The Role of Small Woody Landscape Features and Agroforestry Systems for National Carbon Budgeting in Germany

Abstract

The intensification of food production systems has resulted in landscape simplification, with trees and hedges disappearing from agricultural land, principally in industrialized countries. However, more recently, the potential of agroforestry systems and small woody landscape features (SWFs), e.g., hedgerows, woodlots, and scattered groups of trees, to sequester carbon was highlighted as one of the strategies to combat global climate change. Our study was aimed to assess the extent of SWFs embedded within agricultural landscapes in Germany, estimate their carbon stocks, and investigate the potential for increasing agroforestry cover to offset agricultural greenhouse gas (GHG) emissions. We analyzed open-source geospatial datasets and identified over 900,000 hectares of SWFs on agricultural land, equivalent to 4.6% of the total farmland. The carbon storage of SWFs was estimated at 111 ± 52 SD teragrams of carbon (Tg C), which was previously unaccounted for in GHG inventories and could play a role in mitigating the emissions. Furthermore, we found cropland to have the lowest SWF density and thus the highest potential to benefit from the implementation of agroforestry, which could sequester between 0.2 and 2 Tg of carbon per year. Our study highlights that country-specific data are urgently needed to refine C stock estimates, improve GHG inventories and inform the large-scale implementation of agroforestry in Germany.

Carbon storage in old hedgerows: The importance of below‐ground biomass

“…Besides the higher SOC accrual, the consideration of litter and necromass C stock (totalling 11 ± 2 Mg ha −1 /4% of total C stock) also resulted in more C, as this C stock was not accounted for in previous estimates (e.g. Drexler et al, 2021;Golicz et al, 2021). Gross et al (2022) also highlight the importance of deadwood for C stocks in hedgerows.…”

“…Estimates of the C sequestration potential of hedgerows have recently been published in meta-analysis and modelling studies, and indicate a high C sequestration potential in both soil and biomass (Drexler et al, 2021;Mayer et al, 2022;Zellweger et al, 2022). Golicz et al (2021) estimate that there are currently around 900,000 ha of small woody landscape features, such as hedgerows or woodlots, in Germany.…”

“…Based on the meta-study by Drexler et al (2021), these were estimated to store a total of 36.3 ± 22.2 Tg C in the biomass and 74.8 ± 30.3 Tg C in the soil, corresponding to about 34% of total agricultural biomass C stock and 6% of total agricultural soil organic carbon (SOC) stock in Germany. Golicz et al (2021) state that the conversion of 1-10% of German cropland to hedgerows could sequester between 14 ± 52 and 143 ± 107 Tg C over 30 years. However, these calculations were based on limited empirical data on hedgerow C stocks.…”

“…Golicz et al. (2021) estimate that there are currently around 900,000 ha of small woody landscape features, such as hedgerows or woodlots, in Germany. Based on the meta‐study by Drexler et al.…”

“…Golicz et al. (2021) state that the conversion of 1–10% of German cropland to hedgerows could sequester between 14 ± 52 and 143 ± 107 Tg C over 30 years. However, these calculations were based on limited empirical data on hedgerow C stocks.…”