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Images, UC QuakeStudies

A view down Cashel Street from the Bridge of Remembrance, showing earthquake damage to several buildings along Cashel Mall. In the background the Hotel Grand Chancellor can be seen, a Christchurch hotel that was badly damaged in the February 2011 earthquake. The collapse of a key supporting shear wall caused the building to visibly lean to one side.

Images, UC QuakeStudies

A photograph of the earthquake damage to the Avonmore House on the corner of Hereford Street and Latimer Square. Large cracks have formed in the building, causing sections of the masonry to crumble. The windows on the Hereford Street side of the building have bent out of shape and many of the glass panes have shattered. USAR codes have been spray painted on the column next to the door. In the distance wire fencing has been placed across the street as a cordon.

Research Papers, Lincoln University

Tree mortality is a fundamental process governing forest dynamics, but understanding tree mortality patterns is challenging because large, long-term datasets are required. Describing size-specific mortality patterns can be especially difficult, due to few trees in larger size classes. We used permanent plot data from Nothofagus solandri var. cliffortioides (mountain beech) forest on the eastern slopes of the Southern Alps, New Zealand, where the fates of trees on 250 plots of 0.04 ha were followed, to examine: (1) patterns of size-specific mortality over three consecutive periods spanning 30 years, each characterised by different disturbance, and (2) the strength and direction of neighbourhood crowding effects on sizespecific mortality rates. We found that the size-specific mortality function was U-shaped over the 30-year period as well as within two shorter periods characterised by small-scale pinhole beetle and windthrow disturbance. During a third period, characterised by earthquake disturbance, tree mortality was less size dependent. Small trees (,20 cm in diameter) were more likely to die, in all three periods, if surrounded by a high basal area of larger neighbours, suggesting that sizeasymmetric competition for light was a major cause of mortality. In contrast, large trees ($20 cm in diameter) were more likely to die in the first period if they had few neighbours, indicating that positive crowding effects were sometimes important for survival of large trees. Overall our results suggest that temporal variability in size-specific mortality patterns, and positive interactions between large trees, may sometimes need to be incorporated into models of forest dynamics.