EVALUATION OF DIAMETER AND TOTAL HEIGHT OF MIXED PLANTING WITH PORTABLE LASER SCANNER
Name: KLISMAN OLIVEIRA
Publication date: 29/08/2022
Advisor:
Name |
Role |
|---|---|
| GILSON FERNANDES DA SILVA | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ANDRÉ QUINTÃO DA ALMEIDA | External Examiner * |
| GILSON FERNANDES DA SILVA | Advisor * |
Summary: The use of remote sensing equipment has been growing in the forestry
scenario, associated with time savings and reduction of field work that can bring
to projects, one of which is Light Detection and Ranging (LiDAR). The objective
of the present work was to estimate the total height and diameter at breast
height of different species in a mixed forest stand with Light Detection and
Ranging data. A forest inventory was carried out to collect diameter at breast
height and total height, from twelve different species of the Atlantic Forest,
being collected ten class centers by species, totaling 120 measured arboreal
individuals. The collections took place by means of a Portable Laser Scanner
(PLS), the walking was carried out with the equipment in the eight areas
studied, ranging from two to ten years of age. Through the walking, it was
possible to generate the 3D point cloud of the plantations, from WHERE the
segmentation and cleaning of the studied trees was carried out, thus generating
a point cloud for each isolated tree. Through the TreeLS and LiDR packages of
the R software, it was possible to extract the metrics of diameter at breast
height and total height of the point clouds of each tree. At the end of the
segmentation, 92 trees of eleven different species were isolated, among the
problems found for the isolation of the trees, the competition of the younger
plantations with weeds and invasive trees. Another problem found was the
competition between crowns, taking into account the intertwining between
crowns and obstruction of the lasers by obstacles, which generated occlusions
and noise, which made it impossible to isolate the trees. For the diameter
metric, species in general the RMSE reached a value of 38.17%, the species
Schizolobium parahyba obtained the best statistics reaching an RMSE of
13.14% and Bias 40.65%. The best statistics that Schizolobium parahyba
arrived at can be associated with the similarity of growth with commercial
species, from which the metrics in the used packages are usually processed.
For the total height data obtained with PLS, the general RMSE (%) was 15.14
%, while its bias (%) was 17.73 %, in which four studied species obtained
RMSE (%) below 10%, being Ceiba speciosa, Inga edulis, Tibouchina
granulosa and Cedrela fissilis, being C. fissilis the only species with RMSE (%)
below 5%. The species in general showed overestimated results of diameters at
breast height and difficulty in segmenting the trees, WHEREas the total height
metrics were obtained with greater precision, and similar to the statistics found
in the literature.
Keywords: remote sensing; forest inventory; forest variables; forest
management; point cloud.
