during the past two decades the use of lignocellouse fibers in reinforcing composites has attracted much research activities. in the present work, date palm fiber was used for production of composites compatible withliving environment. the fibers were pre-treated chemically to remove impurities. in order to verify and compare the effectiveness of the pretreatment methods, lignin, ash, moisture ...

We compared the tolerance of hiba (Thujopsis dolabrata var. hondae Makino), beech (Fagus crenata Blume) and oak (Quercus serrata Thunb.) to creep and glide pressures of snow. The top/root (T/R) ratio of hiba trees ranged between 7.1 and 41.4 compared with 3.6-10.9 and 1.0-12.4 for beech and oak, respectively. However, if prostrate stems bearing adventitious roots were included in the root compo...

A constitutive model for the stress-strain relationship of single forest root system was developed in order to provide theoretical foundations for the mechanisms of soil-reinforcement by root system and offer a reliable basis for the analysis of root tensile strength character. This study started a general form of linear and non-linear stress-strain relation that was mathematically defined by f...

ZI E M E R, R. R. 1978. An apparatus to measure the crosscut shearing strength of roots. Can. J. For. Res. 8: 142-144. Loss of tree root strength after timber cutting is a principal mechanism leading to slope failure and landslides. Measurement of root shear strength changes can be useful in evaluating effects of logging on slope stability. The simple apparatus described measures shear strength...

In this research scotch pine (Pinus sylvestris L.), Eastern beech (Fagus orientelis L.), oak (Quercus petraea L.) samples have been covered with polyurethane, acrylic, cellulosic varnish. In order to determine the physical changes which occurred on varnish layers caused by steam and wet heat, the samples were exposed to TS 4982 EN 12721 wet heat and TS EN 438-2 steam. According the results, the...

The tensile strength of rocks plays a noteworthy role in their failure mechanism, and its determination can be beneficial in optimizing the design of the rock structures. Schistose rocks due to their inherent anisotropy in different foliation directions show a diverse strength at each direction. The purpose of this work was to compare and assess the tensile strength of phyllite, which was obtai...

Impacts of elevated ground-level ozone (O(3)) on nitrogen (N) uptake and allocation were studied on mature European beech (Fagus sylvatica L.) and Norway spruce (Picea abies [L.] Karst.) in a forest stand, hypothesizing that: (i) chronically elevated O(3) limits nutrient uptake, and (ii) beech responds more sensitively to elevated O(3) than spruce, as previously found for juvenile trees. Tree c...