Konstantin Olschofsky

Modeling the CO2-effects of forest management and wood usage on a regional basis

BackgroundAt the 15th Conference of Parties of the UN Framework Convention on Climate Change, Copenhagen, 2009, harvested wood products were identified as an additional carbon pool. This modification eliminates inconsistencies in greenhouse gas reporting by recognizing the role of the forest and timber sector in the global carbon cycle. Any additional CO2-effects related to wood usage are not considered by this modification. This results in a downward bias when the contribution of the forest and timber sector to climate change mitigation is assessed. The following article analyses the overall contribution to climate protection made by the forest management and wood utilization through CO2-emissions reduction using an example from the German state of North Rhine-Westphalia. Based on long term study periods (2011 to 2050 and 2100, respectively). Various alternative scenarios for forest management and wood usage are presented.ResultsIn the mid- to long-term (2050 and 2100, respectively) the net climate protection function of scenarios with varying levels of wood usage is higher than in scenarios without any wood usage. This is not observed for all scenarios on short and mid term evaluations.The advantages of wood usage are evident although the simulations resulted in high values for forest storage in the C pools. Even the carbon sink effect due to temporal accumulation of deadwood during the period from 2011 to 2100 is outbalanced by the potential of wood usage effects.ConclusionsA full assessment of the CO2-effects of the forest management requires an assessment of the forest supplemented with an assessment of the effects of wood usage. CO2-emission reductions through both fuel and material substitution as well as CO2 sink in wood products need to be considered.An integrated assessment of the climate protection function based on the analysis of the study’s scenarios provides decision parameters for a strategic approach to climate protection with regard to forest management and wood use at regional and national levels.The short-term evaluation of subsystems can be misleading, rendering long-term evaluations (until 2100, or even longer) more effective. This is also consistent with the inherently long-term perspective of forest management decisions and measures.

Operational assessment of aboveground tree volume and biomass by terrestrial laser scanning

Biomass extraction from branches by TLS systems is not affected by scanning distance.A straightforward algorithm is presented that simplifies biomass measurements of complex branch geometries using TLS.The combination of biomass measurements from individual scan positions by averaging provides reliable biomass figures. The assessment of aboveground tree biomass (AGB) is essential to the evaluation of tree populations in forests, open landscapes, and urban areas. The predominant method used to determine AGB relies on error-prone functions derived from the statistical relationships of tree attributes and biomass. Terrestrial laser scanning (TLS) offers a new approach that replaces statistical AGB estimates with consistent measurements.Aboveground tree biomass (AGB) comprises stems and branches. While the biomass assessment of stems is straightforward, TLS measurements of tree crowns are far more complex because of branch overlapping. Because placing reflecting targets in the crowns of tall standing trees is impractical, yet necessary for merging the point clouds from different laser scan positions, TLS measurements often fail in operational applications.This study introduces a straightforward algorithm that simplifies biomass measurements of complex branch geometries using TLS and derives AGB by averaging measurements from individual scanning positions. We verified our approach through an experimental setup of branching systems with different complexities and known true biomass volumes. The results show that biomass extraction from branches by TLS systems is not affected by scanning distance. The combination of biomass measurements from individual scanning positions by averaging provides reliable biomass figures. Compared to the known true biomass figures, the overall accuracies achieved by our approach are 95% or higher, which brings the operational application of TLS for AGB measurements within tangible reach.

Effects Evaluation and Risk Assessment of Air Pollutants Deposition at European Monitoring Sites of the ICP Forests

The study presents modelled critical deposition load exceedances for over 4,700 representatively selected forest plots in 21 European countries. It is based on measured soil data, different deposition scenarios and an application of the Simple Mass Balance (SMB) model. Effects of climate change on critical loads and exceedances are presented for 108 intensive monitoring plots in 17 countries. Results suggest hardly any more exceedances of critical loads for acidity in the near future. In contrast, even a maximum feasible emission reduction scenario which will leave 10 % of the forest sites unprotected against nitrogen effects by the year 2020. Full implementation of existing clean air legislation will result in 20 % of unprotected forest sites. Forests are less sensitive compared to other ecosystems as for these areas with exceedances are up to 58 %. Under a climate change scenario, decreasing critical loads suggest increasing sensitivity towards nutrient nitrogen inputs. When comparing critical load exceedances over the period 2020–2100, the share of ‘safe’ sites is assumed to decrease from 60 % (constant climate) to 50 % (climate change).