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Jozef Pajtík, Bohdan Konôpka and Róbert Marušák

Abstract

One of the expected consequences of climate change and its inherent phenomena to forest ecosystems is the gradual modification of their tree species composition (i.e. expansion of resistant species instead of less resistant ones). Climate change accompanied with increasing temperatures and a lack of precipitations may present a threat especially to spruce stands in the European part of the temperate zone. European beech is one of the possible forest tree species which might replace the potentially endangered spruce. In this paper, we observed, by using a combination of continual measurements and destructive whole-tree sampling, standing stocks of above-ground biomass (i.e. stem, branches, and foliage) and its annual net primary productivity (NPP) in naturally regenerated young stands of beech and spruce. We intentionally selected a site where the changing climate conditions are better suited to the ecological demands of beech rather than spruce (the species is dominant in the observed area). We recorded only small differences in the standing stock of stems of the beech, if based on tons per ha. However, this is in favor of spruce if based on cubic meters per ha. The largest difference between the species was found for the standing stock of foliage, spruce retained three times the biomass of beech. Also, beech allocated more carbohydrates to stem than spruce. On the other hand, we estimated nearly the same production of foliages and branches in both stands.

Open access

Bohdan Konôpka and Jozef Pajtík

Abstract

The study focuses on two young stands of European beech (Fagus sylvatica) and Norway spruce (Picea abies) of the same age (12-yearold) with similar sized trees grown at near identical sites. After performing a destructive sampling technique which included all tree compartments except fine roots; allometric equations were constructed for all tree components. Diameter at stem base (do) was utilized as an independent variable for the equations. The models expressed not only biomass of woody parts (branches, stem and coarse roots) and foliage but also foliage area and specific leaf area (SLA). Results indicate that the basic morphological properties of foliage vary in both species along the vertical crown profile. In spruce, contrasting values of needle area and SLA were recorded among needle sets (based on year of establishment). On a tree level, both spruce and beech had similar foliage areas however, beech had a larger biomass comprising of woody parts while spruce biomass was dominated by foliage. Therefore the leaf mass ratio (LMR) defined as the ratio between foliage biomass and total tree biomass, as well as leaf area ratio (LAR) defined as the ratio between leaf area and total tree biomass were much larger in spruce than in beech species. On a stand level, spruce manifested a higher value (18.64 m2.m−2) of leaf area index (LAI) than beech (12.77 m2.m−2). Moreover, while the biomass of foliage was 4.6 times higher in spruce than in beech, total biomass of woody parts were similar in both stands. These contrasts indicate very different growth strategies and biomass allocations between beech and spruce at the young growth stages

Open access

Tibor Priwitzer, Jozef Pajtík, Bohdan Konôpka, Jozef Ištoňa and Pavel Pavlenda

Alokácia uhlíka v lesnom ekosystéme - prípadové štúdie z mladých borových porastov

V príspevku sú uvedené výsledky zo stanovenia uhlíkových zásob v lesných ekosystémoch na príklade mladých borových porastov. Stromová biomasa na experimentálnych plochách bola stanovená po jednotlivých komponentoch (korene, kmeň, vetvy a asimilačný aparát) s využitím meraných dát a alometrických rovníc. Na základe priamych meraní sa vypočítalo množstvo biomasy prízemnej vegetácie a opadu. Okrem toho bola stanovená aj zásoba pôdneho uhlíka. Celkové zásoby uhlíka boli vyjadrené v tonách na hektár

Open access

Jozef Pajtík, Tomáš Čihák, Bohdan Konôpka, Katarína Merganičová and Petr Fabiánek

Abstract

Although tree mortality is an essential process in forests, tree death still remains one of the least understood phenomena of forest development and dynamics. Therefore, we focused on annual mortality rates together with annual felling rates in the Slovak and Czech forests. We used data from the long-term national monitoring (periods of 1988–2017 in Slovakia and 1992–2017 in the Czech Republic). More than 24.6 thousand trees were assessed together in both countries. We calculated mortality and felling rates derived from two variables: basal area and number of trees. For these purposes, we selected five tree species/genera, specifically: Norway spruce, pines, European beech, oaks and common hornbeam. We recorded large inter-annual fluctuations of mortality rates in all tree species/genera. In both countries, spruce and pines had the highest mortality rates, while beech had the lowest mortality rates. Confrontation of long-term climatic data (especially annual precipitation totals) with mortality data indicated that drought was probably the most relevant factor causing tree death. On the other hand, no significant temporal trend, either increasing or decreasing, in tree mortality was found for any tree species/genera. As for all five selected tree species/genera together, significantly higher mean annual mortality rate derived from the number of trees was found in the Czech Republic (1.09%) than in Slovakia (0.56%). This finding indicates that tree mortality is often caused by combined effects of external unfavourable factors and competition pressure in forest stands.

Open access

Bohdan Konôpka, Jozef Pajtík and Miriam Maľová

Abstract

Fine roots (defined by a maximum diameter of 2 mm) and assimilatory organs are the compartments which rotate carbon much faster than any other tree part. We focused on quantification of fine roots in young European beech and Norway spruce trees growing under the same ecological conditions. Standing stock of fine roots was estimated by soil coring during 2009 - 2012. Fine root production was established by the in-growth bag method. Standing stock and productions of fine roots were comparable in both tree species. The quantity of fine root biomass (at a soil depth of 0 -50 cm) varied inter-annually between 6.08 and 7.41 t per ha in the beech and from 5.10 to 6.49 t per ha in the spruce stand. Annual production of fine roots (soil depth of 0 - 30 cm) was between 1.11 and 1.63 t ha-1 in beech and between 0.95 and 1.54 t.ha-1 in spruce. We found that fine root standing stock at the beginning of each growing season was related to climatic conditions in the previous year. Annual fine root production was influenced by the climatic situation of the current year. In general, a maximum standing stock of fine roots as well as a relatively slow fine root turnover is expected in young forest stands. Whereas production of fine roots prevailed over mortality in a favorable year (sufficiency of precipitations and slightly above-average temperatures in 2010), there was a reverse situation in an unfavorable year (drought episodes in 2011). We concluded that although both forest types represented contrasting turnovers of assimilatory organs (once a year and once in 5 years in beech and spruce respectively), fine root turnover rates were very similar (approx. once per four years).

Open access

Vladimír Šebeň, Bohdan Konôpka and Jozef Pajtík

Abstract

In Slovakia, the contribution of young stands to the total forest area has been increasing in the last decade. However, scientific attention to these stands was previously very sparse and they were usually not included in local and country carbon stock estimates. Therefore, we focused on the calculation of tree biomass and necromass in young beech and spruce stands as well as on their development during the period of nine years (aged from 4 to 12 years). For the calculation, we implemented allometric equations using tree diameter and height as independent variables. The results showed very dynamic changes in biomass (carbon) stock. Specifically, tree biomass increased in the period of 9 years from about 2,000 g to 15,000 g (i.e. cca 1,000 to 7,500 g of carbon) per m2 in beech, and from 4,500 to 12,000 g (cca 2,300 to 6,000 g of carbon) per m2 in the spruce stand. At the same time, the amount of biomass (fixed carbon) was only slightly larger than the accumulated quantity of necromass (carbon loss from living trees). It means that a large portion of carbon was allocated to necromass. We found that not only the foliage fall but also the mass of dead trees, a result of intensive competition, was an important path of carbon flux to necromass. The results proved that although young forests fix much less carbon in their biomass than old stands, they can represent large carbon flux via annual increment of necromass. This indicates that young stands should not be omitted in forest carbon balance estimates of the country.

Open access

Bohdan Konôpka, Jozef Pajtík, Michal Bošeľa, Tomáš Hlásny and Zuzana Sitková

Abstract

We investigated the seasonal dynamics of height increment, as well as total annual height increment, in 2009-2013 on young stands of beech and spruce grown at the same site. The results showed that the inter-annual dynamics of basic stand characteristics, especially tree density, were more obvious in spruce than in beech stands. Much higher tree mortality in spruce was explained by a lower light intensity under the spruce stand canopy and higher tolerance of beech to shade. Large interspecific differences were also found in the timing of height increment. Specifically, the height increment of beech trees started earlier than those of spruce. Moreover, the terminal grew for longer in spruce (nearly 70 days) compared to beech (about 45 days). The comparisons between the courses of the height increment and the ambient factors suggested that global radiation played a principal role. In the beech stand, the maximum height increment rate occurred during the same days as the maximal global radiation in 2009 and 2011, while a decline of the height increment occurred simultaneously with a depression in global radiation in 2012. As for the spruce stand, its one-peak maxima in height increment were related to the maximum of global radiation in 2009 and in 2012. On the other hand, double-peak courses of height increment in 2010 and 2011 may have been related to sudden declines in global radiation. Interspecific differences in height increment timing might play a certain role in cases of unfavourable weather conditions, e.g. drought episodes in the middle part of the growing season when the height increment would be accomplished in beech but would still be ongoing in spruce.

Open access

Bohdan Konôpka, Jozef Pajtík, Vladimír Šebeň and Michal Bošeľa

Abstract

Large-scale disturbances under the conditions of Slovakia, caused especially by storm and bark beetle, bring dramatic decline in carbon budget of the country, besides other negative consequences. The largest disturbance in modern history of the Slovak forestry was the storm damage that occurred in November 2004. The Tatra National Park (TNP) was one of the most affected regions. Thus, in this territory, two transects (T1 – the Danielov dom site and T2 – near the Horný Smokovec village) were established to survey basic dendrometric properties of trees in young stands established after the disaster. The standing stock of aboveground biomass in tree cover for the spring and autumn 2014 was calculated using the recorded variables, i.e. tree height and diameter measured at the stem base, together with the region-specific allometric relations. Then, the Aboveground Net Primary Production (ANPP) in tree cover was estimated with respect to its components (stem, branches and foliage). ANPP was 315 g m−2 per year (Transect T1), and 391 g m−2 per year (Transect T2). The differences in the structure of ANPP, i.e. contribution of tree components, were found between transects T1 and T2. They were caused by the contrasting tree species composition, specifically the ratios between Norway spruce and broadleaved species. Broadleaves allocated more biomass production to foliage than spruce. This phenomenon together with higher turnover (once a year) of foliage caused that broadleaves manifest higher share of fast-cycling carbon in comparison to the amount of carbon sequestrated in woody parts (stem and branches). High variability of ANPP was found within the transects, i.e. among the plots (microsites). As for the representative estimation of the standing stock of aboveground part of tree cover as well as ANPP at the post-disturbance area in the TNP territory, the survey should be performed on a net of research plots. Only this approach enables reliable estimates of carbon amount sequestrated in woody parts, eventually carbon yearly absorbed by young forest stands.

Open access

Michal Bošeľa, Jozef Pajtík, Bohdan Konôpka, Vladimír Šebeň and Tomáš Vida

Abstract

This study was aimed at modelling seasonal variation of stem circumference increments in a mixed stand composed of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.). Moreover, we focused on the quantification of the main climatic factors governing the increments. The measurements were performed at a site established at about 970 m a.s.l. from the locality of Vrchslatina (Central Slovakia). Data was collected from 20 European beech trees and 20 Norway spruce trees, from 2009 to 2012. The increments (measured at 130 cm above ground level) were recorded circa biweekly using manual band dendrometers. Lognormal function was used for the modelling of the seasonal trend of the increments. Hourly-based records of climatic variables such as air temperature, precipitation, and derived vapour pressure deficit were used for the modelling. The effect of climatic parameters on the seasonal variations of the increments was tested by including them directly into the lognormal function. The results suggest that while the sum of precipitation was a better predicting factor for spruce, the mean temperature was the better predictor for beech. In addition, both temperature and vapour pressure deficits also had an effect on the increments of spruce, but these parameters did not contribute to the explanation of the variability of increments for beech. Overall, the variability clarified by the final model was 72% for spruce and 78% for beech. At the same time, climatic parameters as a part of the model helped to explain 10% of the variability for the spruce (precipitations) and 3% of the variability for the beech (temperature). We also found lower variability in the increments of beech compared to spruce. This suggests that for the specific site conditions spruce are more sensitive to environmental conditions than beech

Open access

Vladimír Šebeň, Bohdan Konôpka, Michal Bošeľa and Jozef Pajtík

Abstract

The decline of spruce stands caused by bark beetle outbreaks is a serious economic and ecological problem of forestry in Slovakia. In the preceding period, the decline affected mainly secondary spruce forests. Over the last decade, due to large bark-beetle outbreaks this problem has been observed also in natural spruce forests, even at high elevations. We dealt with this issue in a case study of short-term development of larch-spruce stands in the High Tatras (at a site called Štart). We compared the situation in the stand infested by bark beetles several years after the wind-throw in 2004 with the stand unaffected by bark beetles. We separately analysed the development of the mature (parent) stands and the regeneration. The results indicated that forest decline caused by bark beetles significantly depended on the stand structure (mainly tree species composition), which affected the period of stand disintegration. Mortality of spruce trees slowed down biomass accumulation (and thus carbon sequestration) in the forest ecosystem. In the new stand, pioneer tree species dominated (in the conditions of the High Tatras it is primarily rowan), although their share in the parent stand was negligible. The results showed different trends in the accumulation of below-ground and above-ground biomass in the declined and living stands. In the first years after the stand decline, rowan accumulated significantly more biomass than the main tree species, i.e. spruce. The reverse situation was under the surviving stand, where spruce trees accumulated more biomass than rowan. The different share of spruce and pioneer tree species, mainly rowan, affected the ratio between fixed (in woody parts of trees) and rotating (in foliage) carbon in the undergrowth. Forest die-back is a big source of carbon emissions from dead individuals, and the compensation of these losses in the form of carbon sequestration by future stands is a matter of several decades.