The last 90 years of forestry operations resulted in substantial changes in the structure of forest habitats in the BF managed part. The major influences can be summarised as follows:
- appearance of new habitats – clearcuts and newly created plantations, as they differ qualitatively from treefall gaps in the primeval part (Fuller 2000);
- rejuvenation – the share of young stands has increased from about 20% in primeval forest to almost 70% (Fig. 1);
- ”borealisation” – replanting of formerly deciduous sites with conifers has resulted in a 2/3 reduction of the area occupied by the former oak-hornbeam stands and almost doubling of the conifer-covered by conifers (Fig. 1);
- unification of spatial structure - replacement of fine grained mosaic of diversified species/age tree groups by larger patches of even-aged monocultures (Bobiec et al. 2000)
- reduction of the amount of dead wood/fallen trees due to ”sanitary cuttings” – in the managed oak-hornbeam forest a five-fold reduction in the number of large dead trees (Walankiewicz et al. 2002) and almost hundredfold reduction of the dead wood volume (Bobiec 2002) were recorded;
- insularisation of once continuous old-growth forests – especially pronounced in the deciduous forest, the remaining patches become more and more isolated, the BNP becomes an “island” surrounded by young plantations (Fig. 2).
Fig. 1. Age structure and tree species composition of woods in the primeval (strictly protected part of BNP) and managed parts of the Bia³owie¿a Forest in the early 1990ties (from the Forest Management and Inventory Plans - Anonymous 1995 and unpubl - Tomia³ojæ & Weso³owski, in press). Areas covered with tree-stands younger than 80 years (light hatched) are of secondary origin. For each age its upper age limit is shown. Before large-scale commercial logging started in 1915, the tree species composition and age structure had not differed between the two parts. Nowadays, over two thirds of former oak-hornbeam old-growth has been replaced by coniferous plantations. The area covered by the old-growth stands has dropped to 25%.
Fig. 2. Distribution of the old-growth (>100 years old) stands of natural origin in the Bia³owie¿a Forest. After Gutowski et al. 2000.
Fig. 3. Distribution of White-backed Woodpecker Dendrocopos leucotos in the Polish part of the Bia³owie¿a Forest. Thick dotted line – state border with Belarus. The grid of thin lines shows the division of the forest into one verst (c. 1066 x 1066 m) compartments; black squares – forest sub-compartments in which woodpeckers were recorded. After Weso³owski (1995).
Impact on birds – specialised species dependent on resources abundant only in the old-growth forest – e.g. secondary hole nesters and some woodpeckers are in most difficult situation (Tomia³ojæ & Weso³owski, in press). Though these species could breed in various types of primeval forest, yet they are not versatile enough to accept habitats created by forestry operations. The distribution and numbers of White-backed Woodpecker Dendrocopos leucotos (Appendix II species, Bern Convention) a species dependent on dead deciduous wood, has been severely restricted in the managed part. Its distribution there is very patchy (Fig. 3), and the species is largely absent even from the oak-hornbeam stands (a habitat regularly occupied in the strictly protected part of BNP). It is estimated that its numbers in the managed part is only 25-33% of the pre-management level (Weso³owski 1995). Similarly, the current presence of Three-toed Woodpecker Picoides tridactylus (Appendix II species, Bern Convention), a species dependent on dying and dead spruces is strongly reduced outside the strictly protected part of BNP, to 15-20% of the pre-management level (Weso³owski et al. in prep). There are no quantitative data on secondary hole nesters, but removal of almost three quarters of the old-growth stands (see above) could not have any detrimental impact on their numbers and distribution. All these specialists are critically dependent on the retention of the remnants of old-growth stands, but these are exactly the fragments on which logging operations are concentrated. If their removal is not prevented, these species will vanish form the managed part, and only some vestige pairs, with no prospects for a long-term survival, would remain exclusively in the strictly protected part of the BNP (Weso³owski 1995, Weso³owski et al. in press, Tomia³ojæ & Weso³owski in press)
Sources
Anonymous. (1995): Raport o stanie Puszczy Bia³owieskiej. Regionalna Dyrekcja Lasów Pañstwowych, Bia³ystok.
Fuller, R.J. (2000): Influence of treefall gaps on distributions of breeding birds within interior old-growth stands in Bia³owie¿a forest, Poland. Condor 102: 267–274.
Bobiec, A., van der Burgt, H., Meijer, K. & Zuyderduyn, C. (2000): Rich deciduous forests in Bia³owie¿a as a dynamic mosaic of developmental phases: premises for nature conservation and restoration management. Forest Ecology and Management 130: 159–175.
Bobiec, A. (2002): Living stands and dead wood in the Bia³owie¿a Forest: Suggestions for restoration management. Forest Ecology and Management 165: 121–136.
Gutowski J., Jêdrzejewski W., Bobiec A., Faliñski J. B., Oko³ów Cz., Popiel J., Jêdrzejewska B., Brzeziecki B., Korczyk A. 2000. Principles of the Bia³owie¿a National Park functioning after its extension onto the entire Polish side of the Bia³owie¿a Primeval Forest (proposition). [In Polish, with English summary]. Zasady funkcjonowania Bia³oweiskeigo parku narodowego powiêkszonego na ca³y obszar polskiej czêœci Puszczy Bia³owieksiej - propozycja. Bia³owie¿a, Bia³owieski Park Narodowy.
Tomia³ojæ l., Weso³owski T. In press. Where the East and West meet: Diversity of the Bia³owie¿a Forest avifauna in space and time. Journal f. Ornithologie
Walankiewicz, W., Czeszczewik, D., Mitrus, C. & Bida, E. (2002): Snag importance for woodpeckers in deciduous stands of the Bia³owie¿a Forest. Notatki Ornitologiczne 43: 61–71. [In Polish, with English summary]
Weso³owski, T. 1995. Value of Bia³owie¿a Forest for the conservation of white-backed woodpecker (Dendrocopos leucotos) in Poland. Biological Conservation 71: 69–75.
Weso³owski, T., Czeszczewik, D., Mitrus, C. & Rowiñski, P. (In press). Birds of the Bia³owie¿a National Park. Notatki Ornitologiczne. [In Polish, with English summary].
Officially reported logging rates stayed within 97-133 thousands m3 during this period. (Fig. 1). Totally 1.7 mln m3, were removed from the forest in 1989-2002, and almost 600 000 m3 in the last five years (1998-2002). To these figures one should add volume of illegally logged trees. There are no accurate estimates of this black(grey) exploitation, but according to some estimates there could amount to even 25 thousands m3/year.
No influence of conservation measures on exploitation rates is discernible. Neither establishment of the Promotional Complex in 1994, nor transfer of 5000 ha from the managed forest to the Bia³owie¿a National Park in 1996, nor introduction of a moratorium on cutting in the old-growth patches in 1998 has had any effect on cutting rates. Especially striking is the fact, the diminishing area available for logging by 5000 ha has not resulted in any decline of the volume of timber extracted. The declines visible in the graph stem from diminishing market demand on timber during the years of economic crisis and not from restrictions put by conservation measures. This picture clearly demonstrates that so far the forestry administration manages to overcome all the limitations and logging continues unabated.
Fig. 1 Exploitation rates - volume of marketable timber sold by three Bia³owie¿a Forests superintendencies (Bia³owie¿a, Browsk, Hajnówka) in the years 1990-2001. Following the Forestry Administration statistics
Fig. 2. Share of deciduous trees in volume of big timber extracted by three Bia³owie¿a Forests superintendencies (Bia³owie¿a, Browsk, Hajnówka) in the years 1997-2001 and proportion of deciduous stands in the managed part of the Forest. Following the Forestry Administartion statistics.
Despite restrictions, large deciduous trees are used out of proportion. Though, the deciduous stands of all types cover currently only 47% of the area under forestry administration, they constitute from 51 to 74% of timber extracted. Only in the bark beetle (Ips typographus) outbreak years (e.g. 2001) proportion of deciduous logs taken declines. Such pattern of exploitation denotes, that the types of forest to be especially protected under the Bern Convention - oak-hornbeam and riverine forests (originally occupying >75% of the Forest area), instead of being protected are actually very heavily (out of proportion) utilised.
The forestry plans currently being prepared for the management of the logged part of the Bia³owie¿a Forest in the next 20 years seriously fail to provide for adequate protection of the forest in the following ways:
- the now existing moratorium on cutting of largest trees is to be lifted
- removal of dying trees and dead wood (pest control, sanitary cuttings) is to be continued
- logging in old-growth stands are to be continued at the current rate
- habitats to be protected under Bern Conventions: oak-hornbeam and riverine stands, are to be intensively exploited
3A. Resolution of the Scientific Council of the Bia³owie¿a National Park (Rada Naukowa BPN) - January 12, 1995.
3B. Resolution of the Nature Protection Committee of the Polish Academy of Science (Komitet Ochrony Przyrody PAN) - January 13, 1995.
3C. Opinion of the State Council of Nature Protection (Pañstwowa Rada Ochrony Przyrody) - January 13, 1995
3D. Position of the Scientific Committee „Man and Environment” of the Polish Academy of Sciences (Komitet Naukowy „Cz³owiek i ¦rodowisko”przy Prezydium PAN) - February 22, 1995.
3E. Resolution of the General Assembly of the Polish Academy of Science (Zgromadzenie Ogólne Polskiej Akademii Nauk) - May 19,1995.
All these documents unanimously conclude that the whole area of Bia³owie¿a Forest should be protected as a national park