No abstract

No abstract

No abstract

No abstract

No abstract

Macropores formed by roots are crucial channels for preferential flows in forest soils that are largely responsible for water percolation and solute leaching. Using dual‐tracer experiments (Brilliant Blue FCF and bromide [Br−]), this study investigated the preferential flows of water and solutes in a deciduous forest dominated by Quercus variabilis Bl. and a coniferous forest mainly planted with Platycladus orientalis (L.) Franco. Dye‐stained patterns and concentrations of Brilliant Blue and Br− were obtained in vertical soil profiles (0–30 cm), whereas stained and unstained roots were collected and analyzed in horizontal soil profiles to a 30‐cm soil depth. Brilliant Blue and Br− were mainly accumulated in the 0‐ to 20‐cm soil depth, which had greater total root length density than the 20‐ to 30‐cm soil depth (P < 0.05). Only part of the roots facilitated the preferential flows, with finer roots (i.e., diameter <1 mm) contributing the most. More intriguingly, the coniferous forest soil had a greater degree of preferential flows and greater tracer concentrations at deeper soil depth than the deciduous forest soil, suggesting the importance of tree species and forest composition on water and solute transport in forest ecosystems. Core Ideas Roots enhanced preferential flows, with the primary contribution from finer roots. Brilliant Blue and Br− tracers mainly accumulated in soils with abundant roots. Preferential flows were greater in coniferous forest than deciduous forest.

No abstract

Photosynthetic capacity and leaf life span generally determine how much carbon a plant assimilates during the growing season. Leaves of deciduous tree species start senescence in late season, but whether the senescent leaves still retain capacity of carbon assimilation remains a question. In this study, we investigated leaf phenology and photosynthesis of a subtropical broadleaf deciduous tree species Liquidambar formosana Hance in the central southern continental China. The results show that L. formosana has extended leaf senescence (more than 2 months) with a substantial number of red leaves persisting on the tree. Leaf photosynthetic capacity decreases over season, but the senescent red leaves still maintain relatively high photosynthetic capacity at 42%, 66% and 66% of the mature leaves for net photosynthesis rate, apparent quantum yield, and quantum yield at the light compensation point, respectively. These results indicate that L. formosana may still contribute to carbon sink during leaf senescence.