How can forest management increase biomass accumulation and CO2 sequestration? A case study on beech forests in Hesse, Germany

Abstract

Background: While the capability of forests to sequester carbon dioxide (CO 2) is acknowledged as an important component in fighting climate change, a closer look reveals the difficulties in determining the actual contribution by forest management when indirect and natural impacts are to be factored out. The goal of this study is to determine the direct human-induced impacts on forest growth by cumulative biomass growth and resulting structural changes, exemplified for a dominating forest species Fagus sylvatica L. in central Europe. In 1988, forest reserves with directly adjacent forest management areas (under business as usual management) were established in the federal state of Hesse, Germany. Thereof, 212 ha of forest reserve and 224 ha of management area were selected for this study. Biomass changes were recorded for a time span of 19 to 24 years by methods used in the National Inventory Report (NIR) and structural changes by standard approaches, as well as by a growth-dominance model. Results: The results indicate a higher rate of cumulative biomass production in the investigated management areas and age classes. The cumulative biomass growth reveals a superior periodic biomass accumulation of about 16%. For beech alone, it is noted to be about 19% higher in management areas than in forest reserves. When harvests are not included, forest reserves provide about 40% more biomass than management areas. The analysis of growth-dominance structures indicates that forest management led to a situation where trees of all sizes contributed to biomass increment more proportionally; a related increase in productivity may be explained by potentially improved resourceuse efficiency. Conclusions: The results allow a conclusion on management-induced structural changes and their impact on carbon sequestration for Fagus sylvatica L., the dominating forest species in central Germany. This affirms a potential superiority of managed forests to forests where the management was abandoned in terms of biomass accumulation and reveal the impact and effect of the respective interventions. Especially the analysis of growth-dominance structures indicates that forest management resulted in more balanced dominance structures, and these in higher individual biomass increment. Forest management obviously led to a situation where trees of all sizes contributed to biomass increment more proportionally.

Limited sink but large storage: Biomass dynamics in naturally developing beech (Fagus sylvatica) and oak (Quercus robur,Quercus petraea) forests of north‐western Germany

“…Halpin and Lorimer (2016) have shown that, in the later stages of old growth, biomass may indeed decline. These results have led to diverging positions regarding the climate protection potential of naturally developing unmanaged forests (Griscom et al., 2017; Höltermann et al., 2020; Jandl et al., 2019; Krug, 2019; Kun et al., 2020; Schulze et al., 2020).…”

Biomasa aérea de familias botánicas en un bosque siempreverde piemontano sometido a grados de intervención

“…Los bosques coadyuvan a mitigar el cambio climático global mediante el almacenamiento de carbono en la vegetación y en el suelo, así como en el intercambio con la atmósfera. La creciente preocupación y demanda por llevar a cabo estudios de biomasa posibilita comprender el funcionamiento de los bosques y, a su vez, entender cómo los cambios de uso del suelo pueden alterar la estructura, biodiversidad y los servicios ecosistémicos; esto último podría ser revertido o atenuado mediante un adecuado manejo (Krug, 2019;Mori et al, 2017;Tong et al, 2020). Los bosques se destacan por su gran capacidad de fijar carbono en sus estructuras leñosas (Trugman et al, 2018); pues, el fuste de un árbol almacena aproximadamente el 84 % de biomasa, de la cual el 46 % es carbono (Tobías-Baeza et al, 2019).…”

Evaluating the mitigation effectiveness of forests managed for conservation versus commodity production using an Australian example

“…Comparisons based on stands of a similar age (Bouriaud et al., 2019), or range in ages (Krug, 2019), or over a rotation period (Klein et al., 2013), do not reflect fully the impact of human activities on the forest age distribution and, therefore, the total ecosystem carbon stocks or the characteristics of ecosystems that maintain stable stocks. Landscape‐scale metrics (S1) are more appropriate as they account for the spatial scales at which ecological and evolutionary processes and natural disturbance regimes operate, such as described by Net Biome Production (Schulze et al., 2000).…”

“…The mutual reinforcing of climate change and biodiversity loss means that assessment of mitigation strategies needs to consider the consequences for biodiversity (Pörtner et al., 2021). Investment in emissions reduction activities, particularly related to forest management, can result in poor mitigation and conservation outcomes if decisions are based on inappropriate comparisons related to the land area, use of reference levels, and time horizons (Klein et al., 2013; Bouriaud et al., 2019; Krug, 2019), which result in flawed analyses. Such analyses fail to properly reveal the actual change in the atmospheric carbon stock of different activities at the land areas and time horizons relevant for decision making.…”