Aydın Kahriman

Estimation of Crown Closure and Tree Density Using Landsat TM Satellite Images in Mixed Forest Stands

The objective of this study was to investigate the relationship between crown closure and tree density in mixed forest stands using Landsat Thematic Mapper (TM) reflectance values (TM 1- TM 5 and TM 7) and six vegetation indices (SR, DVI, SAVI, NDVI, TVI and NLI). In this study, multiple regression analysis was used to estimate the relationships between the crown closure and tree density (number of tree stems per hectare) using reflectance values and vegetation indices (VIs). The results demonstrated that the model that used SR and DVI had the best performances in terms of crown closure (R2 = 0.674) and the model that used the DVI and SAVI had the best performances in terms of tree density (R2 = 0.702). The regression model that used TM 1, TM 3 together with TM 4 showed the performances of the crown closure (R2 = 0.610) and the regression model that used TM 1 showed the performances of the tree density (0.613). Results obtained from this research show that vegetation indices (VIs) were a better predictor of crown closure and tree density than other TM bands.

Leaf anatomical notes on Cirsium Miller (Asteraceae, Carduoideae) from Turkey

Here, we describe the leaf anatomical characters of 26 Cirsium taxa (33 accessions) native to the northeast region of Turkey, with the aim of evaluating their taxonomic significance within the taxa. Leaf anatomies of all taxa were characterized and compared using cluster analysis and multidimensional scaling analysis. The transverse sections of the leaves showed various numbers of vascular bundles and accessory bundles. In addition, significant differentiations were observed in the midrib and lamina thickness, the height and width of vascular bundle, and number of stomata, and epidermal cell wall patterns in the abaxial and adaxial surfaces among the taxa. These results demonstrate that the compared anatomical characters among taxa are partly in accordance with their sectional delimitation in the Flora of Turkey. However, our data suggest that some taxonomic re-arrangements might be necessary. Based on its anatomy, we propose that the Cirsium taxa can be treated as pioneers. Some ecological interpretations are also made.

Site index models for Calabrian pine in the central Mediterranean region of Turkey

ABSTRACT Stem analysis data of 432 trees were obtained from even-aged, pure natural stands of Calabrian pine in the central Mediterranean Region of Turkey. Eight dynamic site equations derived with the Generalized Algebraic Difference Approach (GADA) were compared, based on autoregressive analysis and a thorough evaluation of the goodness of fit. We used generalized nonlinear least squares methods for model fitting. The adjusted coefficients of determination (0.9825–0.9842), root-mean-square errors (0.8004–0.8435 m), and Akaike’s information criterion differences (0–145) indicated a good fit of the eight site index equations. The Hossfeld equation (M3) provided the best result. The Durbin-Watson test statistic did not reveal an autocorrelation issue while the Hossfeld equation provided a satisfactory solution to the serial correlation problem in stem analysis data as time series using autoregressive modeling. This study presents new site index models for Calabrian pine forests in the central Mediterranean region of Turkey where it is the most important commercial tree species. The site index equation, based on the Hossfeld model is recommended for height growth prediction and site classification of Calabrian pine stands in the central Mediterranean region of Turkey, providing a new basis for growth prediction and yield estimation in these important forest ecosystems.

Determination of stand structure in even-aged Oriental Beech Forests in Turkey

Este estudio tuvo como objetivo desarrollar un modelo de rendimiento de rodales para bosques puros y uniforme de Fagus orientalis en la provincia de Sinop, norte de Turquia. Los datos se obtuvieron de 238 parcelas de muestreo de rodales con edad de 24-131 anos, indice de sitio de 19,0-35,9 m e indice de densidad relativo de 2,2-10,8. Con sistemas de ecuaciones generadas fueron determinados numericamente la edad del rodal, el indice de sitio y la densidad de los rodales, incluyendo la determinacion numerica de los efectos de las interacciones de los factores individuales, dobles y triples. En los rodales coetaneos, el aumento principal de los valores dependio de la edad, el indice de sitio y la densidad. La cantidad de tallos por hectarea disminuyo a medida que el rodal envejecia y el indice de sitio aumentaba; la cantidad, sin embargo, aumento en paralelo con la densidad del rodal. El incremento de volumen anual actual alcanzo un pico a los 30-35 anos en todos los grupos de indice de sitio y de niveles de densidad, y comenzo a caer despues. El incremento anual del volumen medio escala su pico a los 65-75 anos en todas las clases de indice de sitio y niveles de densidad, antes de comenzar a disminuir. Los resultados se encontraron de acuerdo con las normas reconocidas de crecimiento. El modelo de rendimiento de rodales se evaluo como tabla de rendimiento de variable de densidad utilizada para la estimacion de los rodales restantes, eliminados y totales

The construction of diameter-height models based on nonlinear mixed effect regression equations for oriental spruce located in mixed oriental spruce-scotch pine stands at Trabzon Forest District

The goal of this study is to determine the effects of various timber preservers on bending strength (BS), modulus of elasticity (MOE) and internal bond (IB) of particleboard, and whether the levels of those of effecs are importance or not The following material were used for manufacturing of experimental boars; wood chips, urea-formaldehyde and various wood preservers. The urea-formaldehyde were utilized according to the ovendry weight of the chips, the other chemicals were treated as to the ovendry weight of the adhesive. The chips were impregnated with solutions of the preservers in the gluing machine before adhering treatment. The boards were manufactured by pressing at temperature 150°C and pressure 25–28 kp/cm2. As a result; the mechanical properties of the board have increased with increasing of using amounts of impregnating substances. According to the control, the rates of increase have ranged from 2.01% to 34.93% for BS, from 2.67% to 49.18% for MOE, and from 0.50% to 42.13% for IB. For BS and MOE, while this increase is unimportant statistically in the boards impregnated with pine rosin, alcid resin and immersol WR, it is important in the other boards. For IB, the increase has not significance in the boards treated with boric acid/borax, tanalith CBC and tanalith CBC/boric acid/borax, whereas it has significance in the others. Keywords: Impregnation, Industrial wood chips, Particleboard, Mechanical properties.

Doğu Karadeniz Göknarı-Doğu Ladini Karışık Meşcerelerinde Çeşitli Yarışma Endekslerinin Tek Ağaçların Çap Artımındaki Etkilerinin İncelenmesi

The aim of this study is to investigate statistical relations between each of 12 competition indices (both distance-dependent and distance-independent) and diameter growth of trees. Also we investigated the relations between each of 12 competition indices together with diameter at breast height and diameter growth. For that reason, six sampling plots (ranging from 1000 to 2000 m2 in size) were taken from in mixed stands of Caucasion fir and Oriental spruce located within the Forest Management Districts of Torul and Artvin. Our results from those sampling plots were in agreement with general growth models. Regression analysis between each of competition indexes and diameter growth resulted in coefficients of determination (R2) values ranging from 30 to 64%. The distance-dependent competition indices gave stronger correlations with diameter growth than the distance-independent competition indexes. Coefficients of determination were even higher when competition indexes and dbh were used together as independent variables (R2 = 0.31 - 0.82).