Dynamics of tree diversity in undisturbed and logged subtropical rainforest in Australia

In subtropical rainforest in eastern Australia, changes in the diversity of trees were compared under natural conditions and eight silvicultural regimes over 35 years. In the treated plots basal area remaining after logging ranged from 12 to 58 m2 per ha. In three control plots richness differed little over this period. In the eight treated plots richness per plot generally declined after intervention and then gradually increased to greater than original diversity. After logging there was a reduction in richness per plot and an increase in species richness per stem in all but the lightest selective treatments. The change in species diversity was related to the intensity of the logging, however the time taken for species richness to return to pre-logging levels was similar in all silvicultural treatments and was not effected by the intensity of treatment. These results suggest that light selective logging in these forests mainly affects dominant species. The return to high diversity after only a short time under all silvicultural regimes suggests that sustainability and the manipulation of species composition for desired management outcomes is possible

First observations of ecological surveillance plots on afforested open-cast spoil in South Wales

The object of this project was to initiate a long-term study of the development of soil, vegetation and fauna on 'restored', afforested open-cast sites in the South Wales coalfield. The task was to establish and observe 'permanently' detectable, subjectively sited plots~ marked by durable underground steel rods, precisely positioned by National Grid co-ordinates. Records were designed to be accessible and intelligible for recurrent observation, by any observers who might be in touch with any institution where these observations are lodged...</p

Tree life histories in a montane subtropical forest: species differ independently by shade-tolerance, turnover rate and substrate preference

1. To investigate life‐history differentiation and an objective functional classification of tree species we analysed the demography of 29 species in subtropical montane forests in north‐western Argentina. 2 We computed 13 growth, demographic, abundance and distribution variables based on: (i) two 5‐year re‐measurements of stems ≥ 10 cm diameter at breast height (d.b.h.) in 8 ha of old growth forest and 4 ha of secondary forest; (ii) assessments of tree crown illumination; and (iii) sapling counts under shade and on landslides. 3 We assessed the potential confounding effects of stem size and crown illumination on absolute stem diameter growth rate for the 24 most abundant species. As diameter increased, one species showed significant increases in growth rate and five showed significant reductions. Seventeen species grew significantly faster with increased exposure to light and we controlled for this confounding effect in the computation of diameter growth rates for subsequent analyses. 4 A principal component analysis resulted in three meaningful and interpretable axes of demographic variation across species. The first axis (interpreted as shade tolerance) indicates that trees of species with inherently high growth rates tend to have well‐exposed crowns at 10–30 cm d.b.h., have high density of trees in secondary forest and are less tolerant of shade. 5 The second axis (turnover) shows that in old‐growth forest short‐lived species, with high mortality rates, size‐class distributions with a steep negative slope and low dominance, persist due to high rates of recruitment (to ≥ 10 cm d.b.h.). 6 The third axis indicates that species that colonize landslides have lower tree recruitment rates and greater growth variability in secondary forest, reflecting spatio/temporal differences in species’ recruitment linked to differences in their substrate requirements for regeneration. 7 Maximum height and diameter are correlated with the first and second axes, indicating that higher rates of both growth and survival permit some species to attain large size. 8 All three demographic axes depict separate trade‐offs that confer competitive advantage to each ‘demographic type’ under contrasting ecological conditions (of light availability, disturbance frequency and disturbance intensity), thus underpinning species’ coexistence in dynamic forest landscapes.Fil: Easdale, T. A.. University of Wales; Reino UnidoFil: Healey, J. R.. University of Wales; Reino UnidoFil: Grau, Hector Ricardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Malizia, Agustina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Investigaciones Ecológicas de las Yungas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin