Growth responses of Pinus sylvestris (L.) to burial by drift sand and its application to the reconstruction of aeolian dune development

Abstract

Sand dunes represent unique environments that increase the biodiversity, geodiversity, or ecosystem services of landscapes. The knowledge of past sand dune development is crucial for realizing their effective protection. Dendrogeomorphic methods represent an effective tool for the reconstruction of geomorphic processes, but their application in aeolian geomorphology is limited. This state can be caused by limited knowledge of the tree growth responses (particularly microscopic anatomical ones) to burial by sand. Thus, tree growth responses to sand burial were studied in detail for one of the most extensively distributed tree species on European dunes – Pinus sylvestris (L.) in this study. Four buried P. sylvestris individuals occupying selected dunes in the Borská lowland (SW Slovakia) were exhumed and densely sampled at vertical distances of 5 cm. The results evidenced the distinct macroscopic growth responses of trees to burial in the form of abrupt growth suppression (51.8% on average) in four various years of sand accumulation (1990, 1994, 1999, 2012). The intensity of the increment response was not dependent on the burial depth but expressed a significant correlation with the mean tree ring series sensitivity (r = 0.68–0.93). In addition, growth suppression was always accompanied by a distinct anatomical response in the form of an increase in cell lumen area (103.5% on average). The intensity of this response was significantly dependent on the depth of burial. Both main forms of responses (abrupt growth suppression and cell lumen area increase) were detected even in the non-buried parts of stems (up 15 cm above the ground). Finally, the sand accumulation rate was calculated (2.5 cm year−1 on average) and spatially interpolated regarding the microtopography of the dune. The limits and uncertainties (absence of some expected tree growth responses) as well as the advantages (data about past dune development without monitoring) of dendrogeomorphic methods in aeolian geomorphology are discussed.