Friday, 9 March 2018

Research of large wood in a semi-arid stream

Our latest accepted article deals with the topic of instream wood in an ephemeral stream, which drains mountainous Mediterranean landscape of southwest Crete, Greece. We made a detailed inventory of large wood in the valley floor of 4-km-long reach. We analysed a total of 795 large wood pieces, and the mean observed abundance of instream wood was generally lower (ca. 14 m3/ha of active valley floor or ca. 20 pieces per 100 m of stream length) than is usually documented for more humid environments. The trees living in the valley floor acted as important instream wood supply agents (by tree throws or the supply of individual branches) and flow obstructions during large flood events, causing storage of transported large wood pieces in jams. On the opposite, the trees growing on adjacent, very steep hillslopes were less important in resulted instream wood budget. The geomorphic function of instream wood in the studied stream can only be perceived to be a spatially limited stabilising element for sediments, which was documented by a few accumulations of coarse clastic material by woody steps and jams.   

Studied stream

Large wood step with upstream sediment deposition

Living trees acting as flow obstructions during large floods. Note deposited large wood by these trees.