Journal of Forest and Wood Products
Year:2010 | Volume:63 | Issue:2|Papers Count:10

Cultivation of rapeseed plant is expanding and larger volume of residues from its stalk is produced which necessitate its proper utilization. Therefore, properties of APMP pulps from rapeseed stalks are investigated. A combination of 2, 3 and 4% NaOH and 3, 4, 5, and 6% H2O2 is used for chemical pretreatment of stalks. Pretreatment time and temperature as well as DTPA and sodium silicate were kept constant at 35 minutes , 75oC, 0.5% and 3% (O.D. basis ) respectively. Treated stalks were defiberated using 25 cm laboratory disk refiner and total yield range was measured between 61.24 – 69.56%. Since both NaOH and H2O2 charge did not significantly affect the total yield, based on visual indication of pulp brightness, Then pulp samples produced using 3% NaOH and 3-6% H2O2 were selected for further analysis. All pulps were refined to 400 ml CSF and then 60 g/m2 handsheets were made. Tear index and tensile index of handsheets varied between 4.48-6.02 mN.m2/g and 12.53-22.71 N.m/g respectively. The influence of H2O2 addition on these properties was significant at 99% level. Optical properties of handsheets including brightness, opacity, yellowness, color factors L*, a* and b* were measured at 66.1-68.44%, 87.20–89.55%, 14.53-17.65, 90.01-90.045, 1.02-1.34 and 8-9.68 respectively. The effect of H2O2 addition on measured properties was significant at 99%. Overall the results indicate that the newsprint paper could be produced from APMP of rapeseed stalks.

The objectives of this study were to determine the composition and density of the persistent soil seed bank of Darkola oriental beech (Fagus orientalis Lipsky) forest and comparison of its seed bank composition with its above- ground vegetations. The study of ground vegetation was carried out with releve method and the soil seed bank was estimated by the seedling emergence method. For this purpose 52 releves were made by systematic- selective method with consideration of indicator stand concept. In each releve, soil samples were collected in each releve by using 20 cm × 20 cm square metal frame in 6 repetitions at the beginning of 2007 growth season. The metal frame was hammered into the soil to a depth 10 cm. Sixty- three species representing 57 genera and 36 families emerged from soil seed banks with Lamiaceae, Poaceae and Asteracea being best represented. The mean density of seedlings for the study area was 4202 seedlings/m2. Hypericum androsaemum L. exhibited the highest density with 1590 seedlings/m2, followed by Athyrium flix- femina (L.) (1227 seedlings/m2), Cardamine impatiens L. (570 seedlings/m2), Rubus hyrcanus Woron (286 seedlings/m2) and Pteris cretica L. (152 seedlings/m2). Alnus subcordata C. A. Mey was the only one tree that with the mean density 6.8 seedlings/m2 contributed in the soil seed banks. Forbs, with the possession of 90% seed bank flora, were the most numerous growth forms. The comparison of seed bank and above vegetation revealed that 28 species in the soil seed bank are absent in the vegetation and 44 species in the vegetation do not occur in the seed bank. This result not only explains low similarity between soil seed bank and vegetation but also confirm that the most species of ground vegetation do not depend on the soil seed bank for regeneration.

Air filter paper is made by combination of cellulosic and resin with specific permeability confronting with passing air flow. In this research, manufacturing of a sample car air filter paper has been done. At the first step, the constituents of the commercial filter paper were identified and after that different filter papers have been manufactured in the laboratory. Sample filter papers were manufactured using kenaf fibers and different acrylic resin contents at the laboratory and tested under standard conditions in order to evaluate their physical and mechanical properties. Comparison of the properties with those of imported standard air filter papers showed that kenaf fibers with 20-30% (based on dry weight) acrylic resin (solvable in water) and Tg=33oC are appropriate for the manufacture of various types of standard air filters. The obtained properties of sample car air filter papers made in the laboratory with 86gr/m2 were found very close to the imported filter papers.

In this study, the capability of acetylated poplar particles with isocyanate and urea formaldehyde resin in manufacturing particleboard of single-layer and three layers for studying the effects of these variables on sound absorbing coefficient, roughness and hardness of surface of manufactured boards, was investigated. The acetylation degrees at high, medium, and zero (control) levels, type of resin (isocyanate and urea formaldehyde) and use place of acetylated particle that are composed 50 percent of board weight and are used either in surface layers or in all places of board, were considered as variables. The results indicated that use of isocyanate resin in single-layer board with medium level acetylated particles in the major frequencies had high sound absorbing coefficient in comparison with the other boards. Not only surface roughness of boards is improved by increasing acetylation degree in three layer board with isocyanate resin in comparison with blanks with urea formaldehyde resin but also surface hardness of board is increased. Sound absorbing coefficient in the major frequencies on single-layer board with medium level acetylation and with isocyanate resin was the highest. The smoothest surfaces appeared on three layer board with high level acetylation and with isocyanate resin that had the hardest surface.

Ecological potential assessment of forest stands on the basis of existence criteria in forest ecosystems could be one of benefit points for forest ecosystems management. For this purpose, the forest stands of Darabkola region (Acer insign, Quercus castaneifolia, Pinus brutia, Carpinus betulus - Zelkova carpinifolia with Quercus castaneifolia) were assessed with respect to nine criteria (soil pH, total nitrogen, extractable phosphorous, exchangeable solution K-, earthworm biomass, number per hectare of trees, mean of diameter at breast height, total height of trees, and canopy area of trees). Analytical Hierarchy Process (AHP) used to assessment of forest stands. Results showed that the maximum local priority was estimated for Pinus brutia stand from acidity point of view. The other criteria have highest value in Acer insign forest stand. The minimum value of number per hectare and total nitrogen was considered in Quercus castaneifolia forest stand, whereas  the least value of extractable phosphorous, earthworm biomass, mean of diameter at breast height and canopy area devoted to Pinus brutia forest stand. Minimum soil pH, exchangeable solution K- and total height of trees were estimated at the mixed forest stand. The calculated overall priority showed that with respect to criteria, the Acer insign stand has higher ecological potential compare to the other stands. Whereas, Quercus castaneifolia, Pinus brutia, mixed forest stands had next priority, respectively. Pay attention to obtained results, Acer insign stand has more appropriate conditions and efficiency compared to the others at present condition.

Forest roads are one of the most essential infrastructures for managing forested areas. Sustainable forest road network and preserving construction costs need permanent road maintenance. Road monitoring is key element in road maintenance principles. In this study the forest road network of Namkhaneh district was monitored, cross section values of roads were measured and were compared to standard ones. Also the effect of number and distance between samples were assessed. The results showed that all cross section values of existing roads have significant differences with standard valued. In the case of three samples, only running surface and depth of ditches are standard and all other parameters were significantly different compared to standard values. The results of ANOVA revealed that running surface of five segments of the network have significant differences. Average distance of culverts and turnout in the district were 267±25 and 184±25 meters, respectively. Meanwhile, about 99.2℅ of samples had standard gradient but only 9℅ of the samples showed standard crown and cross section.

The anatomical and chemical properties of date palm tree fronds (leaves), which are gathered from date palm tree annual pruning, were investigated in this study. The palm used in this research was Stamaran or Sayer cultivar, which is the most predominant cultivar in Khuzestan province. To study the anatomical and chemical properties of the palm frond, the TAPPI standard was used. Leaf Stalk fiber length, diameter, lumen diameter, and cell wall thickness were measured at 1393.66 mm, 18.1 mm, 7.65 mm, and 5.23 mm respectively and leaflet fibers were measured at 1413.71 mm, 15.18 mm, 7.06 mm, and 4.06 mm respectively. Chemical composition was measured for both leaflet and leaf stalk. Chemical composition of the leaf stalk was as follows: cellulose 38.26%, lignin 22.53%, hemicellulose 28.17%, extractives 5.08%, and ash 5.96%. Chemical composition of the leaflet was as follows: cellulose 40.21%, lignin 32.2%, hemicellulose 12.8%, extractives 4.25%, and ash 10.54%. The slenderness ratio, flexibility ratio, and raunkel ratio calculated in Leaf Stalk was 77, 42.26%, and 136.73% respectively and in Leaflet was 93.13, 46.5%, and 115% respectively. It is important to know about these parameters for making composite products.

Nowadays continuous utilization of resources and their sustainable management is of great importance in forest management planning. By studying different principles, criteria and indicators to assess forest sustainability it is evident that one of the important criteria in this context is biodiversity. This study aims at assessment of forest sustainability by species diversity using data obtained from 0.1 ha sample plots commonly applied in forest management plans. The current research was done in Querco-Carpinetum in Patom district, Educational and Experimental Forest of Kheyroud. Some parts of above-mentioned association are located in 115 and 117 compartments in which logging practices were done, are referred to as logged area and some parts located in steep slopes of 107 compartments are considered as unlogged area. After laying out inventory grid (75 m × 100 m) in the study area, 40 sample plots were located in unlogged Area and 39 sample plots in logged area. Species and DBH of all tree individuals >2.5 cm, species and two perpendicular crown diameters of shrubs, altitude a.s.l., aspect and slope were recorded on each sample plot. In this research, in addition to richness indices, evenness and heterogeneity indices were also calculated by "Ecological Methodology" software package. The results showed that number of species and Margalef indices were significantly greater in unlogged area than logged area. The evenness indices (Simpson and Smith & Wilson) were significantly greater in unlogged area. All of the heterogeneity indices were significantly higher in unlogged area. However, index of species number and heterogeneity indices in shrub layers were greater in logged area.