Application Technique Of Digital Forestry In Daxing'an Mountains' Demonstration Area

The characteristics of forestry resource information are large numbers of data, much categories, wide sources, complicated structure, and high cost for obtaining. With the development of building basal establishment of national information, the development of digital forestry is currently insistent demands of forestry development. Real-time data, which was provided by digital forestry, will provide important technology support for alarming national ecology and decision-making of environment. Using the inventory data of forest resources and all kinds of map (including topographic map and forest map) for Tahe Forest Bureau of the Daxing'an Mountains' demonstration area, the interrelated techniques of digital forestry were studied in this paper by combining with multitude software. As a result, data of forest resources were issued to internet with electronic map (including forest map, distribution map of forest resources, and so on). A set of standard and criteria of Tahe forest bureau was established, and forest resource data could be shared to users. Net user could conveniently and real-time know status of Tahe forest bureau and acquire any kind of forestry data they needed. This study has made progressed at following results:(1) Based on resources characteristic of Tahe forestry bureau, the standards of digital foretry for the non-spatial data and spatial data of forest resources was developed according to contents of "The standard and criteria of digital forestry (1)".(2) The Digital Elevation Model (DEM) was developed: a) 47 topographic maps of 1:5 0000 scale in Tahe forestry bureau were scanned by 300 dpi and the images were geometric corrected, vector. Each map was mosaiced according to the standard and criteria of digital forestry, b) Error of evaluating contour value was quickly found by using the method of rough TIN for the first time. The result showed this method had prominent effect, c) In TIN module of ARC/INFO, Digital Elevation Model was generated by using method of the linear interpolate and the binary quintic polynomial interpolate, respectively, d) Precision test of two interpolate methods were performed by using the method of checking point. The result showed that precision of binary quintic polynomial interpolate method was higher than linear interpolate method. Mean square root of error for method of the binary quintic polynomial and linear was 2.20m, and 5.44m, respectively, e) Digital Elevation Model, which was generated from the interpolate method of binary quintic polynomial, was used to analyze digital terrain and to extract the aspect map and slope map. The DEM provided basal data for digital forestry platform and the spatial distribution of forest resources and it is basis for the digital forestry application in forest management.(3) Net platform of digital forestry was constructed: a) The Brower/Server applicationmode and Client/Server application mode were compared for the aspect of choosing application mode. As the result, B/S mode was applied in this study, b) Several WebGIS developing platform of B/S mode were introduced. ArcGIS Server was chosen by comparing the several net platforms. ArcGIS Server was newly protrusive product of GIS software by ESRI Company. For ArcGIS Server, the Poising many user loads was sustained and high GIS function was provided. The use of ArcGIS Server could keep ahead in the same way and it was also a significant landmark in prior, c) In the way of realizing technique of net platform, J2EE (Java 2 Platform Enterprise Edition) was chosen for balancing effectively disposal loads between client and server and debasing evidently demand of Broad Band, then capability of system was improved, d) J2EE and ArcGIS Server were chosen to construct net platform of digital forestry for the first time in this paper. The procedure of constructing net platform environment and configure software environment variable were expatiated in detail. The result showed that involved software was much and the procedure was complicated, but combination of these multiple software had the characteristics of opening, agility and strong expansibility, e) ArcGIS Server and Java ADF were used to construct Web application for issuing in internet. The templates provided by Java ADF were used as start point of system development. Developer could customize special interface for more usage, f) Landing interface, user's setting interface, platform interface of digital forestry and displaying interface were customized through using JSP (Java Server Pages) technique, ASP (Active Server Pages) technique and JSF (Java Server Frame).(4) Applications of digital forestry: a) Based on the forest resource data of Tahe forest bureau in 1997 year, forest stand volume and dispersed tree volume of fifty years in the future were predicted by using stand growth and yield model of natural stands in north part of Daxing'anling's area. It will provide dynamic data of forest resources for compiling the planning of sustainable forest management and appraising the benefit of forest ecology in demonstration area, b) According to the aspect and slope terrain factors, average aspect value and slope value of each sub-compartment were calculated by programming Avenue language of the Arc View. Then, designs of the forest cutting, forest thinning, and forest generation were performed by different restrictive conditions, c) Taking forest farm as a unit, fire danger classes were synthetically determined from the evaluation values of forest resource characteristics. Forest fuel types were divided for taking into account eight factors, each factor was marked and given scale weight. Map of forest fuel type was formed according to caloric assessment value of forest fuel. It will provide basis data for predicting and forecasting forest fire.