Interpretation of upper-storey canopy area in subtropical broadleaved forests in Okinawa Island using laser scanning data

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

Digital Mapping of UMK Jeli Campus Using Drone Technology

Aerial or satellite images are conventionally used for geospatial data collection and in producing a topographic map. The Unmanned Aerial Vehicles (UAV) technology such as drone has developed by providing very high spatial and temporal resolution data at a lower cost. Nowadays, drones not only use for military purpose but also been utilized widely by the public community for mapping, monitoring, video capturing activities and as a hobby. This present study focuses on the utilization of drone technology to produce a digital map of UMK Jeli Campus. The objective of this study is to access the capability and the accuracy of the drone in producing a digital map. Parrot ANAFI and DJI FC6310 devices were used as a platform to acquire digital images of the study area. After capturing the digital images, ground control points were established with the aid of a handheld global positioning system (GPS) device. Images were processed using Agisoft Photoscan software to produce a digital map of UMK Jeli Campus. This study shows that UAV can be used for producing a digital map at sub-meter accuracy and it can also be used for diversified applications

Safeguarding serenity: Assessing tree risks and hazards in UMK Jeli Campus for sustainable management

The UMK Campus Jeli, a renowned public university in Malaysia, has been operating for a decade. This study aimed to investigate potential risks and hazards associated with trees located near campus buildings. Such proximity can impact drainage, leading to water pooling that increases the risk of mold and rot formation. This study covered an extensive sampled area of 0.05 km²within the campus area. The Basic Tree Risk Assessment Survey was employed using a quantitative approach to systematically record and categorize information while conducting visual evaluations to assess tree risks. A total of 44 individual trees were recorded, representing 15 different species and 12 families. The Clusiaceae family dominated, accounting for 17% of the recorded trees, while the Malvaceae family constituted the smallest proportion at 2%. Notably, the Prunus avium tree posed the highest risk due to its proximity to buildings, which could potentially lead to mold and mildew growth over time. Implementing the Basic Tree Risk Assessment methodology holds significant value for the management unit at UMK Campus Jeli, providing essential insights for planning and maintaining tree health while preserving the campus's aesthetic appeal

Effects of Torrefaction Process on Chemical Properties of Small Diameter Acacia mangium Wood

Torrefaction refers to a thermal process that involves the processing of biomass in a torrefied to produce a "charred" product that can be utilised as a fuel or as a soil amendment. People need energy sources to meet their basic needs and live the kind of life they want. Acacia mangium was selected in order to produce biochar and determine the lignocellulosic affected by the holding temperature and residence time. The chemical properties of torrefied Acacia mangium biochar were investigated at different holding temperatures and residence times. Torrefaction were carried out at several process temperatures, ranging from 200 to 300°C, with residence time ranging from 30 to 90 minutes. According to the findings, the effects of holding temperature and residence time on the chemical properties of torrefied Acacia mangium biochar was carried out. The results show that the chemical properties decreased with an increase in both the holding temperature and residence time except for the lignin percentage content. It shows that as the holding temperature and residence time increased, the lignin content increased. The results shows that the chemical properties are decreased, except for the lignin content, which is not affected by the factors. The chemical bond in lignin content is hard for breaking down. Hence, torrefaction is accountable for the decrease of chemical properties and the breaking of chemical bonds in chemical properties

Landform classification for site evaluation and forest planning: integration between scientific approach and traditional concept

In this paper, we present an automated classification method of landform elements using an application of SAGA GIS software. The spatial assessment was done on the Yambaru forest area (YFA) in the northernmost part of Okinawa Island, Japan. This task is performed through the detailed elevation grid analyses from DTM of YFA with a spatial scale of 10 × 10 m2 supported by The Geospatial Information Authority of Japan. The classification has ten classes; high ridges, midslope ridges, upland drainage, upper slopes, open slopes, plains, valleys, local ridges, midslope drainage and streams. Classes were defined using the ‘topographical position index’ module and selected terrain variables were integrated to vegetation data for site evaluation. Information on terrain characteristics is very important to explain geographical constraints and map variability of natural resources in maintaining sustainable forest management as well as supporting decision making processes. Taking this into account, we adapted a traditional concept of forest terrain introduced by Sai On, a council member of the Ryukyu Kingdom (former name of Okinawa Island) when evaluating the potential site for forestry use

Accuracy of LiDAR-based tree height estimation and crown recognition in a subtropical evergreen broad-leaved forest in Okinawa, Japan

Aim of study: To present an approach for estimating tree heights, stand density and crown patches using LiDAR data in a subtropical broad-leaved forest.Area of study: The study was conducted within the Yambaru subtropical evergreen broad-leaved forest, Okinawa main island, Japan.Materials and methods: A digital canopy height model (CHM) was extracted from the LiDAR data for tree height estimation and a watershed segmentation method was applied for the individual crown delineation. Dominant tree canopy layers were estimated using multi-scale filtering and local maxima detection. The LiDAR estimation results were then compared to the ground inventory data and a high resolution orthophoto image for accuracy assessment. Main results: A Wilcoxon matched pair test suggests that LiDAR data is highly capable of  estimating tree height in a subtropical forest (z = 4.0, p = 0.345), but has limitation to detect small understory trees and a single tree delineation. The results show that there is a statistically significant different type of crown detection from LiDAR data over forest inventory (z = 0, p = 0.043). We also found that LiDAR computation results underestimated the stand density and overestimated the crown size.Research highlights: Most studies involving crown detection and tree height estimation have focused on the analysis of plantations, boreal forests and temperate forests, and less was conducted on tropical and/or subtropical forests. Our study tested the capability of LiDAR as an effective application for analyzing a highly dense forest.Key words: Broad-leaved; inventory; LiDAR; subtropical; tree height.Abbreviations: DBH: Diameter at Breast Height, CHM: Canopy Height Model, DEM: Digital Elevation Model, DSM: Digital Surface Model, LiDAR: Light Detection and Ranging, YFA: Yambaru Forest Area

Digital Mapping of UMK Jeli Campus Using Drone Technology

Aerial or satellite images are conventionally used for geospatial data collection and in producing a topographic map. The Unmanned Aerial Vehicles (UAV) technology such as drone has developed by providing very high spatial and temporal resolution data at a lower cost. Nowadays, drones not only use for military purpose but also been utilized widely by the public community for mapping, monitoring, video capturing activities and as a hobby. This present study focuses on the utilization of drone technology to produce a digital map of UMK Jeli Campus. The objective of this study is to access the capability and the accuracy of the drone in producing a digital map. Parrot ANAFI and DJI FC6310 devices were used as a platform to acquire digital images of the study area. After capturing the digital images, ground control points were established with the aid of a handheld global positioning system (GPS) device. Images were processed using Agisoft Photoscan software to produce a digital map of UMK Jeli Campus. This study shows that UAV can be used for producing a digital map at sub-meter accuracy and it can also be used for diversified applications

Safeguarding serenity: Assessing tree risks and hazards in UMK Jeli Campus for sustainable management

The UMK Campus Jeli, a renowned public university in Malaysia, has been operating for a decade. This study aimed to investigate potential risks and hazards associated with trees located near campus buildings. Such proximity can impact drainage, leading to water pooling that increases the risk of mold and rot formation. This study covered an extensive sampled area of 0.05 km²within the campus area. The Basic Tree Risk Assessment Survey was employed using a quantitative approach to systematically record and categorize information while conducting visual evaluations to assess tree risks. A total of 44 individual trees were recorded, representing 15 different species and 12 families. The Clusiaceae family dominated, accounting for 17% of the recorded trees, while the Malvaceae family constituted the smallest proportion at 2%. Notably, the Prunus avium tree posed the highest risk due to its proximity to buildings, which could potentially lead to mold and mildew growth over time. Implementing the Basic Tree Risk Assessment methodology holds significant value for the management unit at UMK Campus Jeli, providing essential insights for planning and maintaining tree health while preserving the campus's aesthetic appeal