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Using aerial photographs to remotely assess tree hollow availability

Citation

Koch, AJ and Baker, SC, Using aerial photographs to remotely assess tree hollow availability, Biodiversity and Conservation, 20, (5) pp. 1089-1101. ISSN 0960-3115 (2011) [Refereed Article]


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The final publication is available at http://www.springerlink.com

Official URL: http://www.springerlink.com

DOI: doi:10.1007/s10531-011-0018-z

Abstract

Tree hollows provide critical habitat for many species worldwide. The conservation of hollow-bearing trees presents a particular challenge for forest managers, partly due to difficulties in predicting their occurrence across a landscape. We trialled a novel approach for assessing relative hollow availability, by remotely estimating mature crown cover and senescence from aerial photographs in Tasmania, Australia. These estimates were tested against plot-based field assessments of actual occurrence of hollow-bearing trees. In dry forest we conducted ground-based surveys of hollows for all mature trees ([50 cm dbh) in 37 half-hectare plots. In wet forest, we conducted helicopter-based surveys of hollows for all mature trees in 45 oldgrowth plots (0.29–4.63 ha). Aerial photographs (1:10,000–1:25,000) were used to classify the senescence and cover of mature crowns in each plot. Regression analysis showed that, in dry forest, hollow-bearing tree densities were strongly related to the remote assessment of mature crown cover, with an 8% increase in variability explained if senescence was also included (R2 = 0.50). In wet forest, mature crown cover alone was the best model (R2 = 0.53 when outliers were removed). Assessing senescence was less important in dense wet forests than dry forest because trees take longer to form mature-shaped crowns and so mature-shaped crowns aremore likely to have hollows. These results suggest that, with skilled photo-interpretation, aerial photographs can be useful for remotely assessing the relative density of hollowbearing trees. This approach has the potential to greatly improve conservation planning for hollows and hollow-dependent fauna.

Item Details

Item Type:Refereed Article
Research Division:Environmental Sciences
Research Group:Environmental Science and Management
Research Field:Environmental Management
Objective Division:Environment
Objective Group:Environmental and Natural Resource Evaluation
Objective Field:Environmental and Natural Resource Evaluation not elsewhere classified
Author:Koch, AJ (Ms Amelia Koch)
Author:Baker, SC (Dr Sue Baker)
ID Code:69518
Year Published:2011
Web of Science® Times Cited:8
Deposited By:Geography and Environmental Studies
Deposited On:2011-04-21
Last Modified:2012-03-26
Downloads:0

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