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Quantifying dieback in forests is useful for land managers and decision makers seeking to explain spatial disturbances and understand the cyclic nature of forest health. Crown condition is assessed as reference to dieback in terms of the density, transparency, extent and in-crown distribution of foliage. At 20 sites in the Yalgorup National Park, Western Australia, a total of 80 Eucalyptus gomphocephala crowns were assessed both in situ (2008) and using two acquisitions (2008 and 2010) of airborne imagery. Each tree was assessed using four crown-condition indices: Crown Density, Foliage Transparency, the Crown Dieback Ratio and Epicormic Index combined into a single index called the Total Crown Health Index (TCHI). The airborne imagery is like value calibrated then classified and modelled using in situ canopy condition assessments resulting in a quantification of crown-condition change over time. Comparison of Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI) and a novel...

Estimates are made of transport energy use and petrol costs in 38 zones of Perth. An average outer northern suburban household spent around $2000 on petrol in 1984 compared to $660 for households in inner Fremantle. The differences are due primarily to land use rather than income and indicate certain directions for urban planning and policy.

A range of separate traffic and corridor studies from Perth are analyzed together with an international comparison of thirty-two cities to seek an answer to this question. The data suggest that free flowing traffic does not save energy or lower emissions overall in a city despite the apparently clear advantages for individual vehicles. The mechanisms for this in terms of travel distances, alternative modes and sub optimal vehicle usage are outlined together with the characteristics of cities where lower fuel use is apparent. Some implications for urban road project justification and traffic engineering practice are suggested.