The Influence of tree size and Microenvironmental changes on the wood Anatomy of Roupala Rhombifolia

Abstract

We analysed how variation in microenvironmental conditions and stem size affects the wood anatomy of Roupala rhombifolia in three contrasting habitats in the same study area: open field, hilltop forest and riparian forest. The wood anatomy features analysed were: vessel area and density, vessel element length, fibre length, and ray width and height. Vegetation cover and soil attributes were also quantified and integrated into the analyses. Separate analyses were performed on i) raw anatomical data and ii) residuals from linear fits between wood anatomical features and plant height and stem diameter. Raw data showed a clear difference between specimens from riparian forest and open fields, which represented the most mesic and xeric anatomical features respectively. After residual extraction to correct size-related variation, only fibre length and vessel area differed between habitats. Vessel areas in riparian forest differed from those in hilltop forest, but were similar to those in open fields. This result can be explained when vegetation cover and soil are considered together. While open field and hilltop forest have similar soils and lower moisture availability when compared to riparian forest, water demand in open fields is lower, presumably resulting in higher water availability.