Abstract
In the Velký Tisý pond, located between Třeboň and Lomnice nad Lužnicí, old tree stumps protrude from the muddy bottom in the area of the so-called Přesecká Bay in the south-eastern part of the pond. It can be assumed that they are a remnant of a forest from before the pond was built in 1505.
A short report in this journal (1975) dealt with the question of the origin of the pond name ("tis" means yew in Czech) and reported that five wood samples taken from the stumps were in fact determined as yew trees. From the point of view of today's distribution and ecological demands of yew, the occurrence of yew stands at the site on a flat peat bog would be very surprising.
We took samples from five of these stumps and determined them based on the anatomical structure of the wood using a reflected light microscope. We showed that the samples were from a pine tree in all cases.
A pine forest can be expected at the site but an ecological sensation in the form of possible yew stands on the peat bog most likely did not take place. It is not possible to say whether the samples were incorrectly determined in the seventies or whether there really were some yew trees that we missed with our sampling.
In support of the first option, we recorded an anatomic structure resembling spiral thickenings of the tracheid walls in some of our samples. Spiral thickenings are a key identification feature for yew wood.
However, a similar structure can occur also in pine wood in stressed and growth-atypical parts of the wood. Presence of such structures in the unstable swamp environment at the site is not surprising.
We commonly observed big window-like pits in the cross-field that are typical for pine wood.