P-M: The use of wood cannot be generalised. What conditions need to be satisfied?
F.-J. Radermacher: In essence the focus is on saving time. We need to use the time saved at a political level. The focus must be on innovations which will lead to a new energy system which can be used all around the world; a system which is economic, environmentally friendly and climate-neutral. The time saved from the generation of negative emissions is a decisive approach. This is where wood comes into play. Clearly the use of wood as a raw material is a far more effective approach than the use of wood to create energy since the sequestered CO2 is released when the energy is produced. Generally speaking then wood should be put to material use and only those parts of trees should be used for energy generation which are regarded as waste and which cannot be used for material, longer term applications.
P-M: Let us summarise: what needs to happen in terms of wood usage in order to create a positive future?
F.-J. Radermacher: We need to initiate global reforestation efforts. Reforestation is always expedient, even on degraded soils. It is also helpful to put the felled wood to material use, whereby ideally such use should extend over 50, 100 or even more years. Basically the period of time before the wood is used to generate energy or thus rots and in this way releases the bound CO2 should be kept as long as possible. Time savings are currently an all-important issue.
P-M: On average and depending on the application, timber constructions bind the CO2 taken from the atmosphere for 30 years. What happens after that? Are we not simply postponing the problem? Or is wood a longterm solution as a CO2 store?
F.-J. Radermacher: I don't know how you arrived at 30 years. If we were to start major reforesting campaigns on the degraded soils of the tropics, CO2 would be absorbed from the atmosphere up until the trees are felled. That is around 40 to 50 years. Following that, the large majority of the wood should be put into material use. Such usage can, in part, extend well beyond 30 years and last up to 100 or 200 years. Even with usage of (just) 30 years, in combination with the 40 years of tree growth, this would cover a period of 70 years. This opens up new opportunities. Once again, it is about saving time. CO2 is only removed from the atmosphere whilst the trees are growing. This effect can only be achieved once. When the trees are felled, new ones must be planted immediately to ensure climate neutrality.