Premium
Cover plus: ways of measuring plant canopies and the terms used for them
Author(s) -
Wilson J. Bastow
Publication year - 2011
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.1111/j.1654-1103.2010.01238.x
Subject(s) - cover (algebra) , ecology , environmental science , plant cover , geography , canopy , physical geography , remote sensing , biology , engineering , mechanical engineering
Abstract Aim: To clarify the concepts and terms that have been used in recording plant canopies and the methods used for measuring them. Concepts: The concepts considered are cover, top cover, repeated cover, number of layers, proportion of repeated cover and leaf area index ( LAI ). Variants include canopy cover, basal area and leaf area density . Other terms have been used in the past, some are now ambiguous and some are counter‐intuitive. Measurement:Cover and its related concepts can be measured by point intercept, line intercept, angle sampling, charting and image analysis, canopy transmittance, complete enumeration, clipping and allometry. The common procedure of adding the cover of individual species to calculate a “total cover” is invalid: a nonsense number is produced. Other measures of abundance: Cover‐abundance, density, frequency, biomass and calorific values can also be used to measure abundance. They are related to cover . Especially, shoot frequency at a point is cover (the point intercept method). Subjective estimates: There are severe problems with cover‐abundance scales, such as that of Braun‐Blanquet. Estimation of abundance “by eye”, by “informed guess”, etc. has too often compromised results in vegetation science.