Agroforestry can contribute significantly to carbon sequestration in agricultural lands, as carbon accumulates both in tree biomass and the soil. One of the oldest, yet declining, forms of agroforestry in Europe are hedgerow-bordered fields. An analysis of historical maps of our study area in Belgium shows that 70% of the hedgerow network was cleared since 1960, creating a large number of ‘ghost’ hedgerows. We selected arable fields next to hedgerows, 'ghost' hedgerows and grass strips to study how hedgerow trees influence SOC stocks and how much of these are still present after hedgerow clearing. SOC stocks to a depth of 23 cm reached up to 81.7 ± 28.8 Mg C ha⁻¹ in hedgerows, storing a considerably larger amount of soil carbon compared to grass strips (56.6 ± 14.5 Mg C ha⁻¹). These built-up stocks were completely gone in 'ghost' hedgerows (57.9 ± 14.1 Mg C ha⁻¹). In the fields adjacent to hedgerows, SOC stocks were only slightly (and insignificantly) increased compared to stocks in fields with grass strips (56.4 ± 6.3 vs 55.6 ± 5.0 Mg C ha⁻¹) with an exponential decay up to 30 m from the margin. This trend was still limitedly detectable in 'ghost' hedgerowbordered fields, however stocks were not elevated anymore (53.9 ± 6.1 Mg C ha⁻¹). Since 1960, 4 957 ± 1 664 Mg C from the soil alone were released back into the atmosphere due to hedgerow removal in the study area. The implementation of a strict hedgerow conservation policy would thus be a highly effective climate change mitigation measure in agricultural landscapes.

由于树木生物量和土壤中都积聚了碳，农用林业可以大大促进农田中的碳固存。在欧洲，最古老但仍在下降的农林业形式是篱笆篱笆的田地。对我们比利时研究区的历史地图进行的分析表明，自1960年以来，已清除了70％的树篱网络，从而形成了大量的“幽灵”树篱。我们选择了篱笆，“幽灵”篱笆和草条旁边的耕地，以研究篱笆树如何影响SOC存量，以及清除篱笆后仍有多少？在23厘米深的SOC中，树篱中的SOC含量高达81.7±28.8 Mg C ha ^-1，与草条相比，存储的土壤碳量要大得多（56.6±14.5 Mg C ha ^-1）。这些积压的库存完全被“幽灵”树篱所淘汰（57.9±14.1 Mg C ha ^-1）。在与树篱相邻的田地中，SOC的存量与带草的田间（56.4±6.3 vs 55.6±5.0 Mg C ha ^-1）的存量相比仅略有增加（微不足道），并且距边缘的指数衰减最大为30 m 。在“幽灵”树篱边界的田地中仍可有限地检测到这种趋势，但是种群数量不再增加（53.9±6.1 Mg C ha ^-1）。自1960年以来，由于研究区域的绿篱去除，仅土壤中的4 957±1 664 Mg C被释放回大气中。因此，实施严格的树篱保护政策将是一种有效的农业景观减缓气候变化措施。