A more comprehensive dendrochronological research began, when
a Dendroclimatochronological Group was founded at the Flora
and Geobotany section of the Botanical Institute on 1st
January 1968. Laboratory of Dendroclimatochronology was founded
on the
basis this Group in 1976 (in 2003 re-organized into a
Group of Dendroclimatology and Radiometrics of Environmental Research
Centre). Founder of the Laboratory - Dr. Habil.
T.
Bitvinskas.
Name of the Laboratory (in Greek dendro - tree, klima - climate, chronos - time) outlines the main research directions, based on a tree radial growth and its connection to various environmental factors.
A region of searching for old trees have involved many eastern
countries. Routes of expeditions extended from Murmansk to the
Carpathians and from Lithuania to Mongolia. Analyzing the collected
material was found that the duration of radial growth cycles
changes from the North to South. 22 and 33-year
cycles are characteristic in
the North, while in the South - 11-year cycles are typical. Besides
short cycles, long-term cycles of several hundreds and millennia in
duration also exist. They could be analyzed only in the long-term
chronologies.
Long-term chronologies have been constructed using tree-ring
series of excavated timber from bogs, river sediments and
archaeological
buildings. A rich dendrochronological material in
Užpelkių tyrelis and Aukštoji plynia raised bogs enabled to compile a
long-term
chronology of pine, spanning the last 2200 years. This work was
performed by Dr.
R. Pukienė
and published in the dissertation "Pinewood
growth
dynamics in Užpelkių Tyrelis oligotrophic bog during the Subatlantic
period" (1997).
Construction of the long-term chronologies is connected to the
radiocarbon 14C
dating. For radiocarbon dating our group is equipped with modern liquid
scintillation counter LSC-1220.
During 1968-2003 a huge collection of historical timber
have been collected in the Laboratory. One of the most important - a
collection of subfossil
oak
from
Smurgainiai (Byelorussia) gravel pit. The
radiocarbon dates of the oldest timber reach 5350 BC. Approximately
from the same age (5000 BC) is oak timber found near Biržai
in 2001.
Research has shown that for the reliable reconstruction and forecast of a climate the long-term tree-ring series should be constructed from trees, growing in similar site conditions. For this purpose, Dr. Jonas Karpavičius investigates the response of the growth of pines on different geohydrological conditions to a climate.
In the Station for Dendrochronological and Botanical research,
located in Vaišnoriškė
village of Aukštaitija National Park research on
seasonal radial
growth and meteorological observation has been conducted
since 1976. Measurements of a ground water level in
the bog between
lakes Žiegžmaris and Ešerinis since 1997
has been carried
out.
Main scientific results achieved in the Laboratory are recorded in the monograph by T. Bitvinskas (1974) "Dendroclimatological research", publications of Laboratory in 1978, 1981, 1984, 1987 and conferences: Vilnius (1971), Kaunas (1972), Vilnius - Leningrad (1975), Tbilisi (1976), Vilnius (1976), Archangelsk (1978), Vilnius - Palanga (1983), Irkutsk (1983, 1987), Tucson (1994), Glivica (1995), Moundon (1996), Savonlina (1997), Kaunas (1998), Malborg (1999), Gozd Martuljek (2001), Davos (2001), Obergurgl (2003), Kaunas (2003), Rendsburg (2004), Viterbo (2005), Riga (2007). Scientist from many countries has visited our Laboratory: the Czech republic, Estonia, India, USA, Kazakhstan, Poland, Russia, Finland and Germany.
Because our Laboratory of Dendroclimatochronology was a leader in
the former Soviet Union, Dendrochronological Data
Bank in 1980 was founded here. During a short time Bank
has accumulated
a huge amount of information on a tree rings from different
geographical
regions. Laboratory of dendrochronology was one of the organizers of
International Scientific Conference "Eurodendro - 98" on 17-21st
June 1998 in Kaunas.
Heads of the Dendrochronological Laboratory (1976-2003)