Drowned Forests in the Gulf of Gdansk (Southern Baltic) as an Indicator of the Holocene Shoreline Changes - The Baltic Sea Basin - page 224

Fig. 11.4 Scuba diver sampling a tree trunk
11.3 Results
The water depth in the area of “drowned forest” is between 16 and 17 m, and the
sea bed is almost completely flat (Figs. 11.2 and 11.3 ) , covered by fine and medium
sand with current-wave ripple marks. During the study, the distance between the
crests was about 10-20 cm and their height 1-2 cm. The thickness of sand var-
ied from a few to a dozen centimetres. Below the sand, gyttja with many plant
remains, wood fragments and intercalations of peat occur. Over an area of a few
dozen hectares, many fallen tree trunks and stumps rooted in situ in gyttja were
observed and sampled (Fig. 11.4 ) .
According to dendrological data of 17 samples of wood, mainly alder ( Alnus
sp.) trunks were found, but only one sample of oak ( Quercus sp.) trunk. The wood
samples represent mainly relatively young trees. The oldest one was 54 years old.
The ages of the fallen trees are as follows: three trunks - 50-54 years, five trunks -
40-50 years, four trunks - 30-40 years, five trunks - <30 years old.
The investigated tree trunks did not die at the same time. According to dendro-
grams of three trunks (Fig. 11.5 ) , two of them died at the same time, whereas one
tree fell several years earlier.
Four samples of wood among the three samples of alder and one sample of oak
wood were dated by 14 C method (Table 11.1 ) .
Radiocarbon dating indicates that the trees did grow between 8,000 and 7,920
BP (conventional radiocarbon years), i.e. in the early Atlantic period. According to