To develop an antioxidant assay, the oxidation of phenolics and ascorbic acid by cupric ferricyanide in solution was estimated. Solutions (pH 6.6) were kept clear with citrate and gelatin. Reaction kinetics of the color formation at 480 nm indicated further slow increase after initial fast reaction with a sample. With the active phenolics (tannic acid, quercetin, rutin, chlorogenic acid), sufficiently stable endpoint was reached at 35 °C by 90 min. Calibration showed deviation of 5–10 % from the linearity. Antioxidant mixtures of tannic, chlorogenic, and ascorbic acids indicated small positive interaction between tannic and chlorogenic acids. Extracts from forest trees and green tea responded in the same way as individual phenolics to the oxidation. Common plant osmolytes in excess did not interfere with the analysis of tannic acid for its reducing activity. Due to a poor endpoint with ascorbic acid, a method for stabilizing the endpoint was looked further. Borate, molybdate, and lower pH greatly inhibited the reaction with ascorbic acid during the slow phase. By the presence of copper ions, it was possible that the autoxidation of ascorbic acid produced hydrogen peroxide during the slow phase. However, hydrogen peroxide gave substantial color response. Solvent N-methylpyrrolidone at low level inhibited or decreased the color formation for several analytes, suggesting that an analyte-dependent activation of oxygen could cause decolorization of cupric ferrocyanide. Current findings indicated that the cupric ferricyanide antioxidant reaction can be potentially developed to an assay for estimating reducing activity in extracts from woody plants or green tea.

Trees in cutaway peatland are growing in difficult conditions. Fertilization with nutrient-rich wood ash helps improve growth conditions. Photosynthesis and carbohydrate concentration along leaf anatomy were studied on plots treated with 10 and 5 t ha−1 wood ash (WA10 and WA5) and on untreated (Control) plot to explain the physiological background of the differences in tree growth. The leaves from WA10 had the largest leaf area, total thickness, the thickest mesophyll and also significantly larger average values of all anatomical parameters of the shoots. The photosynthetic assimilation was significantly higher on treated plots at 200 and 400 ppm CO2 levels. In leaves on the treated plots, the sucrose concentration was lower while that of starch was higher than in trees on untreated soil. The differences in the maximum photosynthesis were relatively small. At unit ground, the leaf area provided for a wood ash-treated tree an efficient surface for CO2 assimilation, light interception and some starch storage during the growing period.

The effects of clinker dust and wood ash on Norway spruce and Scots pine seedlings were compared in buried pots. Clinker dust (0.5 kg m(-2)) and wood ash (0.5 kg m(-2)) were applied to the surface of a nutrient-poor mineral soil. In the second year, the increase in soil pH by the dust and ash were larger than in the first year. Both alkaline treatments caused a large increase in the needle potassium (K) concentration. An excess of soil K relative to magnesium (Mg) was observed by decreased Mg concentration in needles shortly after treatment. However, Mg concentration in needles stayed in the sufficiency range. Current results confirmed earlier findings that despite a positive effect on base cation nutrition, wood ash has a low potential for increasing the biomass of forest stands on mineral soils due to the N limitation in these soils.

Interactions between photosynthetic rate, transpiration, content of soluble carbohydrates, leaf dimensions and structural parameters and growth of hybrid aspen (Populus tremula × P. tremuloides Michx.) were studied in relation to soil pH and chemical composition. The investigations were conducted in two plantations on former agricultural lands in North Estonia. One plantation was established on a territory influenced for a long time by alkaline cement dust pollution before plantation establishment and the other on an unpolluted territory. At pH 7.4 and higher concentrations of Ca, K, Mg, N and P in soil on the polluted area inhibition of height growth and diameter at breast height, leaf area and dry mass was observed compared to the unpolluted plantation with an optimum soil pH of 6.7. Differences in hybrid aspen leaves in the two plantations were related to the lower net photosynthetic and transpiration rates and higher starch and sucrose contents in the polluted plantation. Leaves from alkaline soil had a thicker palisade mesophyll layer and lower number of stomata at abaxial epidermis. The relatively low N concentration in leaves in the polluted area was associated with the low height and diameter at breast height of trees.

Waste management of clinker dust by spreading it on forest soil was studied in a 25-year-old Scots pine stand on acidic sandy soil. Clinker dust (0.5 kg m − 2), fertiliser (N, P, K, Mg, 0.05 kg m − 2; N 190 kg ha − 1) and untreated soil were applied on 120-m2 plots in four replicates. The fertiliser was included to confirm the nutrient limitation in the stand. Clinker dust increased the soil pH by 1.2 units relative to the pH of 4.6 in the untreated soil by the second year. Soil K and Mg concentrations were larger in the dust and fertiliser treatments. Nutrient diagnostics indicated that needles of untreated trees were deficient in N and K. Fertiliser treatment indicated that the growth of trees was limited by N, since the fertiliser tended to increase needle K, N, N/P, needle dry mass and diameters of stem and shoots. By an auxiliary dataset, no effects of the dust and fertiliser on possible excess of the micronutrient Mn were observed. Clinker dust increased needle K concentration, but due to the N limitation, there was no increase in the growth of stems, branches, shoots and needles. It was concluded that in plots of 120 m2 application of clinker dust at a rate of 0.5 kg m − 2 was safe for the 21-year-old Scots pine stand in this trial on an acid nutrient-poor sandy soil during 4 years after the treatment.

Hybrid aspen plantations established on soils with different pH and chemical composition were studied. At higher pH and Ca, K, Mg and P in the soil of a former arable land, influenced by alkaline dust pollution long before plantation establishment, an inhibition of growth, diameter at breast height, as well as of the annual growth was observed, compared to unpolluted plantations. The differences in hybrid aspen leaves, branches and stems from trees growing under optimal growth conditions and those from polluted areas consisted in higher sucrose, starch, glucose, fructose and hemicelluloses contents, and lower lignin and cellulose contents in the trees from polluted plantations. The relatively high C/N ratio was associated with the lower N concentration and height growth of the trees growing in the polluted area. This finding suggests that, although no differences occurred in the total C concentration among trees from different plantations, an altered partitioning was established between the compartments of trees, as to starch and total soluble carbohydrates.

Ecosystems on dunes are influenced by critical environmental factors (mineral nutrients, water deficiency, etc.) considered decisive for their existence. The present paper is based on studies carried out on dunes on the coastal area of the Baltic Sea, southwest Estonia. The nature of forest ecosystems on dunes was studied from the aspects of chemical characteristics of soil, vascular plant species richness and diversity. Sampling sites on the dunes with different heights were selected in Cladina and in Vaccinium vitis-idaea site-type Scots pine forests. Vascular plant species richness and diversity were related to edaphic gradients. On the dune with a height of 32.1 m a.s.l., significant relationships were revealed between the number of species of ground vegetation, pH, volumetric water content in soil and the position of the sample plots. No relationships were revealed between the number of vascular plant species, soil pH, volumetric water content and mineral nutrients on the dune with a height of 9 m a.s.l. The most frequent and abundant plant species on the higher dune were Deschampsia flexuosa, Vaccinium vitis-idaea and V. myrtillus; the highest number of species were found at the bottom of the dune, while on the top only some xeromorphic species such as Festuca ovina, Sedum acre and Crepis tectorum occurred. On the lower dune, the most frequent were Vaccinium vitis-idaea, V. myrtillus and Melampyrum pratense, while V. uliginosum was found only on the bottom and slope and Empetrum nigrum on the top of the dune.

Studies were carried out in 1999, 2005 and 2007 in the area of Kunda cement plant in Northeast Estonia on sample plots 3 km W and 2.5 and 5 km E of Kunda. As control stands, two plots for pine and spruce were established in Lahemaa National Park (34-38 km W of Kunda). The selected pine and spruce stands were 75-85-year-old Myrtillus site type, of 0.7-0.8 density and II quality class, with moderately dense or sparse understorey. The values concerning needle density and number of needle scars were higher for shoots formed in the period of higher pollution than for the shoots grown under a considerably lower pollution load. Although the cement dust pollution has notably decreased from year to year, the number of needle pairs per 1 cm of the shoot was 1.8-2.1 times greater in the shoots formed in 1998 than in those formed in 2003, whereas the changes were statistically reliable. Possibly the low temperatures at the time of shoot and needle formation affected the density of needles on all sample plots, and thus the number of needles on shoots formed in 2003 was many times smaller. After the significant fall in the pollution load since 1996 the length growth of needles intensified around Kunda cement plant, at the same time no changes occurred in the length growth of needles in the control area. As compared to the data from 1998, the length growth of pine needles had improved, especially 2.5 and 5 km E from the cement plant, needles being respectively 1.5 and 1.1 cm longer than 6 years ago. The stimulation of the growth of pine and spruce needles 2.5 and 5 km E of the cement plant may be a sign of a positive effect of reduced doses of cement dust in soil. The greater length of pine and spruce needles is the reason for the larger biomass of the needles. (C) 2010 Elsevier B.V. All rights reserved.

Short-term effects of different doses (0.25; 0.5 and 1.0 kg m(-2)) of wood ash (WA), peat ash (PA) and their mixture (MA) applied to peat substrate on the mineral composition and growth of seedlings of Betula pendula were investigated. The experiments were conducted with 1-year-old seedlings planted in vegetation pots. The pH of the substrate was increased by 0.4-0.9 units during the vegetation period compared to the control. The peat substrate was poor in nutrients, except N. The substrate treated with WA had higher concentrations of K, Mg, Mn, Fe, P, Zn, Cr and Pb, but a lower N concentration compared to the control. The substrate treated with PA had higher concentrations of Ca, Mg, N and P. The concentrations in the MA treatment were intermediate between WA and PA. The ashes increased K and lowered the concentration of Ca. A decrease in N in seedlings was found under the influence of WA and MA. An increase in K and P was found in all compartments of seedlings, while the concentrations of Ca, Mg, Cu, Zn, Cd and Cr in seedlings were affected irregularly depending on types and doses of ashes used. The uptake of Cd, Cr and Pb did not reach phytotoxic levels; however, increased concentrations of Cd and Pb were found in roots. A positive influence of ash application on growth was found. The heights and root collar diameters of all ash-fertilised treatments exceeded those of the control seedlings in most cases. (C) 2010 Elsevier Ltd. All rights reserved.

Bioenergeetikas tekkivate jäätmete kasutamine metsanduses Negative environmental impacts of fossil fuel combustion have increased the use of biomass for energy production. As a consequence of the increased use of biofuels, the production of ashes will increase greatly in the near future. Because of relatively high contents of plant nutrients, biofuel ashes can be recycled as mineral fertilisers to compensate for the loss of nutrients resulting from tree harvesting. The present review aims to summarise the available information on factors affecting the quality of the wood and peat ash and the implications arising from ash application as fertiliser in the forest ecosystems. The understanding of the wood ash as fertiliser originates from the traditional slash-and-burn agriculture. During combustion most elements in wood are retained in the ash. The quality and chemical composition of ashes depends on many factors. The major elements in the ashes are calcium, potassium, magnesium, manganese, sodium, iron, phosphorus and sulphur. Trace elements found in different ash include barium, boron, cadmium, copper, mercury and zinc. The most abundant elements in peat ash are silicon, iron and aluminium. Ashes are characterised by high alkalinity with pH in the range from 11 to 13. Ashes raise the pH and reduce the total acidity in the humus layer and in the top of the mineral soil. The addition of wood ash does not result in a significant growth increase on mineral soils but increases the tree growth on peat soils. The Cd in wood ash did not become bioavailable and harmful to forest biota. The application of wood ash did not change or even decreased the 137Cs activity within forest soil. Wood ash application increased the coverage of the ground vegetation in upland forests and on peatland. Increase in microbial activity and growth rate after ash treatment was observed.

The growth of Scots pine and its suitability for afforestation of post-mining landscapes in Northeast Estonia were assessed in comparative analytical studies by using morphological parameters and mineral nutrition characteristics. The growth and nutrient uptake of Scots pine growing on post-mining substrate were compared with the characteristics of pines of the same age (22-23 years) in a Calluna forest site type predominant in North Estonia in similar climatic zone. Results of the analyses of soil upper layers showed that the concentration of N and P in soil did not differ between the opencast spoil and Calluna site, but significantly higher pH of soil and concentrations of K, Ca, and Mg were found in mine spoil. The concentrations of K and Mg in needles were significantly higher in the post-mining area, but the concentrations of N, P, and Ca did not differ significantly. Comparison of the needle nutrient concentration with the standard for optimum concentrations revealed P deficit in the post-mining area and P and K deficit in the Calluna site. Scots pine formed longer and thinner needles and shoots in the post-mining substrate than in the Calluna site. It was assumed that in the post-mining area the growth of pines is predominantly dependent on K and Ca concentrations in their tissues as the biomass of needles was strongly correlated with the K/Ca ratio, whereas the biomass in the Calluna site was correlated with the N/P ratio. The height and diameter of trees were significantly larger in the post-mining area.

Drought tolerance of Scots pine in diverse growth conditions on a dune estimated on the basis of carbohydrates and chlorophyll fluorescence in needles Variation in the needle carbohydrate concentrations in Scots pine along the height profile on a forested dune in south-western Estonia were measured in spring. To assess the tolerance of trees, carbohydrate concentrations were compared with shoot morphology and photosystem II quantum efficiency (chlorophyll fluorescence). To test a potential effect of drought events on trees, chlorophyll fluorescence was measured in needles after drying and recovery, and dependcies of the treatment effects on the location on the dune were looked for. Water concentration in detached needles was reduced by a partial drying in laboratory. Needles were recovered by an addition of water. Carbohydrate concentrations were rather constant irrespective of shoot morphology and the tree location on the dune. The reduction in the photosynthetic efficiency, observed after the treatment, depended on the site. The results indicated that trees growing at lowest relative heights on the dune were potentially more vulnerable to drought than other trees on the dune at relative height of 5 to 25 m.

The aim of the current study was to test the suitability of microwave heating for stopping carbohydrate transformations in plant material. Needles and branches of Pinus sylvestris were treated in microwave oven (2.45 GHz, 800W) and compared to the samples treated in boiling ethanol (96 %). In extracts obtained from the microwaved material the ratio of sucrose to hexoses (glucose and fructose) decreased, while ethanol treatment resulted in stable extracts. The carbohydrate composition in dry samples estimated after a month of storage was persistent. The boiling of needles in ethanol in microwave oven gave the same results as boiling on a heating plate. In the woody material, differently from the needles, the total concentration of measured carbohydrates depended significantly on the preparation method. In the case of needles, the treatment of plant material in ethanol was better suited for the determination of carbohydrate levels than the microwave treatment.

Long-tcrni impact of dust (pH 12.3-12.9, supernatant of dust:watcr 1:3) from a ccmcnt plant on tlic growth and contcnt of carboliydratcs and nutricnt composition was studicd in Norway sprucc, whitc sprucc, black sprucc, Scots pinc, and Douglas fir in ficld cxpcrimcnts. A comparative analysis indicatcd a dccrcasc in thc contcnts of starch and licniicclluloscs and thc intlucncc on thcir partitioning bctwccn organs of trccs. Elcvatcd contcnts of K and Ca in thc cnvironnicnt and in tlic trccs rcduccd thc contcnt of N and its allocation witliin tlic organism (r,,,B = -0.727, p Piceu crbies > P i r l ~ s ylveslri.~ > Picea glarrco > P. rnoriunu.

The present study is the first attempt to carry out an inventory of greenhouse gas (GHG) fluxes in the forests of Estonia. The emission and uptake of CO as a result of forest management, forest conversion and abandonment of cultivated lands in Estonia was estimated. The removal of GHG by Estonian forests in 1990 exceeded the release about 3.3 times. Changes in the species composition and productivity of forest sites under various simulated climate change scenarios have been predicted by using the Forest Gap Model for the central and coastal areas of Estonia. The computational examples showed that the changes in forest community would be essential.2