Lukáš Bílek

Effect of Air Pollution on the Health Status of Spruce Stands

This paper presents the results of research on local air pollution (nitrogen and sulfur concentrations) and on the changes in the health status of trees observed in spruce stands in the period 1980–2011 in the Krkonoše Mountains National Park. Data on precipitation and sulfur and nitrogen deposition were collected in regular 2-week intervals from 1994 to 2010. Precipitation was measured at 5 monitoring stations; the health status of forest stands was evaluated on 6 research plots located in stands dominated by Norway spruce (Picea abies [L.] Karst) in zones where there has been a significant threat from air pollution since 1980. The health status of spruce stands was assessed on the basis of the degree of defoliation, classified into 6 levels. In all localities since 1994, the total deposition of sulfates decreased significantly, from 50–80 kg ha−1 year−1 to 8–13 kg ha−1 year−1; however, no clear trend in the development of nitrogen deposition could be stated. The mean defoliation of living and all trees was 32% (± 0.5 SE) and 63% (± 0.8 SE), respectively, on plots with autochthonous stands, and 91.5% (±5.8 SE) and 97.6% (±1.7 SE), respectively, on a plot with an allochthonous stand. The defoliation of living and all trees differed across research plots. Despite a negative relationship between defoliation of all trees on plots and atmospheric deposition of sulfur (P  =  0.012; r  =  −0.25), air pollution in the Sudeten still represents a serious hazard for the forest ecosystem. This relationship differed across research plots (F[5, 96]  =  110, P < 0.001). Close-to-nature management techniques aimed at the enhancement of forest complexity and preferential use of autochthonous populations of trees in timely regenerated forest stands may be of crucial importance for the restoration and preservation of these mountain forest ecosystems.

Effect of Tree Layer and Microsite on the Variability of Natural Regeneration in Autochthonous Beech Forests

ABSTRACT The present study describes natural regeneration on five permanent research plots (PRP) in juvenile growth and development phases (regrowth and advanced growth) in autochthonous beech forests in Broumovské stěny National Nature Reserve located in the Protected Landscape area in the northeast part of Czech Republic. The stands of herb-rich beech forests were studied in the optimum to break-up stage. Natural regeneration was not evenly spaced but rather was clustered. Mean regeneration density ranged from 1,472 to 44,888 recruits per ha. European beech (Fagus sylvatica L.) made up 78.5–98.0% of all regeneration. Sycamore maple (Acer pseudoplatanus L.) was also relatively abundant. Regeneration dominance and abundance responded to the mature stand canopy, soil skeleton, microrelief, ground vegetation cover, and surface characteristics. The results suggest a relationship between recruit height and microrelief in 4 out of 5 PRPs. We found statistically significant differences in height of natural regeneration (F(2,18843) = 191.8, P <0.001) on mounds (74.0 cm), on slopes (119.5 cm) and on pits (121.0 cm) due to high soil skeleton content on mounds with numerous rock outputs, minimum amount of fine earth and lower water retention, both necessary for recruit growth. In addition to the character of microrelief, the growth of natural regeneration was negatively influenced by mature stand density and canopy indicators.

Spatial pattern of relict beech (Fagus sylvatica L.) forests in the Sudetes of the Czech Republic and Poland

Horizontal structure of forest stands largely affects the competitive relationships between tree individuals and plays a significant role in the stand dynamics. The present study describes horizontal structure on nine permanent research plots (0.24–0.25 ha) in the regeneration and tree layer of autochthonous European beech (Fagus sylvatica Linnaeus) stands in the wide altitudinal gradient in protected areas in the Czech Republic and Poland. The spatial structure was classified in productive herb-rich beech sites, through acidophilic beech sites, exposed sites, to beech fragments near the timberline. The spatial pattern of tree layer was regular in the lowest parts of the altitudinal gradient of beech, random in the middle parts and aggregated in the beech forests under the hilltop phenomenon and extreme edaphic site. Nevertheless, trees in lower tree layers showed a tendency to the aggregated pattern, similarly like the strong aggregation of natural regeneration. In most cases, the parent stand had a significant negative effect on natural regeneration at a smaller distance (to 0.8–4.2 m). The spatial pattern of dead wood was mostly random. Because of the great plasticity of beech crowns, crown centroids were more regularly distributed than tree stems. The average displacement of crown centroids from the stem base was 1.5 m with the prevailing direction of 52.7% down the slope. Projected canopy cover was on average 10.7% higher compared to the canopy simulated by circular crowns.

Diameter increment of beech in relation to social position of trees, climate characteristics and thinning intensity

We present the results of research on diameter increment in beech stands in the area of Hostýnské and Vsetínské vrchy. The data were collected on three series of permanent research plots (PRP) in middle-aged stands in the property of BFP Forests and Estates of Tomas Baťa, Ltd. established for the evaluation of the effect of different thinning regimes. Each series consists of one control plot and two plots with different treatment intensity. The objective of this paper was to assess the increment response of beech individuals in the first year after a thinning intervention and to evaluate the increment of sample trees in relation to the social position of tree in the stand and the climate trends in the last 30 years. The diameter increment was evaluated on harvested sample trees, after the thinning treatment the growth reaction of standing sample trees of the main stand was evaluated based on their dendrometric characteristics. To calculate the radial growth of beech, the annual ring increment series were cross-dated individually (to eliminate errors caused by missing annual rings) using statistical tests in the PAST4 application software (Knibbe 2007) and then subjected to visual inspection according to Yamaguchi (1991). If a missing annual ring was found, a ring 0.01 mm wide was inserted in its place. The individual curves from PRPs were then detrended and an average annual ring series was created in the ARSTAN software. First a negative exponential spline was used, and then the 30-year spline was applied (Grissino-Mayer et al. 1992). The response of tree radial growth to climatic factors was evaluated using the DendroClim software. The method of single pointer years analysis was used to estimate the influence of extreme climatic events on diameter growth. One year after thinning, the harvest intensity had no significant effect on the radial growth of dominant trees (F(4, 293) = 1.0, P > 0.05), but oppositely, differences in the average diameter increment of co-dominant trees on PRPs were statistically significant (F(4, 362) = 2.6, P < 0.05). The diameter increment of dominant trees in 1978–2013 showed positive correlations with the March temperatures of the current year (r = 0.27) and negative ones with June–September (r = –0.28 to –0.43) and November (r = –0.36) of the last year and April, June and July (r = –0.35 to –0.44) of the current year. Negative correlations of temperature in the growing season of the current year were similar to dominant trees, only the impact was weaker in April to August (r = –0.28 to –0.32). According to the results of the PCA analysis, annual ring width was negatively correlated with temperatures in the vegetation season of the last year and current year, July, April and June temperature of the current year, and with precipitation in January–March of the current year.

Carbon sequestration in soil following afforestation of former agricultural land in the Czech Republic

Abstract Soil organic carbon (SOC) is a great component of the global carbon cycle and plays significant role in terms of climatic changes and agricultural land-use. An important management concern is the extent of SOC stocks sequestration when farmland is converted to forest stands. We have reviewed the literature about changes in SOC stock in relation to altitude and stand age and sought differences between former agricultural land and origin forest stands. Accumulation of SOC was monitored in 17 examples (41 samples) in 9 locations across the all Czech Republic with focus on the main tree species Norway spruce (Picea abies [L.] Karst.). Results showed a significant increase of SOC stock in an afforested farmland with increasing stand age. Another factor was the altitude. With increasing altitude, the carbon stock in our model gradually decreased. From the data analyzed comparing forest stand and former agricultural land, similar carbon sequestration was documented for both variants with higher SOC for forest stands. However, other conditions affecting SOC stock should be taken into consideration, especially silvicultural management, topography, disturbances, soil properties and cultivation. The general tendencies of SOC changes at the investigated sites are comparable to those in other studies across the Europe.

Struktura a modelový vývoj lesních porostů v NPR Trčkov – CHKO Orlické Hory, Česká republika

Abstract The paper deals with the research of structure and dynamic development of stands in National Nature Reservation Trčkov, located in Protected Landscape Area Orlické Mts. (Czech Republic). The research was carried out in spruce-beech stand with admixed fir and sycamore maple. Two permanent research plots (PRP 1 and PRP 2), for each with area of 0.25 hectare were chosen as an object of our research. FieldMap technology was used for field measurement. Compared PRP were characterized by the same typological, soil, phytocenology and stand parameters, but different method of protection against game damage. Results showed that deer is considered to be limiting factor for successful development of natural regeneration of autochthonous tree species. The tree species proportion of natural regeneration occurred in PRP 1 with fencing was sufficient, contrary to PRP 2 (outside fencing) owing to site and stand conditions. The results of biometric measurements and predicted simulation by Sibyla growth simulator showed multi-layer stand structure and productive spruce-beech stands with interspersed fir and sycamore maple. We also found depleted phase of regeneration according to frequency and tree species proportion, as well as beginning of grow up stadium, especially related to fir and sycamore proportion and/or beech and spruce. It is concluded that growth visualization and simulation confirmed the hypothesis about long-term effect of game to species, spatial and age structure and development of concerned autochthonous population.

Impact of applied silvicultural systems on spatial pattern of hornbeam-oak forests

Abstract The spatial pattern of forest closely affects tree competition that drives the most of processes in forest ecosystems. Therefore, we focused on evaluation of the horizontal structure of high forest, coppice with standards and low forest in hornbeam-oak forests in the Protected Landscape Area Český kras (Czech Republic). The horizontal structure of tree layer individuals with crown projection centroids and natural regeneration was analysed for durmast oak (Quercus petraea (Matt.) Liebl.), European hornbeam (Carpinus betulus L.) and small-leaved linden (Tilia cordata Mill.) stands. Horizontal structure of the tree stems of the studied tree species in high forest was random, in oak it was moderately regular. In coppice with standards it was random in oak, in hornbeam and linden it was aggregated within 3 – 5 m and random up to a larger spacing. In low forest at a distance of 4 – 6 m the horizontal structure of the three studied tree species was aggregated while it was random at a larger spacing. The horizontal structure of natural regeneration was aggregated in all forest types. In coppice with standards and high forest, parent stand had significant negative effect on the natural regeneration at smaller distance (to 1.4 m from the stem). Crown centroids were more regularly distributed than tree stems, especially in low forest (2.0 m) and in linden (2.3 m). Our results contribute to existing knowledge about silvicultural systems and their impact on hornbeam-oak forests with implications for forest management and nature protection.

Long-term transformation of submontane spruce-beech forests in the Jizerské hory Mts.: dynamics of natural regeneration

Abstract The paper deals with development of the natural regeneration of even-aged spruce-beech forests during their transformation to uneven-aged stands with diversified structure at the Jedlový důl area in the Protected Landscape Area Jizerské hory Mts., Czech Republic. Shelterwood management system and free felling policy based on selection principles has been applied there since 1979 with the support of admixed tree species of the natural species composition, especially silver fir (Abies alba Mill.). The research was focuses on structure and development of natural regeneration with the emphasis on ungulate damage and interaction with tree layer from 1979 to 2015. In the course of 36 years, the regeneration structure was diversified towards the close-to-nature tree species composition, spatial and age structure. The number of regeneration recruits increased in average from 941 to 41,669 ind ha-1. During this period share of European beech (Fagus sylvatica L.) significantly (p < 0.01) increased (by 53.6%), while the share of Norway spruce (Picea abies [L.] Karst.) decreased (by 51.5%), such as damage caused by ungulate (by 61.4%) with the highest loses on sycamore maple (Acer pseudoplatanus L.), rowan (Sorbus aucuparia L.) and silver fir. Moreover, the parent trees had a significant negative influence on natural regeneration at smaller spacing (within a 1 - 5 m radius from the stem). Both, regeneration potential and effective role of the tree layer during the forest transformation has been confirmed as important prerequisites for ongoing forest transformation.