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Sains Malaysiana 44(1)(2015): 107–113
Interpretation of Upper-Storey Canopy Area in Subtropical
Broadleaved Forests in Okinawa Island Using Laser Scanning Data
(Interpretasi
Ruang Kanopi Lapisan Atas Hutan
Subtropika Berdaun
Lebar di Pulau Okinawa Menggunakan
NOOR JANATUN NAIM BINTI JEMALI1,3*, MASAMI SHIBA2 & AZITA AHMAD ZAWAWI1
Kagoshima
University, Faculty of Agriculture, University of the Ryukyus,
Senbaru-1,
Nishihara
903-0216 Japan
2Faculty of
Agriculture, University of the Ryukyus, Senbaru-1,
Nishihara 903-0213,
Okinawa, Japan
3Faculty of
Earth Sciences, Universiti Malaysia Kelantan, Locked
bag No.100, 17600 Jeli, Kelantan
Malaysia
Received: 21
October 2013/Accepted: 30 July 2014
ABSTRACT
Conventional forest inventory practice
took huge of effort, and is time- and cost- consuming. With the
aid of remote sensing technology by light detection and ranging
(LiDAR),
those unbearable factors could be minimized. LiDAR
is able to capture forest characteristic information
and is well known for estimating forest structure accurately in
many studies. Forest monitoring related to forest resource inventory
(FRI)
becomes more effective by utilizing LiDAR data
and it is tremendously useful, especially to distinguish information
on density, growth and distribution of trees in a selected area.
In this study, LiDAR data was utilized aimed to
delineate crown cover and estimate upper-storey canopy area in Yambaru Forest using object-based segmentation and classification
techniques. Agreement between field survey and LiDAR
data analysis showed that only 33.7% of upper-storey
canopy area was successfully delineated. The low accuracy level
of canopy detection in Yambaru Forest area was expected mainly due to tree structure,
density and topographic condition.
Keywords: Canopy area; LiDAR; Okinawa; subtropical forest;
upper-storey
ABSTRAK
Amalan inventori hutan secara konvensional memerlukan tenaga kerja, masa dan kos yang tinggi.
Dengan
bantuan teknologi penderiaan jarak jauh seperti imej
LiDAR, faktor-faktor
tersebut dapat
diminimumkan. LiDAR
mampu mencerap
maklumat berkenaan
ciri hutan dan
banyak kajian
telah membuktikan teknologi ini dapat
menganggarkan struktur
hutan dengan tepat.
Pemantauan hutan
berhubung inventori sumber hutan (FRI)
menjadi lebih
efektif dengan penggunaan data LiDAR dan ia
sangat bermanfaat terutama bagi membezakan
informasi kepadatan
hutan, pertumbuhan dan taburan pohon
di kawasan terpilih.
Dalam kajian ini, data LiDAR
digunakan untuk
menganggarkan lapisan
atas kanopi pokok
dengan menggunakan
teknik pengelasan dan segmentasi berdasarkan objek. Keputusan
kajian menunjukkan hanya 33.7% ruang kanopi lapisan atas pokok dapat
dikesan hasil
perbandingan antara analisis data LiDAR dengan data daripada tinjauan lapangan. Aras ketepatan yang rendah
dalam mengesan
kanopi di kawasan Hutan Yambaru menggunakan
data LiDAR dijangka
disebabkan oleh faktor-faktor pengaruh seperti struktur pokok, kepadatan dan keadaan
topografi di kawasan
tersebut.
Kata kunci: Hutan subtropikal; keluasan kanopi; lapisan atas; LiDAR;
Okinawa
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*Corresponding author; email: idiana0303@yahoo.com
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