Epsilon Archive for Student Projects

Abstract

Mortality patterns were assessed in an old growth beech stand in southern Sweden. A
previous inventory of 1200 trees in 1996 was used as a base for an inventory in 2006.
Mann-Whitney U test was used to compare statistical distribution between living and
dead trees of those inventoried in 2006. Dendrochronological reconstruction was
applied for assessment of the temporal patterns of mortality. The mortality rate was
18% in ten years, affecting mainly larger diameter classes >40cm dbh. During the
study period, 6.9 % of the total amounts of living trees became high stumps, from
which 45% subsequently died. In understory trees, growth reactions and scars related
to tree falls and canopy damage increased by over 80 % between the 1970’s and the
1990’s, suggesting an increasing disturbance rate over this period. The causes of death
could not be attributed to disturbances by themselves, but rather to a combination of
fungal infection (mainly Fomes fomentarius) and wind in most cases. The mortality
level found in this beech population is rather high compared to other studies in
European deciduous forest. Since the age of the stand is near the reported maximum
of the species, mortality is likely to be high in the future. Damaged beech trees that
survive a long time (over ten years) provide unique substrate for species assemblages,
constituting a desirable feature for conservation.