J. S. Grewal
Conservator of Forests, Working Plan Circle, Maharashtra Forests Working Plan Circle, Maharashtra Forest Department, Nagpur
Email: [email protected]
Integration of MIS and GIS is a powerful planning and decision support tool for the Working Plan Officer.
In Maharashtra, GIS is being used in the preparation of working plans. Working with GIS during the last two years has helped us to visualize its wide application not only for working plan preparation but also in the field of implementing and monitoring of forestry activities.
Forest Management Functions
Basically a forest manager has to perform the following core functions:
To be able to perform these functions a forest manager has to seek answers to many questions of the following type:
- What treatment/action is required in which part of his forest?
- What are the viable alternatives available?
- Which is the best alternative?
- What will be the sequence of actions?
- Who will be responsible for carrying out each of the actions?
- Who will be monitoring the performance of plan?
To find clear answers to questions of the above kind a lot of data is required. Moreover this data has to be in such a format that it can be viewed and synthesised easily and quickly. Some of the typical data needs of a forest planner are listed below. This list is by no means exhaustive,A it is indicative only.
Data needs for forest planner
- Forest cover
- Crown density
- Regeneration status
- Site quality
- Negative influences
- Sensitive spots
- Topo features
- Climatic data
- Moisture regime
- Biotic influences
Need for digital databases
The problem with the non-digital databases arises because of the sheer volume of data. It is very difficult to synthesise and comprehend such large volumes through manual systems. The other major problem with manual systems is that of retrieval. Information is generally collected from various sources and at various times, which not only overloads the system but makes it very unreliable and inconsistent too.
Managers for land-based systems have to invariably deal with multitude of maps.
These maps are available on different scales and at times even in different projection systems, which makes it very difficult to manipulate geographical information. Because of these and many more problems it is much more convenient to capture data digitally and centrally.
Integration of remote sensing data with GIS related decision support systems could make the job of land managers very easy.
Application of GIS to Working Plan preparation
Forestry being a long term business, foresters have been preparing perspective plans for minimum time horizons of 10 to 15 years. The smallest unit of management in India is considered a compartment. Based on physiography and crop characteristics each compartment isis allotted to a particular working circle and a package of management practices is prescribed for each working circle. The underlying assumption in this conventional approach is that physiographic features and crop are uniform in the whole compartment. This was true to some extent till about half a century ago when pressures on forests were not as high as these are today. If we look at the compartments today we find a lot of variability within each compartment both in terms of the crop as well as the other conditions prevailing there. To illustrate the point a typical forest cover map is shown.
The area shown in the map is from North Dhulia Forest Division. Dark green colour represents well-stocked forest, light green colour signifies under-stocked forest and yellow colour is for barren patches. Such a situation is very common in all our forests these days. Such varied conditions cannot be addressed to properly by allotting the compartment as a unit to any particular working circle. This is especially so when we are trying to step up our effort in the direction of intensive management. Solution lies in prescribing many types of treatments within each compartment by delineating it into sub-units. But unlike compartments these sub-units of the compartment cannot be of permanent nature and hence cannot be permanently delineated on the ground. Such a concept has been adopted in our approach to working plans for the past some years. Working plan officer prescribes that each coupe be delineated into the following types of areas:
- Areas with more than 25° slope
- 20 m wide buffer along the drainage network
- Under stocked areas (crown density 0.1 to 0.4)
- Blanks (crown density <0.1)
- Well stocked areas (crown density >0.4)
Different type of treatment is specified for each of the above categories of areas. The actual task of judging and delineating the areas on the ground is left to the last man in the field. Each division has hundreds of coupes due for working each year hence the above task is assigned to many persons with varying degrees of experience and knowledge. The treatment map is prepared based on ocular estimation. This process results in rather inaccurate and inconsistent treatment maps. All the treatments are supposed to be carried out according to these treatment maps. Hence the weakness of the present practice is self-evident.
Working plan officer too has to base his calculations on rough estimations, as he does not have very accurate and consistent stock maps to work with. Moreover the input for him is rather fixed and it is almost impossible for him to generate many alternate strategies before picking the best ones.
This task of preparation of treatment maps/ stock maps can be achieved quickly with much more accuracy and consistency by using remotely sensed data in GIS environment. Working plan officers can not only provide the territorial staff with accurate treatment maps but they can improve their own calculations of yield etc. also. This has been achieved for more than half a dozen divisions in the state of Maharashtra and all future revisions of working plans are proposed to be based on this approach.
Besides delineating the coupe areas on the basis of crown density and physiographic features working plan officer requires an extensive forest inventory data to base his prescriptions in terms of different treatments. We are using random start systematic line sample plot method for inventory data collection. The whole area of the division is divided into grids of 600m X 600m on the Survey of India topo sheets. These maps are provided to the field inventory units. They locate these points on the ground by chain & compass survey and then layout sample plots for tree enumeration and regeneration survey. So for every 36 ha. area on the ground we have a sample plot.
The inventory data collected from the field used to be partially processed by the field inventory teams themselves. Thereafter this processed data was sent to the Chief Forest Statistician for its statistical analysis. In this process lot of time of the field units was wastedand the whole process was very lengthy. In order to overcome these shortcomings an Inventory Management System has been designed by the author which not only processes the data but acts as a decision support system for the working plan officer to use the inventory information much more meaningfully. Moreover the data captured through the system is dynamically linked to GIS environment to make the whole system much more powerful planning and monitoring tool.
The above mentioned integration of MIS and GIS is not only a powerful planning tool for the Working Plan Officer but these digital databases are very potent decision support and monitoring tools for the implementing managers in the real time mode also. In the GIS environment they can make innumerable queries to find answers to their day to day management questions.
A typical workflow used for the preparation of working plans is shown in the given flow chart.
Fig1: Typical Workflow used for preparation of Working Plans