Ladislav Paule

Faculty of Forestry, Technical University, SKB96053 Zvolen, Slovakia

The forest land in Slovakia is about 1.94 million hectares, out of which 90% belongs to the Carpathians. In the Polish Carpathians, the forests cover about 480 000 ha, in the Ukrainian Carpathians about 1 500 000 ha and approximately 5 500 000 ha belong to the Carpathians mountain range in Romania. This means that the Carpathian forests cover about 9 million hectares in total.

The present distribution of trees in European forests has been influenced by several factors:

- the natural migration of tree species in the post-glacial period (different refugia and geographical conditions B mountain ranges B influence migration),

- long-lasting human activity before the period of modern forestry,

- a short period of modern forestry (in Europe about 100B200 years),

- the influence of human activities and human-caused processes during the period of industrialization.

 

 

The forest stand area of Slovakia covers in total 1 904 339 ha (Table 1). The proportion of Norway spruce is 27.5% and that of conifers is 43.1%. The most common broadleaved species in Slovakian forests (European beech) covers in total 29.8%. The present proportion of Norway spruce is higher than the original one. It is estimated (Han…inský 1972) that originally Norway spruce covered about 10% and during the last century it replaced the silver fir (e.g. 15% in 1920 and 5% at present).

Natural distribution of the Norway spruce forests in Slovakia is in altitudes between 600 m and the upper tree limit, which is usually in the altitudes of 1400-1500 m. The upper tree limit is usually created by the mixed Norway spruce and larch stands (e.g. the southern slopes of the High Tatras or Norway spruce with the admixture of rowan or stone pine). In all mountain ranges the Norway spruce creates the upper tree limit except in the Eastern Beskydes where in the Carpathian disjunction the Norway spruce is missing and the beech reaches the highest altitudes.

Indigenous occurrence of the Norway spruce populations is in all mountain ranges of central and northern Slovakia. It is missing in the Little Carpathians and Štiavnické vrchy and in eastern Slovakia. In eastern Slovakia the Norway spruce's natural range is disrupted by the Carpathian disjunction, i.e. from Košice toward the Ukrainian border and further into CarpathoBUkraine a 200-km zone is without spruce. From the northern side of the Carpathians, the limit of natural occurrence of Norway spruce reaches Tarnawa, i.e. more or less the border of Slovakia.

One of the classifications of forest vegetation cover was elaborated on by Prof. A. Zlatník who, on the basis of an intensive investigation of the Carpathian forests in Slovakia and in Carpatho-Ukraine, described the natural character of forest cover in eight vegetation levels, which could be defined as the climax geobiocenoses which are conditioned by certain geography, macro- and mesoclimate in given altitudes. The forest vegetation zones are usually named according to prevailing tree species and correspond with the first five altitudinal geographic zones usually applied in geobotany (planar, colline, submontane, montane, oreal, subalpine, alpine and nival):

- Oak forest vegetation zone

- Oak-beech forest vegetation zone

- Beech-oak forest vegetation zone

- Beech forest vegetation zone

- Beech-fir forest vegetation zone

- Beech-fir-spruce forest vegetation zone

- Spruce forest vegetation zone

- Mountain pine forest vegetation zone.

 

The principal characteristics of forest vegetation levels are as follows (Table 2):

- increasing intensity of solar radiation

- decreasing temperature (for each 100 m, 0.54EC)

- increasing number of frost days

- increasing difference between air and soil temperatures

- decreasing vegetation period

- increasing precipitation total (but only up to a certain altitude over the upper vegetation limit)

- increasing proportion of snow precipitation

- increasing number of foggy days

- increasing evaporation

- rapidly decreasing air humidity with temperature decrease.

The ecological characteristics of the forest vegetation zones are given in the paper of Van…ura (this volume). The natural range of Norway spruce covers the following forest vegetation zones: beechBfir, beechBfirBspruce and spruce forest vegetation zone. In the first two forest vegetation zones, the occurrence of mixed forests is prevalent (broadleaves with spruce admixture or spruce with silver fir admixture), while in the last forest vegetation zone the pure spruce forests prevail.

In Table 3 is shown the proportion of the individual stand formation of spruce forests and mixed forests with spruce: spruce-silver firBbeech and silver fir-beech according to individual forest vegetation belts. From this table it is clear that the proportion of the spruce forests within the beechBfir, beechBfirBspruce and spruce forest vegetation belts could be considered as more or less natural. The occurrence of Norway spruce in the 1st to 4th vegetation belts is not natural and partially also that within the beechBfir and beechBfirBspruce forest vegetation belts could be considered as the replacements of silver fir in the mixed stands.

Table 3. Proportion (%) of individual forest formations (types) in forest vegetation belts

In the forest practices of Slovakia there are several methods of genepool conservation in situ and ex situ.

1. National parks and largeBscale protected areas

2. Gene reserves (bases)

3. Approved stands for seed procurement (A and B category).

 

1. Reproduction plantations ex situ

2. Genebanks (seed)

3. Clonal archives

4. Seed orchards

5. Experimental trials.

 

The first regulation aimed at the seed procurement only from approved stands originated in the territory of Slovakia in 1938 and in the Czech Republic in 1939. In the sense of this law, the seed of conifers (Norway spruce, silver fir, Scots pine and European larch) could be procured only in approved forest stands of A and B category and seed transfer was allowed only within silvicultural zones. The silvicultural zones were defined according to their geographical distribution and the length of the vegetation period:

- subalpine regions with the vegetation period shorter than 100 days,

- mountains with cooler climate with the vegetation period 100-129 days,

- mountains with mild climate and vegetation period 130-165 days,

- lowlands and hills with plain climate and vegetation period longer than 165 days.

 

Subsequently, this regulation was renewed in 1965 and since 1985 and 1988 there are new regulations valid for the Slovak and Czech Republics. It has to be noted that these two different regulations for both republics of former Czechoslovakia were necessary due to different ecological conditions and history of the forest stands.

Following these regulations there are two different categories of approved stands, A and B, and a new term was introduced for the territory of SlovakiaC`seed zone'. The seed zone is defined as the zone with similar conditions within which seed transfer is allowed. Exceptionally, seed transfer is allowed between individual zones (as stated in the regulation).

For Norway spruce there are seven seed zones in Slovakia (Fig. 1), five of which are within the natural range and two are outside the natural range. Vertical transfer of seed is allowed for altitudes up to 1200 " 200 m and over 1200 " 100 m in the Tatra seed zone and in other zones over 1200 " 150 m from the altitude of forest stands.

It has to be noted that there are two seed zones into which it is prohibited to import seed: the Tatra seed zone (Tatra National Park) and the Beskydy-Orava seed zone which is adjacent to the Polish Beskydes (Istebna and Rycerka) and also to the Moravian Beskydes.

At present there are in total 6075.25 ha of approved Norway spruce stands of the A category and 16 328.81 ha of stands of the B category, selected 345 phenotypically superior plus trees (in total 3171) and established 4.50 ha of clonal seed orchards and 2 ha of seedling seed orchard (Stará Lesná) (in total 202.82 ha of seed orchards of all species). The highest proportion of the Norway spruce approved stands is in Northern Slovakia (2958 ha of A category and 7907 ha of B category) and in Central Slovakia (1668 ha or 2887, respectively), while in the Tatra National Park alone there are 722 ha of the approved stands of the A category and 1554 ha of stands of the B category.

The gene reserves (bases) are, in the forestry practice of Slovakia, a new item aimed at genepool conservation in situ. The gene bases are in general units of the gene conservation practices established in the regions of the most valuable genepool and the size is usually several hundreds of hectares (200-2000 ha). In comparison, the size of approved stands is equal to the size of a stand as a forest management unit, which is usually a maximum of 10-15 ha. The gene bases usually include the forest stands of different age classes with the aim to maintain the dynamic aspect of genepool conservation. From the forest management point of view, the gene bases are forest stands with a special management regime, in which natural regeneration is the principal method of regeneration allowed (the artificial regeneration with plants originating from the local seed sources is allowed). At present 44 gene bases are established in Slovakia (in total 12 673 ha) of which 3154.46 ha are declared to conserve the genepool of Norway spruce. From those seed orchards should be mentioned those which are aimed at the gene conservation of Beskydy spruce (region adjacent to Polish Beskydes), those in the High Tatras and in the Low Tatras.

Seed stands are special units established mainly for genepool conservation in situ or ex situ for the purposes of conservation and future procurement of seed. In general the seed stands are progenies (from natural regeneration or artificial regeneration as open-pollinated progenies) of the approved stands of A category.

In total 127 seed stands are established in Slovakia (not identical with seed stand according to the OECD/EEC regulations) with the area of 635.5 ha and of this number 37 seed stands of 196.5 ha are established for Norway spruce. Forty percent of Norway spruce seed stands are established ex situ and 60% in situ. From those established in situ 40% again originate from natural regeneration and the remaining 60% originate from artificial regeneration.

In Slovakia there are in total seven provenance trials (12 to 49 provenances) established from the material of the IUFRO 1964/68 Norway spruce Inventory Provenance Experiment (Holub…ík 1980) and four provenance trials being part of the IUFRO 1972 provenance experiment with Polish Norway spruce provenances. There exist only single-progeny tests with 42 open-pollinated progenies of a single stand from the Tatra National Park (considered also as a seedling seed orchard).

In the seed bank established in Liptovský Hrádok there are in total 75 seedlots with Norway spruce (363.5 kg). They are stored with the aim to cover the seed needs in the period of lower crops as well as for scientific and genepool conservation purposes. In Slovakia all seed used in forestry practice has to originate from approved stands only. Each seedlot has a 10-digit code which should be maintained also in the nurseries and planting stock. In the Semenoles, Liptovský Hrádok, there are at present 332 units (8996.65 kg) of Norway spruce seed from approved stands. At present, there are no pollen and tissue banks established in Slovakia.

There are in Slovakia in total 292 state nature reserves and 74 protected sites with the total area of 79 415 ha. The proportion of Norway spruce in the state nature reserves is 37.74% and in protected sites 20.64%; almost 48% of all state nature reserves are found in the spruce-fir-beech and spruce forest vegetation zone (Vološ…uk 1993). In contrast to many neighbouring countries there are in Slovakia several remnants of spruce or mixed virgin forests with spruce occurrence. The best known of them are Pod Chlebom (222.77 ha) and Rozsutec (650 ha) in the Little Fatra, „ierny KameÁ (34.40 ha) in the Great Fatra, Babia Hora (530.33 ha) and Pilsko (580 ha) in the West Beskydes and Kotlov đµab (46.94 ha), and Podbanské (1800 ha) in the High Tatras (Korpeµ 1995).

Several factors affect negatively the genetic resources of Norway spruce in Slovakia: air pollution, game grazing, abiotic damages (e.g. drought) and subsequent biotic damages (e.g. bark beetle), and improper forest management practices not supporting natural regeneration.

High-elevation Norway spruce populations are usually damaged by air pollution. Most affected are the populations in the Beskydes and the High Tatras on the western to northern slopes facing Ostrava and Katowice industrial regions from which the longBdistance transported pollutants are the main damage factor. Also other air pollution sources are negatively influencing the health state of Norway spruce populations in the Spiš region and the Low Tatras. Along with the decreased vitality and damage of the assimilatory organs the air pollution affects the regeneration processes and decreases flowering intensity and seed production.

Browsing by excess populations of larger ungulates (red deer) is the main factor negatively influencing natural regeneration and the healthy state of middle-aged Norway spruce stands. The worst situation is when the combination of several damage factors (air pollution, insects, deer) occurs.

The negative impact of forest management practices (higher proportion of the artificial regeneration, improper seed transfer, simplification of forest management practices (e.g. replacement of mixed stands by oneBspecies spruce stands, etc.) is also known from the territory of Slovakia and owing to these activities the high proportion of very valuable indigenous Norway spruce stands disappeared.

At present there is not very much information about the genetic diversity of economically important tree species in the Carpathians. However, there are tree species in which the genetic structures and genetic diversities have been systematically investigated, also in the Carpathians, during the last decade. Among these species are the Norway spruce, silver fir (Abies alba) and European beech (Fagus sylvatica). Rather scarce information is available on the genetic structure and diversity of other economically valuable tree species (e.g. oaks, European larch, Scots pine, etc.).

In the abovementioned tree species, research has been predominantly on the geographic variation of allelic frequencies in natural populations, with an aim to understanding the differences between individual regions and/or populations and to understand the migration of individual tree species from the different post-glacial refugia or selection processes. Three examples of intensive investigation of genetic diversity and differentiation in which our team has participated can be given.

The first investigation of the genetic structure of Norway spruce populations from Slovakia was done by Paule et al. (1990). They investigated the genetic structure of adjacent populations and found insufficient genetic differences between adjacent populations but in some cases also between the more distant populations.

The investigation of the geographic variation of Norway spruce in Eastern Europe, including the Carpathians, was done by Bergmann and Gömöry (in preparation) and another investigation of the differences between the Norway spruce virgin forest and naturally and artificially regenerated Norway spruce forest stands was done by Gömöry (1992). Results of this investigation give insight into the structure of the natural Norway spruce forests of Slovakia and show that naturally regenerated forest stands do not significantly deviate from the natural forest of virgin character. Significant deviations could be expected only in the case of artificially regenerated forest stands in which significant narrowing of the genetic diversity could also occur (Gömöry 1992).

The practical gene conservation in Slovakia is carried out in the Forest Research Institute, Zvolen, Research Station Liptovský Hrádok, where the central register of approved stands, seed stands and gene bases is localized. Experts from this research station (Hoffmann, Piovar…i and earlier also Chudík) are responsible for approval of forest stands for seed procurement and also of the approval of genebases (reserves). The coworkers of the Faculty of Forestry of the Technical University in Zvolen (Paule, Gömöry) are involved mainly in basic population genetic research.

The public awareness of the importance of forest genetic resources has been reflected in the updating of laws on the approval of forest stands (1985) and gene reserves (1991) as well as in the preparation of the Law on Plant Varieties which is prepared for approval in the Parliament. This is the first time in the legislation of this country that the Law on Plant Varieties (common with agricultural crops) will be a part of the legislation. It will be compatible with EC and OECD rules.

The next updating of law regulations is under discussion and has considered recent ownership changes in Slovakia.

Reconstruction of the forest seed bank in Liptovský Hrádok is planned for the near future. It will be aimed not only at the technical reconstruction and replacement but also the new regulation on the content (the selection of samples and their quantities) of the Seed Bank will be updated.

The topics of gene conservation are permanently a part of the research programme of the Forestry Research Institute in Zvolen and their research stations in Liptovský Hrádok and Banská Štiavnica. In Liptovský Hrádok there is also a central database on gene resources (approved stands, genebases, seed stands and seed orchards). A part of this research station is Seed Control, an organ of the Ministry of Agriculture which aims to control the forest seed procurement and business in Slovakia.

There are several urgent needs for the conservation of the Norway spruce genepool in Slovakia. Among them, there is the danger of air pollution in several regions with very valuable Norway spruce populations (e.g. Spiš and Beskydy), the grazing by ungulates (e.g. red deer) and the simplification of forest management activities (e.g. replacement of mixed forest by Norway spruce monocultures).

Last but not least there is danger from forest owners themselves. Within the reprivatization process of the Slovak forests the highest proportion of small private forest owners is in the region of the best Norway spruce populations of the Beskydy ecotype of Norway spruce, i.e. Orava and Kysuce.

Gömöry, D. 1992. Effect of stand origin on the genetic diversity of Norway spruce (Picea abies Karst.) populations. Forest Ecol. Manage. 54:215B223.

Han…insky, L. 1972. Lesne typy Slovenska. Priroda, Bratislava.

Holub…ík, M. 1980. [Provenance research of Norway spruce (Picea abies Karst.) in Slovakia]. Lesnícke Stúdie 33:1B95.

Korpeµ, Š. 1995. Die Urwälder der Westkarpaten. Gustav Fischer Verlag, Stuttgart, 305 pp.

Paule, L., A.E. Szmidt and R. Yazdani. 1990, Isozyme polymorphism of Norway spruce (Picea abies Karst.) populations in Slovakia. I. Genetic structure of adjacent populations. Acta Facultatis Foresatalis, Zvolen 32:57-70.

Vološ…uk, I. 1993. The virgin forests and reserves in Slovakia. Pp. 69-74 in European Forest Reserves Workshop. Pudoc Publ., Wageningen.

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