Investigation of timber harvesting impacts on herbaceous cover,forest floor and surface soil properties on skid road in an oak (Quercus petrea L.) stand

In this study, we investigated the timber harvesting effects on some soil properties (sand, silt, clay, pH, electrical conductivity, fine soil <2 mm, coarse soil >2 mm, root mass, organic carbon, moisture equivalent, total porosity, bulk density, moisture and compaction) at soil depths (0–5 and 5–10 cm), herbaceous cover and forest floor (unit mass, organic matter and moisture) on skid road of an oak (Quercus petrea L.) stand in Istanbul Belgrad Forest of Turkey.     

The effects of heat treatment on some technological properties in Uludağ fir (Abies bornmuellerinana Mattf.) wood

Heat treatment is often applied to improve the dimensional stability of woods. In this study, the effect of heat treatment on some mechanical properties of Uluda? fir wood (Abies bornmuellerinana Mattf.) having industrially high usage potential and large plantations in Turkey was evaluated. Samples collected from Bolu Forest Enterprises, Turkey were subjected to heat treatment for varying temperatures and durations. Then, the treated and control samples were tested for some mechanical properties; compression strength, bending strength, modulus of elasticity in bending, janka-hardness, impact bending strength and tension strength perpendicular to grain. The results indicated that treated samples had lower mechanical properties compared to the control samples. In addition, increase in temperature and durations decreased the mechanical properties.     

Characterization of soil phosphorus in a fire-affected forest Cambisol by chemical extractions and P-NMR spectroscopy analysis

This study was conducted to investigate the long-term effects of fire on soil phosphorus (P) and to determine the efficiency of different procedures in extracting soil P forms. Different P forms were determined: labile forms (Olsen-P, Bray-P, and P extracted by anion exchange membranes: AEM-P); moderately labile inorganic and organic P, obtained by NaOH-EDTA extraction after removing the AEM-P fraction; and total organic and inorganic soil P. ³¹P-NMR spectroscopy was used to characterize the structure of alkali-soluble P forms (orthophosphate, monoester, pyrophosphate, and DNA). The studied area was a Pinus pinaster forest located at Arenas de San Pedro (southern Avila, Spain). The soils were Dystric Cambisols over granites. Soil samples were collected at 0-2 cm, 2-5 cm, and 10-15 cm depths, two years after a fire in the burned area and in an adjacent unburned forest area. Fire increased the total N, organic C, total P, and organic and inorganic P content in the surface soil layer. In burned soil, the P extracted by the sequential procedure (AEM and NaOH + EDTA) was about 95% of the total P. Bray extraction revealed a fire-induced increase in the sorption surfaces. Analysis by chemical methods overestimated the organic P fraction in the EDTA-NaOH extract in comparison with the determination by ignition procedure. This overestimation was more important in the burned than unburned soil samples, probably due to humification promoted by burning, which increased P sorption by soil particles. The fire-induced changes on the structure of alkali-soluble P were an increase in orthophosphate-P and a decrease in monoester-P and DNA-P.     

Amenability of European silver fir (Abies alba Mill.) to preservative treatment by the full-cell process in longitudinal,tangential, radial and triplex flow pathways on the base of wood drying

This paper discusses the effects of wood drying upon treatability (as determined by preservative uptake and gain-in-weight retention) of European silver fir on the two moisture content (MC) levels which were designed to be above and below the fibre saturation point (FSP). The treatability behaviour was investigated for individual flow pathways: longitudinal (L$L$, along the stem), tangential (T$T$, along the growth rings) and radial (R$R$, along the rays), and also for the triplex (t$t$, cumulative of all three directions: all faces left open). As the FSP was observed 32.7%, MC of the experimental samples—for each flow path—nominated to around 50% and 9% by recommended kiln drying schedule using a conventional kiln. The samples were then treated with a 2.5% concentration of commercial Tanalith C of CCA (chromium/copper/arsenic) via a mild schedule of full-cell impregnation process using a model pressure treatment plant. Treatability of European silver fir was noticed in different behaviour in either flow paths before and after drying. According to the experimental results, MC regulate the preservative uptake (as the percentage of void volume filled with preservative, VVF%) along the grain (L$L$) and VVF% was improved by kiln drying process effectively, however, it was seemed to be contradictory across the grain (in both T$T$ and R$R$). In the cumulative form (t$t$), treatability—in either above or below the FSP—was appeared to be slightly greater than that for L$L$ due to support of the longitudinal flow. Therefore, it could be suggested that wood material which is subjected to be used in constructional purposes has to be initially dried to below the FSP, and—for efficient preservative treatment—it has to be treated with all faces unsealed (free from any pre-coating and/or painting). This shall be more ideal which in turn influences the quality of treated wood allowing better performance in its service life.     

Impact of different parts of unpaved forest roads on runoff and sediment yield in a Mediterranean area

Surface runoff and sediment production on unpaved forest roads in a humid Mediterranean mountainous area has been studied using a simple portable rainfall simulator at an intensity of 90 mm h^− 1. Thirty six rainfall simulations were carried out on road plots: on the roadbank (12), on the sidecast fill (12), and on the roadbed (12). On the roadbanks, the steady-state runoff coefficient was 85.9% and runoff flow appeared after 63 s on average. On the sidecast fills, the steady-state runoff coefficient was 58.6% and mean time to runoff was 48 s. Finally, on the roadbeds, the steady-state runoff coefficient was 21.5% and mean time to runoff was 41 s. The highest soil loss rate was found on the roadbanks (486.7 g m^− 2), mainly due to low plant cover, soil texture and rock fragments. The total soil erosion on the roadbanks was 3 and 18 times higher than those from the roadbeds and the sidecast fills, respectively. As a consequence, roadbanks can be considered the main source of sediments on the studied sites, but the function of unpaved forest roads as source points for runoff generation is more important.     

Biomass and nutrient content of sessile oak (Quercus petraea (Matt.) Liebl.) and beech (Fagus sylvatica L.) stem and branches in a mixed stand in southern Belgium

Accurate estimates of the amounts of nutrients immobilised in the organs and tissues of different tree species are of prime importance to make appropriate tree species selection and determine the harvesting regime that will ensure forest sustainability. Sixteen sessile oaks (Quercus petraea (Matt.) Liebl.) (64-129 years; stem diameters: 17-57 cm) and twelve beeches (Fagus sylvatica L.) (43-86 years; stem diameters: 9-50 cm) were destructively sampled from a mixed stand located on an acid brown soil in southern Belgium. Statistical models were developed to investigate the differences in nutrient concentrations between tree species, between aboveground tree compartments of the same species, and between tissues of the same compartment. For stem tissues, vertical concentration profiles were described using a versatile equation. Allometric equations were used to predict biomass and nutrient content of tree compartments based on tree dimensions. Broadly speaking, nutrient concentrations tended to be somewhat higher for oak compared with beech, but the amplitude and the direction of inter-species differences varied greatly, depending on the nutrient and the tree compartment. For both species, living branch nutrient concentrations tended to decrease with increasing branch diameter, except for Ca (oak) and Mg (beech). Nutrient concentrations were consistently higher in bark than in wood; this difference between tissues was quite pronounced for Ca, particularly in the case of oak. The biomass and nutrient content equations were used to investigate the effects of tree species and harvesting regime on nutrient exports at harvesting. For equivalent harvesting scenarios, beech was found to induce higher Mg exports than oak, and inversely for Ca. Assuming stand clear cutting, complete tree harvesting would increase average nutrient exports from 65% (Ca) to 162% (P) compared with a stem-only harvesting scenario. These results provide valuable information in the current context of the more intensive utilization of forest products.     

The effects of some manufacturing factors on surface roughness of sliced Makoré (Tieghemella heckelii Pierre Ex A.Chev.) and rotary-cut beech (Fagus orientalis L.) Veneers

In this study, the effects of veneer thickness, cutting speed, knife bevel, vertical and horizontal opening, and drying temperature on surface roughness of sliced Makore veneer and rotary-cut beech veneer were evaluated. Makore logs for sliced veneers and beech logs were used for rotary-cut veneers manufacturing. Before veneer manufacturing, the Makore and beech logs were steamed indirectly at 80 °C for 50 and 36 h, respectively. Roughness measurements were conducted according to DIN standard 4768 by using stylus profilometer. The sliced radial and tangential veneers were grouped and evaluated separately. Results showed that veneer thickness, cutting speed and knife bevel had a significant effect on surface roughness for the sliced veneers, but veneer drying temperature did not affect significantly the surface roughness. In general, surface roughness of the veneer increases with increasing veneer thickness. However, increases in cutting speed decreased the surface roughness. The most suitable knife bevel was 17.5° for manufacturing sliced veneers from Makore. For rotary-cut veneers, vertical and horizontal opening had a significant effect on the surface roughness. The results indicated that vertical opening should be about 50% and horizontal opening about 80–90% of veneer thickness to minimize the surface roughness in manufacturing rotary cut veneer from oriental beech.     

Nature reserve selection on forest fragments in a suburban landscape (Rome, Central Italy): indications from a set of avian species

A set of avian forest species, known from the literature as fragmentation-sensitive, was considered as the target in nature reserve planning following a conceptual framework. Their abundance was investigated in an 'archipelago' of oak woodland fragments embedded in a suburban landscape matrix of central Italy. None of the four species were found in any wood fragment smaller than 10 ha. The presence/absence analysis of woodland fragments studied showed that the study species were present, however, in larger fragments, highlighting the strategic role of habitat size and isolation for the persistence of these species at local scale. Species numbers and their total abundance were significantly and directly correlated to overall species richness of each fragment: in this landscape context our study species shows characteristics of serving as focus and surrogate species of bird richness. The selected species are area-sensitive and poor dispersers: however, they are still relatively widespread, at a regional scale. Although the abundance of individual species may be affected by stochastic factors, total abundance of this forest bird guild may constitute a useful dependent variable that can provide rapid quantitative data needed for planning strategies at local scales.     

The effects of phytophagous insects on water and soil nutrient concentrations and fluxes through forest stands of the Level II monitoring network in the UK

The effects of insect defoliators on throughfall and soil nutrient fluxes were studied in coniferous and deciduous stands at five UK intensive monitoring plots (1998 to 2008). Links were found between the dissolved organic carbon (DOC), nitrogen (N) and potassium (K) fluxes through the forest system to biological activity within the canopy. Underlying soil type determined the leaching or accumulation of these elements. Under oak, monitored at two sites, frass from caterpillars of Tortrix viridana and Operophtera brumata added direct deposition of ~ 16 kg ha⁻¹extra N during defoliation. Peaks of nitrate (NO₃-N) flux between 5 and 9 kg ha⁻¹ (×5 usual winter values) were recorded in consecutive years in shallow soil waters. Synchronous rises in deep soil NO₃-N fluxes at the Grizedale sandy site indicate downward flushing, not seen at the clay site. Under three Sitka spruce stands, generation of honeydew (DOC) was attributed to two aphid species (Elatobium abietinum and Cinara pilicornis) with distinctive feeding strategies. Throughfall DOC showed mean annual fluxes (6 seasons) ~ 45-60 kg ha⁻¹ compared with rainfall values of 14-22 kg ha⁻¹. Increases of total N in throughfall and NO₃-N fluxes in shallow soil solution were detected — soil water fluxes reached  8 kg ha⁻¹ in Llyn Brianne, ~ 25 kg ha⁻¹ in Tummel, and ~ 40 kg NO₃-N ha⁻¹ in Coalburn. At Tummel, on sandy soil, NO₃-N leaching showed increased concentration at depth, attributed to microbiological activity within the soil. By contrast, at Coalburn and Llyn Brianne, sites on peaty gleys, soil water NO₃-N was retained mostly within the humus layer. Soil type is thus key to predicting N movement and retention patterns. These long term analyses show important direct and indirect effects of phytophagous insects in forest ecosystems, on above and below ground processes affecting tree growth, soil condition, vegetation and water quality.     

Assessing the effects of fluoxetine on Physa acuta (Gastropoda, Pulmonata) and Chironomus riparius (Insecta, Diptera) using a two-species water-sediment test

Fluoxetine has been tested in a two-species water-sediment system, which allowed a two-generation study with Chironomus riparius and a partial life-cycle with the freshwater snail Physa acuta to be performed at the same time. The design considered the continuous application of fluoxetine to overlaying water for nominal concentrations of 31.25, 62.5, 125 and 250 μg/L. A fifth treatment (87.5 μg/L) level consisted of pulse applications once a week. Measures of water and sediment concentrations were determined once a week and at the end of experiment (day 44), respectively. The fate study demonstrated that water dissipation can be explained by partitioning of fluoxetine to sediment. At the end of experiment, the percentage of detected fluoxetine was up to 10-fold higher in sediment than in overlaying water. The employed two-species test allowed distinguishing, in the same exposure conditions, effects due to waterborne exposure together ingestion at the sediment surface (freshwater grazing snail P. acuta) and exposure by burrowing activities (sediment-dwelling insect larvae C. riparius). The effect assessment showed a stimulation of P. acuta reproduction at lower concentrations (31.25 and 62.5 μg/L), while the opposite effect was observed at the highest treatment (250 μg/L). Additional studies should be conducted to establish if the statistically significant differences observed in F0 sex ratio at the 62.5 μg/L and F1 adult emergence at 31.25 μg/L of C. riparius have a toxicological significance. This study showed that fluoxetine can affect reproduction of freshwater molluscs. The results of the present study may contribute to knowledge on ecotoxicology of pharmaceuticals, about which little data is available. The possible consequences and implications for targeting the environmental risk assessment of fluoxetine are discussed.     

Use of biomarkers to show sub-cellular effects in meadow voles (Microtus pennsylvanicus) living on an abandoned gold mine site

Run-off from mine tailings ponds constitutes the main anthropogenic release of arsenic in Canada. As a potential consequence, wildlife not normally exposed to arsenic under other circumstances may receive toxicologically relevant concentrations of arsenic compounds in their food and water. To test this hypothesis, and to determine if arsenic is being transported through trophic levels, the arsenic concentrations in members of a short food chain (soil-plant-meadow vole) were measured. Arsenic concentrations were higher in exposed organisms compared with those from a reference location. However, elevated concentrations of arsenic do not necessarily indicate impact, and consequently a biomonitoring study was undertaken to determine if there were sub-cellular effects of exposure in meadow voles (Microtus pennsylvanicus) as a consequence of arsenic exposure. In this work, adenosine triphosphate (ATP) and liver glutathione (GSH) levels were used as biomarkers of exposure and the frequency of red blood cell micronuclei (mono- and polychromatic) was used as a biomarker of effect. ATP results were not conclusive but there was a statistically significant relationship between a reduction of GSH in vole livers and increased liver arsenic concentrations. A statistically significant relationship was also observed between increased micronucleated monochromatic red blood cells in voles from arsenic contaminated sites compared to a background location. The results of the GSH and monochromatic red blood cell investigations suggest that there are possible sub-cellular effects on these voles as a consequence of dietary arsenic exposure. This is the first field study in which such effects have been observed in voles living near mine tailings.     

Speciation of lead, copper, zinc and antimony in water draining a shooting range—Time dependant metal accumulation and biomarker responses in brown trout (Salmo trutta L.)

The speciation of Pb, Cu, Zn and Sb in a shooting range run-off stream were studied during a period of 23 days. In addition, metal accumulation in gills and liver, red blood cell ALA-D activity, hepatic metallothionine (Cd/Zn-MT) and oxidative stress index (GSSG/ tGSH levels) in brown trout (Salmo trutta L.) exposed to the stream were investigated. Fish, contained in cages, were exposed and sampled after 0, 2, 4, 7, 9, 11 and 23 days of exposure. Trace metals in the water were fractionated in situ according to size (nominal molecular mass) and charge properties. During the experimental period an episode with higher runoff occurred resulting in increased levels of metals in the stream. Pb and Cu were mainly found as high molecular mass species, while Zn and Sb were mostly present as low molecular mass species. Pb, Cu and Sb accumulated on gills, in addition to Al origination from natural sources in the catchment. Pb, Cu and Sb were also detected at elevated concentration in the liver. Blood glucose and plasma Na and Cl levels were significantly altered during the exposure period, and are attributed to elevated concentrations of Pb, Cu and Al. A significant suppression of ALA-D was detected after 11 days. Significant differences were detected in Cd/Zn-MT and oxidative stress (tGSH/GSSG) responses at Day 4. For Pb the results show a clear link between the HMM (high molecular mass) positively charged Pb species, followed by accumulation on gills and liver and a suppression in ALA-D. Thus, high flow episodes can remobilise metals from the catchment, inducing stress to aquatic organisms.     

Influence of sex, maturity and reproduction on PCB and p,p′DDE concentrations and repartitions in the European hake (Merluccius merluccius, L.) from the Gulf of Lions (N.W. Mediterranean)

The main objective of this work was to establish the influence of sex, maturity and reproduction on the contamination of the demersal fish Merluccius merluccius by organochlorine compounds. Polychlorinated biphenyls (PCBs) and p,p′DDE were quantified in muscle, liver and gonads of female and male hakes collected in the Gulf of Lions in 2004 and 2005. Observed levels appeared higher than the population of the Bay of Biscay and lower than the population of the Thyrrenian Sea. Contaminant fingerprints were roughly constant whatever the studied organ and the hake biological condition. Concentrations varied significantly according to the sex and maturity of hakes. Mature specimens were more contaminated than immature, and males presented higher levels than females. This sex effect can be linked to a lower growth rate of males, and a contaminant elimination during female spawning. Gonadal contamination depends on the importance of lipid content and increases with the maturation degree. Although the main organ of energy and PCB storage is the liver, muscle appears as the main contributor to the gonad contamination.     

Effects of laying order and experimentally increased egg production on organic pollutants in eggs of a terrestrial songbird species, the great tit (Parus major)

In this study, concentrations and profiles of organic pollutants were investigated in a passerine species with a large clutch size, the great tit (Parus major). In the first clutches, mean egg concentrations decreased significantly in relation to the laying order from 3025 ± 416 ng/g lw to 2267 ± 386 ng/g lw for sum PCBs and from 989 ± 339 ng/g lw to 695 ± 320 ng/g lw for sum DDTs. Sum PBDE concentrations also decreased in relation to the laying order from 68 ± 10 ng/g lw to 53 ± 11 ng/g lw, but not significantly. Although laying order effects were found, variation in concentrations within clutches was smaller than among clutches. To further investigate the impact of laying large numbers of eggs on levels and profiles of organic pollutants, initiation of replacement clutches was experimentally induced. Mean sum PCB and sum PBDE concentrations were significantly lower in eggs of replacement clutches compared to first clutches. In addition, first clutches had a higher contribution of the higher chlorinated and more persistent PCB congeners, CB 170, 180 and 183, and a lower contribution of CB 52, 95 and 149 compared to replacement clutches. Because of the differences in concentrations and profiles between the first and replacement clutches, the combined use of eggs from both the first and replacement clutches for monitoring purposes is not recommended. In conclusion, we suggest that, due to the larger variation among clutches compared to the variation within clutches, one randomly collected great tit egg from a first clutch is useful as a biomonitoring tool for organic pollutants. To our knowledge, this is the first study in which the impact of an experimentally increased clutch size on the levels and profiles of contaminants in eggs has been investigated.