Ecological trends in the wood anatomy of Vaccinioideae (Ericaceae s.l.)

The ecological wood anatomy of 128 vaccinioid wood samples (including 115 species, 35 genera), collected between 39°S and 60°N latitude and 10 m to 3400 m altitude is studied. Several wood anatomical features within the subfamily, viz. tangential vessel diameter, average length of tracheary elements, height of multiseriate rays, and presence of prismatic crystals are negatively correlated with increasing latitude, while vessel density and helical thickenings show a positive correlation with increasing latitude. Similar latitudinal trends are found within the genus Vaccinium (31 species studied). The correlation between various wood anatomical features and latitude is surprisingly high despite the fact that most tropical species grow in montane regions, which are rather similar to the temperate, non-tropical habitats as regards climatic conditions. Altitudinal trends, however, are weak. The impact of different life forms (shrubs, trees and lianas) and the amount of precipitation also plays a significant role in various continuous wood features. Furthermore, some of these anatomical features are correlated with each other. Part of the variation in vessel characters may be the result of functional adaptations to different climatic zones and environments, especially with respect to conductive efficiency and safety.