Yazarlar
- Aksakal, V.(1)
- Bayram, B.(1)
- Guvendi, Engin(1)
- Topal, M.(1)
- Yaǧanoǧlu, M.(1)
- Yener, Ismet(1)
Yayınlar
- MakaleAçık Erişim2023Predicting and Mapping Dominant Height of Oriental Beech Stands Using Environmental Variables in Sinop, Northern Turkey
Yener, Ismet; Guvendi, Engin
The dominant height of forest stands (SDH) is an essential indicator of site productivity in operational forest management. It refers to the capacity of a particular site to support stand growth. Sites with taller dominant trees are typically more productive and may be more suitable for certain management practices. The present study investigated the relationship between the dominant height of oriental beech stands and numerous environmental variables, including physiographic, climatic, and edaphic attributes. We developed models and generated maps of SDH using multilinear regression (MLR) and regression tree (RT) techniques based on environmental variables. With this aim, the total height, diameter at breast height, and age of sample trees were measured on 222 sample plots. Additionally, topsoil samples (0–20 cm) were collected from each plot to analyze the physical and chemical soil properties. The statistical results showed that latitude, elevation, mean annual maximum temperature, and several soil attributes (i.e., bulk density, field capacity, organic carbon, and pH) were significantly correlated with the SDH. The RT model outperformed the MLR model, explaining 57% of the variation in the SDH with an RMSE of 2.37 m. The maps generated by both models clearly indicated an increasing trend in the SDH from north to south, suggesting that elevation above sea level is a driving factor shaping forest canopy height. The assessments, models, and maps provided by this study can be used by forest planners and land managers, as there is no reliable data on site productivity in the studied region.
- MakaleYalnız künye2010An analysis of the factors affecting birth weight and actual milk yield in swedish red cattle using regression tree analysis
Topal, M.; Aksakal, V.; Bayram, B.; Yaǧanoǧlu, M.
Performance records (birth weight and actual milk yield) on 206 Swedish Red cattle maintained at private organic diary cattle enterprise in Kelkit district of Gümüşhane province, in Turkey, were analyzed through regression tree method to determine the effects of some factors affecting birth weight and actual milk yield. The birth weight of calves averaged as 41.034±4.218 kg. Out of total calves born, twin born calves were 2.9%. Single born calves were heavier (41.185±3.840 kg) than twin born (36.000±10.545 kg). The results revealed that the most significant variable affecting birth weight was birth type, followed by birth season, sex and body condition score (BCS2) of the dam during birth. Lactation period and peak milk yield were important variables affecting the actual milk yield in the dairy herd under investigation.