European beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.) rotation in the Carpathians—A developmental cycle or a linear trend induced by man?

Forest Ecology and Management 258 (2009) 347–356

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European beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.) rotation in the Carpathians—A developmental cycle or a linear trend induced by man? Toma´sˇ Vrsˇka a,*, Dusˇan Adam a, Libor Hort a, Toma´sˇ Kola´rˇ b, David Janı´k a a b

Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Department of Forest Ecology, Lidicka´ 25/27, 602 00 Brno, Czech Republic Mendel’s Agricultural and Forestry University in Brno, Department of Forest Botany, Dendrology and Geobiocenology, Zemeˇdeˇlska´ 3, 613 00 Brno, Czech Republic

A R T I C L E I N F O

A B S T R A C T

Article history: Received 30 April 2008 Received in revised form 22 February 2009 Accepted 2 March 2009

A detailed historical survey was made to assess the impact of humans on fir–beech forests in the northern Carpathians. Research findings are compared with results from repeated tree layer measurements in eight of the most well-preserved reserves of fir–beech stands in the region. Documentary evidence is provided showing that the historical and contemporary spontaneous development of fir–beech stands throughout the northern Carpathians is identical. The replacement of beech by fir occurred predominantly in the period from the 15–18th centuries, primarily due to grazing and litter raking. Starting in the 19th century, fir was replaced predominantly by beech under the influence of changing social conditions, since the dieback of the ‘‘grazing’’ fir generation had not yet been completed. Air pollution damage and other factors in the fir dieback were only secondary accelerating phenomena. These changes of tree species cannot be interpreted as the natural rotation of two beech generations within the life cycle of one fir generation, as has been the previous explanation. The development is rather a linear trend induced by man, which has occurred simultaneously throughout the northern Carpathians. The current dynamics of spontaneous development are affected by the high stock of hoofed game and by the absence or reduced numbers of predators. ß 2009 Elsevier B.V. All rights reserved.

Keywords: Fagus sylvatica Abies alba Natural forest Development cycle Carpathians

1. Introduction The dynamics of European natural temperate forests have been systematically studied since the 1930s (Zlatnı´k, 1934, 1935). The first ideas concerning the cyclical development of forests published by Watt (1947) focused on the theory of biomass increase and loss. During the 1950s and 1960s, a large amount of data gathered from research plots in natural forest reserves in Switzerland, Slovenia, Bosnia and Herzegovina, Austria, Czechia, Slovakia, Poland and Germany made it possible to formulate the first theories on the cyclic development of European natural temperate forests (Korpel’, 1958; Leibundgut, 1959; Zukrigl et al., 1963). The development of mixed temperate forests was defined as a more-or-less closed cycle in which the rotation of tree generations occurs on the mosaic of small-scale (ca. up to 0.20 ha) disturbances. Very occasionally, this development might deviate towards regeneration in the form of great disturbances of ‘‘boreal’’ size, e.g. after a windstorm; however, it then returns to the small-scale rotation of tree generation by gradual succession. This

* Corresponding author. Tel.: +420 541 126 263; fax: +420 541 246 001. E-mail address: [email protected] (T. Vrsˇka). 0378-1127/$ – see front matter ß 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.foreco.2009.03.007

cyclical development was first characterized in individual stages (Leibundgut, 1959, 1978; Zukrigl et al., 1963; Mayer et al., 1987). Based on long-term research, the development cycle was later defined in three stages – growth, optimum and disintegration (decline) – with various phases predominating during respective stages depending on site conditions and disturbance type (Korpel’, 1995). Most research in Central and Eastern Europe has been focused on the fir–beech vegetation zone, i.e. at lower and intermediate mountain elevations, where a number of nature reserves exist which are relatively little affected by humans (Pru˚sˇa, 1985; Mayer et al., 1987; Leibundgut, 1993; Korpel’, 1995; Diaci, 1999). On the European scale, the most significant region within the fir–beech zone is the mountain massif of the Carpathians, with the most extensive stretches of natural forests in the European temperate zone (Commarmot and Hamor, 2005), and with many research facilities conducting long-term research (Leibundgut, 1993; Korpel’, 1995; Vrsˇka, 1998; Vrsˇka et al., 2000, 2001; Jaworski et al., 2002; Podlaski, 2004; Paluch, 2005, 2007). Long-term data series on Carpathian fir–beech stands led to a precise theory on the periodical rotation of tree species in the fir– beech zone: there are two generations of European beech (Fagus sylvatica), each of about 200–250 years, that develop within the

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Fig. 1. Location of the study area and research sites.

sub-level of one silver fir (Abies alba) generation (ca. 400–450 years). The fir repeatedly regenerates in the understory of the second beech generation, all this taking place on a small-scale mosaic (Korpel’ and Saniga, 1993; Korpel’, 1995; Saniga, 1999a,b). This cyclical development theory and its specificity to the fir– beech zone followed from the assumption that today’s natural forest reserves were subject to minimum human impact in the past—with tolerance being given to patch felling of individual trees, charcoal production in the vicinity of some reserves only exceptionally, and possibly the local impact of grazing on adjacent pasturelands (Korpel’, 1967; Korpel’ and Saniga, 1993; Korpel’, 1995; Podlaski, 2004). The possible long-term and intensive human impact on these reserves in the Carpathians has never been taken into account. At the same time, the anthropogenic influence on changes in the representation of fir and beech at lower and midmountain elevations has been documented in other parts of Europe (e.g. Ma´lek, 1971, 1981; Motta and Garbarino, 2003). In studying the developmental dynamics of Carpathian fir– beech forests, many authors have already noted the decreasing share of fir in research plots and the replacement of fir by beech. However, all these authors built their hypotheses on the deeprooted paradigm that existing fir–beech reserves in the northern Carpathians were relatively little affected by humans, and that former anthropogenic activities had no impact on current developmental dynamics. The objectives of their studies were varied, including the examination of spatial patterns between fir and beech (Paluch, 2006, 2007), a more precise description of the cyclical development definition (Podlaski, 2004), the study of relations between live and dead wood (Saniga and Schu¨tz, 2002), an evaluation of changes in the stand structure (Jaworski et al., 2002), and relations between the tree layer, herb layer and soil environment (Vrsˇka, 1998; Vrsˇka et al., 2000, 2001). In this paper, repeated surveys performed from 1994 to 2007 in the Carpathian fir–beech reserves situated in the Czech Republic and Ukraine are used to study the issue of fir–beech dynamics with respect to the long-term decline in silver fir. The paper has four basic objectives: (i) to investigate and evaluate the historical

human impact on natural forests in the Northern Carpathians (focusing on the most well-preserved natural forest reserves), (ii) to analyze and compare the spontaneous development of these natural forest reserves, (iii) to answer the question of whether the rotation of beech and fir is actually a cyclical rotation as suggested by contemporary theories, and (iv) to consider the question of silver fir’s future in strictly protected forest reserves. 2. Materials and methods 2.1. Natural conditions The sizeable massif of the Carpathian Arch is the dominant mountain range of Eastern Europe (Fig. 1), its length stretching across the territories of six countries—the Czech Republic, Slovakia, Poland, Hungary, Ukraine and Romania. The Carpathians form a part of the Central- and East-European region of mixed broadleaved-coniferous forests (Otto, 1994), and the dominant forest communities are beech- and fir–beech (Mı´chal, 1968; Korpel’, 1995; Kusbach, 2002). In the northern half of the Carpathian Arch, the fir–beech forest zone occurs at a considerable range of elevations, from 600 m a.s.l. in the western part of the Arch (Razula) up to 1250 m a.s.l. on the southern slopes of the eastern Carpathians (Pop Ivan) (Table 1). These fir–beech forests occur on varied geological bedrocks: (i) on flysh formed of Godulian Upper Cretaceous sandstones typical of the western section (Razula, Salajka, Mionsˇı´) (Pru˚sˇa, 1985); (ii) on tufas and andesites (Badı´n) alternating in the central part with granodiorites and quartz diorite (Dobrocˇ) (Korpel’, 1995); (iii) on gneisses and phylites (Pop Ivan) typical of the eastern section. Soil environments are very diverse as well—with typical mesotrophic cambisols predominant (Korpel’, 1995; Vrsˇka, 1998; Vrsˇka et al., 2000, 2001). Mean annual temperatures range from 5 to 6 8C at lower altitudes in the western section (Anonymous, 1960; Kusbach, 2002) up to 4–5 8C at higher altitudes (Korpel’, 1995). Mean annual total precipitation amounts are highest in the western section, ranging from 1050 to 1370 mm (Razula, Salajka, Mionsˇı´) (Anonymous, 1960; Kusbach,

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Table 1 Characteristics of individual localities. Locality

Country

Latitude

Longitude

Area fully measured (ha)

Years of measurement

Altitudinal range (m a.s.l.)

Data source

Razula Salajka Mionsˇı´ Badı´n Dobrocˇ Stuzˇica ‘‘V’’ Stuzˇica ‘‘VI’’ Pop Ivan

CZ CZ CZ SK SK SK SK UA

498210 3000 N 498240 0000 N 498320 0000 N 488410 0000 N 488410 0000 N 498050 0000 N 498050 0000 N 478570 3000 N

188230 0000 E 188250 2000 E 188390 3000 E 198020 3000 E 198410 3000 E 228370 3000 E 228370 3000 E 248180 0000 E

22.84 19.03 2.54 24.60 49.88 0.50 0.50 3.57

1972, 1974, 1957, 1957, 1978, 1971, 1971, 1934,

600–812 715–820 778–844 700–850 700–1000 800–1000 800–1000 1153–1258

Own data Own data Own data, Duda (2004) Korpel’ (1995); Saniga (1999b) Saniga (1999a) Korpel’ (1995) Korpel’ (1995) Own data

2002), slightly decrease in the central section to 850–960 mm (Badı´n, Dobrocˇ), and again slightly rise in the eastern part up to 850–1000 mm (Stuzˇica) (Korpel’, 1995). 2.2. Study sites, and data collection and processing This study focused on an assessment of the most well-preserved fir–beech reserves in the northern half of the Carpathian Arch, in which long-term measurements of the tree layer have been conducted (Table 1). All areas included in this study are currently strictly protected forest reserves left to spontaneous development (Table 1), and do not have any management measures focused on tree species selection or planting. In order to make precise assessments of the current developmental dynamics of Carpathian fir–beech forests, our team repeatedly conducted detailed measurements in three localities in the Czech Republic (Mionsˇı´, Razula, Salajka) (Vrsˇka, 1998; Vrsˇka et al., 2000, 2001; Duda, 2004) and in one Ukrainian locality (Pop Ivan). Data on the evolution of localities in Slovakia were taken from the published literature (Korpel’, 1995; Saniga, 1999a,b). Surveyed sites were subject to repeated measurements of standing and lying, live and dead trees reaching a diameter at breast height (DBH) of 10 cm, the whole-area regeneration of tree species (tree height from 0.1 m), and topographic objects. Parameters recorded for standing trees were: species, DBH, height, stem character (live, dead, twin stem, etc.). Parameters recorded for lying stems were: species, DBH, length of the lying segment, character of the lying segment (whole stem, stem fragment). Lying branches were not included. Each tree was allocated an identification number to enable repeated identification. In this way, the tree life cycle (and individual parts of the life cycle) could be monitored from the time it attained the minimum DBH until decomposition. These repeated measurements were carried out with the use of the FieldMap computer-aided data collection tool (http://www.fieldmap.cz). The measured data then served for the construction of tree maps on a scale of 1:1000 (Vrsˇka, 1998; Vrsˇka et al., 2001; Duda, 2004). Using the tree maps, we conducted subsequent repeated surveys in the reserves (Table 1). Stem volumes were determined from volume tables of tree species (Anonymous, 1952) according to DBH and fitted height. Basal area, height curves, stem volumes and tabular synthesis were calculated with PraleStat software (http://www.pralestat.wz.cz). In the Ukrainian locality Pop Ivan, measurements made in 1934 (Zlatnı´k et al., 1938) were repeated at research plot no. 12 situated in the fir–beech vegetation zone, which is now included in the Carpathian Biosphere Reserve. Here, the tree maps were not constructed but rather results of the whole-area tree layer inventory were repeatedly calculated using the same volume tables and calculation algorithms as in 1934 (Zlatnı´k et al., 1938). Data from Slovak reserves were acquired from whole-area tree layer inventories in the Badı´n and Dobrocˇ localities (Korpel’, 1995; Saniga, 1999a,b), and in two plots of 0.5 ha each at the Stuzˇica

1995 1994 2004 1977, 1997 1988, 1998 1991 1991 2004

locality (Korpel’, 1995), which was included because of the lack of better data from that part of the Carpathians. For easy comparison, the data were converted to values per hectare. For better orientation in the figures, numbers on other admixed tree species (Norway spruce, sycamore maple, Scotch elm) are not included, since these tree species amount to less than 10% of the total in all localities except for Dobrocˇ, where they amount to about 20%. Comparison of data on tree representation in each diameter class was made with the same diameter class intervals as those used by the authors of the original measurements (Zlatnı´k et al., 1938; Korpel’, 1995; Saniga, 1999a,b; Duda, 2004). A comparison of the distribution in diameter classes was performed by using a two-sample Kolmogorov–Smirnov test (K–S test). The history of the anthropogenic impact on natural Carpathian fir–beech forests was studied mainly from the common literature available for the territories of Czechia, Slovakia and Ukraine. Important sources of information were the so-called ‘‘Historic forest surveys’’ elaborated for individual regions at the Czech Forest Management Institute (www.uhul.cz) in the 1960s and 1970s, and where they are currently available. 3. Results 3.1. The historical impact of humans in the northern Carpathians European lowland and upland forests have been affected by humans and gradually cultivated since the Neolithic Age (Vera, 2000). In general, regions with high mountain massifs were colonized during the late medieval and early modern times by progression from the valley floor upwards toward the timber line (Motta and Garbarino, 2003). However, most ridges in the Carpathians do not have sharp peaks, but rather the hilltops are flat and were originally overgrown with climactic spruce stands or mixed woods of spruce with beech and fir (Bohn et al., 2000; Sukhariuk and Voloshchuk, 2005). The original timber line was vertically decreased by 200–300 m due to colonization (Sukhariuk and Voloshchuk, 2005). These elevations were particularly favourable for grazing and were colonized concurrently with the valleys. Thus, they became subject to forest conversion or total clearing of trees by the local population from the valleys (communal pasturelands) (Svoboda, 1940) as well as by newcomers of the so called Wallachian colonization, spreading through the Carpathian Arch from the 13th century and culminating in the 16th century in the north-western Carpathians (Kavuljak and Sulik, 1952; Zˇaloudı´k, 1984). This is how a chain of mountain pastures came into existence on the main ridges of the Carpathians (‘‘polana’’ in Czech, ‘‘pol’ana’’ or ‘‘polianka’’ in Slovak, ‘‘polonina’’ in Ukrainian), on which sheep, goats and cattle were grazed. Because of this system, a belt of forests was preserved between the pasturelands near communal units in the valleys and the mountain ridge pastures, which was saved from extensive clear-cutting and complete conversion. These forests were

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exempted from clear-cutting because they had a stabilization function to protect settlements in the valleys, as well as serving for the protection of hilltop pastures and for variety of food for animals. Trees were felled individually for technical purposes related to the presence of shepherds on mountain ridges (building and repairs of sheep pens and huts, fences, etc.). The presence of livestock in the forest forced game (red deer, roe deer) to move further away and the predator populations of wolf, bear and lynx started to be gradually eradicated through the increased protection of herds. In addition, the forests were subject to intensive litter raking. These fundamental effects lasted at full intensity until approximately the end of the 18th century (Barta´k, 1929; Zlatnı´k, 1934; Svoboda, 1939, 1940; Kavuljak and Sulik, 1952; Nozˇicˇka, 1957; Zˇaloudı´k, 1984). In addition, charcoal was produced on milder slopes and closer to settlements (Barta´k, 1929; Nozˇicˇka, 1957; Zˇaloudı´k, 1984; Mil’anova´ and Jo´zsova´, 2003). Conditions became almost ideal for the regeneration of fir and partly also spruce (Fig. 2) because:  The grazing livestock in forests – especially at more fertile sites (Western Carpathians) – browsed all vegetation of the herb layer together with young tree saplings, focusing nearly exclusively on beech, sycamore maple and/or other broadleaves (Kavuljak and Sulik, 1952).  Litter raking and more intensive trampling resulted in soil surface changes and hence in modified physical and biological

properties of the upper soil layer. The continuous layer of litterfall, which was normally difficult to penetrate for emerging fir seedlings, was mechanically disturbed and gradually removed (Ma´lek, 1971). Beech seeds have a greater amount of nutrient reserves than fir seeds, and so roots of germinating seedlings can more easily push through the litterfall layer.  The stock of game was reduced and wildlife became less of a limitation for fir growth (Zˇaloudı´k, 1984). In the mid-18th century, Maria Theresa issued the ‘‘Imperial Patent concerning woods and timber’’ (1754 for Bohemia and Moravia, 1756 for Silesia, 1769 for Slovakia) (Konsˇel, 1934; Milanova´ and Jo´zsova´, 2003), with Chapter 13 (on grazing large and ovine livestock and grass mowing) mentioning their total prohibition (Strejcˇek et al., 1983). Despite this official ban, the patent was enforced only very slowly. As recently as at the beginning of the 19th century, grazing forests occupied 26% and mountain pastures 30% of the official acreage of forest land in the Czech part of the Carpathians (Musiol, 1971; Zˇaloudı´k, 1984). In the most remote corners of the northern Carpathians, grazing and Alpine dairy farming ceased to exist as late as the second half of the 19th century (Zlatnı´k, 1934). A general rule holds that the more eastwards in the Carpathians, the longer forest grazing persisted. With the cessation of grazing, silver fir became dominant in stands that had not been converted into commercial spruce forests (Vrsˇka et al., 2000; Zˇaloudı´k, 1984). Conditions for the regeneration of tree species changed fundamentally (Fig. 2):  A new litterfall layer started to develop from the remaining beech trees – it caused worsening of conditions for the regeneration of fir – and being no longer hampered by livestock browsing, the natural regeneration of beech started to increase.  In the late 19th century, these as yet commercially unconverted forests became the last refuges for some game species (e.g. wood grouse) and hence became favoured places of forest owners with romanticist thinking, who saved such forests from logging and conversion to spruce monocultures (e.g. the Mionsˇı´ locality) (Jancˇı´k, 1959).  A complete return of predators that had almost been eradicated never occurred (Nozˇicˇka, 1957).  On the contrary, these protected forest districts showed an increase in the stock of hoofed game like red deer, roe deer, which prefer browsing on fir saplings. The tolerance of fir to browsing is much lower than that of beech, and young firs (up to DBH of about 20 cm) showed damage and increased mortality due to bark stripping (Zˇaloudı´k, 1984). This is the situation in which the reserves were found at the beginning of the 1950s (Pop Ivan in the 1930s). 3.2. Dynamics of silver fir

Fig. 2. Diagram of human impact on Carpathian fir–beech forests.

Changes in the representation of tree species according to tree counts per hectare are illustrated in Fig. 3. All eight studied localities show a decreasing proportion of silver fir during the period examined. The highest decreases were recorded in Mionsˇı´ (80%) within 47 years and in Salajka (40%) within 20 years. Similar decreases were found in the localities Stuzˇica V and Stuzˇica VI (25%) within 20 years. In these localities, however, fir had reached its minimum counts and the stand dynamics were already governed by beech. The results of the Kolmogorov–Smirnov test (Table 2) indicated that the DBH distributions differed significantly in the localities Pop Ivan, Stuzica VI, Razula, Mionsi, Badin and Dobroc (Table 2). Lower diameter classes’ representation is decreasing in these localities.

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351

Fig. 3. Changes in the representation of fir and beech according to stem count per 1 ha.

According to changes in timber volume per hectare (Fig. 4), a decrease in the representation of silver fir was recorded in all localities except for Pop Ivan. This also correlates with the decreased number of stems. It is evident from Fig. 5 that all monitored silver fir populations slowly progressed to higher diameter classes while their numbers considerably dropped. None of the localities exhibited even a small increase in the new fir population in the lowest diameter classes. At the Pop Ivan locality, the population of silver fir progressed to higher diameter classes, but the tree numbers in these diameter classes did not decrease compared with the year 1932 (Fig. 5). Nevertheless, fir shows an identical trend towards a decreasing proportion in all studied localities, in spite of the fact that the localities represent relatively extensive reserves on the European

scale, which are furthermore at least 600 km distant from one another. 3.3. Dynamics of European beech The proportion of European beech according to tree counts per hectare (Fig. 3) shows an exactly opposite trend to that of silver fir. With the exception of Stuzˇica V and Stuzˇica VI, the beech representation is rapidly increasing, particularly so in Mionsˇı´ (310%) within 47 years and in Salajka (155%) within 20 years. In the all localities K–S test revealed significant differences in the DBH distributions (Table 2) with the increasing representation of lower diameter classes. Thus, beech is unambiguously expanding, replacing fir at sites where fir dieback has created gaps.

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352

Table 2 Results of the Kolmogorov–Smirnov test comparing the DBH distributions. Locality

Pop Ivan Stuzica V Stuzica VI Salajka Razula Mionsi Badin Dobroc

Comparison years

1934–2004 1971–1991 1971–1991 1974–1994 1972–1995 1957–2004 1977–1997 1978–1998

Abies alba

Fagus sylvatica

D

D0.05

D

D0.05

0.307 0.272 0.038 0.034 0.113 0.332 0.059 0.135

0.082 0.355 0.326 0.074 0.099 0.25 0.053 0.027

0.053 0.169 0.202 0.191 0.292 0.678 0.181 0.057

0.045 0.099 0.095 0.046 0.044 0.082 0.023 0.022

D: test criterion, D0.05: critical value for two-sample Kolmogorov–Smirnov test, DBH distributions differ if D > D0.05.

Changes in timber volumes (Fig. 4) show that this generation of beech is indeed new, since the increased proportion of beech is not as marked as would be expected due to the younger trees not having reached high gains in volume. It is clear that the majority of the European beech population has gradually moved to middle diameter classes (Fig. 5) as the number of trees gradually decreases and their volume gradually increases. In Mionsˇı´, the large differences (Figs. 3–5) result from the long interval between the repeated measurements (47 years). The longest interval between repeated measurements is at Pop Ivan (70 years) and shows only a mild increase of beech in both tree counts and volumes, which correlates with a more minor decrease of tree counts and unchanged volumes for silver fir. This once again corroborates the later start of the gradual dieback of the grazed

Fig. 4. Changes in the representation of fir and beech according to stem volume per 1 ha.

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353

Fig. 5. Changes in the representation of fir and beech in diameter classes per 1 ha.

generation of silver fir, and hence the more recent end of these activities (Figs. 3 and 4). In general, the development of beech is opposite to that of fir, and beech becomes unambiguously dominant in the Carpathian fir–beech natural forests and governs their current developmental dynamics.

3.4. Changes in stand structure Changes in the structure of the studied forest stands occur simultaneously with changes in the tree species representation. For example, Fig. 6 shows the current structural changes at Razula; these are identical to those found at Salajka (Vrsˇka, 1998), Mionsˇı´

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Fig. 6. Stand structure change in the Razula locality in the period from 1972 to 1995.

(Duda, 2004; Vrsˇka et al., 2000), Badı´n (Saniga, 1999a) and Dobrocˇ (Saniga, 1999b). On the transect from 1972 (Fig. 6), the last grazing generation of silver fir is still surviving and the new regeneration is dominated by beech. Fir is regenerating naturally as well, but the rapidly growing beech canopy creates such heavy shade that the fir seedlings cannot survive. The situation in 1995—after 23 years, precisely documents the current conditions, with the grazing generation of fir nearly approaching its end and the beech starting height differentiation in the absence of fir.

4. Discussion 4.1. Other impacts on fir and beech dynamics The historical replacement of native fir–beech forests in central parts of the Czech Republic outside the Carpathians has been documented with the examples of litter raking and longterm livestock grazing (Ma´lek, 1971, 1976, 1980, 1981). The same findings have been reported, e.g. by Motta and Garbarino (2003) in their study of anthropogenic impacts in the southern Alps in Italy. Despite these findings, the influence of humans on

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the developmental dynamics of fir–beech forests in the northern Carpathians was not widely accepted. The decline of fir and the invasion of beech were attributed to a range of other circumstances. Chmelarˇ (1959b) studied the effect of the spectral composition of light on the emergence of fir seedlings. He observed that natural regeneration of fir is hampered by a low proportion of the blue component and a surplus of the green and red components of the spectrum. Precisely this spectral situation occurs under direct insolation and in stands with more intense shading by the broad leaves of deciduous trees and leaves of broadleaved herbs. At the same time, however, he proposed (Chmelarˇ, 1959a) that the decline in fir is neither due to the dieback of mature trees, seed shortages nor the inappropriate composition of upper soil layers, but rather the decline of fir seedlings, which occurs in several stages: in the period after the first year of life, in the period from the 4–5th year of life, and in the period from the 8–9th year of life. He concluded that the main reason for the disappearance of fir was the gradual disappearance of mycorrhiza due to air pollution and subsequently due to the changed soil environment, and therefore understood forest reserves in the Western Carpathians as being ˇ eha´k (1963) stands undisturbed by humans (Chmelarˇ, 1957). R underscored the important influence of hoofed game on the decline of natural fir regeneration, which he studied on a series of research plots. He cast doubts on the conclusions drawn by Chmelarˇ (1959a,b); however, neither of these authors dealt with the historical impact on the forests by humans in connection with the changes in species composition. Kantor (1966, 1967) mentioned four of the most significant causes in the decrease of fir, of which three relate to natural forests: (i) the phylogenetic age, (ii) ecological factors (drought, heavy frost, air pollution impact, etc.), and (iii) insect pests and phytopathogens (Dreyfusia nordmanniana Eckst., D. piceae, resp. Dasycypha calyciformis (Wild.) Rehm., Armillaria mellea (Wahl.) Karst.). There is no doubt that smoke damage played a significant role in the Western Carpathians, namely by the transmission of noxious substances from industrial agglomerations (Vacek et al., 2003) near Ostrava (Czech Republic) and Katowicze (Poland). This phenomenon particularly affected less stable commercial forests with admixed fir and in natural forests where the oldest fir generation suffered accelerated disintegration, was unable to regenerate and was physiologically weakened. However, this assuredly strong impact cannot explain the present absence of a younger fir generation in the remnants of natural forests, because its effect had gradually increased and then peaked during the 1970s and 1980s. Starting from the 1990s, a pronounced decrease has occurred in noxious emissions, and they no longer cause of fir dieback or explain the lack of regeneration. Moreover, these effects were stronger in the western part of the Carpathian Arch and are not documented at all from the eastern part. Results from the research of damage to forest stands by air pollution are not able answer questions about the dynamics and mutual competition of fir and beech, especially since the best preserved reserves in the northern Carpathians, lying at least 600 km away from each other, have experienced the same developmental process. The only possible answer is that this identical evolution resulted from the former activity of humans in the forests. 4.2. The future of silver fir in strictly protected forest reserves Silver fir is entirely missing in the lowest diameter classes of monitored localities. Its representation in the natural regeneration stages below the usual limits for tree measurement is very low (Korpel’, 1995; Saniga, 1999a,b; Vrsˇka et al., 2000, 2001; Duda, 2004; Ujha´zy et al., 2005). In the northern Carpathians, fir is

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currently limited by two factors: (i) the expansion of beech and (ii) the reduced or zero presence of the predators of hoofed game. Even under the current expansion of beech, fir still has a chance to regenerate, particularly on higher, concave parts of slopes where the layer of beech foliage is very thin or non-existent. At the same time, plots must be prevented from reaching the growth stage (sensu Korpel’ and Saniga, 1993; Korpel’, 1995) in which the density of the beech canopy is so high that fir cannot long endure the heavy shade (Fig. 6). Even if conditions are favourable for fir regeneration, it would still be intensively browsed by game, whose stock is not sufficiently limited by hunting or predators. Moreover, forest reserves today are islands in the midst of large stretches of cultivated forests and have become a preferred refuge for wildlife (Scherzinger, 1996) because: (i) animals find a better food supply there in the natural tree species composition, (ii) there is sufficient tranquillity in them, without the noise of forest machines and with minimum intrusion by people, (iii) there is shelter provided by the natural regeneration, and tangles of downed trees. These three effects are most apparent in the Czech Republic, with spruce monocultures predominant in the surroundings of fir– beech reserves (Vacek et al., 2003) and with a minimum of hoofed game predators (Hell et al., 2001). The situation is better in Slovakia, where the species composition is nearer to the natural condition (Korpel’, 1995) and the stocks of predators are higher (Hell et al., 2001). The best situation is currently found in the eastern Carpathians, where the populations of predators are highest, surrounding large complexes of forests out of the reserves have a near-natural species composition (Commarmot and Hamor, 2005), and hunting is used more than game keeping. This view offers an apparent west-east gradient, with the worst conditions for the future spontaneous regeneration of silver fir in the strictly protected forest reserves occurring in the west. Fir has not yet reached its population minimum (Figs. 3–5) and is theoretically capable of reproduction in the forest stands (although to a limited extent). However, the population minimum of silver fir is relatively close to being reached, in the western part of the Carpathians especially. Therefore, it is necessary to address priorities in the management of strictly protected forest reserves: (i) If priority is seen in the spontaneous development of the ecosystem, which should proceed according to the model of potential natural vegetation (sensu Tu¨xen, 1956) after having been affected by humans, then secondary anthropogenic impacts like the overpopulation of game, should be prevented. It is possible due to protection of fir seedlings against browsing at the ‘‘optimum’’ and ‘‘disintegration’’ stages. (ii) If we wish to monitor the development of this ecosystem under conditions altered by humans (as the current conditions certainly cannot be called ‘‘natural’’), we have to be prepared for the variant without fir. If this occurs, then new and as yet unknown competitive linkages between these tree species may surprise us. 5. Conclusions Actual natural fir–beech forests in the mountain massif of the Carpathians were affected by anthropogenic activities in the past, particularly by sheep and cattle grazing, litter raking, charcoal production in charcoal pits, and by patch cutting of individual trees. In the period from the 14th to the 18th centuries, the representation of fir gradually increased due to human activity at the cost of beech. Changed social conditions in the second half of the 18th century and at the beginning of the 19th century created markedly better conditions for beech regeneration. The subsequent expansion of beech has not yet ended. On the contrary, in

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strictly protected forest reserves, the species has continued to enjoy a certain advantage over fir, due to the disturbed relations between herbivores and predators. It is not possible to use the theory on the periodical rotation of natural fir–beech forests, where two generations of European beech (F. sylvatica), each of about 200–250 years, develop within the sub-level of one silver fir (A. alba) generation (ca. 400–450 years). The best preserved reserves in the northern Carpathians, lying at least 600 km away from each other, have experienced the same developmental process. This is not a natural rotation actually, but linear trend induced by man. Silver fir may become a very rare and even extinct species in contemporary strictly protected forest reserves under current conditions influenced by humans. Its fate will depend on the management methods selected. Acknowledgements This project was supported by the Czech Ministry of Environment within the framework of Project no. MSM 6293359101. The authors wish to express their thanks to Toma´sˇ Duda, David Horal, Kamil Kra´l, Pavel Unar, Pavel Sˇamonil, Bohumil Jagosˇ, Daniela Pliskova´, Petra Dolezˇelova´, Pavel Popela´rˇ and Toma´sˇ Myslikovjan for their assistance in data collection and comments during the paper preparation. References Anonymous, 1952. Hmotove´ tabulky. Lesprojekt, Brandy´s nad Labem. ˇ eskoslovenske´ socialisticke´ republiky (tabulky). C ˇ esky´ Anonymous, 1960. Podnebı´ C hydrometeorologicky´ u´stav, Praha. Barta´k, J., 1929. Z minulosti sˇta´tneho lesne´ho hospoda´rstva v okolı´ Banskej Bystrice ˇ Slovenska Grafia, Banska´ Bystrica. a Stary´ch hor. Knihtlacˇiaren Bohn, U., Neuha¨usl, R., Gollub, G., Hettwer, C., Neuha¨uslova´, Z., Schlu¨ter, H., Weber, H., 2000. Map of the Natural Vegetation of Europe. Scale 1:2. 500. 000. Part 3: Karten. Landwirtschaftsverlag, Mu¨nster. Chmelarˇ, J., 1957. Studie o vy´voji jedle v podmı´nka´ch prˇirozene´ho, cˇloveˇkem neovlivneˇne´ho lesa, jako prˇı´speˇvek k rˇesˇenı´ ota´zky celkove´ho u´stupu jedle. Ph.D. Thesis. Vysoka´ sˇkola zemeˇdeˇlska´, Brno. Chmelarˇ, J., 1959a. Prˇirozena´ obnova jedle (Abies alba Mill.) v pralesove´ rezervaci ‘‘Mionsˇı´’’ v Moravskoslezsky´ch Beskydech. Lesnictvı´ 5, 225–238. Chmelarˇ, J., 1959b. Vy´znam intensity a spektra´lnı´ho slozˇenı´ sveˇtla pro vy´voj semena´cˇku˚ jedle (Abies alba Mill.). Prˇı´rodoveˇdny´ cˇasopis Slezsky´ XX, 59–82. Commarmot, B., Hamor, F.D. (Eds.), 2005. Natural Forests in the Temperate Zone of Europe—Values and Utilisation. Swiss Federal Research Institute WSL, Birmensdorf & Carpathian Biosphere Reserve, Rakhiv. Diaci, J. (Ed.), 1999. Virgin Forests and Forest Reserves in Central and East European Countries. University of Ljubljana, Ljubljana. Duda, T., 2004. Dynamika vy´voje synuzie drˇevin v NPR Mionsˇı´. Degree Thesis. Mendelova zemeˇdeˇlska´ a lesnicka´ univerzita v Brneˇ, Brno. Hell, P., Slamecˇka, J., Gasˇparı´k, J., 2001. Vlk v slovensky´ch Karpatoch a vo svete. PaRPRESS, Bratislava. Jancˇı´k, A., 1959. Obdobı´ ‘‘Teˇsˇı´nske´ sˇkoly’’ v lesnı´m hospoda´rˇstvı´ Beskyd. Lesnictvı´ 5, 53–82. Jaworski, A., Kolodziej, Z., Porada, K., 2002. Structure and dynamics of stands of primeval character in selected areas of the Bieszczady National Park. J. For. Sci. 48, 185–201. Kantor, J., 1966. Sˇlechteˇnı´ jedle. Vysoka´ sˇkola zemeˇdeˇlska´, Brno. Kantor, J., 1967. Prˇı´speˇvek ke studiu neˇktery´ch deˇdicˇny´ch vlastnostı´ jedle bı´le´ (Abies alba Mill.). Lesnicky´ cˇasopis 13, 308–318. ˇ eskoslovenska´ Matice lesnicka´, Konsˇel, J. (Ed.), 1934. Naucˇny´ slovnı´k lesnicky´. C Pı´sek. Korpel’, Sˇ., 1958. Prı´spevok k sˇtu´diu pralesov na Slovensku na prı´klade Badı´nskeho pralesa. Lesnı´cky cˇasopis 4, 349–385. Korpel’, Sˇ., 1967. Dobrocˇsky´ prales, jeho sˇtruktu´ra, vy´voj a produkcˇne´ pomery. ˇ eskoslovenska´ ochrana prı´rody 5, 321–355. C Korpel’, Sˇ., Saniga, M. (Eds.), 1993. Symposium u¨ber die Urwa¨lder. Forstliche Fakulta¨t der Technischen Universita¨t Zvolen, Zolen. Korpel’, Sˇ., 1995. Die Urwa¨lder der Westkarpaten. Gustav Fischer Verlag, Stuttgart, Jena, New York. Kavuljak, A., Sulik, J., 1952. Les a pasenie. Ora´cˇ, Bratislava. ˇ R. Kusbach, A. (Ed.), 2002. Oblastnı´ pla´ny rozvoje lesu˚–prˇı´rodnı´ lesnı´ oblasti C ˇ erny´mi lesy. Lesnicka´ pra´ce, Kostelec nad C ¨ ber Zweck und Methodik der Struktur- und Zuwachsanalyse Leibundgut, H., 1959. U von Urwa¨ldern. Schweizerische Zeitschrift fu¨r Forstwesen 110, 111–125. ¨ ber die Dynamik europa¨ischer Urwa¨lder. Allgemeine Forst Leibundgut, H., 1978. U Zeitschrift 33, 686–690. Leibundgut, H., 1993. Europa¨ische Urwa¨lder. Paul Haupt, Bern.

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