Mature Pine Forest Research Articles

Effects of Climate Change on Scots Pine (Pinus sylvestris L.) Growth across Europe: Decrease of Tree-Ring Fluctuation and Amplification of Climate Stress

From an economic perspective, Scots pine (Pinus sylvestris L.) is one of Europe’s most important tree species. It is characterized by its wide ecological adaptability across its natural range. This research aimed to evaluate the forest structure, productivity and especially radial growth of heterogenous pine stands in 16 research plots in the Czech Republic, Poland, Spain and Great Britain. The study assessed the tree-ring formation and its relationship to climate change for each country, using 163 dendrochronological samples. The stand volume of mature pine forest ranged between 91 and 510 m3 ha−1, and the carbon sequestration in the tree biomass was 40–210 t ha−1. The stands had a prevailing random distribution of trees, with a high vertical structure close to selection forests (forest stands with typical very diverse height, diameter and age structure). Spectral analyses showed a substantial decrease in fluctuations in the tree-ring index and a loss in natural growth cyclicity in the last thirty years. The results also evinced that mean air temperature was the most important factor influencing the radial growth compared to precipitation totals. Pine thrives in precipitation-stable locations, as shown by the results from Great Britain. The conclusions of this study confirm the fundamental effect of ongoing global climate change on the dynamics and growth of pine forests in Europe.

THE FORMATION OF SPRINGTAIL ASSEMBLAGES (HEXAPODA, COLLEMBOLA) ALONG A RETREATING TSEY GLACIER, NORTH OSSETIA – ALANIA

Successional changes in springtail communities were studied along a retreating Tsey Glacier at 2336 to 2071 m a.s.l. Springtails were collected from 10 sites of different ages ranging from 1 to 170 years. The sites covered the main stages of surface overgrowth, from a bare ground through a grassy-shrub stage to mixed and then mature pine forests. Springtails appeared already during the first year after the glacier’s retreat and were represented by a species of the genus Desoria, a peculiar inhabitant of bare rocky-sandy soils. During the first 7–14 years of succession, rapid changes in population and species composition repeatedly occurred. Both abundance and species diversity of springtails sharply increased at the grassy-shrub stage (14 years) and reached their maximum at later ones. Starting with this intermediate stage, springtail assemblages were primarily composed of widespread generalists belonging to euedaphic and hemiedaphic life forms. Beginning from this point, the pace of succession gradually slowed down. Approximately 100 years since, springtail communities reached a level of diversity similar to that found in mature mountain forest communities in the region. However, their species composition and structure remained quite distinctive. A comparison with similar foreign studies showed the composition of periglacial springtail communities to exhibit high-level regional specificity.

Patterns of Florida Bonneted Bat Occupancy at the Northern Extent of Its Range

Abstract The Florida bonneted bat Eumops floridanus is a rare, endemic bat of South Florida that roosts in woodpecker cavities and anthropogenic structures such as roofing tiles, chimneys, and bat houses. The northernmost occurrences of the bonneted bat are from mature pine forests at the Avon Park Air Force Range, Florida. We used ultrasonic acoustic recorders to understand bonneted bat activity and habitat occupancy. We modeled occupancy using a hierarchical Bayesian analysis and included site- and time-specific covariates of detection probability and site-specific covariates of occupancy. Probability of detection was low throughout Avon Park Air Force Range but increased with Julian date. In most habitats, occupancy was poorly estimated, except for flatwood mature pinelands where occupancy was low (0.23 ± 0.06). As distance from red-cockaded woodpecker colonies increased, occupancy decreased (β = −1.19 ± 0.26 SD). At the northernmost extent of the range, and throughout much of the historic range, increasing the expanse of mature, fire-maintained forest systems will increase habitat for the bonneted bat and lead to faster population recovery.

Post-harvest energy chipping feasibility in mature pine forests in the Coastal Plain of the US South

ABSTRACT Research indicates that integrated systems, in which roundwood and energy chips are produced simultaneously, produce energy chips at the lowest cost. However, integrated systems may be feasible on a narrow range of sites. Post-harvest chipping, in which roundwood is harvested by one logging crew and energy chipping conducted independently by a second crew, may allow chips to be produced from more harvest sites. The goal of this study was to evaluate the feasibility of recovering logging residues and non-merchantable stems using post-harvest systems. Time-and-motion studies were conducted on both roundwood harvesting and post-harvest chipping on three harvest tracts on the Savannah River Site in the Coastal Plain of South Carolina. Hourly machine costs were estimated using the machine rate method. Harvesting costs per tonne were calculated using a modified Auburn Harvesting Analyzer. Energy chips were produced at an average estimated cost of $22.04 green t−1 (USD, onboard truck) and $31.96 t−1 delivered. Requiring the feller-buncher to fell and bunch non-merchantable stems reduced feller-buncher productivity by an average of 42% but did not reduce system productivity. This study suggests that post-harvest energy chipping can be a cost-effective alternative.

Eyes from the sky: Application of satellite-based indices to assess vegetation casualty on Grand Bahama Island one year post-Hurricane Dorian

In the last two decades, major hurricanes have devastated the forest landscape of Grand Bahama. To capture the extent of the pine forest loss on Grand Bahama, we used satellite-based indices (NDVI, NDMI, and NBR) from Landsat and Sentinel-2 images and the support vector machine algorithm to estimate vegetation casualty pre- and post-Hurricane Dorian. We estimated that from 2004 to 2020, Grand Bahama lost 90.9% and 58.6% of its pine and mangrove forests, respectively. In the 15 years before Hurricane Dorian (2004–2019), stressors that included three major hurricanes (Hurricane Jeanne, Frances, and Wilma) resulted in a 44.5% (246.0 km2) loss of the pine forest vegetation on the island. Later, Hurricane Dorian, a Category 5 tropical cyclone, made landfall in Grand Bahama in 2019 and resulted in further loss of pine vegetation (46.3% of the original vegetation [256.1 km2]) and more than half of the mangrove forests after flooding 67.0% (919.3 km2) of the island. Although mean NDVI and NDMI began to exhibit pre-hurricane seasonal patterns half a year after Hurricane Dorian struck, their values remained abated one year following the storm.To account for the effects of seasonal fires, we evaluated pine vegetation for evidence of forest fires during the dry and wet cycles of the year from 2018 to 2020. We found that seasonal forest fires temporarily reduced the pine forest understory vegetation but minimally impacted the pine vegetation between the reported years. The total area of forest impacted by fires was 11.3%. These low-intensity fires burned 67.3 km2 (22.5%; 2018), 31.8 km2 (10.6%; 2019), and 21.3 km2 (7.1%; 2020) of the intact mature pine forest (299.5 km2) pre- and immediately post-Hurricane Dorian. Even though we were able to detect and map areas of pine regeneration in previously hurricane-killed pine forest, Hurricane Dorian eliminated these young pines. Overall, Grand Bahama experience a significant loss of its forest after the major hurricanes of 2004, 2005, and 2019. This research reports new findings on hurricane-related damage to the pine forest ecosystem in Grand Bahama, providing valuable information regarding the ecological consequences of severe hurricanes on these types of forests.

Forest Growing Conditions Affect the CO<sub>2</sub> Emission from the Soil Surface in the Middle Taiga Pine Forests of the Komi Republic

Obtaining the experimental data on soil respiration is relevant due to significant range of CO2 emission estimates in different ecosystems. The aim of work was to characterize CO2 emission from soil surface of pine forests growing in different conditions on North-East of European part of Russia. The studies have been carried out in immature and mature pine forests Sphagnosa, Myrtillus and Lichen types located in the Institute of biology of the Komi Science Center, RAS forest stations. Carbon dioxide emission was measured using LI COR 8100 during the May-October periods in 2008–2017. A brief weather conditions characteristic was given. Higher values of the CO2 flux from the soil surface was observed in July (1.9–2.9 g С m–2 day–1 in Sphagnosa type) and August (2.5–6.6 g С m–2 day–1 in Myrtillus and Lichen types). The year-to-year variability and influence of weather conditions on soil respiration were shown. The soil temperature had a close and positive relationship (R2 = 0.49–0.77) with CO2 emission whereas correlation with soil moisture was weak. During summertime the efflux of C-CO2 in a pine forest of Myrtillus type was 188–442 g C m–2, during the vegetation period (01.05–30.09) – 279–563 g C m–2 and the snowless period (01.05–31.10) – 308–583 g C m–2, which is 1.5–1.8 times higher than in the pine forests of Sphagnosa and Lichen types during the snowless period (р = 0.014) and growing season (р = 0.020). In summertime the losses of carbon were similar (р = 0.106). The pine forests of Sphagnosa and Lichen types were comparable in С-СО2 efflux both during the vegetation and the snowless periods (p 0.05). These data are important in assessing the expenditure part of the carbon balance in forest ecosystems in the European North-East of Russia.

Влияние рубок ухода на биологическую устойчивость сосняков защитного назначения Северного Казахстана

The article presents the results of thinnings in pineries of the Kazakh uplands in Northern Kazakhstan carried out for an over 70-year period and their influence on biosustainability (on the example of the state national natural park «Burabay»). The research objects are high-density mature pine forests growing in dry forest conditions. The results of research have shown that to the average values of the vital status indicator (VSI), the complex estimated indicator (CEI) and the tree slenderness coefficient (H/D), pine stands in most sections are characterized as «weakened». In forest stands after thinning of strong and very strong intensity of thinning in terms of tree slenderness coefficient (H/D) the pine forests is assessed as healthy. It is proved that the vital status maximum credible indicators of the pine forests and the implementation of forestry practices in them is the tree slenderness coefficient. The largest number of trees (up to 70 % of the total number of trees) with tree slenderness coefficient an H/D value of less than 100 in the pine forest after very high intensity thinning is evaluated. A large number of trees with H/D < 100 in the forests proves a weak competition between trees in the forests and higher resistance to natural and anthropogenic factors are proved. The data obtained show a positive effect of strong thinning on the increase in the radial growth of pine trees. For formation of sustainable pine forests in dry growing conditions in Northern Kazakhstan with thinning one-two steps with 26–35 % of the stock volumes destruction at the age of 25–30 years and 40–50 years, and with subsequent increment felling in them is recommended.

Soil transfers from intact to disturbed boreal forests neither alter ectomycorrhizal fungal communities nor improve pine seedling performance

Abstract Forest disturbances can alter mycorrhizal fungal communities with consequences for subsequent plant establishment and growth. One possible mitigation strategy to promote forest recovery following disturbances is inoculation with soil from late‐successional forests. However, whether these soil transfers change the composition of resident fungal communities and how seedling growth responds to such transfers is unknown. To test whether soil transfers can mitigate disturbance‐mediated impacts on ectomycorrhizal fungal (EMF) communities, we transferred soils containing fungal inoculum collected from conspecific late‐successional forests into stands disturbed by wildfire, mountain pine beetle outbreak, clear‐cut logging or salvage logging. Afterward, lodgepole pine seeds were sown to measure germination, establishment and growth of seedlings, and to characterize root‐associated and soil EMF communities by sequencing the ITS1 rDNA region. Despite evidence that soil inocula contained viable EMF communities, transfers did not impact the root‐associated or soil EMF community composition, or seed germination, seedling establishment and growth. Resident EMF community composition remained unchanged upon transfers of fungi from late‐stage successional forests, and disturbance type singularly explained the EMF community composition associated with roots and soils. Ectomycorrhizal fungal taxa typically associated with mature pine forests were particularly abundant on roots of seedlings growing in plots impacted by beetle outbreak, while ‘early‐stage’ EMF taxa were associated with seedlings growing in wildfire and logging disturbances. Synthesis and applications. Following disturbances, soil and root‐associated EMF exhibit high functional redundancy, as seedling performance did not vary with differences in EMF community composition across disturbance types. Our findings suggest that soil transfers are unlikely to be an effective strategy in these stands and may be better targeted to highly degraded forests. The presence and abundance of EMF in disturbed forests should be assessed before committing to soil transfers as part of restoration.

Forest structure determines nest box use by Central European boreal owls

Nest boxes represent a popular tool to support secondary cavity-nesting species. Surprisingly, the benefits and limitations of nest boxes for target species in different environments are poorly understood. We performed a 3-years experimental study in two different Central European forests to evaluate nest box use and breeding performance of boreal owl (Aegolius funereus) — a species well known for its readiness to occupy nest boxes. Based on territorial vocalisation, two boreal owl populations 200 km apart were similarly abundant in their environments. However, only the boreal owl population in young restored Norway (Picea abies) and blue (Picea pungens) spruce-dominated forests on mountain plateaus readily occupied nest boxes with the occupancy reaching 8–15%. Nest boxes lost their supporting function for the boreal owl in mature Scots pine (Pinus sylvestris)-dominated forests in the lowland, where the nest box occupancy reached 0–1%. As a result, the population of boreal owls that used nest boxes in the young restored forests produced 10 times more fledglings than the population inhabiting mature Scots pine forests. We explain the differences by the contrasting availability of natural tree cavities between the two study areas being much higher in mature Scots pine forests. For the first time, this study documents differences in nest box use despite similar food availability and population size of the target species. The study provides the findings-related recommendations for deploying nest boxes for boreal owls and points out a general lack of practical guides.

The oldest Pinus nigra plantations in the central Apennines: distribution and floristic-vegetational characterisation

This paper represents the first syntaxonomic study on the Pinus nigra subsp. nigra artificial stands in the Apennines. It refers exclusively to the mature Pinus nigra forest plantations in the central Apennines that were planted before the 1950s, and then not managed. The mature Pinus nigra forest plantations in the central Apennines are distributed within four National Parks, on limestone substrata, mainly with southern aspects and rugged slopes, and at elevations ranging from 655 m to 1670 m a.s.l.. Two new phytosociological associations are described here and classified in the alliance Junipero communis–Pinion nigrae: Orthilio secundae–Pinetum nigrae and Digitalidi micranthae–Pinetum nigrae. The association Orthilio secundae–Pinetum nigrae comprises the relative mesophilous mature pine forests of the supratemperate thermotype in the plant landscape context of the alliance Aremonio agrimonioidis–Fagion sylvaticae potential vegetation belt. The Digitalidi micranthae–Pinetum nigrae comprises the thermophilous pine forests occurring on rocky stands within mesotemperate and lower supratemperate thermotypes in the potential belt of alliance Carpinion orientalis woods. The comparison of these two new associations and the phytosociological literature concerning the natural communities of Pinus nigra in the Apennines highlights their floristic and coenological autonomy.

Seasonal Variations in Litter Layers' Characteristics Control Microbial Respiration and Microbial Carbon Utilization Under Mature Pine, Cedar, and Beech Forest Stands in the Eastern Mediterranean Karstic Ecosystems.

The forest floor is hotspot of several functions integral to the stability of forest ecosystems. However, seasonal variations in litter decomposition rate contribute to biochemical and structural heterogeneity in the forest floor carbon (C) and nutrient cycling. We investigated the influence of seasonal variations in litter layers' micro-climate (temperature and moisture content) and chemical characteristics such as pH, electrical conductivity (EC), total organic C (TOC), total nitrogen (TN), and C/N ratio on microbial respiration, biomass, and C use efficiency under mature (> 80years stage age) pine, beech, and cedar forests in eastern Mediterranean Karstic ecosystems. In contrast to significantly higher microbial respiration in fall, winter, and spring under pine, beech, and cedar forests, the significantly lowest microbial biomass C (MBC) and microbial biomass N (MBN) were observed in winter under each forest. Microbial C use efficiency, measured as the metabolic quotient (qCO2 = CO2/MBC), varied strongly between forest stands and seasons but was generally higher in winter. The significant positive correlations between litter layer and microbial biomass C/N ratios, under beech and cedar forests, suggested strong CN stoichiometric coupling and microbial adaptation to substrate resource stoichiometry. qCO2 correlated significantly negatively with litter layers' temperature, positively with moisture content and EC. However, qCO2 had significant negative relationships with pH in pine and beech forests but significant positive under cedar forest. qCO2 showed significant positive relationships with C/N ratios under all forests but much stronger in beech and cedar forests suggesting higher C respired per unit MBC with an increase in C/N ratio. Despite variations between forest species, the highest MBC/TOC and MBN/TN ratios in fall indicated greater C and N incorporation into microbial biomass. Changes in MBC/MBN ratios under pine (9.62-10.6), beech (8.63-15.6), and cedar (7.32-16.2) forests indicated the shift in microbial communities as fungi have a higher C/N ratio than bacteria. Stepwise regression analysisfurther revealed that microbial respiration and biomass were controlled differentlyby litter layer characteristics in each forest. This study suggested that qCO2 independently or with other microbial indices can show litter layers' controls on organic matter turnover in Karst ecosystems and, taking into account the strong seasonal variations, can enhance the predictive potential of decomposition models.

Impact of harvesting methods and forest floor displacement on nutrient stock of Scots pine ecosystems in the Central Anatolia Region of Turkey.

Concern about the negative effects of logging residue extraction on the sustainability of forest ecosystems has been rising recently. Tree residues, including leaves, branches, bark and roots, left in the forest after logging may supply most of the nutrients for tree growth. The aim of this study was to (i) determine the carbon and nutrient stocks in different components and (ii) model the carbon and nutrient stocks in tree biomass of a mature Scots pine forest. The study site was located on the Turkmen mountain range in the Central Anatolia Region of Turkey. In sample plots, stand measurements were made, and samples collected from trees, soil and the forest floor for analysis of carbon and nutrients and the stock of each nutrient per unit area were calculated. Data were analysed using analysis of variance and regression analysis. Significant differences were found in carbon and nutrient concentrations and stocks between ecosystem components. C, Ca, Mg, Na, Fe, Cu and Mn stocks were higher in wood; the N stock was higher in needles, and P, K, S and Zn stocks were higher in roots. In the ecosystem, trees had the highest C stock; the soil had the highest N, P, K, Ca, Mg, Na, Cu, Zn and Mn stocks, and the forest floor had the highest Fe and S stocks. Therefore, it is critical that the forest floor is protected as it is an important element of the ecosystem nutrient cycle and source of Fe and S stocks. Maximum attention should be paid to leaving behind needles, bark, roots and thin branches with low economic value to minimise carbon and nutrient loss in the nutrient-limited forests. Equations predicting carbon and nutrient stocks through stem volume can be used for estimation of nutrient loss due to biomass removed from the system through interventions, contributing to sustainable forest management.

ACCUMULATION OF 137Cs BY LICHEN HYPOGYMNIA PHYSODES (ON THE EXAMPLE OF THE GOMEL REGION)

The paper presents the results of determining the 137Cs content in the biomass of the lichen Hypogymnia physodes, which growing in pine forests on the territory of the Gomel region with various levels of radioactive contamination.The research was carried out both in conditionally clean and radioactively contaminated areas with 137Cs soil contamination density from 37 to 1488 kBq m-2. The high accumulating capacity of the lichen Hypogymnia physodes in relation to 137Cs was shown, as well as an increase in the concentration of the radionuclide in the lichens biomass with an increase in the density of soil contamination. Differences in 137Cs accumulation by the lichen Hypogymnia physodes, growing in uneven-aged pine stands, were noted. The lowest concentrations of 137Cs were noted in the samples growing in mature pine forests, while thalli sampled from young pine stands contain significant amounts of the radionuclide.

Net Primary Production of Carbon in Pine Forests on European North-East of Russia (Republic of Komi)

The accumulation of carbon of organic matter by forest phytocenoses during photosynthesis is their most important function, mitigating climate change on the Earth. The literature provides data that the territory of the Russian Federation is a large sink of atmospheric carbon. However, the estimates of the sink, as well as the values ​​of the net primary production (NPP) of forest ecosystems, vary widely. This paper presents materials describing the net carbon production of phytomass in pine forests of different types of growing conditions in the northern and middle taiga of the Komi Republic. Premature, mature, and old-growth pine forests of green moss, lichen, and sphagnum types have been studied at forest stations. The carbon sequestration by the forest stand is assessed by biological productivity using sample trees. The regression equations for the dependence of the increments of individual organs of a sample tree on the stem diameter at a height of 1.3 m are composed. A statistically significant relationship is found between these parameters, characterized by high trend approximation values ​​varying from 0.44 to 0.99 (at 95% significance level). It is calculated that, under the conditions of the European Russian northeast, the NPP of carbon in pine phytocenoses varies within the range of 1.9–4.5 t C ha–1 year–1. It is established that the tree stand accounts for 32–73% of the total NPP. With increasing soil moisture and moving northward, the participation of plants in the ground vegetation increases in the total NPP. It is noted that a significant part of the NPP of carbon of the tree layer of pine forests is formed by the photosynthetic apparatus and the stem wood. Based on these data, the conversion relations between NPP and wood volume/carbon stock in the stand for pine forests of the northern and middle taiga are derived.

Response of Drainage Water Quality to Fertilizer Applications on a Switchgrass Intercropped Coastal Pine Forest

The objectives of this study were (1) to test the hypothesis that fertilizer applications do not increase nutrient fluxes on a switchgrass/pine forest (IC) when compared to a mature pine forest (MP) and (2) to evaluate post-fertilization (post-fert, 2014–2016) fluxes of nitrogen (N) and phosphorus (P) on IC and compare them to those observed during switchgrass growth prior to fertilization (pre-fert, 2012–2014) and site preparation for switchgrass establishment (site prep, 2009–2012). Nitrogen and P were applied to IC, a paired pure switchgrass site (SG), and MP, each about 25 ha in size, in June 2014, and again in June 2015 for the IC and SG sites only. Nitrogen and P concentrations were measured biweekly and rainfall and drainage outflow were measured continuously. During post-fert, the mean N concentrations and total loads were lower (p < 0.05) in IC than in SG and MP. The mean NO3-N concentration and loads in IC were lower during post-fert than during site prep. The post-fert phosphate concentrations in IC were lower than they were during pre-fert and site prep. Frequent N and P applications in IC did not significantly (α = 0.05) increase N and P fluxes, likely due to plant uptake and sorption on the acidic site.

Tree diametric-species diversity is affected by human impact in old Scots pine dominated forest in boreal Fennoscandia

BackgroundForest structural and compositional variability is of fundamental importance for forest ecosystem functioning and species diversity. The purpose of this research was to examine how human impact has affected the compositional-structural diversity of mature pine-dominated boreal forest in boreal Fennoscandia. For this a new approach was used, based on the classification of tree sizes by the diameter at breast height (dbh) and tree species, resulting in a new variable, the diametric-species, the variation of which describes the compositional-structural diversity of the forest. This variable was used to compare the structural-compositional diversity among three forest classes with different degree of human influence, using rarefaction as the main tool of analysis, complemented by analyses based on common diversity indices.ResultsThe results showed that the near-natural forest was the most diverse and the managed forest the least diverse. On the other hand, the diversity of near-natural and selectively logged forests were similar, suggesting that selectively logged forests are equal to the natural forest in their compositional-structural diversity. The analysis solely on tree species showed no significant differences among the forest classes of different human impact. The Shannon diversity index showed no significant difference between the forest classes for the diametric-species and tree species classifications only, but the Simpson index signaled a slight difference between the selectively logged and managed forest classes for the diametric-species classification. Furthermore, the Sorensen index detected a difference among forest classes in the diametric-species classification.ConclusionsForest utilization had an adverse impact on forest compositional-structural diversity of mature Scots pine forests. The analysis also shows that the novel approach based on diametric-species classification could be a useful tool for forest diversity analysis and comparison, especially in species-poor forests such as the boreal forest.

Common Swifts (Apus apus) nesting in mature pine forests in Corsica

Tree breeding in holes has been recorded for the Common Swift (Apus apus) mainly in Northern Europe and Siberia. This behaviour, considered as ancestral, has also been noted in Corsican forests. Although marginal in terms of numbers, it is a perennial phenomenon. We present here a synthesis on the distribution and the characteristics of nesting sites, and we compare these breeding sites to the occurrences in continental Europe and Northern Africa. Our data add to the body of arguments in favour of the preservation of mature forests of the Corsican Pine on the island.

Variability in colour, metallic lustre, and body size of <i>Carabus arvensis</i> Herbst, 1784 (Coleoptera: Carabidae) in relation to habitat properties

Objectives are to elucidate whether populations of Carabus arvensis Herbst, 1784 from contrasting habitats differ in (i) colour, (ii) brightness of metal lustre, or (iii) body size (length of elytra, of elytra + pronotum, and width of pronotum). Two large populations were studied, originating from (a) open heathland, being a remnant from more widespread heaths during former centuries, and (b) mature pine forest established 100–150 years ago on sandy agricultural land. Heath individuals had significantly more brilliant metal lustre and mostly lighter, vivid copper colour than pine forest individuals, which were typically black with a violet shade and slightly larger in size. The two populations are nowadays isolated, which was probably not the case 1–2 centuries ago, when both sites studied were treeless. The usually blackish colour of the forest population could be a recent adaptation to the changed environment, though some influence of processes such as genetic drift cannot be excluded.

Responses of soil mite communities (Acari: Oribatida, Mesostigmata) to elemental composition of mosses and pine needles and long-term air pollution in Scots pine (Pinus sylvestris L.) stands.

Air pollution is an important threat to biodiversity via deposition of high amounts of heavy metals or nutrients (macroelements). In forest ecosystems contamination can be found in plant tissues and the soil environment including soil mesofauna. However, there is little information on how it influences soil mesofauna. Hence, the aim of the study was to evaluate the reaction of soil mites (Acari: Oribatida, Mesostigmata) to long-term air pollution in mature pine (Pinus sylvestris L.) forests in southwestern Poland. The study was conducted in late autumn between October 2008 and 2010 in eight 5000 m2 plots, each within a Scots pine stand. Concentrations of macroelements (C, N, S, Ca, Mg) and heavy metals (Cu, Cr, Cd, Ni, Pb, Zn) were measured in 40 samples of pine needles and 36 bryophyte samples. In total, 360 soil samples were collected for the soil mesofauna analysis. Results of the study include correlations between the sample plot, the year and the soil mite abundance. Among the macroelements analyzed, calcium affected the abundance of mite species the most. Soil mite communities from different forests were dominated by the same species, despite the fact that we found in total 150 mite species, among which there were 106 species of oribatid mites and 44 species of mesostigmatid mites. It seems that, among the elements analyzed, calcium plays the most important, positive role for mite communities. Magnesium had a positive effect on abundance of both mite groups, while nitrogen had a negative effect on diversity of oribatid and mesostigmatid mite communities. Our study indicated that oribatid and mesostigmatid mite communities are stable in areas of long-term contamination, as we did not observe distinct changes in structure and diversity of soil mite assemblages along the pollution gradient.

Early responses of vascular plant and bryophyte communities to uniform shelterwood cutting in hemiboreal Scots pine forests

Shelterwood (SW) cutting is considered a sustainable harvest method but its impact on understorey diversity of Scots pine (Pinus sylvestris) forests has not been thoroughly studied. Our aim was to clarify how uniform SW cutting in interactions with soil scarification, deposition of logging residues and altered light conditions affects the species richness and composition of vascular plants and bryophytes and how different species groups and individual species vary in their responses to SW practices. We monitored permanent vegetation plots in nine mature pine forests of hemiboreal Estonia before, shortly after and 3–4 years after SW harvesting. The results indicated that the effect of uniform SW harvesting was species group specific as the majority of vascular plant species groups as well as mosses and epigeic bryophytes increased in richness, however, the species richness of epiphytic and epixylic bryophytes decreased. Late-successional species showed two types of responses to SW harvesting: either reduction of cover or reduction followed by a recovery. Soil scarification favoured early-successional bryophyte species as well as the richness of tree seedlings and dwarf-shrubs but diminished the cover of Vaccinium myrtillus, Vaccinium vitis-idaea and Hylocomium splendens. The harvest-induced changes in the species composition were more pronounced for bryophyte communities than for vascular plants. Retention of green trees and dead-wood is important in SW harvesting for sustaining the vulnerable epixylic and epiphytic bryophyte species. To summarise, uniform SW harvesting increases the species richness of vascular plant and bryophyte communities in pine forests - at least in the short term.