In August, after having acquired the necessary permit, John took the first samples of heartwood from selected Vachellia (camelthorn trees) in the Khan River valley. Armed with the tree corer, successfully tested in May this year (see blog “Trees as weathermen”), and with a generator hired in Swakopmund, he set out.
The generator, loaded in Swakopmund with the help of three men, was dauntingly large and heavy. How to load and unload it single-handed, and ten times, at each one of the trees selected? Norman and Avril from Swakop Uranium had arranged to meet him, at some stage, to observe and help but John needed to get on with the job. Newly acquired sand-tracks turned out to make a helpful ramp, up which he could haul the generator using a tension strap.
The dog watched with interest. Norman and Avril got temporarily lost. The drill he had purchased in Windhoek burned out, but fortunately after the last sample had been taken, and the corers stood up to the test. The photograph below shows the magnitude of the task: centuries of camelthorn wood present a formidable medium. Supporting the drill with strapping helped to keep it steady.
The ten AMS samples sent off by courier to the radiocarbon dating laboratory in the USA got stuck in Johannesburg for a week, for bureaucratic reasons that turned out to be quite baseless, but Norman organized the funds from Swakop Uranium with seamless efficiency. Beta Analytic, the lab we use, gave the samples high priority and processed them in time for the results to be available for John to present at the SASQUA conference on Saturday 15th (see our previous blog for information on the conference). We’ll publish general comments on these dates after the conference. Our expectations of trees germinating during the Medieval Warm Period were upheld, but there were some surprises!