Peat Bogs as Biological Archives

Peat Bogs as Biological Archives: Lennart von Post and the Development of Pollen Statistics during World War I

Christer Nordlund



By exploring the early history of quantitative palynology, especially the cultural processes and material practices through which pollen became data and peat bogs turned into biological archives, the aim of this project is to show how applied field science may give rise to basic laboratory science due to the articulation and establishment of a new type of data.

The point of departure is that Ice Age theory brought a perception that the flora of the places that once had been covered by ice caps had emerged via a post-glacial colonization process. In Scandinavia, this perception stimulated research in plant geography with the purpose of discovering how the colonization had taken place. When and whence the flora had migrated into the countries and how its spread across the lands had occurred became central scientific problems, whose solutions were expected to contribute to the understanding of how nature had ”created” the different countries. Another purpose of such studies was to gain knowledge about climate fluctuations in the past. Conclusions about the history of vegetation were first drawn from studies of the composition of the contemporary plant cover, but just as contemporary geology, the most important material practice soon became the utilization of natural landmarks – in this case, quaternary plant relics – preserved in clay deposits, lime tufas and peat mosses: places that were given the status of ”biological archives”.

The plant relics used as data were first and foremost macrofossils, such as preserved stumps, branches and leaves. Within the frame of local research schools, such as ”rational botanical analysis” or ”modern biological plant geography”, such data was in turn interpreted in accordance with theories of the evolution of floras or plant communities. However, in 1916, at the 16th Convention of Scandinavian Naturalists in Kristiania (Oslo), a novel quantitative method for the analysis of vegetation history was presented. The idea behind the method, initially called “pollen statistics” and later known as pollen analysis, was to utilise fossil pollen from peat bog deposits as data. According to Lennart von Post (1884–1951), the scientist who delivered the lecture, it was only possible to use fossil material as reliable data if the plants were represented in great quantity, and if the fossils remained unaffected by the “archive”. In the historiography of palynology von Post’s lecture remains a classic. Pollen from postglacial deposits had indeed been used before, but through the launch of the so-called pollen diagram, by which von Post was able to visualise his findings, the method reached a breakthrough. The advantage of the pollen diagram was that it summarized a large amount of data and showed when each species of tree had appeared, as well as how the occurrence of each individual species varied over time and from place to place. But the method was not without problems. One problem was how the pollen curves were to be interrelated chronologically; another had to do with credibility: were peat bogs really trustworthy as “archives”?

In this project the articulation of pollen as data and peat bogs as archives will be analysed and thoroughly contextualized. Historical plant geography had its academic seats at the universities, at schools of forestry and at state geological surveys. But since research was often conducted in connection with moss farming, peat harvesting, lime quarrying and coal mining, such practical activities had significance in the development of knowledge as well. When it comes to quantitative pollen analysis, the hypothesis is that it was strongly linked to a certain peat bog inventory, conducted in southern Sweden by the Geological Survey in the 1910s. The motive behind this inventory – which was managed by von Post – was economical and political: to pave the way for a domestic peat industry and secure energy resources during World War I. In the end, the inventory did not affect the state of the nation, but it was not without value. It strongly contributed to the development of pollen analysis, simply because it was data collected during this fieldwork that made up the empirical foundation for von Post’s celebrated method. In order to facilitate further studies, the Geological Survey also stored the pollen samples in a certain Pollen archive. Hence, one may say that the data travelled, from a biological archive to a scientific one.