Casuarina Research Articles

Increased Post-Drought Growth after Thinning in Pinus nigra Plantations

In Mediterranean seasonally dry regions, the rise in dieback and mortality episodes observed in pine afforestations has been related to higher drought intensity and lack of appropriate management, which enhance competition between trees for water and light. However, there is little understanding of the benefits of silviculture for plantations under seasonal drought stress. A combination of dendrochronology and wood C and O isotope analyses was used in three Black pine (Pinus nigra) plantations to work out the responses of radial growth (BAI, basal area increment) and water-use efficiency (WUEi) to thinning treatments (removal of 40% of the stand basal area). Thinning had a positive effect on BAI and WUEi, reduced drought sensitivity, and reduced the temporal dependence on the previous year’s growth. These results were significant even 13–14 years after thinning and coherent for the three study sites. Differences were found between the sites regarding the physiological mechanisms of adaptation. In two sites, we inferred the enhanced WUEi was due to increased photosynthetic rates (A) at constant stomatal conductance (gs). In the third site, which had higher tree density and therefore competition, we inferred increases in both A and gs, with the former being proportionally larger than the latter.

Shrinkage pattern assessment for black pine juvenile wood delimitation

Juvenile wood is associated with shrinkage and a high probability of warping and checks in end products, reducing their value and even causing them to be rejected for structural purposes. This work studies the variations in yearly shrinkage caused when wood passes from green to dry state. The methodology proposed is based on the juvenile wood (JW) location using annual shrinkage variations. Pinus nigra Arn. grown using different silviculture techniques was chosen for study because its wood is characterized by severe shrinkage problems. This characteristic is analyzed in the radial and angular directions, of which the latter is a different methodology for evaluating warping problem rather than the commonly used ratio of anisotropy. It takes into account the annual measurements obtained from a disc cut from the tree trunk at various heights. The results were compared with the segregated JW and mature wood (MW) area obtained by radial densitometry pattern variation methodology. The results show that radial shrinkage is higher near the pith but stabilizes earlier (3–7 rings) than angular shrinkage (9–11 rings). Nevertheless, the opposite initial radial pattern occurs in angular shrinkage, which is low near the pith but increases annually towards the bark until it stabilizes. No clear effect of height in the tree when comparing the radial shrinkage patterns obtained along the bole can be defined. Silviculture practices have no significant influence on shrinkage percentage. Shrinkage and densitometry methodologies show differences in the quantification of JW volume percentage between JW and MW estimation. Results show that radial shrinkage pattern methodology, which is associated with warping problems, classifies a higher tree volume as good quality for end uses in comparison to the use of radial densitometry pattern methodology. On the other hand, if classified by radial densitometry pattern variation, warping problems associated with JW should not be a problem when sawn.

Effect of sample preparation procedure on standardless wavelength dispersive X-ray fluorescence analysis of plant samples

XRF (X-ray fluorescence analysis) has been applied as the method for analysis of plant samples, but not in its full potential. This method would be highly suitable for monitoring programs and screening studies. A simple sample preparation procedure makes this technique time and cost-effective, although the absence of adequate calibration standards for some analyzed matrices can be a significant limiting factor. Nevertheless, this obstacle can be overcome by the development of the so-called “standardless method” approach. It is important to explore the possibilities and limitations of such method applied to an analysis of plant materials. The accuracy of XRF analysis is highly dependent on the physical characteristics of the sample, which can be significantly affected by the sample preparation procedure. Variations of 3 crucial sample preparation parameters: the mass of the samples (from 1 to 5 g), binder ratio (from 0 to 25% of wax), and pressing pressure (from 10 to 25 t) were tested on needles obtained from two widespread conifer species: Pinus nigra and Abies alba. For most elements, the correlation between the concentration and the change of the binder ratio was statistically significant, while there was no statistically significant correlation between the concentration and the change of the pellet mass and applied pressure. For both types of needles, an estimated systematic error was always higher than a random error. The difference between two types of errors has been higher among samples with different wax content than in samples with different pellet mass, while the variation of applied pressure did not introduce any significant systematic error. On average the change of wax content inflated the value of systematic error by 18 and 13% for the pine and fir needle samples (respectively), while the change of the sample mass has introduced systematic error in lesser extent, on average it was 11% for pine needles and 10% for fir needle samples. The change of pelletizing pressure affected the results by only 3.9% for both conifer needles.

A decision-level fusion approach to tree species classification from multi-source remotely sensed data

In this study, an object-oriented, decision-level fusion method is proposed for tree species classification based on spectral, textural, and structural features derived from multi-spectral and panchromatic imagery and Light Detection And Ranging (LiDAR) data. Murphy's average method based on the Dempster Shafer theory (DST) was used to calculate the combined mass function for decision making purposes. For individual feature groups, the mass functions were calculated using the support vector machine (SVM) classification method. The species examined included Norway maple, honey locust, Austrian pine, blue spruce, and white spruce. In addition to these species, a two- or three-species compound class was included in the decision process based on the normalized entropy in the presence of conflict that was itself determined according to whether individual groups of features were consistent. The developed method provided a mechanism to identify tree crowns, which could not be classified to one single species with a high confidence due to the conflict among feature groups. Data used in this study were obtained for the Keele Campus of York University, Toronto, Ontario. Among the 223 test crowns, 204 crowns were assigned to one single species, and the overall classification accuracy was 0.89. A decision could not be made for 19 crowns with confidence, and as a result, a two- or three-species compound class was assigned. The classification accuracy was higher than that obtained using SVM classification based on individual and combined spectral, structural, and textural features.

Afforestation with Pinus nigra Arn ssp salzmannii along an elevation gradient: controlling factors and implications for climate change adaptation

Key MessageThe first bottleneck in Spanish black pine survival through afforestation is the lack of resistance to drought in their initial life stages.Spanish black pine (Pinus nigra Arn ssp. salzmannii) is the most widely distributed pine species in mountain areas of the Mediterranean Basin and is commonly used for afforestation in endangered and degraded areas. Despite its importance, little is known regarding the factors driving seedling survival for this species, which may hamper afforestation success in Mediterranean areas. In this study, we assessed the effects of seed origin and plantation site along a natural gradient with contrasting elevation and climatic conditions in a Mediterranean forest in Central-Eastern Spain. Our results showed: (1) higher seedling survival rates when seed origin differed from plantation site (25.3 ± 5.4%) compared to same origin and plantation site (5.3 ± 2.7%); (2) higher survival probability (~ 20%) for high and medium elevation seeds (colder and wetter locations) compared to the warmer and drier low elevation sites (15%); (3) higher seedling survival (~ 40%) at higher elevation sites compared to low-elevation sites (< 20%); and (4) increased hazard of seedling death with decreasing elevation of the plantation site. We also reported a complete mortality at the drier sites after the first summer following the plantation. Overall, the combination of seeds from medium elevation and high elevation plantation sites increased the survival of Spanish black pine. These results have direct implications for forest management of Spanish black pine in Mediterranean regions, particularly in current and future climate change scenarios.

Differences in temperature sensitivity and drought recovery between natural stands and plantations of conifers are species-specific

Forests are being impacted by climate and land-use changes which have altered their productivity and growth. Understanding how tree growth responds to climate in natural and planted stands may provide valuable information to prepare management in sight of climate change. Plantations are expected to show higher sensitivity to climate and lower post-drought resilience than natural stands, due to their lower compositional and structural diversity. We reconstructed and compared the radial growth of six conifers with contrasting ecological and climatic niches (Abies pinsapo, Cedrus atlantica, Pinus sylvestris, Pinus nigra, Pinus pinea, Pinus pinaster) in natural and planted stands subjected to seasonal drought in 40 sites. We quantified the relationships between individual growth variability and climate variables (temperature, precipitation and the SPEI drought index), as well as post-drought resilience. Elevated precipitation during the previous autumn-winter and current spring to early summer enhanced growth in both natural and planted stands of all species. Temperature effects on growth were less consistent: only plantations of A. pinsapo, C. atlantica, P. nigra, P. pinea, P. sylvetris and a natural stand of P. nigra showed negative impacts of summer temperature on growth. Drought reduced growth of all species in both plantations and natural stands, with variations in the temporal scale of the response. Drought constrained growth more severely in natural stands than in plantations of C. atlantica, P. pinaster and P. nigra, whereas the inverse pattern was found for A. pinsapo. Resilience to drought varied between species: natural stands of A. pinsapo, C. atlantica and P. pinaster recovered faster than plantations, while P. pinea plantations recovered faster than natural stands. Overall, plantations did not consistently show a higher sensitivity to climate and a lower capacity to recover after drought. Therefore, plantations are potential tools for mitigating climate warming.

Phytochemical Screening of Volatile Organic Compounds in Three Common Coniferous Tree Species in Terms of Forest Ecosystem Services

Multiple positive effects that forests have on human health and overall well-being have been reported widely in the literature. Still, multiple elements of this relationship remain unidentified and unexplained. In this study, the composition of leaf volatile organic compounds (BVOCs) content in three common coniferous species: the Austrian pine (Pinus nigra), Scots pine (Pinus sylvestris) and Spruce (Picea abies), was analyzed. The specificity of BVOCs content in the examined species and their genotypes is observed as a plant potential to evaporate these organic compounds and potentially improve human health and well-being. Principal component analysis applied on BVOCs content among species showed significant differences between compounds that have previously been characterized as having positive effects on human health by acting as anticancer, anti-inflammatory, antiviral and antibacterial. Variations among genotypes of the investigated species were observed in the content of BVOCs relevant for human health improvement, such as limonene, terpinolene, β-pinene, linalool, camphene, camphor, citronellol and α-cadinol. The observed intra- and inter-species variations in the BVOCs content provide an appropriate base for further research on the forest–human health relationship, breeding and selection of the most suitable genotypes for human health improvement, and could I mpact the sustainable management of forests.

Influence of Prescribed Burning on a Pinus nigra subsp. Laricio Forest: Heat Transfer and Tree Vitality

Surface fuel removal is crucial to facilitate the mitigation of severe fires in forests. Prescribed burning is often used by forest managers, thanks to its low cost and high efficiency in hard-to-reach areas. The determination of heat transfer between fires and trees has rarely been carried out on living species and consequently, their long-term effects on tree physiology are still not fully understood. In this study, a multidisciplinary approach was conducted to evaluate the impact of a late spring (June) prescribed burning on a Mediterranean pine forest (Pinus nigra subsp. laricio). The surface fuels consisted of a 656 g m−² needle litter, mixed with a few scattered living herbaceous strata. During the fire spread, measurements of the inner and outer trunk temperatures were made at the base of 12 trees with an average bark thickness of 19.4 ± 7.0 mm. The fireline intensity and flame residence time were in the range of 110–160 kW m−1 and 220–468 s, respectively. Despite a maximum heating rate at the cambial area of 4.37 °C min−1, the temperature of these tissues remained below 60 °C, a critical threshold above which thermal damage will occur. In addition, prior- and post-fire physiological monitoring was performed over a long time period (2.5 years) on 24 trees, using sap flow, chlorophyll fluorescence and gas exchange measurements. All parameters remain highly correlated and indicate that the burned trees did not suffer physiological damage. Moreover, drought resistance strategies were not altered by the prescribed burning. The thermal insulation capability of the bark allowed the functional tissues to experience low heat stress that did not affect tree vitality.

Chemotaxonomic Study of Four Subspecies of Pinus nigra Arn. Grown in Common Garden Based on Essential Oil Composition

The aim of this study was to investigate the chemical diversity of Pinus nigra Arn. essential oils. The research was carried out on the needles collected from eighteen provenances of black pine grown in common garden located in West-Northern Tunisia and belonging to four different subspecies (Pinus nigra subsp. nigra, Pinus nigra subsp. salzmannii, Pinus nigra subsp. pallasiana, and Pinus nigra subsp. laricio). Essential oil yields ranged from 0.19% to 0.68%. The obtained essential oils have been analyzed by GC-FID and GC-MS apparatus. Twenty-three constituents accounting about 98% of total essential oil composition were identified. The essential oil compositions appeared to be very different according to their origin. Thus, five main essential oil chemotypes were identified in Pinus nigra plants: caryophyllene oxide, camphene, ß-caryophyllene, α-amorphene, and germacrene D. The chemotaxonomic value of the essential oil compositions was discussed in relation to the results of the multivariate statistical test, including a detailed survey of the available literature data.

Effects of exogenous melatonin supplementations on some elemental contents in Anatolian black pine (Pinus nigra J.F. Arnold. subsp. pallasiana (Lamb.) Holmboe) seedling tissues

A multi-directional relationship may be conceivable between elements and melatonin in sessile organisms. Melatonin is an important hormone that helps regulate metabolism. This study investigated how different doses (0 μM/control, 250 μM, 500 μM, 1000 μM, and 1500 μM) of exogenous melatonin supplementations (EMS) affected the elemental contents in Anatolian black pine (Pinus nigra Arnold. ssp. pallasiana (Lamb.) Holmboe) seedling tissues (root, stem, and needle). Two different application forms (root-dipping and needle-spraying) were selected in the study. In the samples of seedling tissues, sodium (Na), potassium (K), calcium (Ca), iron (Fe), aluminum (Al), magnesium (Mg)/ppm; chrome (Cr), cobalt (Co), copper (Cu), manganese (Mn), nickel (Ni), phosphorus (P), selenium (Se), silicium (Si), silver (Ag), sulfur (S), zinc (Zn), and molybdenum (Mo)/ppb were analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES). Of the 18 elements examined, there was a statistically significant difference (p&lt;0.05) between all seedling tissues and different doses of EMS. The results show that EMS may have the regulatory effect on seedling tissue element metabolism.

Field performance of Austrian pine bareroot seedlings in comparision to seedlings pattern and density in the nursery

The Austrian pine (Pinus nigra Arnold) is a species often used in afforestation/reforestation programs in Serbia and region. Seedlings quality has a great role in outplanting survival and growth. Nursery cultural practice has a central influence on seedlings morphological attributes, so we tested seedlings quality from different seedbed densities and seedlings patterns and their outplanting success. Two-year-old bareroot seedlings were grown in very high densities (110 seedlings m-1 in rows and 750 seedlings m-2 across all seedbed space) and high densities (65 seedlings m-1in rows and 450 seedlings m-2 across all seedbed space). Morphological attributes (root collar diameter - RCD, height - H, sturdiness coefficient - SQ, root length – Rl, dry weight of shoot - SDW and root - RDW, shoot to root ration - S:R and quality index - QI) of seedlings from different densities were tested in the nursery before outplanting and compare with seedlings survival and growth (root collar diameter – RCD1 and height – H1) one year after field growing. Seedlings from different densities had accepted RCD (&gt;3 mm) for field planting and there were significant differences in their morphological attributes, except Rl and S:R. The best survival was recorded at seedlings from highest seedbed densities (93.33%), opposite with many previous researches. Seedlings grown across all seedbed space (450 seedlings per m-2) keep their advantage in growth after first year, although survival was lowest (46.67%).

Transpiration of Anatolian black pine and sessile oak forest stands in a sub-humid region of Turkey

Transpiration is a key component of the watershed water budget. Therefore, determining the transpiration of forest stands with different characteristics have been of interest for watershed hydrology and forest management practices in a wide range of environments. The objectives of this study were to compare transpiration of Anatolian black pine (Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe) and sessile oak (Quercus petraea (Matt.) Liebl.) tree stands and to model transpiration based on the measured climatic factors. Stand transpirations were calculated from sap flow measurements made by the trunk heat balance method. We conducted an exploratory factor analysis (PCR) to detect affecting meteorological factors of stand transpiration, and we developed linear regression equations to predict transpiration of pine and oak stands. Mean daily and yearly canopy transpiration (Ec) were 1.05 mm day-1 and 378.3 mm year-1 for the pine stand and 3.52 mm day-1 and 801.7 mm year-1 for the oak stand. There was a highly positive correlation between daily stand transpiration and wind speed, global radiation, air vapour pressure deficit and air temperature, but a negative correlation with relative humidity for both stands. Soil water potential had little effect on stand transpiration. The model equations accounted for 81% of the variations in transpiration for the pine stand and 85% for the oak stand. Therefore, the transpiration of forest stands should be considered for effective vegetation management practices, as model equations to estimate the transpiration of pine and oak stands in the region.

EXTRACTION AND ISOLATION OF ASCORBIC ACID FROM AUSTRALIAN PINE (Casuarina equisetifolia) NEEDLES GROWN IN JOS AND ENVIRONS.

Ascorbic acid was extracted and isolated from the aqueous extract of Casuarina equisetifolia (Australian pine needles) harvested from the main campus, university of Jos, Nigeria. The extraction was carried out via cold extraction (maceration) while the isolation was done using gravimetric analysis. The isolated sample was identified using UV-Vis, FTIR, GC-MS and H-NMR spectrophotometric analysis. Fresh needles (leaves) of Casuarina equiselifolia which contains 61.00±1.6 mg/100g of ascorbic acid was used for this research when compared with related species within same environment. The proximate composition is moisture content (10.27±0.48) %, crude protein (5.98±0.20) %, Crude fibre (22.89±0.35) %, crude fat (3.72±0.24) %, ash (2.34±0.07) %, carbohydrate (54.81±0.27) % and ascorbic acid (61.00±1.60) mg/100g. The molar concentration of ascorbic acid in the sample was (0.02075±0.001) moldm-3 while the weight percent of the lyophilized isolate is (68.04g/500g, 13.608%). The UV-Vis determination gives peaks at 240nm (weak band) and 300nm (λmax). The FTIR spectrophotometric determination gave some distinctive peaks. For this research, only the OHs, the lactone C=O (around 1750 cm-1) and C=C stretch (approximately 1680 cm-1) bands will be considered. The four O-H bands observed in the isolated ascorbic acid 1.0 can be assigned as follows: C(1) – OH (3524.13, O-H stretch, free hydroxyl (alcohol)), C(4) – OH (3404.48,O-H stretch, H bonded (alcohol)), C(3) OH (3303.21, O-H stretch, H bonded (alcohol)), C(2) – OH (3022.28, OH stretch (carboxylic acid)) and the lactone C=O (1751.98 cm-1) and C=C stretch (1654.63 cm-1) bands. The GC-MS indentified Ethane dioic, dimethyl ester (100%) which has a molecular formula C4H6O4 (m/z118.0880) with base peak at m/z 8.0, with the possible loss of C2H2O2 (Acetolactone), a transient species of mass spectrometer. The H-NMR in methanol and deuterated DMSO (Dimethyl sulphoxide) identified the presence of the most deshielded proton and the most acidic proton. There was partial decomposition from the confirmatory titrimetric analysis (56.88% ascorbic acid). The FTIR analysis confirms that the compound isolated is ascorbic acid and further confirmation derived from the UV-Vis. The result of this research should be adopted for the mass production of high quality ascorbic acid in Nigeria.

Disentangling the Relationship between Tree Biomass Yield and Tree Diversity in Mediterranean Mixed Forests

Tree biomass and the diversity relationship in mixed forest have an impact on forest ecosystem services provisions. Tree biomass yield is driven by several aspects such as species identity, site condition, stand density, tree age and tree diversity expressed as species mingling and structural diversity. By comparing diverse degrees of tree mixtures in natural forests, we can gain insight into the ecosystem services provision level and dynamic. Two monitoring sites in the Castilian Northern Plateau (Spain) have been analyzed to disentangle the relationships between biodiversity levels and tree biomass yield. Two permanent one hectare (ha) squared plots were established at Llano de San Marugán and Valdepoza. In each plot, all individual trees were measured (diameter and height), georeferenced and its species identity defined. Tree species in the two sites were Pinus sylvestris, Pinus nigra, Pinus pinea, Quercus pyrenaica, Quercus ilex, Quercus faginea and Juniperus thurifera. From these datasets, ten diversity indices that fall in three categories (species richness indices, species compositional/mingling indices and vertical structural indices) were used as predictor variables to fit several candidate models. By merging the trees by site (without considering the species identity) selected models include individual tree basal area as an explanatory variable combining by addition or interaction with diversity indices. When species are analyzed independently, structural diversity impacts on biomass yield in combination (additive or multiplicative) with tree size is negative for Pinus nigra and positive for the other species.

Host range, genetic variability, and mating types of Lecanosticta acicola in Slovakia

ABSTRACT In recent years, there has been an apparent Europe-wide emerging presence of brown spot needle blight, a disease of pine species caused by the fungus Lecanosticta acicola. In this study, we report the first well-documented occurrences of the pathogen in Slovakia, identified molecularly using species-specific primers and based on sequencing of the ITS region and TEF1 gene. Among the material collected from 84 locations within the country, L. acicola was present in 17 samples from 13 different locations, mainly distributed in urban environments. Four pine species were identified as hosts, among which, Pinus nigra and P. mugo were found to be the most frequently infected. Analysis of the mating type genes of 24 isolates obtained from two localities revealed the presence of a single mating type in Slovakia. All analyzed ITS sequences of the Slovak isolates were found to be uniform. However, although analysis of the TEF1 gene indicated that all Slovak isolates could be grouped into a single lineage, we detected nucleotide polymorphisms suggestive of a certain degree of genetic diversification within central European populations of the fungus.

Reduced Temperature Sensitivity of Maximum Latewood Density Formation in High-Elevation Corsican Pines under Recent Warming

Maximum latewood density (MXD) measurements from long-lived Black pines (Pinus nigra spp. laricio) growing at the upper treeline in Corsica are one of the few archives to reconstruct southern European summer temperatures at annual resolution back into medieval times. Here, we present a compilation of five MXD chronologies from Corsican pines that contain high-to-low frequency variability between 1168 and 2016 CE and correlate significantly (p &lt; 0.01) with the instrumental April–July and September–October mean temperatures from 1901 to 1980 CE (r = 0.52−0.64). The growth–climate correlations, however, dropped to −0.13 to 0.02 afterward, and scaling the MXD data resulted in a divergence of &gt;1.5 °C between the colder reconstructed and warmer measured temperatures in the early-21st century. Our findings suggest a warming-induced shift from initially temperature-controlled to drought-prone MXD formation, and therefore question the suitability of using Corsican pine MXD data for climate reconstruction.

Forest plant cover and mineral type determine the diversity and composition of mineral-colonizing fungal communities

Soil fungi play a fundamental role in the cycling of nutrients and tree nutrition in forests. As mycorrhizal fungi are closely associated with their host trees and provide them essential base cations and phosphorus, we hypothesize that they actively mine soil minerals and transfer their nutritive content to their host. Therefore, mycorrhizal fungi are expected to be important colonizers of soil mineral surfaces relative to other fungal trophic guilds. To test this hypothesis, 50 μm nylon mesh bags were filled with three different mineral types (i.e. calcite, apatite and obsidian) and buried in the same soil colonized by three forest stands (i.e. beech, Corsican pine and coppice with standards). After an in situ incubation period of 29 months in the topsoil, mineral dissolution was detectable in the mesh bags, and the analysis of the fungal communities was therefore undertaken. Minerals presented a lower fungal biomass than the surrounding bulk soil and no difference between the three mineral types tested was observed. The high-throughput sequencing (HTS) approach showed that the fungal communities differed among the three forest stands, but in each case, mineral associated fungal taxa differed significantly from those in the bulk soil. To a lesser extent, fungal communities further varied between the three mineral types. Overall, trophic inference analyses suggested that two groups of plant-associated fungi, namely the ectomycorrhizal and endophytic fungi, were the major fungal mineral colonizers. Saprophytes also appeared significantly enriched on minerals comparatively to the surrounding bulk soil. Together, our data reveal at local scale that the mineral-associated fungal communities are first determined by the forest plant cover and then by the type of mineral.

Carbon stock estimation by dual-polarized synthetic aperture radar (SAR) and forest inventory data in a Mediterranean forest landscape

Forest ecosystems play a crucial role in mitigating global climate change by forming massive carbon sinks. Their carbon stocks and stock changes need to be quantified for carbon budget balancing and international reporting schemes. However, direct sampling and biomass weighing may not always be possible for quantification studies conducted in large forests. In these cases, indirect methods that use forest inventory information combined with remote sensing data can be beneficial. Synthetic aperture radar (SAR) images offer numerous opportunities to researchers as freely distributed remote sensing data. This study aims to estimate the amount of total carbon stock (TCS) in forested lands of the Kizildag Forest Enterprise. To this end, the actual storage capacities of five carbon pools, i.e. above- and below-ground, deadwood, litter, and soil, were calculated using the indirect method based on ground measurements of 264 forest inventory plots. They were then associated with the backscattered values from Sentinel-1 and ALOS-2 PALSAR-2 data in a Geographical Information System (GIS). Finally, TCS was separately modelled and mapped. The best regression model was developed using the HH polarization of ALOS-2 PALSAR-2 with an adjusted R2 of 0.78 (p < 0.05). According to the model, the estimated TCS was about 2 Mt for the entire forest, with an average carbon storage of 133 t ha−1. The map showed that the distribution of TCS was heterogenic across the study area. Carbon hotspots were mostly composed of pure stands of Anatolian black pine and mixed, over-mature stands of Lebanese cedar and Taurus fir. It was concluded that the total carbon stocks of forest ecosystems could be estimated using appropriate SAR images at acceptable accuracy levels for forestry purposes. The use of additional ancillary data may provide more delicate and reliable estimations in the future. Given the implications of this study, the spatiotemporal dynamics of carbon can be effectively controlled by forest management when coupled with easily accessible space-borne radar data.

The effects of increased exposure time to UV-B radiation on germination and seedling development of Anatolian black pine seeds.

Exhaustion of stratospheric ozone found at a height of 10-30 km around the world causes the solar UV-B (280-320 nm) radiation to penetrate through the atmosphere more, and thus to reach the Earth's surface quicker. The protective ozone layer gets damaged by human activities constantly, and the increasing levels of UV radiation present threats to all life forms, plants, animals, and even microorganisms. However, the studies conducted on the effects of UV radiation on plants, and especially forest trees, are rather limited. In this study, it was aimed to identify the effects of UV-B radiation on some germination and seedling characteristics of Anatolian black pine seeds. Within the scope of the study, seeds were exposed to UV-B radiation for 5, 10, 20, 30, 40, 50, and 60 min for germination experiments; and the germination speed (GS) was calculated as the ratio of the germinated seeds to the solid seeds at the end of the 7th day, whereas the germination percentage (GP) was calculated as the ratio of the germinated seeds to the solid seeds at the end of the 35th day. The seeds reserved for the seedling experiment were exposed to UV-B radiation for 1, 3, 5, and 7 h. With the measurements made at the end of the day, the seedling length (SL), the terminal bud length (TBL), the branch number (BN), the root collar diameter (RCD), the stem fresh weight (SFW), the root fresh weight (RFW), the stem dry weight (SDW) and the root dry weight (RDW), and the rooting percentage (RP) were determined. Variance analysis and Duncan test were applied to the obtained data with the help of SPSS package program. The study results revealed that the exposure time to increased UV-B radiation significantly affected all characters; the least affected character was RP, and that the most affected characters were RDW, SDW, and RCD. As a result of the study, it was found that even the applications with the lowest intensity took effect in most of the characters, that the seedling development decreased by more than 80% in terms of some characters at the end of 7-h application, and that even the decrease in the RP character, which was the least affected by the 7-h UV-B application, was above 50%.

Soil physico-chemical properties have a greater effect on soil fungi than host species in Mediterranean pure and mixed pine forests

Soil fungi are fundamental drivers of forest ecosystem processes. Soil physico-chemical parameters and vegetation features such as host type or stand structure can affect soil fungal communities. However, there is a lack of comprehensive studies describing the relative importance of niche processes (soil physico-chemistry and forest structural drivers) versus neutral processes (geographical distance) driving soil fungal community assemblages, especially in less-studied drought-prone ecosystems such as Mediterranean forests. In this study, we performed Pacific Biosciences sequencing of internal transcribed spacer 2 amplicons to characterize the soil fungal community composition and diversity of 42 forests dominated by either pure Pinus nigra, Pinus halepensis or Pinus sylvestris or a P. nigra–P. halepensis or P. nigra–P. sylvestris mixture. Our specific aims were to identify and disentangle the relative importance of the main soil characteristics and the spatial and forest structural factors that accounted for the greatest proportion of fungal community variation along a regional gradient in the Mediterranean Pre-Pyrenees. Soil parameters accounted for the greatest significant proportion of the total variance in the overall fungal community (25%), in the mycorrhizal (23%) and saprotrophic (22%) communities, while geographical distance accounted for 14% of the variance in the overall fungal community, 7% in the mycorrhizal and 22% in the saprotrophic communities. Conversely, forest structure did not significantly affect the soil fungal community, as fungal composition and diversity did not differ significantly among the pine hosts. Moreover, pH, followed by P and the C:N ratio explained the largest differences in the composition of the overall fungal community and in the mycorrhizal fungal community. By contrast, the largest proportion of differences in saprotrophic composition were explained by geographical distance, closely followed by the C:N ratio and N. Our results show that, in these Mediterranean pine forests, soil parameters are the most important driving forces shaping soil fungal communities at the regional scale given that ectomycorrhizal and saprotrophic fungi were more influenced by soil physico-chemical parameters or geographical distance than by Pinus species or forest structural variables. Finally, P content in soils also emerged as a significant factor driving differences in mycorrhizal communities.