Yvan Alleau mentioned that Horst Linke prefers beech
leaves over oak leaves for Apisto tanks. Well, as I continue my reading
of "The Vegetation of Wisconsin," I have found additional information that may
explain why.
"Beech is taxonomically related to the aks and resembles
them in many of its life-history characters. ... Like the closely
related oaks, the beech is not a nutrient pumper, because its leaves are
strongly acid and low in bases."
So beech leaves would lower the pH, just like oak
leaves, and decay slowly as well. Additionally, there's another
important characteristic of beech leaves that may provide "medicinal"
benefits.
" ... sparseness of the ground layer in beech and
hemlock forests is frequently attributed to the very low light intensity in
such stands, but the recent work of winter and Bublitz (1953) on the toxic
effects of water extracts of European beech leaves may indicate that an
antibiotic reaction is in part responsible for the absence of many herbaceous
species."
Of course, this book is forty years old. So there most
likely is more current research on this subject that would prove or disprove
Curtis' statements. Even though, it does provide some intrigue to the
discussion.