[Show abstract][Hide abstract] ABSTRACT: A novel device for the chemical isolation of α-cellulose from wholewood material of tree rings was designed by the Potsdam Dendro Laboratory. It allows the simultaneous treatment of up to several hundred micro samples. Key features are the batch-wise exchange of the chemical solutions, the reusability of all major parts and the easy and unambiguous labelling of each individual sample. Compared to classical methods labour intensity and running costs are significantly reduced.
[Show abstract][Hide abstract] ABSTRACT: Pinus heldreichii (var. leucodermis) is widespread in the Balkan peninsula and has some scattered and isolated populations in Southern Italy (Todaro et al. 2007). We selected two sites at the western (Italy) and the eastern (Bulgaria) limit of its geographical range distribution, respectively. The Italian site (39° 56'N, 16° 12'E) is located at the timberline (2054m a.s.l.) of Monte Pollino in the Serra di Crispo mountain range. The Bulgarian study site (41° 46'N, 23° 25'E) is situated slightly below the timberline (1900m a.s.l.) of the northern Pirin mountain range, near Mount Vihren. Both sites are characterized by shallow rocky soil and carbonate bedrock (limestone and marble). The Italian site is influenced by humid Mediterranean climate with mean annual temperature at 4° C and 1500mm mean annual precipitation. In contrast, the Bulgarian site is located at in the transition zone between Mediterranean and temperate climate with a mean annual temperature of 1° C and mean annual precipitation of ca. 800mm. We have compared the site chronologies of delta13C and delta18O between AD1600 and AD2003. We will present and discuss common variance in year-to-year variations and long-term variations, as well as response to increasing atmospheric CO2 concentration and climate.
[Show abstract][Hide abstract] ABSTRACT: Climate reconstructions using stable isotopes from tree-rings are steadily increasing. The investigations concentrate mostly on cellulose due to its high stability. In recent years the available amount of cellulose has steadily decreased, mainly because micro-structures of plant material have had to be analyzed. Today, the amounts of cellulose being studied are frequently in the milligram and often in the microgram range. Consequently, homogeneity problems with regard to the stable isotopes of carbon and oxygen from cellulose have occurred and these have called for new methods in the preparation of cellulose for reliable isotope analyses. Three different methods were tested for preparing isotopically homogenous cellulose, namely mechanical grinding, freezing by liquid nitrogen with subsequent milling and ultrasonic breaking of cellulose fibres. The best precision of isotope data was achieved by freeze-milling and ultrasonic breaking. However, equipment for freeze-milling is expensive and the procedure is labour-intensive. Mechanical grinding resulted in a rather high loss of material and it is also labour-intensive. The use of ultrasound for breaking cellulose fibres proved to be the best method in terms of rapidity of sample throughput, avoidance of sample loss, precision of isotope results, ease of handling, and cost.
Rapid Communications in Mass Spectrometry 08/2009; 23(13):1934-40. · 2.51 Impact Factor