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Spatial Distribution Investigation of Forest Resources

2018-06-01 15:55:18

Current Challenges

Forest resources, a vital part of the earth’s terrestrial ecosystem, create the indispensable conditions and environment for the living of human beings. It counts so much for our country’s economic construction and eco-environment improvement as to how to effectively carry out forest resources investigation and make sure an efficient administration and reasonable exploitation of the resources.

The conventional investigations are in-the-field ones conducted by investigators who base their work on topographic maps. While the disadvantages like large human cost, long working cycles, high laboring intensity and low efficiency make them unbefitting for the present demands of a market economy. Therefore, a fresh investigation method is in urgent need.

 

  A Brand-New Solution

The superiorities of the satellite remote sensing (RS) technology lie in its macroscopic view, dynamic monitoring, and convenient access to information, intuitive images and large-coverage ability. The extensive utilization of high-resolution satellite images in forest resources investigation has begun to gain its social-economic benefits

The high resolution of the Jilin-1 satellite imagery and its multi-spectral images can reflect the characteristics of vegetation. It is widely used by forestry workers in forest fire investigation and prevention.

Let’s take the target city for example, to see how the RS technique is applied in the extraction of forest resources spatial distribution data.

We produced the following thematic maps based on the extracted forest resources spatial distribution data after a series of pre-processing of images including radiometric calibration, atmospheric correction, geometric ratification, data fusion, cropping and splicing and analyses of their spectral, textural and plant phonological characters.

Thematic Map of Forest Resources Spatial Distribution in Liaoyuan City, Jilin Province

 

 Conclusions

(1) Forest coverage of the target city is approximately one third as shown in the above image.

(2) Woodlands and farmlands are interlaced and the non-woodlands present as tree-like distribution with human activities getting involved.

(3)Large patches of non-forest land are distributed around waters, which are suitable for human habitation and cultivation and then developed for farmland, industrial land and residential areas.

(4)Most of the rest areas of high elevation and large gradient reserve  relatively massive forest resources, on account of the unfitness for farming or residential purposes.

 

We Can Do More

Our forestry satellite project aims to build a customized satellite constellation for forestry remote sensing usage. It will provide images of spatial resolution less than 5m and up to 25 spectral channels. Forestry remote sensing data services will be provided and generally elevated in terms of forest resources investigation, disaster monitoring, eco-value assessment and other fields.

A four-star networking scheme consisted of sun-synchronous orbit, orbital plane and equiphase distribution is applied in the forestry satellite. The minimum interval between two adjacent satellites in networking takes 30 minutes or less to image the same object. Each star has the capability of large side-sway imaging, which can meet the real-time monitoring requests of natural disasters such as floods and fires.

19 visible near-infrared spectral bands, including 1 panchromatic band and 18 multi-spectral bands are configured in the forestry satellite; 4 short wave infrared spectral bands, 1 medium wave infrared spectral band and 1 long wave infrared spectral band, of a total of 25 spectral bands.

(1)Forest Fire Prevention

The forestry satellites collected RS imagery makes it possible for us to figure out the fire conditions before it occurs, as a forewarning of scientific fire prevention; identify and locate the fire spot and make quick response according to the assessment of fire behavior; help post-disaster assessment and vegetation recovery monitoring.

(2)Forest Resources Survey

25 spectral bands are configured in the forestry satellite to enable it to extract and distinguish the obtained images via varied reflection spectrums from different trees species, such as the evergreens, aquatic plants, ground flora, deciduous forest and shrub, offering basis for forestry resources investigation and protection.

(3)Supervision of Pests and Diseases

Multi-spectral remote sensing imagery of forestry satellites is able to identify, extract, analyze the information of forest diseases and pests and offer pre-warning, evaluation, management and control for the forest diseases and pests, providing basis for the forest recourses conservation.

(4)Forestry Development

Forestry satellites are enabled to accurately estimate forest vegetation parameters such as chlorophyll content, leaf area index and biomass to foster forest resources management and a healthy and sustainable development of forestry.

Multi-spectral RS data is applied to acquire the status quo, spatial distribution, coverage and dynamic changes information of the forest resources, including its coverage changing and overall tendency based on the establishment and demonstration of a 3D model of the forest.

(5)Wetland Monitoring

Wetland RS monitoring and researching can be carried out by means of multi-phase RS imagery. Accurate distribution and dynamic changes data of various wetlands will serve to provide a foundation of scientific decisions for conservation, management and ecological restoration of degraded wetlands to realize the sustainable development of wetland resources.

(6)Desertification Monitoring

Forestry satellite RS images can also be used in the surveillance of land desertification. By analyzing the RS data of the same area during different phases, monitoring and statistical analyses of the evolution of the desertification progress can be realized, to provide data basis for desertification prevention.