Contrasting Water Conduct Strategies of Tree Species with Different Wood Structure in a Typical Temperate Oak Forest of Northern China

Abstract

In Dongling Mountain of northern China, ring-porous and semi-ring-porous tree species coexist in the same regions. Climate change might differently affect these types, and a mechanistic understanding of drought effects on their xylem structure is lacking. We aimed at quantitatively comparing ring width and xylem vessel traits of Quercus liaotungensis, Phellodendron amurense and Juglans mandshurica assessing similarities and differences in their responses to climate variability. P.amurense showed relatively wide ring width and high hydraulic conductivity; Q.liaotungensis showed narrow ring width, less vessel number, big hydraulic diameter; J.mandshurica showed more vessel number, less hydraulic diameter and low hydraulic conductivity. The climatic sensitivity of ring width was much higher for Q.liaotungensis compared with the other trees. The climatic sensitivity of Kh was much higher for P.amurense compared with the other trees. Q.liaotungensis and J.mandshurica had noticeable negative correlations between vessel number and hydraulic diameter, as well as ring width and hydraulic diameter. P.amurense had conspicuous positive correlations between vessel number and hydraulic diameter, and had conspicuous positive correlations between ring width and hydraulic diameter. Under drought conditions, Q.liaotungensis and J.mandshurica preferred to adapt water conduct strategy featured by small and more vessels, whereas P.amurense tended to adapt water conduct strategy featured by more and large vessels. The growth of Q.liaotungensis and J.mandshurica decreased when their water-conducting capacity increased, indicating an extremely unbalanced distribution of carbon and water. P.amurense showed higher ability to cope with both climate inter-annual variations and drought stress compared with Q.liaotungensis and J.mandshurica.

Keywords: tree-ring, xylem vessel traits, water conduct strategies, temperate oak forest