No abstract

In this study, we evaluated the performance of 18 competition indices composed of nine distance-dependent and nine distance-independent indices in explaining the variation in individual-tree diameter growth of Calabrian pine (Pinus brutia Ten.) in the central Mediterranean region of Turkey. The data were obtained from 432 sample plots with varying stand age, site index, and stand density. To evaluate the performance of each competition index, the mean square error reduction approach was used relative to the noncompetition. Also, this study compared fixed and mixed effects models to analyze diameter growth. Statistical analyses showed that the best distance-independent competition indices performed as well as the best distance-dependent competition indices. The distance-independent competition index of Schröder and Gadow (1999; Can. J. For. Res. 29(2): 280–283, doi: 10.1139/x98-199) performed best and is recommended for use in future growth and yield models to be used in the central Mediterranean region of Turkey. Also, the best selection of competitive neighbors was achieved using the area of influence overlap method, whereas the fixed-radius and angle count sampling methods had no significant improvement in quantifying the competition effects. On the other hand, all mixed effects models provided much better fits than their fixed model counterparts.

The objective of this study is to evaluate the relationships between stand parameters (stand volume, basal area and dominant height), and band reflectance values and six vegetation indices (VIs) obtained from pan-sharpened, IKONOS satellite image in Artvin-Genya Mountain located in northeastern part of Turkey. Multiple stepwise regression analysis is used to estimate the stand parameters. The results indicated that a linear combination of EVI and DVI for stand volume and basal area (adjusted R 2 =0.55; a root mean square error (RMSE)=153.53 m 3 ha -1 and adjusted R 2 =0.59; RMSE=12.37 m 2 ha -1 ), respectively, and a linear combination of SAVI, EVI and DVI for dominant height (adjusted R 2 =0.57; RMSE=3.80 m) were better predictors than a linear combination of IKONOS Band 1and Band 4 for stand volume and basal area, and the IKONOS Band 1 and Band 2 for dominant height (R 2 =0.41; RMSE=181.01 m 3 ha -1 , R 2 =0.43; RMSE=14.84 m 2 ha -1 and R 2 =0.45; RMSE=4.62 m), respectively. This study concludes that the regression models developed with IKONOS VIs were able to predict stand parameters better than do the IKONOS band reflectance values in Artvin-Genya Mountain forest areas.

Özet: Bu çalışmada, Antalya ve Mersin yörelerinde yer alan saf ve doğal Kızılçam (Pinus brutia Ten.) meşcereleri için tek, bonitete dayalı tek ve çift girişli ağaç hacim tablolarının düzenlenmesi amaçlanmıştır. Bu amaçla 486 örnek ağaç ve bu ağaçlardan türetilen 6033 adet veri kullanılarak, ağaç hacim denklemleri geliştirilmiştir. Seçilen en uygun hacim fonksiyonlarının düzeltilmiş belirtme katsayısı ( ü .2 ), tahminin standart hatası (Sy.x), ortalama mutlak hata yüzdesi (% OMH) ve toplam hata yüzdesi (% TH) değerleri sırasıyla; tek girişli için 0. Tree Volume Tables for Calabrian Pine in Antalya and Mersin Region Abstract:In this study, it is proposed to construct single, single based on site index and double entry tree volume equations for the pure Calabrian Pine stands (Pinus brutia Ten.) within the border of Antalya and Mersin Regional Forest Directorates, Turkey. Tree volume equations were developed using totally 486 sample trees and 6083 data obtained from these trees. The coefficient of determination (adj-R 2 ), total percent error (PE), and mean absolute percentage error (MAPE) were 0.975, 52.84, -0.457 and 9.756 for single tree; 0.978, 44.84, -0.438 and 9.849 for single tree of the first site index class; 0.976, 54.44, -0.464 and 9.501for single tree of the second site index class; 0.969, 52.96, -0.452 and 9.256 for single tree of the third site index class, and 0.992, 41.26, 0.210 and 5.038 for double-entry tree volume equations, respectively. The first (%6.32) and the second (%0.45) site index values overestimated single-entry tree table values whereas the third site index values (%-4.28) underestimated the single-entry tree table values. The best fitted single, single based on site index and double entry tree volume equations were tested with independent data set for Calabrian Pine stands within the border of Antalya and Mersin Regional Forest Directorates, and concluded that these equations can be used for these stands at the 0.05 significant level.

64 | A Ç Ü O r m a n F a k D e r g 1 5 ( 1 ) : 6 4 --7 2 Sarıçam (Pinus sylvestris L.) Gelişimi Üzerine Ökseotu'nun Etkisi ABSTRACTAim of this study is to investigate of effect of mistletoe (Viscum album) on growth of Scotch pine. The measurements were done on the pure Scotch pine stands of Koçimek locality (Gölbaşı village, Uzundere town, Erzurum province, Turkey). Diameter, double bark thickness, tree-rings and height was measured a total of 60 trees. 30 of them are infested with mistletoe and the others are without mistletoe. To investigate how does mistletoe affects annual tree diameter increment, height growth and double bark thickness, the SPSS package program was used. We tested all data for normal distribution at first. After that, we used paired samples t-test. As a result of this test mistletoe have unfavorable affected diameter increment, double bark thickness and height growth of Scotch pine. The annual diameter increment of Scotch pine trees were reduced by about 40% within 10 years, the height growth of these trees were reduced by about 47% and the double bark thickness of these trees reduced by about 25%.