Research On Monitoring Oil Palm Plantation Changes In Malaysia

In recent decades,oil palm as one of the world's major bulk stock grain and oil crops was getting larger and larger cultivated scale and area with an increasing requirement for it.While its fast planting process boosted the development of national society and economy,severe ecological problems occurred:deforestation and factitious forest burning damaged the balance of regional ecological system and global carbon cycle.Remote sensing technology provides an accurate and real-time earth observation method and possibilities of monitoring global oil palm plantation.Oil palm is generally cultivated in tropics where optical remote sensing data can be seriously interfered by the cloud.Although the Phased Array Type L-band Synthetic Aperture Radar's(PALSAR)data can detect 24-hour earth observation data,its own noise may bring the mapping process undeniable influence.Sample is the key factor of using remote sensing data to conduct land cover mapping,whether it is for classification as training sample or for checking the mapping accuracy as verification sample.These issues restrict the research in terms of global oil palm dynamic monitoring.This research selects Malaysia as the research area,using PALSAR's data for the main with the assistance of Digital Elevation Model's(DEM)data to collect Malaysia's oil palm distribution and conduct a dynamic analysis of oil palm's plantation expansion.Here is this article's main research contents and conclusions:Malaysia is dynamic sample database is established.In total,1930 samples were collected using a hexagonal sampling design.High-resolution images from Google Earth,the Advanced Land Observing Satellite(ALOS)Phased Array type L-band Synthetic Aperture Radar(PALSAR)images and Landsat optical images were used to identify oil palm plantations and other types of land cover.Through analysis of different land cover style was backscattering coefficient,it was found that 6.5 dB(HH-HV)which was suggested by former research to distinguish forest and oil palm was not suitable for oil palm mapping.If threes holding method is used to draw oil palm distribution map,it was suggested to set the threshold value in 7-8 dB(HH-HV).Research of the oil palm distribution in different spatial scales in Malaysia.The PALSAR-2 images of 2015 were used to analyze Malaysia's oil distribution accuracy in different resolutions.The result shows that the accuracy in the resolution of 50m to 250m is better than the other resolutions(the overall accuracy is about 93%while the oil palm's accuracy is around 85%).Besides,through the classification result in 100m resolution,it's calculated that Malaysia's oil palm plantation area is 62,000 km~2,which is the closest(overvalued by 9.92%)to the statistical data of Malaysian Palm Oil Board(MPOB).Therefore,the resolution of 100m in height is the best resolution for Malaysia's oil palm distribution,which can not only control the impact of noise on classification result but also ensure the integrity of space information.Research of oil palm distribution collection method fused with multi-source remote sensing data.The potential of different remote sensing data,optical remote sensing data,and PALSAR in oil palm mapping was analyzed.Two supervised classification machines comprising of support vector machine and Mahalanobis distance are used to compare the oil palm mapping results of Landsat data,PALSAR data,and their combination in two research areas with different landscape features in the Johor State of Malaysia.The results of the two research areas show that the combination of Landsat and PALSAR can lead to the highest overall mapping accuracy.Moreover,in contrast with the oil palm area calculated derived from Google Earth HD image,the combination of Landsat and PALSAR has promising potential in the aspect of oil palm area estimating.The research of oil palm expansion changes in Malaysia.A research was conducted in the oil palm dynamic expansion and forest decline between 2007 to 2015 in Malaysia,and the result shows that Malaysia's oil palm expansion condition during the nine years appears in two forms,and its saturated expansion in the planting area in Peninsular Malaysia is not obvious while East Malaysia's oil palm planting area is expanding rapidly.By analyzing the land cover distribution characteristics of year-by-year oil palm samples,it's found that its plantation has entered the high-altitude localities(over 500m in height).During the nine years,the declined forest area reached 21,400 km~2,of which the major factor is oil palm planting area expansion which accounts for over 90 percent.This research has been innovative in the following aspects:1.The establishment of the world first set of high-density dynamic oil palm samples of the national scale;2.Proposed 50meter to 250 meter was the appropriate resolution for the extraction of oil palm,100 meters is the best resolution;3.For the first time using PALSAR at 100 meters resolution for Malaysia oil palm expansion monitoring;4.A new method of mapping oil palm distribution fused with multi-source remote sensing data is put forward.Malaysian oil palm dynamic monitoring can provide data support for the oil and palm,and supplement the official statistical data.