Environmental Factors’ Effects on Stem Radial Variations of Populus euphratica in the Lower Reaches of the Tarim River in Northwestern China

Microscopic understanding of tree xylogenesis processes and their relationships with environmental factors is important for conservation. To assess the relationship between Euphrates poplar (Populus euphratica) radial growth on short time scales, micro-core samples were collected in lower Tarim River northwest China 2020. We analyzed intra-annual variation P. euphratica its environment. Our results showed that started to manifest stem variations late April (around DOY (day year) 114) stopped displaying early mid-September DOY255), an annual increment 2620.89 μm a maximum rate 22.42 μm/d. The was positively correlated mean temperature (R2 = 0.55, p < 0.01), 0.45, minimum 0.49, surface 0.64, vapor pressure deficit negatively atmospheric 0.41, 0.01) groundwater depth 0.01). are mainly influenced by during main growing period, positive when fluctuation range 4.17~5.38 m. Therefore, reaches groundwater, which has reasonable