A big community in a growing field of interest
All over the world scientists are trying to fit basic biomass equations to different species, regions, DBH ranges or groups of individuals. Forestry Researchers are looking for easy to use universal rules, which offer the possibility to predict the biomass of stands and single trees as a function of easily measurable values. The economic aspects of worthwhile stem biomasses characterized the motivation to find solid predictions from the early 19th century to the present. The fear of consequences of the upcoming climate change made biomass predictions attractive for climate models and carbon cycles. The related climate policy definitions and the call for forest preservation need robust information about the value of forests as a carbon storage and corrective factor for global and regional warming.
Especially small trees are often not covered by carbon storage reports, although they make their contribution to remove CO2 from the atmosphere. One factor of underestimating small trees' biomass is the biomass expansion, which is highly dependent on variables like species, light, soil, micro climatic influences and -the main driver and first target of this project- influences caused by mixtures, like the overyielding effect.
Besides the more related field of carbon storage, a new economic usage of small diameter tree prediction is rising. Short rotation plantations, as well as agro-forestry systems, are solutions to satisfy the hunger for green and renewable energies. Especially farmers with short rotation sites are interested in his expected yield and income.
A third field of interest is the potential of rejuvenation. A healthy and resilient forest needs constant renewal. A system of indicators is able to show which amount of biomass in juvenile tree stands is required to call a forest robust. A forester can easily evaluate the status of a stand's rejuvenescence on the base of simple measurements.
(Annighoefer, 2016)
For this study it was decided to limit the object of research to AGB (aboveground biomass). AGB covers the most fields of interest, like productivity of small diameter trees, carbon stocks and ecosystem services (mixture effects). These elements are affected by regional climate differences, growth stages, density and species composition. Therefor a rough subdivision can be made between biomass equations access generic (species independent), species specific and site specific predictions.
Especially small trees are often not covered by carbon storage reports, although they make their contribution to remove CO2 from the atmosphere. One factor of underestimating small trees' biomass is the biomass expansion, which is highly dependent on variables like species, light, soil, micro climatic influences and -the main driver and first target of this project- influences caused by mixtures, like the overyielding effect.
Besides the more related field of carbon storage, a new economic usage of small diameter tree prediction is rising. Short rotation plantations, as well as agro-forestry systems, are solutions to satisfy the hunger for green and renewable energies. Especially farmers with short rotation sites are interested in his expected yield and income.
A third field of interest is the potential of rejuvenation. A healthy and resilient forest needs constant renewal. A system of indicators is able to show which amount of biomass in juvenile tree stands is required to call a forest robust. A forester can easily evaluate the status of a stand's rejuvenescence on the base of simple measurements.
(Annighoefer, 2016)
For this study it was decided to limit the object of research to AGB (aboveground biomass). AGB covers the most fields of interest, like productivity of small diameter trees, carbon stocks and ecosystem services (mixture effects). These elements are affected by regional climate differences, growth stages, density and species composition. Therefor a rough subdivision can be made between biomass equations access generic (species independent), species specific and site specific predictions.
An Uncovered Niche
The vast majority of volume equation is based on the relationship between DBH(cm) and Height(cm). The simple adding of the dry density gives the dry biomass. Most publications focus on larger diameter trees of 10 cm and higher. Even more rare are published equations for specific biomasses of species. Nevertheless, precise biomass estimates are required for the rising amount of reforestation stands, open woodlands and regions of disturbance. The development of saplings' biomass will help to understand the carbon cycles.
A challenge of my research project is gathering all equations worth considering. A comparable amount of formulas could be five for general broad leave estimations and the same for each species. The calculated biomasses are valid indicators for the fitness of each equation. The differences between real and estimated biomasses per equation and species should deliver robust results.
An even more challenging topic, which is not yet covered by any accessible study, is the influence of mixture to the biomass estimation. All existing equations are based on fitted coefficients that result from monocultural sites. As far as I can observe, there is no consideration of the mixture's influence. The present data allows to check if the estimated biomasses of mixture trees tend to be overestimated or underestimated depending on the kind of mixture. A link to the over yielding effect is present.
(Dutca & Ioras, 2018)
A challenge of my research project is gathering all equations worth considering. A comparable amount of formulas could be five for general broad leave estimations and the same for each species. The calculated biomasses are valid indicators for the fitness of each equation. The differences between real and estimated biomasses per equation and species should deliver robust results.
An even more challenging topic, which is not yet covered by any accessible study, is the influence of mixture to the biomass estimation. All existing equations are based on fitted coefficients that result from monocultural sites. As far as I can observe, there is no consideration of the mixture's influence. The present data allows to check if the estimated biomasses of mixture trees tend to be overestimated or underestimated depending on the kind of mixture. A link to the over yielding effect is present.
(Dutca & Ioras, 2018)
An early appearing
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