Tree rings reveal signs of Europe’s sustainable forest management long before the first historical evidence

Abstract

To satisfy the increasing demand for wood in central Europe during medieval times, a new system of forest management was developed, one far superior to simple coppicing. The adoption of a sophisticated, Coppice-with-Standards (CWS) management practice created a two-storey forest structure that could provide fuelwood as well as construction timber. Here we present a dendrochronological study of actively managed CWS forests in northern Bavaria to detect the radial growth response to cyclical understorey harvesting in overstorey oaks (Quercus sp.), so-called standards. All modern standards exhibit rapid growth releases every circa 30 years, most likely caused by regular understorey management. We further analyse tree-ring width patterns in 2120 oak timbers from historical buildings and archaeological excavations in southern Germany and north-eastern France, dating between 300 and 2015 CE, and succeeded in identifying CWS growth patterns throughout the medieval period. Several potential CWS standards even date to the first millennium CE, suggesting CWS management has been in practice long before its first mention in historical documents. Our dendrochronological approach should be expanded routinely to indentify the signature of past forest management practices in archaeological and historical oak wood.

Historical Forest Management Practices Influence Tree-Ring Based Climate Reconstructions

“…The CWS dataset consisted of TRW series from northern Bavaria (Germany), sampled by Muigg et al (2020b). Stem disks were collected from two actively managed CWS forest stands near Weigenheim (WEIG) and Welbhausen (WELB).…”

“…Stem disks were collected from two actively managed CWS forest stands near Weigenheim (WEIG) and Welbhausen (WELB). To detect signals of CWS in the individual TRW series, we first detected growth releases by using the adapted growth averaging method as described by Muigg et al (2020b). Following the methods proposed in the study by Muigg et al (2020b), we applied a standardized scanning for growth releases at an average chronological interval of 26-36 years with less than 5 years standard deviation (SD) on the TRW data from WEIG and WELB to select 135 trees that showed the strongest CWS signal (hereinafter referred to as CWS dataset).…”

“…The HF dataset consisted only of those trees (128 in total) that did not show cyclic and temporally aligned growth release events (cf. Muigg et al, 2020b) and therefore presumably originated from high forests. Additionally, we merged the CWS and HF datasets (combined dataset) to assess the hydroclimate signal of a hypothetical chronology containing a relatively large proportion of trees (ca.…”

“…Four TRW chronologies were created based on datasets, which contained differing proportions of trees with periodic management-induced growth releases (sustained growth increases). The CWS dataset consisted entirely of trees (135 in total) from actively managed CWS stands (see also Muigg et al, 2020b for further information). In a CWS forest, the reduced competition for light, nutrients and water after periodic understory coppice causes an increased growth in the remaining standards, commonly referred to as release (Müllerová et al, 2016).…”

“…The earliest historical evidence for this practice dates back to the thirteenth century CE (Hausrath, 1982;Hasel and Schwartz, 2006). Dendroarcheological evidence for CWS management in central Europe during the first millennium CE suggests an even longer tradition, at least since the early medieval period (i.e., 500-1000 CE) (Muigg et al, 2020b). The CWS forest management system was used all over medieval and early modern Europe (Short and Hawe, 2012) until it disappeared in most regions by the mid-twentieth century, when fossil fuels had replaced wood as the primary energy source and modern forestry focused primarily on timber production (Groß and Konold, 2010).…”