Spatial concentration in institutional investment in the UK: some comparisons between the retail and office sectors

Geographic diversity is a fundamental tenet in portfolio management. Yet there is evidence from the US that institutional investors prefer to concentrate their real estate investments in favoured and specific areas as primary locations for the properties that occupy their portfolios. The little work done in the UK draws similar conclusions, but has so far focused only on the office sector; no work has examined this issue for the retail sector. This paper therefore examines the extent of real estate investment concentration in institutional Retail portfolios in the UK at two points in time; 1998 and 2003, and presents some comparisons with equivalent concentrations in the office sector. The findings indicate that retail investment correlates more closely with the UK urban hierarchy than that for offices when measured against employment, and is focused on urban areas with high populations and large population densities which have larger numbers of retail units in which to invest.

Spatial and temporal effects of free-air CO2 enrichment (POPFACE) on leaf growth, cell expansion and cell production in a closed canopy of poplar

Leaf expansion in the fast-growing tree,Populus × euramericana was stimulated by elevated [CO2] in a closed-canopy forest plantation, exposed using a free air CO2 enrichment technique enabling long-term experimentation in field conditions. The effects of elevated [CO2] over time were characterized and related to the leaf plastochron index (LPI), and showed that leaf expansion was stimulated at very early (LPI, 0–3) and late (LPI, 6–8) stages in development. Early and late effects of elevated [CO2] were largely the result of increased cell expansion and increased cell production, respectively. Spatial effects of elevated [CO2] were also marked and increased final leaf size resulted from an effect on leaf area, but not leaf length, demonstrating changed leaf shape in response to [CO2]. Leaves exhibited a basipetal gradient of leaf development, investigated by defining seven interveinal areas, with growth ceasing first at the leaf tip. Interestingly, and in contrast to other reports, no spatial differences in epidermal cell size were apparent across the lamina, whereas a clear basipetal gradient in cell production rate was found. These data suggest that the rate and timing of cell production was more important in determining leaf shape, given the constant cell size across the leaf lamina. The effect of elevated [CO2] imposed on this developmental gradient suggested that leaf cell production continued longer in elevated [CO2] and that basal increases in cell production rate were also more important than altered cell expansion for increased final leaf size and altered leaf shape in elevated [CO2].