Morphophysiological responses of Pinus sylvestris L. and Picea obovata Ledeb. to industrial pollution under conditions of Northwestern Russia

Morphophysiological parameters of needles have been studied in Scots pine (Pinus sylvestris L.) and Siberian spruce (Picea obovata Ledeb.) trees of different life states growing under conditions of industrial air pollution with sulfur and heavy metals. Three functional clusters (tentatively named the initial, transitional, and disastrous clusters), each characterized by a certain metabolic status, have been revealed, and their quantitative and qualitative structure has been evaluated. The morphophysiological responses of pine and spruce are shown to be qualitatively different, depending on differentiation of trees with respect to vitality under conditions of industrial pollution. Probable factors accounting for these differences are discussed.     

The Holocene dynamics of vegetation and climatic conditions on the eastern slope of the Subpolar Urals

Changes in the vegetation and climatic conditions on the eastern slope of the Subpolar Urals over the past 10000 years have been reconstructed on the basis of integrated palynological, botanical, and radiocarbon analysis of material from two sections of peat deposits in the floodplains of the Lyapin and Man’ya rivers (the Severnaya Sos’va basin). The dynamics of regional vegetation have been traced: from the herb–shrub tundra in the late postglacial time to the spruce–larch forest–tundra and sparse larch–birch–spruce stands in the Early Holocene, to birch–pine–spruce forests with an admixture of fir in the Middle Holocene, and to northern taiga forests with dominance of Scots pine and Siberian stone pine (similar to present-day forests) in the Late Holocene. The results show that the northern taiga zone of the study region in the period between approximately 5500 and 2500 years BP was occupied by forests of middle and southern taiga facies, as the climate was significantly warmer than it is today.     

Effects of Soil Hydrothermal Conditions on the Complexes of Soil Invertebrates in Coniferous and Deciduous Forest Cultures

The effects of hydrothermal conditions on the complexes of soil invertebrates in 20-year-old cultures of Siberian stone pine, larch, Scotch pine, spruce, birch, and aspen are considered. The role of soil temperature and moisture content in determining the density of pedobionts and their vertical distribution is revealed. Seasonal fluctuations of hydrothermal parameters are shown to affect the vertical migrations of soil invertebrates and the dynamics of trophic structure of their complexes under forest cultures during the growing season.     

Response of the pigment system of conifers to long-term industrial air pollution

To estimate the response of conifers to long-term industrial air pollution at the pigment system level, the dynamics of photosynthetic pigments have been studied in needles of Scots pine (Pinus sylvestris L.) and Siberian spruce (Picea obovata Ledeb.) growing at different distances from the emission source (a pulp and paper mill). It has been shown that the pigment apparatus of spruce. The results show that in spruce, unlike in pine, the pigment apparatus remains unchanged under the effect of weak pollution. Long-term exposure at high levels of industrial emission results in suppression of chlorophyll and carotenoid syntheses in pine but stimulates pigment production in spruce. An increase in the contents of pigments in the needles of conifers growing in the impact zone of the pulp and paper mill reflects a compensatory mechanism of adaptation of their pigment system to long-term stress exposure.     

Mineral composition of assimilative organs of conifers after reduction of atmospheric pollution in the Kola Peninsula

An analysis has been made of changes in the mineral composition of conifer needles in northern taiga forests after reduction of emissions from the Severonickel Copper-Nickel Smelter Complex in the city of Monchegorsk, the most powerful source of air pollution in Northern Europe. The data obtained in permanent monitoring plots in 1991, 1993, 2000, and 2007 have been compared. The results provide evidence for reduction in the concentrations of heavy metals (Cu, Ni, Fe) and sulfur in the needles of spruce and pine trees in areas with different levels of air pollution. However, mineral nutrition of conifers has not been optimized. The plants are insufficiently supplied with nutrient elements such as P, Mg, Mn, and Zn. The contents of these and other elements essential for the normal functioning of needles (in particular, Ca, K, and P) continue to decrease, especially in pollution-induced sparse spruce forests. The most significant alterations of nutrient regime have been revealed in the Siberian spruce.     

Dynamics of snowmelt water composition in conifer forests exposed to airborne industrial pollution

An analysis is made of the spatial variability of snowmelt water composition (within and between biogeocenoses), with regard to its long-term dynamics, in pine and spruce forests exposed to airborne industrial pollution from the Europe’s largest Severonikel Copper–Nickel Smelter Complex. Snowmelt waters from under the tree canopy, compared to those from intercrown areas, contain higher concentrations of chemical elements due to their washing and leaching from tree crowns. This is especially true of spruce forests, since the crowns of spruce trees have a high sorption capacity. Distinct trends in the long-term dynamics of snowmelt water composition, related to reduction of industrial emissions, are observed in background forest areas and defoliating forests but not in the vicinity of pollution sources. It is shown that the main factors determining these dynamics in forests of the Kola Peninsula are edificator tree species, airborne industrial pollution, and, possibly, an increase in the number of days with above-zero temperatures in the period of snow accumulation, which facilitates washing and leaching of chemical compounds from tree crowns.     

Pollution-induced successions in forests of the Kola Peninsula

Trends of changes in the successional status of northern taiga forests exposed to technogenic pollution in the Kola Peninsula are discussed. Main studies of digression in spruce and pine forests are characterized on the basis of the dynamics of species composition of phytocenoses and chemical composition of atmospheric fallout, soils, and dominant plants.     

Appropriateness of needles of different conifer species for the feeding and growth of larvae from two populations of the Siberian moth

A comparison of two Siberian moth populations from the Altai Republic (feeding on Siberian fir) and the Tyva Republic (feeding on Siberian larch) has revealed no differences between them with respect to ecophysiological parameters of larval growth and feeding on needles of the same conifer species under laboratory conditions. The index of appropriateness of food plants for the larvae from both populations decreases in the series larch > fir > spruce > pine. The age-related dynamics of parameters characterizing the feeding and growth of larvae are independent of the population to which the insects belong.     

Analysis of meiotic chromosome aberrations in Siberian spruce (Picea obovata Ledeb.) under conditions of natural and technogenic stress

Meiotic abnormalities have been studied in Siberian spruce growing in the Southern Urals under different ecological conditions: in contrasting natural landscapes (high mountains, plains, river valleys and floodplains), in zones of natural geochemical anomalies, and in areas with different levels of industrial pollution. The results provide evidence for an adverse effect of technogenic pollution and extreme environmental factors on the process of microsporogenesis in the species studied.     

Decline of spruce (<Emphasis Type="Italic">Picea abies</Emphasis>) in forests of Belarus

The decline of spruce stands in Belarus has been analyzed in relation to the dynamics of climatic variables. The results show that this process is correlated with the amount of precipitation, moisture deficit, index of aridity, relative air humidity, and evapotranspiration. Frosts at the onset of the growing season enhance tree die-off, while increase in cloud cover has a favorable effect on the state of spruce stands. Damage to trees occurs mainly in areas with elevated and convex topography and slopes of southwestern aspect, increasing on steeper slopes. The level of die-off is most closely correlated with conditions of the previous year, which is explained by the impact of biological factors (pest insects and phytopathogens) on tree stands already affected by water stress. The decline of spruce stands on a mass scale is also observed in neighboring regions of Russia and counties of East Europe, which is evidence for a low adaptability of spruce to current climate change, including the increasing frequency and severity of dry periods.     

Impact of climate change on vulnerability of forests and ecosystem service supply in Western Rhodopes Mountains

The vulnerability of forest ecosystem services to climate change is expected to depend on landscape characteristic and management history, but may also be influenced by the proximity to the southern range limit of constituent tree species. In the Western Rhodopes in South Bulgaria, Norway spruce is an important commercial species, but is approaching its current southern limit. Using climate sensitive forest models, we projected the impact of climate change on timber production, carbon storage, biodiversity and soil retention in two representative landscapes in the Western Rhodopes; a lower elevation landscape (1000–1450 m a.s.l) dominated by mixed species forests, and a higher elevation landscape (1550–2100 m a.s.l.) currently dominated by spruce. In both landscapes climate change is projected to induce a shift in forest composition, with drought-sensitive species, such as Norway spruce, being replaced by more drought-tolerant species such as Scots pine and black pine at lower elevations. In the higher elevation landscape a reduction in spruce growth is projected, particularly under the more severe climate change scenarios. Under most climate scenarios a reduction in growing stock is projected to occur, but under some scenarios a moderate increase in higher elevation stands (>1500 m a.s.l.) is expected. Climate change is projected to negatively influence carbon storage potential across landscapes with the magnitude depending on the severity of the climate change scenario. The impact of climate change on forest diversity and habitat availability is projected to differ considerably between the two landscapes, with diversity and habitat quality generally increasing at higher elevations, and being reduced at lower elevations. Our results suggest that if currently management practices are maintained the sensitivity of forests and forest ecosystem services in the Western Rhodopes to climate change will differ between low and higher elevation sites and will depend strongly on current forest composition.     

Meteorological factors and Norway spruce condition: Role of site humidity

The aim of this study was to determine the possible effects of meteorological factors on the crown condition of Norway spruce in habitats with different site humidity. In many cases the correlation between meteorological indices and crown condition was stronger and more reliable in habitats with normal humidity than in overmoist habitats. Our results suggest that meteorological conditions during the vegetation period play more significant role compared with dormant period for spruce crown condition.     

Distribution of Fine Roots of Coniferous Trees over the Soil Profile under Conditions of Pollution by Emissions from a Copper-Smelting Plant

The distribution of fine conducting roots of Siberian spruce, Siberian fir, and Scotch pine over the soil profile was studied in the taiga ecosystems polluted with heavy metals and SO₂. Under conditions of heavy pollution, tree roots were not found in the forest litter. Regardless of the level of technogenic load, the largest amount of conducting roots concentrated in the upper layer of mineral soil.     

Scotch Pine Pollen under Conditions of Environmental Stress

Environmental conditions causing stress have a significant effect on the generative organs of Scotch pine. The parameters characterizing pine pollen are subject to significant interannual variations and are closely connected with weather and climatic conditions in the period of pollen formation. Airborne pollutants affect the quality of pine pollen, which is especially apparent in the years favorable for the formation of microspores. The ability of Scotch pine pollen to germinate and form pollen tubes in the regions with different technogenic loads proved to be significantly lower than in tree stands of the background areas.     

A study of the impacts of climate change on the geographic distribution of Pinus koraiensis in China.

The climatic conditions and elevation of the potential distribution area of Korean pine (Pinus koraiensis Sieb. et Zucc) in China were determined by an ecological information system GREEN that has been developed by [Yan H, Booth TH, Zuo H, editors. GREEN--a climatic mapping program for China and its use in forestry. In: Matching trees and sites, ACIAR Proceedings No. 63. Australia: ACIAR, 1996]. The potential distribution areas of this tree species under current and predicted climatic conditions were mapped using IDRISI GIS. Based on the averages of rainfall and temperature predicted by 5 GCMs (GISS, NCAR, OSU, UKMO and MPI, i.e., an "averaged" model) and a new model HadCM2 for 2030, predictions were made on the future distributions of Korean pine. The result shows that the southern boundary of the potential distribution area of Korean pine will have a northward shift of 0.1 degrees to 0.6 degrees in latitude, and the northern boundary will have a northward shift of 0.3 degrees to 0.5 degrees, resulting in an expansion of the potential distribution area by 3.4% according to the average of the five models. However, the distribution areas will be decreased by 12.1% and 44.9% according to the scenarios predicted by HadCM2, which assumes annual increments of CO2 concentrations of 0.5% and 1%, respectively. The authors concluded that if the thresholds were properly selected the actual distribution and potential distribution of a tree species might agree. The projected distribution under changed climatic conditions depends on the GCM scenarios applied. Different GCM scenarios may sometimes give opposite conclusions, as in the case of Korean pine projected by the "averaged" and HadCM2 models.     

Competition factors of edificator tree stand: Quantitative analysis and synthesis

To analyze and quantitatively estimate the contribution of different factors of competition from the edificator tree stand to its effect on plants comprising the lower forest vegetation layer, a set of ecophysiologically based indices of root, light, and integrated competition has been proposed and tested. The results obtained in pine and spruce forests forests of Western Siberia and the Urals show that the growth of the conifer undergrowth is more closely correlated with the index of root competition, and that of heather (Calluna vulgaris (L.) Hull.), with the index of light competition from the edificator tree stand. Moreover, the correlation of their growth with the integrated competition index is 15?C25% stronger than the correlation with the indices of root and light competition, irrespective of forest type.     

Effects of short-term ozone exposure on net photosynthesis,dark respiration,and transpiration of three eastern white pine clones

Net photosynthesis, dark respiration, and transpiration rates were determined during ozone (O₃) exposure for three clones of eastern white pine (Pinus strobus L.) differing in sensitivity to O₃. Fumigations for 4 h with 0.10, 0.20, and 0.30 μL/L O₃ inhibited net photosynthesis of all three clones. Light transpiration was inhibited in both the sensitive and the tolerant clones and was not affected in the intermediate clone. Recovery of net photosynthesis and light transpiration occurred 1 h after the termination of ozonation, with the degree of recovery depending upon clonal sensitivity to O₃ and the O₃ concentration used. Dark respiration increased in the O₃-sensitive clone only, and dark transpiration was unaffected in all three clones after 4-h exposure to 0.30 μL/L O₃. Ozone-induced inhibition of net photosynthesis and stimulation of dark respiration are discussed in relation to clonal sensitivity to O₃.     

Reconstruction of May–June precipitation in the territory of Bashkiria based on Scots pine tree-ring data from the Bugulma–Belebey Upland

The relationship between Scots pine (Pinus sylvestris L.) tree-ring width and temperature and precipitation was analyzed in pine forests on the Bugulma–Belebey Upland, Bashkiria. A close correlation between tree-ring width and the current spring–summer precipitation was revealed. On this basis, a reconstruction of May–June precipitation in the period from 1860 to 1994 was made.     

Assessment of the risk of excess sulfur input into terrestrial ecosystems of the Kola Peninsula

The tolerance of terrestrial ecosystems of the Kola Peninsula to atmospheric deposition of acid-forming sulfur compounds and the risk of their excess input into these ecosystems have been assessed on the basis of the critical load concept. The most sensitive ecosystems (critical sulfur load <400 equiv/ha per year) occupy 58% of the total area of the peninsula. These are mainly pine, spruce, and birch forests (including open and crooked birch forests) growing on podzols formed on sandy boulder-pebble glacial deposits. The zones of ecological risk cover the northwestern and central parts of the peninsula near the Pechenganikel and Severonikel combined works (20% of the total area).     

The hypothesis of hydrochorous dissemination of populations of conifers

A comparative analysis of field observations and experiments on the distance and rate of dispersal of self-sown Scotch pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) progeny has shown that the rate of their hydrochorous dissemination downstream is an order of magnitude higher than the rate of dispersal in upland areas. A hypothesis assigning priority to the role of hydrochory in the expansion of conifer populations to the tundra (periglacial) zone along with climate warming has been formulated and substantiated by comparative isozyme analysis of populations in transects lying along and across rivers.