Annual pollen accumulation rate (PAR) at the boreal and alpine forest-line of north-western Norway, with special emphasis on Pinus sylvestris and Betula pubescens

Environmental Drivers of Holocene Forest Development in the Middle Atlas, Morocco

“…PARs are a useful tool for understanding the behavior of individual taxa, while avoiding the classical problem of interdependence of percentage abundance values (Jensen et al, 2007). The PAR for each taxon is independent of other taxa within the record, and therefore may provide a better representation of the local abundance of the individual taxa (Seppä and Hicks, 2006).…”

The Agrarian Life of the North 2000 BC–AD 1000

“…Pollen, however, is more resistant to biological and aerobic decay due to the content of sporopollenin in the cell wall. Although pollen production is low at the coast and this far north ( Jensen et al 2007), a higher concentration of pollen was expected. Given the indications of long-term exposure of the house ground after abandonment, biological and chemical decay in addition to washout of material during rainfall may be a likely explanation.…”

“…Several pollen analytical investigations from coastal area of northern Norway show indications of temporary farming practice including possible cereal growth during the Bronze Age. The discontinuity in botanical agricultural indices during the last millennium BC, may be linked to the regional climatic deterioration observed by several independent climate proxies as a change to a cooler and more humid climate (Vorren et al 2007). Based on palaeobotanical reconstructions of Holocene July mean temperature from lake sediments in the interior of Troms and northern Finland, Jensen and Vorren (2008); Bjune et al (2004) and Seppä et al (2001), postulate a summer temperature 1-1.5 °C higher than today during the period covering the Late Neolithic and the Bronze Age.…”

“…The start of a successive temperature decline is, however, observed from the Late Bronze Age until the Pre-Roman Iron Age. Several wet shifts (transition from high to low peat humification) possibly related to a regional climate shift are seen in the Sellevoll bog at Andøya during the Late Bronze Age (Vorren et al 2007). …”

Pinus and Betula pollen accumulation rates from the northern boreal forest as a record of interannual variation in July temperature

“…Although pollen monitoring data from northern Fennoscandia were initially collected as a modern reference dataset to interpret Quaternary fossil pollen assemblages (Jensen et al, 2007;Hättestrand et al, 2008), they also provide a time series of PARs (number of grains cm À2 a À1 ) which show that, for the boreal coniferous trees Pinus sylvestris and Picea abies, annual pollen production has a high correlation with July mean temperature of the year before pollen emission. Moreover, the signal is consistent over large areas (Huusko and Hicks, 2009).…”