Determination of individual tree characteristics with terrestrial laser scanning

Abstract

In this study, the potential of Terrestrial Laser Scanning (TLS) data obtained from a single point on determination of some individual tree characteristics was assessed. The study was carried out in two beech stands, two Corsican pine stands, and one Douglas fir stand located in an urban woodland in the North England. The targeted tree attributes including diameter at breast height (DBH), tree height, crown base height, and crown width were determined both by the field measurements and from the laser point cloud data. Totally, we measured the DBH in 127 trees in the beech and Corsican pine plots, and the tree height, crown base height, and crown width were determined in 45 trees in only the Corsican pine plots. However, we were not able to measure any tree attributes on the laser point cloud in the sampling plot taken from Douglas fir stand due to high stand density (1393 trees ha-1). The relationships between field-measured and laser-derived tree attributes were determined using simple regression analyses. The obtained determination coefficients (R2) and root mean square errors (RMSE) were; 0,91 and 5.84 cm for DBH; 0,88 and 1,1 m for tree height; 0,83 and 1 m for crown base height; 0,65 and 0,81 m for crown with, respectively. It was concluded that using laser data obtained from a single scan, a) the DBH in definite rate of individuals might be measured in the forest stands with low density; and similarly in some trees, b) the tree height and the other crown characteristics might be determined in conifer stands with a canopy cover less than 70 percent. Keywords: Lidar, Forest inventory, Stand structure

Keywords

• Lidar, Forest inventory, Stand structure

Yersel lazer tarama ile tek ağaç özelliklerinin belirlenmesi

Abstract

Bu çalışma, sabit bir noktadan Yersel Lazer Tarama (YLT) ile elde edilen veriler kullanılarak bazı tek ağaç özelliklerinin belirlenmesi amacıyla yapılmıştır. Çalışma, Kuzey İngiltere'deki bir kent ormanında bulunan, iki kayın, iki Korsika çamı ve bir Duglas göknarı meşceresinde gerçekleştirilmiştir. Tek ağaçta -çap, ağaç boyu, tepe boyu, tepe çapı- özellikleri, hem yersel hem de lazer nokta bulutu üzerinden ölçülmüştür. Toplam 127 ağaçta (Kayın + Korsika çamı) göğüs çapı ve 45 ağaçta (Korsika çamı) ağaç boyu, tepe boyu ve tepe çapı belirlenmiştir. Sıklığın yüksek olduğu (ağaç sayısı 1393 ha-1) Duglas göknarı meşceresinden alınan örnek alanda ise herhangi bir ölçüm yapılamamıştır. Arazide doğrudan ölçümle elde edilen ve lazer verisinden çıkarılan ağaç özellikleri arasındaki ilişkiler basit regresyon analizleriyle ortaya koyulmuştur. Elde edilen belirtme katsayıları (R2) ve ortalama hata kareleri karekökü (RMSE) değerleri sırasıyla, göğüs çapı için 0,91 ve 5,84 cm; ağaç boyu için 0,88 ve 1,1 m; tepe boyu için 0,83 ve 1 m; tepe çapı için ise 0,65 ve 0,81 m'dir. Tek noktadan taranan lazer verileriyle; a) sıklığın düşük olduğu meşcerelerde belirli miktardaki gövdede göğüs çapı; b) tepe kapalılığının düşük olduğu (<%70) iğne yapraklı ağaç türlerinden oluşan meşcerelerde belirli sayıda bireyde ağaç boyunun ve bazı tepe özelliklerinin belirlenebileceği sonucuna varılmıştır. Anahtar kelimeler: Lidar, Orman envanteri, Meşcere yapısı

Keywords

• Lidar, Orman envanteri, Meşcere yapısı

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