Living stands and dead wood in the Bialowieza forest: suggestions for restoration management

The Bialowieza Primeval Forest (BPF) is the only forest area in temperate Europe where forest communities have developed a natural stand structure and a natural distribution of coarse woody debris ((CWD) = standing dead trees (SDT) + down woody material (DWM)). Stand and dead wood characteristics are influenced by ancient and recent historical factors and current processes, such as fires, competitive exclusion, storms, insect outbreaks, and forest management. The aim of the present study was to relate CWD to stand characteristics in mesic deciduous forest (Tilio-Carpinetum JQ) and riparian forest (Circaeo-Alnetum (CA)). Direct comparison of managed forest to protected forest provides information about the impact of the forestry practices on TC stand and CWD characteristics. Approximately two-fold larger volume of trees was found in the Bialowieza National Park (BNP) TC stands (from 336 to 555 m(3) ha(-1)) than in the commercial forest ((CF), from 239 to 279 m(3) ha(-1)). Irregular distribution of "legacy trees" (DBH > 90 cm) accounted for most of the variability among the TC BNP stands. Even stronger differences within TC stands were revealed among the various developmental phases (from 147 m(3) ha(-1) in degradation phase to 630 m(3) ha(-1) in biostatic-optimal phase). Difference in rate of stand development was responsible for the variability of tree volume within CA (338 m3 ha-1 in early succession stand versus 634 m(3) ha(-1) in close-to-climax stand). CWD (mostly DWM) contributed about one-quarter of the total above ground wood biomass in BNP TC and CA ecosystems, ranging from 87 to 160 m(3) ha(-1). Higher relative abundance of spruce in DWM than in living stand volume and more spruce in old debris than in fresh debris suggests that the end of the spruce mortality wave was imminent. As a consequence, structural and dynamic changes in favour of smaller regeneration units are expected. A mere vestige of CWD was found in the CF ecosystem. Both stand and CWD data show a negative impact of former management on the forest ecosystems. In conclusion, special measures aimed at the restoration of ecological capacity of forest communities, including legacy retention and management for decadence, have been recommended. There is an urgent need for complementary studies to supply information necessary for successful adaptive management of the Bialowieza Primeval Forest. (C) 2002 Elsevier Science B.V. All rights reserved.