Detecting Coppice Legacies from Tree Growth

Woodland Management as Major Energy Supply during the Early Industrialization: A Multiproxy Analysis in the Northwest European Lowlands

Wood and charcoal were key sources of energy during early industrialization in Europe (18th century), preceding the large-scale exploitation of fossil coal. Past timber harvesting implied land transformation and woodland resources management. Therefore, relict charcoal kilns and historical documents of forest management are important sources of information about past woodland composition and structure. However, ancient charcoal kilns are poorly documented in temperate woodlands in the lowlands of western Europe, especially combined with historical written sources. In this study, charcoal production was investigated in an area in NE France, by combining charcoal and historical sources analysis, along with innovative dating methodologies. Thus, by using both radiocarbon and optically-stimulated luminescence dating, we showed that the activity lasted until recent times (19th–early 20th centuries) and Carpinus was the dominant taxon in charcoal assemblage. Moreover, kiln attributes seemed to be independent of topographical variables. Woodlands in this area were subject to a coppice-with-standards management, where small diameter wood was preferred to produce charcoal and large diameter stems, mainly Quercus and Fagus, were traded as timber. The dominance of Carpinus is rather uncommon in charcoal studies but supports the importance of Carpinus as fuelwood since the Middle Ages, as confirmed by many written sources.

Historical Forest Management Practices Influence Tree-Ring Based Climate Reconstructions

Tree-ring widths (TRW) of historical and archeological wood provide crucial proxies, frequently used for high-resolution multi-millennial paleoclimate reconstructions. Former growing conditions of the utilized trees, however, are largely unknown. Potential influences of historical forest management practices on climatic information, derived from TRW variability need to be considered but have not been assessed so far. Here, we examined the suitability of TRW series from traditionally managed oak forests (Quercus spp.) for climate reconstructions. We compared the climate signal in TRW chronologies of trees originating from high forests and coppice-with-standards (CWS) forests, a silvicultural management practice widely used in Europe for most of the common era. We expected a less distinct climate control in CWS due to management-induced growth patterns, yet an improved climate-growth relationship with TRW data from conventionally managed high forests. CWS tree rings showed considerably weaker correlations with hydroclimatic variables than non-CWS trees. The greatest potential for hydroclimate reconstructions was found for a large dataset containing both CWS and non-CWS trees, randomly collected from lumber yards, resembling the randomness in sources of historical material. Our results imply that growth patterns induced by management interventions can dampen climate signals in TRW chronologies. However, their impact can be minimized in well replicated, randomly sampled regional chronologies.

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

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.