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    Effects of land-use regime on soil erodibility indices and soil properties in Unye, Turkey
    (Parlar Scientific Publications (P S P), 2007) Yılmaz, Murat; Usta, Ayhan; Altun, Lokman; Tilki, Fahrettin
    We evaluated the effects of land-use regime on soil erodibility indices and several soil properties in forested, deforested, and cultivated areas in the village of Unye, Turkey. Twelve sample plots (spaced 150 m apart) with northern aspects were established in each land-use regime, and samples were taken at soil depths of 0-20, 20-50, and 50-80 cm. Soil organic matter (SOM), soil reaction (pH), total lime (CaCO3) texture (sand, silt, and clay), dispersion ratio (DR), erosion ratio (ER), colloid-moisture equivalent ratio (C-MER), structural stability index (SSI), field capacity (FC), wilting point (WP), and available water capacity (AWC) were analyzed. The average (of the three soil depths) AWC, FC, and WP values were not affected by the site, although site, soil depth, or both significantly affected other analyzed soil variables. Deforestation and subsequent tillage practices resulted in an almost 20% decrease in clay content, a 33% decrease in SOM, a 15% decrease in AWC, a 51% decrease in total CaCO3, a 24% decrease in SSI, a 60% increase in DR, and a 98% increase in ER relative to undisturbed forest soil. At cultivated and forested sites, the ER and DR increased with increasing soil depth. At deforested sites, ER and DR were lowest at 50-80 cm. SOM was the highest at 0-20 cm in the forested sites. Decreasing SOM, clay content, and SSI, as well as increasing DR and ER were outcomes of deforestation. These results indicate that the conversion of forest into cropland deteriorates some soil properties, especially SOM and SSI, and alters the stability of soil aggregates, thus increasing the susceptibility of deforested sites to erosion.
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    Effects of thinning intensity on the growth of narrow-leaved ash ( Fraxinus angustifolia subsp. oxycarpa ) plantations
    (2013) Çiçek, Emrah; Yılmaz, Faruk; Özbayram, Ali Kemal; Efe, Mehmet; Yılmaz, Murat; Usta, Ayhan
    Narrow-leaved ash (Fraxinus angustifolia) is one of the important broadleaved tree species, and it is becoming more important in European forestry because of its valuable wood and fast growing ability. Despite its wide natural range and high economic value, there is little or very limited information about the effects of thinning on the growth and development of ash stands, especially in plantations. In this study, 2 thinning experiments were carried out to determine the effects of thinning intensity on the growth of diameter, height, basal area, and volume in narrow-leaved ash plantations over a 6-year period in Adapazarı, Turkey. In the stands prior to thinning, mean diameter and stem number were about 31 cm and 416 trees ha 1 in the first experiment (at 36 years with 3 x 2 m initial spacing), respectively. The values were 24 cm and 544 trees ha 1 in the second experiment (at 22 years with 3.7 x 3.7 m initial spacing), respectively. Randomized block design with 3 replications was used in both experiments. The thinning treatments were as follows: removal of the basal area at 0% (control), 22% (moderate), and 39% (heavy) in the first experiment, and 0% (control), 19% (moderate), and 28% (heavy) in the second experiment. The 6-year results showed that thinning increased the diameter increment significantly, and the increase in diameter increment was positively correlated with the thinning intensity in both experiments. However, thinning intensity did not significantly affect increments of height, basal area, and volume. Moreover, increments of diameter, height, basal area, and volume were higher in the second experiment than in the first experiment.
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    Effects of thinning intensity on the growth of narrow-leaved ash (Fraxinus angustifolia subsp oxycarpa) plantations
    (Tubitak Scientific & Technical Research Council Turkey, 2013) Çiçek, Emrah; Yılmaz, Faruk; Özbayram, Ali Kemal; Efe, Mehmet; Yılmaz, Murat; Usta, Ayhan
    Narrow-leaved ash (Fraxinus angustifolia) is one of the important broadleaved tree species, and it is becoming more important in European forestry because of its valuable wood and fast growing ability. Despite its wide natural range and high economic value, there is little or very limited information about the effects of thinning on the growth and development of ash stands, especially in plantations. In this study, 2 thinning experiments were carried out to determine the effects of thinning intensity on the growth of diameter, height, basal area, and volume in narrow-leaved ash plantations over a 6-year period in Adapazart, Turkey. In the stands prior to thinning, mean diameter and stem number were about 31 cm and 416 trees ha(-1) in the first experiment (at 36 years with 3 x 2 m initial spacing), respectively. The values were 24 cm and 544 trees ha(-1) in the second experiment (at 22 years with 3.7 x 3.7 m initial spacing), respectively. Randomized block design with 3 replications was used in both experiments. The thinning treatments were as follows: removal of the basal area at 0% (control), 22% (moderate), and 39% (heavy) in the first experiment, and 0% (control), 19% (moderate), and 28% (heavy) in the second experiment. The 6-year results showed that thinning increased the diameter increment significantly, and the increase in diameter increment was positively correlated with the thinning intensity in both experiments. However, thinning intensity did not significantly affect increments of height, basal area, and volume. Moreover, increments of diameter, height, basal area, and volume were higher in the second experiment than in the first experiment.
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    Relationships between environmental variables and wood anatomy of Quercus pontica C. Koch (Fagaceae)
    (Parlar Scientific Publications (P S P), 2008) Yılmaz, Murat; Serdar, Bedri; Altun, Lokman; Usta, Ayhan
    We investigated the relationships between various soil characteristics and anatomical wood attributes of Quercus pontica C. Koch. Wood and soil samples were collected from Rize-Ikizdere-Cimil and Rize-Findikli, Turkey, where Q. pontica is widely distributed. The soil samples were analyzed for particle size distribution (sand, silt, and clay content), pH, organic matter, field capacity (moisture equivalent), wilting point, and available water capacity (AWC). Wood samples were obtained alone, with soil samples. To determine fiber characteristics, fibers were prepared using Schultze's method and measured under a microscope. We found significant correlations between wood anatomical features and soil characteristics. Altitude was 2 positively correlated with the number of vessels per mm (r=0.98, p < 0.01) and tracheld fiber wall thickness (r=0.36, p < 0.05). Altitude was negatively correlated with the length of vessel members (r=-0.83, p < 0.01), the radial diameter of vessel elements in latewood (r=-0.89, p < 0.01), the tanuential diameter of vessel elements in latewood (r= -0.96, p < 0.01), the height of uniseriate rays (r=-0.68, p < 0.01), and the number of uniseriate rays per mm (r=-0.89, p < 0.0 1). AWC was negatively correlated with the number of vessels per mm 2 (r=-0.74, p < 0.01). Furthermore, vessel element length (r=0.63), radial diameter of vessel elements in latewood (r=0.68), tangential diameter of vessel elements in latewood (r=0.73), height of uniseriate rays (r=0.68), and number of uniseriate rays per mm (r=0.53) were positively correlated with AWC (p < 0.01).