Ecological Factors in Wood Evolution: A Floristic Approach

Abstract

Wood florulas from southwestern Australia were analyzed to determine whether wood anatomy is sufficiently correlated with ecology so that vessel element features can be said to have a predictive value. Indices for vulnerability (vessel diam: vessels per sq. mm) and mesomorphy (vulnerability × vessel element length) were calculated for each species in the following florulas: karri forest understory, coastal granitic slopes, bogs, sand heaths, and desert. Wood indices for the species studied and for each florula show that these florulas form a sequence in increasing xeromorphy in the order listed. Genera represented in more than one florula validate the trends. Data for Gyrostemonaceae, Loranthaceae, and Cupressaceae are calculated separately because these are succulents, epiparasites, and conifers, respectively. Comparison with categories from floras elsewhere in the world shows the flora of Western Australia as a whole to be relatively xeromorphic. The indices devised show promise of great reliability because correlations with rainfall, temperature, and other factors are very close. Functional nature of the vessel element is thereby believed to be clarified.