Vegetation structure: using visual estimates
Indicators of tree structure include leaf area index, leaf angle distribution, crown cover, stem density, tree height, tree basal area, and vertically-projected fraction of foliage and branches covering the ground. Estimates of vertically projected cover (crown cover, leaf cover, branch cover, grass cover) are simpler to make when in the field and are particularly suited to Australian environments.
References:
J.D. Armston, R.J. Denham, T.J. Danaher, P.F. Scarth, T.N. Moffiet, Prediction and validation of foliage projective cover from Landsat-5 TM and Landsat-7 ETM+ imagery, Journal of applied remote sensing, 3 (2009) 033540.
Specht, R.L., & Specht, A. (1999). Australian Plant Communities: Dynamics of Structure, Growth and Biodiversity. Oxford: Oxford University Press