Climatic significance of the marginalization of Scots pine (Pinus sylvestris L.)c. 2500 BC at White Moss, south Cheshire, UK

Abstract

Subfossil wood from White Moss, south Cheshire, has become the focus of palaeoenvironmental research employing not only conventional coring, pollen analysis, radiocarbon dating and dendrochronology on pine and oak, but also the exhumation of in situ peat areas and dendroecology of the pine ring-width records. Initial dendrochronological research at the site yielded five pine chronologies dating from 3520 to 2462 cal. bc. These and other data indicate three episodes of pine colonization of the mire in the period between 3643 and 1740 cal. bc. Comparison of the pollen and spore records suggest that pine became marginalized at the site c. 2500 cal. bc after successive episodes of increased wetness, and this may represent a staged response to climatic deterioration. Two oak chronologies were dated by reference to the Belfast and to English oak master chronologies to 3228-2898 bc and 2190-1891 bc, respectively, showing the possible co-existence of pine and oak on the mire for part of the time. Further dendrochronological work on subfossil pine at the site resulted in a chronology (WM4) that was cross-matched with pine from elsewhere in England, and subsequently dated absolutely to 2881-2559 bc. Detailed dendroecological information, such as fire episodes and periods of environmental stress indicated in the tree-ring records, have been assigned, precisely and accurately, to calendar years in prehistory. The detailed data show the potential for both dendroecological and wider palaeoclimatic and palaeoenvironmental information that may become available from prehistoric bog-pine chronologies, which might then permit precise correlation and comparisons of proxy-climate data between sites.

Holocene vegetation and climate dynamics of the boreal alpine ecotone of northwestern Fennoscandia

“…Mire surface wetness and nutrient deficiency may explain a diminished reproduction capability of Pinus sylvestris and is connected by Mighall et al (2004) with the sudden decrease in Pinus pollen and macro-and megafossils around 4000 cal. yr BP in mires of the northern parts of the British Isles (Bridge et al, 1990;Gear and Huntley, 1991;Pilcher et al, 1995;Lageard et al, 1999). The next marked reduction in forest at Mt Skrubben is seen ca.…”

Animating tree colonization and growth

“…Measurements of annual ring-widths were made using a measuring stage and software (Input and Dendro © Tyers 1999) as described by Lageard et al (1999). Resultant data for each tree included number of annual rings at c. 30 cm above the ground (no correction was made for sampling height), and estimated year of germination (minimum estimate / samples were not taken from trunk base).…”

Hydrogeomorphic control on tree growth responses in the Elton area of the Cheshire Saltfield, UK

“…Schweingruber, 1988), and ring widths were measured to 0.01-mm accuracy (cf. Lageard et al, 1999). Chronology building followed dendrochronological conventions (Schweingruber, 1988;Hillam, 1998) and used crossmatching programs based on Baillie and Pilcher (1973) and Munro (1984) (Tyers, 1999).…”