Developing Height-Diameter Models for Natural Scots Pine Stands in Sinop Region

Abstract

In this study, diameter (D)-height (H) models were developed for natural Scots pine (Pinus sylvestris L.) stands in Sinop region. In the model development phase, a total of 904 D and H data obtained from 184 sample plots were used. In addition, various stand variables were measured and calculated. Within the scope of the study, various model forms including only diameter variable and diameter and stand variables were considered. The success and prediction behavior of the developed models were evaluated through various error criteria, prediction-observation and prediction-error graphs. According to the findings, the model including only diameter variable explained a significant part of the variance in measured height values, but showed a problem of varying variance in errors (Model coefficient of determination=0.90). The generalized H-D models including diameter and various stand variables were found to have a better variance explanation value (Model coefficient of determination=0.94) and showed a constant variance in errors. As a result of statistical and graphical evaluations, it was concluded that generalized H-D models can be used with confidence in pure and natural Scots pine stands in Sinop region.

Keywords

• Allometric relationships
• forest inventory
• scots pine

Sinop Yöresi Saf ve Doğal Sarıçam Meşcereleri için Çap-Boy Modellerinin Geliştirilmesi

Öz

Bu çalışmada, Sinop yöresi doğal Sarıçam (Pinus sylvestris L.) meşcereleri için çap (D)-boy (H) modelleri geliştirilmiştir. Model geliştirme aşamasında, 184 örnek alandan elde edilen toplam 904 adet D ve H verisi kullanılmıştır. Bununla birlikte çeşitli meşcere değişkenleri de ölçülmüş ve hesaplanmıştır. Çalışma kapsamında sadece çap değişkeni ve çap ile birlikte meşcere değişkenlerini içeren çeşitli model formları dikkate alınmıştır. Geliştirilen modellerin başarısı ve tahmin davranışı çeşitli hata ölçütleri, tahmin-gözlem ve tahmin-hata grafikleri üzerinden değerlendirilmiştir. Elde edilen bulgulara göre, sadece çap değişkenini içeren model ölçülen boy değerlerindeki varyansın önemli bir kısmını açıklasa da hatalarda değişen varyans problemi göstermiştir (Model belirtme katsayısı=0.90). Çap ile birlikte çeşitli meşcere değişkenlerini içeren genelleştirilmiş H-D modelleri ise hem daha iyi bir varyans açıklama değerine sahip (Model belirtme katsayısı=0.94) hem de hatalarda sabit bir varyans göstermiştir. İstatistiksel ve grafiksel değerlendirmelerin sonucu olarak, genelleştirilmiş H-D modellerinin Sinop yöresinde yayılış yapan doğal Sarıçam meşcerelerinde güvenle kullanılabileceği söylenebilir.

Anahtar Kelimeler

• Allometrik ilişkiler
• orman envanteri
• sarıçam

Kaynakça

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