Christie Allan

Bio: Christie Allan is an academic researcher. The author has contributed to research in topics: Forest produce & Forest management. The author has an hindex of 2, co-authored 2 publications receiving 596 citations.

The Cerrados of Brazil: Ecology and Natural History of a Neotropical Savanna

Abstract: This volume accompanies Flora of China text Volume 4, published in 1999. Included are 394 figures representing 816 species (;75% of the taxa represented in the text volume) in the families Cycadaceae (8 species), Ginkgoaceae (1 species), Araucariaceae (2 species), Pinaceae (84 species), Taxodiaceae (11 species), Cupressaceae (27 species), Cephalotaxaceae (9 species), Taxaceae (11 species), Ephedraceae (14 species), Gnetaceae (6 species), Casuarinaceae (2 species), Saururaceae (3 species), Piperaceae (42 species), Chloranthaceae (11 species), Salicaceae (240 species), Myricaceae (4 species), Junglandaceae (24 species), Betulaceae (62 species), and Fagaceae (242 species). The Sciadopityaceae, included in the text volume, is omitted from the illustrations volume.

Non-Wood Forest Products 13. Resource Assessment of Non-Wood Forest Produce. Experience an Biometric Principles

Abstract: This volume accompanies Flora of China text Volume 4, published in 1999. Included are 394 figures representing 816 species (;75% of the taxa represented in the text volume) in the families Cycadaceae (8 species), Ginkgoaceae (1 species), Araucariaceae (2 species), Pinaceae (84 species), Taxodiaceae (11 species), Cupressaceae (27 species), Cephalotaxaceae (9 species), Taxaceae (11 species), Ephedraceae (14 species), Gnetaceae (6 species), Casuarinaceae (2 species), Saururaceae (3 species), Piperaceae (42 species), Chloranthaceae (11 species), Salicaceae (240 species), Myricaceae (4 species), Junglandaceae (24 species), Betulaceae (62 species), and Fagaceae (242 species). The Sciadopityaceae, included in the text volume, is omitted from the illustrations volume.

Novel ecosystems: theoretical and management aspects of the new ecological world order

Abstract: We e xplore the issues relevant to those types of ecosystems containing new combinations of species that arise through human action, environmental change, and the impacts of the deliberate and inadvertent introduction of species from other regions. Novel ecosystems (also termed ‘emerging ecosystems’) result when species occur in combinations and relative abundances that have not occurred previously within a given biome. Key characteristics are novelty, in the form of new species combinations and the potential for changes in ecosystem functioning, and human agency, in that these ecosystems are the result of deliberate or inadvertent human action. As more of the Earth becomes transformed by human actions, novel ecosystems increase in importance, but are relatively little studied. Either the degradation or invasion of native or ‘wild’ ecosystems or the abandonment of intensively managed systems can result in the formation of these novel systems. Important considerations are whether these new systems are persistent and what values they may have. It is likely that it may be very difficult or costly to return such systems to their previous state, and hence consideration needs to be given to developing appropriate management goals and approaches.

Land cover mapping of the tropical savanna region in Brazil.

Abstract: The Brazilian tropical savanna (Cerrado), encompassing more than 204 million hectares in the central part of the country, is the second richest biome in Brazil in terms of biodiversity and presents high land use pressure. The objective of this study was to map the land cover of the Cerrado biome based on the segmentation and visual interpretation of 170 Landsat Enhanced Thematic Mapper Plus satellite scenes acquired in 2002. The following land cover classes were discriminated: grasslands, shrublands, forestlands, croplands, pasturelands, reforestations, urban areas, and mining areas. The results showed that the remnant natural vegetation is still covering about 61% of the biome, however, on a highly asymmetrical basis. While natural physiognomies comprise 90% of the northern part of the biome, only 15% are left in its southern portions. Shrublands were the dominant natural land cover class, while pasturelands were the dominant land use class in the Cerrado biome. The final Cerrado’s land cover map confirmed the intensive land use pressure in this unique biome. This paper also showed that Landsat-like sensors can provide feasible land cover maps of Cerrado, although ancillary data are required to help image interpretation.

Fire-mediated dieback and compositional cascade in an Amazonian forest.

Abstract: The only fully coupled land–atmosphere global climate model predicts a widespread dieback of Amazonian forest cover through reduced precipitation. Although these predictions are controversial, the structural and compositional resilience of Amazonian forests may also have been overestimated, as current vegetation models fail to consider the potential role of fire in the degradation of forest ecosystems. We examine forest structure and composition in the Arapiuns River basin in the central Brazilian Amazon, evaluating post-fire forest recovery and the consequences of recurrent fires for the patterns of dominance of tree species. We surveyed tree plots in unburned and once-burned forests examined 1, 3 and 9 years after an unprecedented fire event, in twice-burned forests examined 3 and 9 years after fire and in thrice-burned forests examined 5 years after the most recent fire event. The number of trees recorded in unburned primary forest control plots was stable over time. However, in both once- and twice-burned forest plots, there was a marked recruitment into the 10–20 cm diameter at breast height tree size classes between 3 and 9 years post-fire. Considering tree assemblage composition 9 years after the first fire contact, we observed (i) a clear pattern of community turnover among small trees and the most abundant shrubs and saplings, and (ii) that species that were common in any of the four burn treatments (unburned, once-, twice- and thrice-burned) were often rare or entirely absent in other burn treatments. We conclude that episodic wildfires can lead to drastic changes in forest structure and composition, with cascading shifts in forest composition following each additional fire event. Finally, we use these results to evaluate the validity of the savannization paradigm.

Comparative fire ecology of tropical savanna and forest trees

Abstract: Summary 1Fire is important in the dynamics of savanna–forest boundaries, often maintaining a balance between forest advance and retreat. 2We performed a comparative ecological study to understand how savanna and forest species differ in traits related to fire tolerance. We compared bark thickness, root and stem carbohydrates, and height of reproductive individuals within 10 congeneric pairs, each containing one savanna and one forest species. 3Bark thickness of savanna species averaged nearly three times that of forest species, thereby reducing the risk of stem death during fire. The allometric relationship between bark thickness and stem diameter differed between these two tree types, with forest species tending to have a larger allometric coefficient. 4The height of reproductive individuals of forest species averaged twice that of congeneric savanna species. This should increase the time necessary for forest species to reach reproductive size, thereby reducing their capacity to reach maturity in the time between consecutive fires. 5There was no difference in total non-structural carbohydrate content of stems or roots between savanna and forest species, though greater allocation to total root biomass by savanna species probably confers greater capacity to resprout following fire. 6These differences in fire-related traits may largely explain the greater capacity of savanna species to persist in the savanna environment.