Gunes Uçar

• Istanbul University

Abies species naturally grown in Turkey are represented by four species and two subspecies. Abies equi-trojani (Aschers & Sint.) and Abies bornmulleriana (Mattf.) occur in western and northwestern regions. Abies cilicica subsp. isaurica (Coode & Cullen) and Abies cilicica subsp. cilicica (Antoine & Kotschy) Carr. are widespread in the southern part...

This study is to investigate the effect of the geographic variation on the composition of needle oils of Abies bornmuelleriana endemic to Turkey. Samples were taken from the stands distanced up to 500 km from each other. By means of GC-MS/FID analyses, it was found that main compounds making up about 90 percent of the needle essential oils exhibit...

Industrial Crops and Products j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / i n d c r o p a b s t r a c t The structures of condensed tannin from Pinus brutia bark were characterized by means of GC–MS, solid and liquid state 13 C NMR and MALDI-TOF MS analyses. The results indicated that the monomeric units building...

As a new approach, the acidity that wood exhibits under moderate conditions is assayed by stimulated dissociation of weak wood acids in lightly basic secondary phosphate solutions. To assure a sufficient dissociation of hardly soluble weak acids in the solution, the amount of wood suspended in Na(2)HPO(4) solutions should be small but vary dependin...

The MeOH extracts of wood and bark from Quercus hartwissiana have been investigated by GC-MS after derivatization, as well as by classical spectroscopic methods. The results for the free compounds revealed that ellagic acid, catechin, gallic acid, quercitol, and also long chain fatty acids, sugars, and sitosterol were the essential compounds in woo...

Abies nordmanniana, A. bornmülleriana, A. equi-trojani and A. cilicica, four native fir species in Turkey, were characterized by means of GC/MS and GC-FID analyses of their needle essential oils. Large amounts of δ-3 carene, present in needles of A. nordmanniana and A. cilicica subsp. cilicica differentiated these species, since this compound is no...

Wood age, i.e., number of years that have passed after the annual rings of xylem tissue developed from cambium, had a strong negative impact on the volatile acid content of wood of the two oak species, Quercus petraea and Q. frainetto. Up to 80% of acetyl groups were cleaved off in the heartwood zones close to the pith if the living oak trees were...

Black pine (Pinus nigra subsp. pallasiana) is widely distributed in Turkey. It is one of the most popular trees for timber use. Because of the biomass potential value, the aim of the present study was to elucidate the composition of both main and extractive components of Turkish black pine cones. In order to determine the extent of the change in th...

The effect of the storage on the wood acidity was investigated by storing of fresh wood chips from two angiosperm and two gymnosperm species up to one year. Cold water-, hot water- and enhanced acidity in acetate and phosphate solutions were determined titrimetrically at certain intervals during one year. The study demonstrated considerable differe...

In order to differentiate two varieties of Cupressus sempervirens, volatile foliage isolates obtained from 12 trees of variety horizontalis and 12 trees of var. pyramidalis were analyzed by GC and GC/MS. About 86–87% of total peak areas of chromatograms consist of monoterpenes and evaluating their composition in qualitative and quantitative manner...

Recent and fossil woods from the genus of Sequoiadendron, as well as their milled wood lignins were investigated by means of FTIR spectroscopy and pyrolysis GC/MS technique. Though almost same in appearance the differences in band intensities of FTIR-spectra reveals the distinctly increased aromatic character and the oxidation in fossil specimens....

The volatile extracts from needles of two varieties of Anatolian black pine, Pinus nigra subsp. pallasiana var. pallasiana and pyramidata were investigated by GC–MS. Generally, the composition of extracts was similar but the proportion of some compounds differed. The increased proportion of β-pinene is distinct in the variety pallasiana, whereas hi...

The viscosity of copper ethylenediamine (CED) solutions of pulps exhibits a decrease with time, while the viscosity loss is insignificant when the time between dissolution and measurement is just 15–20 min. Time of 1 h or longer would lead to noticeable differences from the initial viscosity. The viscosity of the solution at the beginning can be es...

To estimate the volatile acids from soft- and hardwoods a simple method was developed. Since the main part of volatile acids originates from acetyl groups of wood polyoses alkaline hydrolysis was applied, upon acidifying the free acetic acid was liberated and distilled. Acetic acid, with small amounts of other volatile acids, was then estimated by...

Volatile needle and wood extracts of oriental spruce obtained from trees grown naturally in eastern Black Sea regions and in an cultivated stand near Istanbul were analysed by GC–MS. Despite considerable differences in both tree-to-tree and natural-to-cultivated aspects, the needle and wood extracts exhibit characteristic compounds, which might be...

SubjectSap- and heartwood extracts obtained by successive extractions with cyclohexane, chloroform, ethanol and hot water from J. foetidissima and J. oxycedrus were tested for their antifungal activity by using the agar plate method. Generally, the extractive substances of heartwoods soluble in nonpolar or slightly polar solvents show higher activi...

Classical standard hydrolysis of polysaccharides with 72% sulfuric acid was modified in 2 manners. In order to avoid treatment in an autoclave at 120°C under pressure, wood or pulp material was first swollen in cold 77% acid followed by hydrolysis steps in diluted acid solutions. Further, the neutralization of the hydrolyzate with dilute barium hyd...

, J. foetidissima and J. oxycedrus. Among the compounds the monoterpenes exist in minor amounts while the sesquiterpenes including their oxygenated members as well as sesquiterpene alcohols consist of the majority of the whole substances. The existence of some compounds of the oils might be attributes of the species and their sap- and heartwood. On...

var. pallasiana, naturally grown in eastern Thrace, were analyzed by means of GC-MS with regard to tree growth rate and chemotaxonomic purposes. High amounts of sterols but less resin acid content are distinctive for slow growing wood. Compared to extractives of Anatolian black pine, Thracian wood yields greater amounts of resin acids but somewhat...

The volatile wood extracts of three black pine trees two of which from afforestation stands (Demirköy, Topcular) and the third one from a natural stand (Kastro), all in Eastern Thrace (Turkey), were comparatively studied by means of GC/MS. The woods of two trees from the afforested stand (Demirköy) and natural stand located close to the Black Sea e...

The hot water- and total acidity of some important hard- and softwoods were correlated to hot water and 1% alkali solubilities. In this manner a positive correlation exists and in case of hardwoods a plot, an expected increasing curve, can be observed. However, due to an insufficient number of data the correlations of softwoods are somewhat ambiguo...

The bark and wood of an endemic oak species in Turkey, Q. vulcanica, were investigated with regard to main components, phenolics as well as extractives. About 66 % of extract free wood consists of polysaccharides, i.e. cellulose and polyoses. Heartwood was found to be rich in ellagitannins, while in bark proanthocyanidins occurred in larger amounts...

The corrosion of metals in contact with wood, discoloration of wood itself, undesirable effects on wood preservatives and the curing of the synthetic resins especially glues in fiberboards, particleboards and some other effects could be traced back to the acidity of wood. Thus, this phenomenon is of a great importance in the wood utilization. In th...

A fossil bark from a complete Sequoia trunk recovered near Istanbul (Turkey) was investigated to assess the degree of degradation of some of its components with respect to a modern Sequoia. Polyoses were studied by cation exchange technique while terpenes with GC/MS analyses of the dichloromethane extracts. Exchange measurements have shown the loss...

Except for small amounts of neutral compounds, the ethanol extracts from fossil Sequoia wood contained over 80% polymeric substances. The bulk of materials was separated into fractions by column chromatography and investigated by means of UV- and FTIR spectroscopy. According to the results the polymeric products are a type of Brauns lignins. Both s...

Two well preserved stems of fossil sequoiadendron giganteum excavated in Turkey were studied using electron microscopic and chemical methods.Chemical analysis included determination of main constituents (lignin, cellulose, polyoses) as well as detailed analysis of extractives recovered with different solvents and applying e.g. FTIR, GC, GC-MS techn...

A tree of the speciesAbies bornmülleriana which had stood in a fresh water lake for about 300 years and its counterpart from a forest nearby were comparatively investigated. Few differences regarding the structure, chemical composition and mechanical behaviour of wood were found. Ein Baum der GattungAbies bornmülleriana M. stand rund 300 Jahre lan...

The wood of P. nigra vars pallasiana and pyramidata was analysed with regard to the main components lignin and holocellulose, as well as extractives. The lignin content was unusually low. Most of the extractives were fatty and resin acids. The var. pyramidata is richer in resin acids and differs also in the ratio of abietane- and pimarane-type acid...

The dilute acid pretreatment in a plug flow reactor and alkali pretreatments with caustic solutions at different conditions followed by enzymatic hydrolysis resulted in drastically improved glucose yields for aspen and hybrid poplar. The acid pretreatment conditions must be carefully chosen to open the cellulosic structure allowing rapid diffusion...