J OURNAL OF FOREST PRODUCTS & INDUSTRIES, 2013, 2(2), 53-57 ISSN:2325–4513(PRINT) ISSN 2325 - 453X (ONLINE )
Physico-Chemical Characterization of Wood from Maclura Pomifera (Raf.) C.K. Schneid. Adapted to the Egyptian Environmental Conditions Mohamed Z.M. Salem*1, Nashwa H. Mohamed2 1
Forestry and Wood Technology Department, Faculty of Agriculture (EL-Shatby), Alexandria University, Alexandria, Egypt. E-mail: firstname.lastname@example.org 2 Agricultural Research Center, Horticulture Research Institute, Forestry Department, Antoniades Gardens, Alexandria, Egypt. E-mail: email@example.com (Received: January 30, 2013; Accepted: February 27, 2013) Abstract— In the present study the evaluation of physico-chemical characterization of wood from Maclura pomifera adapted to the Egyptian environmental conditions was achieved. Fiber length, specific gravity and chemical composition: the lignin, cellulose, hemicellulose, extractives, hot water solubility, cold water solubility, 1 % alkali solubility and ash contents were determined. The results revealed that fiber length of M. pomifera wood was 0.87 mm. The dry, green and basic densities were 0.83±0.090 g/cm3, 0.91±0.1g/cm3 and 0.62±0.07 g/cm3. The lignin, cellulose, hemicellulose, extractives, hot water solubility, cold water solubility, 1% alkali solubility and ash content were 40±2.45 %, 33.34±2.76 %, 17±1.34 %, 8.09±1.34 %, 6.62±0.98 %, 4.12±0.87 %, 21.6±2.54 % and 0.45±0.03 %, respectively. This is the first report about the chemical and physical properties of the wood from M. pomifera grown in Egypt.
Index Terms— Maclura pomifera, physico-chemical characterization, fiber length, lignin, cellulose, hemicellulose.
I. INTRODUCTION name Maclura pomifera comes from William Maclure The(1763–1840) an early American geologist; and pomifera which means “fruit-bearing” for the large fruits that it produces on the female trees. It is a small to medium size tree 36 to 65 feet tall, with deeply furrowed bark and thorny branches. The trunk is usually short and divides into several prominent limbs with upward arching branches. The root system is diffuse and covers large areas with its lateral spread. Leaves are deciduous, simple, and alternate or are in clusters at the end of short spurs. Their shape ranges from broad-ovate to ovate-lanceolate. Leaves are 2 to 5 inches (in.) long and 0.75 to 2.5 in. wide and have entire margins. Leaf blades are dark green, smooth and waxy above; paler green with a few hairs beneath. The color turns translucent yellow in the fall.
Osage orange trees native to North America are dioecious and wind pollinated with flowers appearing in mid-May to June. Staminate (male) flowers are globular or in short cylindrical clusters, green, hairy, with 4 stamens and large yellow anthers, but no petals. Pistillate (female) flowers are in dense, globular clusters, 0.75 to 1.0 in. diameter at the base of a leaf. The fruit or “Hedge ball” is produced in September and is a multiple fruit consisting of many seeded druplets fused into a globose, yellow-green structure approximately 3 to 5 in. in diameter. Female trees may start to bear fruit at about 10 years old. The individual oval shaped seeds are imbedded in the fleshy calyx and are 0.3 to 0.5 in. long. Seeds are initially cream colored, but will turn brown with age and exposure to air [1,2,3,4]. Historically Osage-orange [(Maclura pomifera (Raf.) Schneid.)] belonging to family Moraceae was used by Native American tribes to produce wooden bows thus the French name bois d’arc or ‘wood of the bow’ . Oil extracted from the seeds has been tested for its potential as biodiesel. The isoflavone pomiferin has been studied for its antioxidant activity. Osage orange has also had proteolytic enzymes recently discovered in its fruit . The heartwood is the most decay-resistant of all North American timbers, mainly because it contains an antifungal agent. This and 2'3,4',5,7, pentahydroxyflavone were extracted from the hardwood . Several additional flavones and xanthones have been isolated from fruits, roots, and heartwood . Today Osage orange trees are used for fence posts, due to their unusual ability to resist decay from soil born organisms, to provide livestock enclosures. Both song birds and upland game birds find shelter and food below its low hanging branches . It produces no saw-timber, pulpwood, or utility poles, but it has been planted in greater numbers than almost any other tree species in North America . The heartwood, bark, and roots contain many extractives of actual and potential value in food processing, pesticide manufacturing, and dye-making. Osage-orange is used in landscape design, being picturesque
J OURNAL OF FOREST PRODUCTS & INDUSTRIES, 2013, 2(2), 53-57 ISSN:2325–4513(PRINT) ISSN 2325 - 453X (ONLINE ) 54 rather than beautiful, and possessing strong form, texture, and character.
Figure 1: Different parts of Maclura pomifera
There are many exotic trees like M. pomifera which cultivated as a representative model of the species in Egypt and adapted in our environment condition. We have not enough information about those species under our condition including; growth habits, chemical components and wood properties for the best economic uses. In our survey there is a lack in information about the physical and chemical properties of Osage-orange wood. Subsequently, the present work is devoted to evaluate the chemical and physical properties of wood from the rarely M. pomifera tree grown in Alexandria city, Egypt.
II. MATERIALS AND METHODS Locality description under Alexandria wizard The botanical classification of Osage-orange is shown in Table 1. There are three old exotic of Osage-orange trees located in Antoniadis garden, Alexandria, Egypt, one male and the others are females. The trees located in 780487, 80484, 780485 E and 3453678, 3453671, 3453675 N. The average of their diameter at dbh is 45.5 cm, trunk branched at 2.5 m height and the average of total height is 5 m. Leaves are deciduous, simple, alternate, 5 cm long, 2 cm wide, light green and the distance between thorns about 2 to 3 cm. Leaves are deciduous under the Egyptian environmental conditions at winter and it is wind pollinated with flowers appearing in March. The fruit resembles an orange, yellowish green, about 6 cm in diameter (Figure 1). Table 1 Botanical classification of Maclura pomifera (Raf.) C.K. Schneid. Kingdom Plantae – Plants Subkingdom Tracheobionta – Vascular plants Super division Spermatophyta – Seed plants Division Magnoliophyta – Flowering plants Class Magnoliopsida – Dicotyledons Subclass Hamamelididae Order Urticales Family Moraceae – Mulberry family Genus Maclura Nutt. – maclura Species Maclura pomifera (Raf.) C.K. Schneid. – Osage Orange Preparation of wood samples The juvenile wood samples of Osage orange were collected from the branches with a diameter average about 5 cm from the three trees in October 2012. The wood samples were divided into three groups; the first group was milled using a small laboratory mill to obtain a 40-60 mesh meals, the second was cut into pieces with a dimensions of 20 × 20 × 30 mm, and the third was cut to chips.
Physico-Chemical properties determination Specimens of 20 × 20 × 30 mm for wood density and shrinkages were soaked in distilled water for 72 hours to ensure the moisture content above the fiber saturation point. At this point, the dimensions in all three principal directions (longitudinal, radial and tangential) were taken. Simultaneously, samples were weighed to the nearest 0.001 g for saturated weight and the saturated volume was calculated based on these dimension measurements. Once the specimens were reached approximately 12% moisture content, the weight was taken again and the dimensions were measured in all three directions. Finally, the samples were oven-dried at 103°C until a constant oven-dry weight was attained. Thus, wood density, longitudinal, radial and tangential directions were measured for each specimen. The wood density was based on the oven-dry weight ratio to green (saturated) volume and dry volume. On the other hand, the specific gravity was calculated by the maximum moisture content method . Three samples (20 ×20 ×30 mm) were used to evaluate the shrinkage (α). The total shrinkage (αmax) from the green to the oven-dried conditions in radial (αr) and tangential (αt) directions and the volumetric shrinkage (αV) were tested according to the following formulae ,
li max li min 100 % li max V max V min v max 100% V max
J OURNAL OF FOREST PRODUCTS & INDUSTRIES, 2013, 2(2), 53-57 ISSN:2325–4513(PRINT) ISSN 2325 - 453X (ONLINE ) 55
where i is the longitudinal or radial or tangential direction, lmax is the size at a moisture content above the fibre saturation point, lmin is the size of the oven-dried samples, Vmax is the volume at a moisture content above the fibre saturation point, and Vmin is the volume of the oven-dried samples. For fiber length determination; wood chips were macerated in mixture of glacial acetic acid and 30 % hydrogen peroxide (1:1) at 60 °C for approximately 24 hr. After delignification, the material was washed by distilled water several times and reduced to fibers by mild shaking. The macerated fiber at each sampled point were stained with 2% Safranin pigment and their length measured to the nearest 0.01 mm using a projecting microscope. Fifty readings per each sample were taken and averages were calculated . Extractives content of wood meals (40-60 mesh) were calculated based on oven-dry weight. The procedure is based on National Renewable Energy Laboratory (NREL), Chemical and Testing Task Laboratory Analytical Procedure # 010 . The air-dried wood meal was extracted by 95% ethanol (100-120 ml) for 24 hours in a Soxhlet apparatus. Subsequently, cellulose, hemicelluloses and lignin contents were determined using wood meal free-extractives based on oven-dry weight. Cellulose content was determined by treatment of 1 gram of extractive-free wood meal with 20 ml of 3% nitric acid and boiling for 30 min. The solution was filtered and the residue was treated by 25 ml of sodium hydroxide (3%) and boiling for 30 min. The residue was filtered, washed with worm water, dried and weighed . Hemicellulose content was determined by treatment of extractive-free wood meal (1 g) with 50 ml sulfuric acid (2%) and boiling for 1hr. under refluxing and filtrated. The residue was washed with 500 ml hot distilled water, dried and weighed . Klason lignin content was determined by treatment the extractive-free wood meal (0.5 g) with a mixture of 85 % phosphoric acid and 75 % sulfuric acid (in a ratio of 1:6) at 35 °C. After one hour, the samples were boiled for half hour with 200 ml distilled water, filtrated, dried and weighed . The ash content of wood meals is defined as the residue remaining after ignition at 575 ± 25°C for 3 hours or longer if necessary to burn off all the carbon. It is a measure of mineral salts in the fiber, but it is not necessarily quantitatively equal to them . The cold-water solubility was determined by soaking 2 g of wood meal in 300 ml distilled water for 48 hr at room temperature, filtrated, dried and weighed . The solubility in hot water was calculated by boiling 2 g of sawdust wood with 100 ml distilled water for 3 hour, filtrated, dried and weighed . wood density and fiber length determine whether the quality of raw material is suitable for a specific use in the paper industry.
The solubility of wood meal alkaline was determined by boiling of 2 g wood meal by hot 1 % sodium hydroxide (100 ml) at 100 °C for 1 hr. The residue was washed with hot distilled water and then with 50 ml of acetic acid (10 %). Finally the residue was washed with hot distilled water, dried and weighed . Statistically, all the results are expressed as mean values ± standard deviation (SD). III. RESULTS AND DISCUSSION The fiber length as a biometrical property of Osage-orange wood was found to range between 0.84 mm and 0.90 mm with an average value of 0.87 mm. Table 2 presents the physical properties of Osage-orange wood. The dry, green and basic densities were 0.83±0.090 g/cm3, 0.91±0.1 g/cm3 and 0.62±0.07 g/cm3, correspondingly. Table 2 Physical properties of Osage-orange wood
Physical properties Dry density (g/cm3) Green density (g/cm3) Basic density (g/cm3) Longitudinal shrinkage (%) Radial shrinkage (%) Tangential shrinkage (%) Volume shrinkage (%)
Value* 0.83±0.09 0.91±0.1 0.62±0.07 0.22±0.006 3.78±0.05 5.63±0.08 9.63±0.8
*: Values are the mean ±SD of three measurements Table 3 Chemical components of Osage-orange wood
Chemical Components Cellulose (%) Lignin (%) Hemicellulose (%) Extractives (%) Hot water solubility (%) Cold water solubility (%) 1 % Alkali solubility (%) Ash (%)
Value* 33.34±2.76 40±2.45 17±1.34 8.09±1.34 6.62±0.98 4.12±0.87 21.6±2.54 0.45±0.03
*: Values are the mean ±SD of three measurements Wood basic density is considered one of the most important features in genetic improvement programmers  and is one of the most often studied wood quality traits [21,22]. It is a complex feature influenced by cell wall thickness, the proportion of the different kind of tissues and the percentages of lignin, cellulose and extractives . Both
Fiber length also has impacts on paper characteristics, such as strength, optical properties and surface quality .
J OURNAL OF FOREST PRODUCTS & INDUSTRIES, 2013, 2(2), 53-57 ISSN:2325–4513(PRINT) ISSN 2325 - 453X (ONLINE ) 56 As can be seen in Table 3, the lignin, cellulose, hemicellulose, extractives, hot water solubility, cold water solubility, 1% alkali solubility and ash content were 40±2.45 %, 33.34±2.76 %, 17±1.34 %, 8.09±1.34 %, 6.62±0.98 %, 4.12±0.87 %, 21.6±2.54 % and 0.45±0.03 %, respectively. The present results are in agrees with the previously reported results, where chemically the wood contains of 41.22 % lignin and 0.33 % ash . Furthermore, the content of cellulose was lower than the amount regular appears in the hardwoods. Previously, it has been observed that at the same height level, the lignin, extractives and ash decreased from pith to the bark, while cellulose increased by increasing the age. This is supported by the fact that the juvenile wood has higher lignin and lower cellulose content compared to the mature wood. The extractives and ash content of juvenile wood was also found to be lower than the mature wood [25,26]. In this study the wood of Osage-orange contains 8.09±1.34% of extractives and this amount is slightly higher than the extractives found in the hardwoods. Previous reported about the types and the chemical composition of the extracts revealed that the wood of Osage-orange contains 9.4 %tannin . Osage-orange is a small, rapid-growing tree; the wood is very dense, has high strength properties, and is resistant to decay. The general morphological and chemical difference between sapwood, discolored sapwood, and heartwood of Osage-orange has been studied . Additionally, the dyestuffs from the wood were morin (2´,4´,5,7-tetrahydroxyflavonol) and maclurin REFERENCES  Burton, J. D. 1973. Osage-orange: an American wood. USDA Forest Service, FS-248. Washington, DC. 7 p.  Keeler, H. L. 1900. Our Native Trees and How to Identify Them. New York: Charles Scriber's Sons. pp. 186–189.  Rollings, W. H. 2005. The Comanche. Philadelphia: Chelsea House Publishers. p. 25. ISBN 978-0-7910-8349-9.
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