inconceivable number of different macromolecules as proteins. Thus, natural biological complexity arises from the multifarious combination of building blocks.     

Self-healing concrete for sustainable buildings. A review

Environmental Chemistry Letters - A total of 12 billion tons of concrete materials are produced annually, about 2 tons per person. More sustainable buildings are thus needed to decrease the carbon...