Measured and modelled source water δ18O based on tree-ring cellulose of larch and pine trees from the permafrost zone

• Published in: IForest (Viterbo) Vol. 13; no. 1; pp. 224 - 229
• Main Authors: Churakova-Sidorova, OV, Lienert, S, Timofeeva, G, Siegwolf, R, Roden, J, Joos, F, Saurer, M
• Format: Journal Article
• Language: English
• Published: Potenza The Italian Society of Silviculture and Forest Ecology (SISEF) 30.06.2020; Italian Society of Silviculture and Forest Ecology (SISEF)
• Subjects: Cellulose; Climate; conifers; Dominant species; drought; Extreme environments; Forest ecosystems; Fractionation; Growing season; Hydrologic cycle; Isotopes; Larix cajanderi; Organic matter; Oxygen isotopes; Permafrost; permafrost thaw depth; Pine trees; Pinus sylvestris; Precipitation; siberia; Soil depth; Soil structure; Terrestrial ecosystems; Tree rings; Trees; Water depth; δ18o of source water; Switzerland; Germany; Siberia
• ISSN: 1971-7458; 1971-7458
• DOI: 10.3832/ifor3212-013

To identify source water for trees growing on permafrost in Siberia, we applied mechanistic models that quantify physical and biochemical fractionation processes, leading to oxygen isotope variation (δ18O) in plant organic matter. These models allowed us to investigate the influence of a variety of climatic factors on tree-ring cellulose from two dominant species: Larix cajanderi Mayr. from northeastern Yakutia (69° 22′ N, 148° 25′ E, ~ 250 m a.s.l.) and Pinus sylvestris L. from Central Yakutia (62°14′ N, 129°37′ E, ~ 220 m a.s.l.). The climate of the region is highly continental with short growing seasons, low amount of precipitation and these forest ecosystems are growing on permafrost, which in turn impact the water cycle and climate variation in the δ18O of source water. We compared outputs of the Land surface Processes and eXchanges (LPX-Bern v. 1.3), and Roden-Lin-Ehleringer (RLE) models for the common period from 1945 to 2004. Based on our findings, trees from northeastern and central Yakutia may have access to additional thawed permafrost water during dry summer periods. Owing to differences in the soil structure, active thaw soil depth and root systems of trees at two Siberian sites, Larix cajanderi Mayr. trees can access water not more than from 50 cm depth, in contrast to Pinus sylvestris L. in Central Yakutia which can acquire water from up to 80 cm soil depth. The results enhance our understanding of the growth and survival of the trees in this extreme environment.