|Role of Remote Sensing in Forest Management
C. B. S. Dutt
A. S. Sadhasivaiah
During the british regime, the forest survey and sound forest management was extended to all lands bearing trees in India and to minor forest products (e.g. gum arabic). As early as in 1856 a forest department was established in Burma by the British and the concepts of environmental Forestrywere being applied in India before the end of the
Suggest that over 40% of one votoe european Forests is used as a source of energy and that energy remains the single most important use of wood in volume terms.
With the uncertainity of energy prices in the future and of the growth world wide in the consumption of energy, predicted to exceed 2% a year , the demand for wood energy can be expected continued increasing. Within a decade the most urgent need of many local communities in the developing countries will be the massive harnessing of their resources to renew forest supplied through plantations and agro- Forestry, and where preactised the “Slash – and burn” of natural forests based on short cutting cycles. In response to the situation remote sensing can be expected to be used increasingly to collect urgently needed data, especially as related to monitoring changes in forest cover, assessing landus and frorest land degradation, evaluationg the productivity of the land and providing
The increased awareness due to mounting population exerting pressure on forests for fuel and timber besides grazing for cattle. This has led to most of India’s forest left with poor carrying capacity. The forests began to dwindle. And now the country have much less of its land area under forest cover than is required to maintain its environmental
Considering the fact, India is currently carrying out biennial monitoring of forest cover using satellite data on 1:250,000 scale. However the system of forest management in India is almost 120 years old and remained as a state subject. The policy formulation and strategic planning is at the central level. For effective
The present scenario of remote sensing applications in forest management is widely applied in the areas of:
Forest Cover Monitoring/ Surveillance
The forest cover at the national level is being biennially monitored using remote sensing data and it is estimated that India has 19.47% of forest cover (1989-91) out of the total expected 33% of forest cover as per India’s forest policy. So far Forest Survey of India (FSI) has broughtout sucessfully four assessments on
This information is more relevant in the context of assessing rate of degradation grossly at the state/district level in terms of closed and open forests. However, the extended use of this information for effective
The extended use surveillance maps for the treatment area maps would need a serious consideration by all the state forest departments for prioritisation:
CLOSED FORESTS (40% and above crown density) treatment area I for consideration to conservation zone.
OPEN FORESTS (less than 40% crown density) treatment area II for consideration as forest produce zone for careful management.
DEGRADED FORESTS (less than 10% crown density) treatmen area III for gap planting, JFM activities by peoples involvement.
Thus for the above treatment area maps the satellite based remote sensing especiallyusing the digital methods would prove to be an effecctive tool and in generation of information within a short span of ltime and a digital data base.
The studies carried out in Uttar Kannara by comparitive evaluation of detailed stock map prepared from aerial photograbphy and confirmity and confidence in adopting satellite data for preparation of stock maps with suitable modifications. However, the satellite based stock maps showed. The aggregation of patches due to the limitation of resolution and contribution of terrain noise, In any case the level of information obtained with respect to stocking is of the order of 70% and above. The study broughtout the scope of reconnaisance level stock map preparations at the district level for preparation of management plans.
The study carried out in parts of western Ghats of Karnataka demonstrated the feasibility and to build volume from the enumerated data on a time & cost effective manner.
Role of Remote Sensing in Forest Management
The Forest Volume Estimation and Generation of Volume Tables
The satellite based multi phase approach forest inventories with defined objectives provide ample data for further processing and computation of volume and yield tables. The enumerated data during the inventory could be systematically organised strata wise ad a suitable local and stand regressions could be generated fr further computation of species wise volumes. The predominant species volume equations thus generated would form the base for computation of tatal standing volume based on the plot enumeration data. The inventory data analysis in the Uttar kanara Circle using satellite base stratification sampling approaches have yielded better observations in development of local and stand tables and to compute stand volume. The standing volume information through inventory data analysis would form as a baseling data to bring out correlation with ground crown density maps. This in a way to say once the relationships are established which are generally local specific with respect to volume and density it is possible to estimate the total growing stock of the area by generation of stack maps and conversion through establised volume functions. The experience in generation of such stock to volume estimations in western Gats have shown promissing to explore to avoid cumber some, field inventories. The study also discussed in detail the importance of cull factor for estimating merchantable yield.
Stock Tables Prepartion and Yield Calculation
From the stratifield sampling and inventory data analysis it is feasible to calculate and generate stock tables with respect to number of species diameter and height wise distribution. Such an information with the available knowledge of minimum girth area for extraction it is possible to calculate the yield and also to compute the annual coupes based on equiproductive areas. The technique of data analysis and generation of stock tables developed in parts working plans project have revealed greater scope for extending towards management information system specifically for the working plans at district level on stock tables and yield calculations.
Ecological Consideration and Zonation of Forests
With the increased pressure on forest all over the world as well as in India the growing concern of forest management has shown shift in its priority from production foresty to conservation Forestry. In the light of thi the scientific management of forest and categorisation of the area into different zones have been adopted by the Karantaka State forest department as part of Western Ghats Eco-restoration project. Towards this NRSA and Karnataka Forest Department jointly carrying out a project in a area of 10,280 sq. km in Uttar Kanara forest circle by generation of multi-thematic information on 1:25,000 scale using aero-space techniques. The thematic information generated are forest density and height maps, forest type maps, slope and aspect maps, drainage map upto first order channels, volume class maps besides consultation of contour maps with the available topographical sheets. The availability of such an enormous data base when feed into the Geographic Information System enhances interpretability of the data and to classify the area into different zones required for effective forests management practices on a scientific footing. Accordingly the forests are proposed for categorization of zones for specific management practices, the zonation is the process of describing the physical consequences of the management plans, which have been understood for sustainable forests resources in the area. It is essentially link between management practices. The zonation in the process of describing the physical consequences of the management plans which have been understood for sustainable forests resources in the area. It is essentially link between management objectives and physical operations on the ground.
Accordingly using multi-thematic information the zonation of any area could be prepared with the below given logic. (Table 2)
The below given process com The study carried out in the parts of Western Ghats showed adequacy of the tool and approach.
Table 2 Forest Zonation Matrix
|Zone 1||+||4.5||>20||>50||High||Nil+||Managroves Grassland|
|Zone 2||+||3.5||>20||>35-50||Medium||Sparse/Nill||Any Type|
|Zone 3||+||2.3||>20||>35-50||Medium||Inhabited||Any Type|
|Zone 5||Reve All Lands Falling in “C” and “D” Lands||W. L|
Remote Sensing and Biodiversity Studies
The forest management while through its forest inventory and zonation of the area can revolve ecologically sensitive and diversity wish rich areas through use of satellite data applications in conjunctive use of other ancillary data discussed as above in the zonation. It is estimated that the tree diversity is estimated to around 200 species in the northern parts as Western Ghats exhibited a great diversity between the plots and along the gradients. The extended application of forest inventory and enumeration including shrub layer and herb layer would enhance forest management system for preservation of ecologically rich zones and to account diversity of the areas. The initial probabilistic diversity zones should be narrow down using satellite data and the consistency of patchiness as a function of landscape dynamics could be used as an element for bio-diversity studies.
Forestry Conversion Studies
With the rapid destruction of forests and encroachment the use of multi-temporal satellite data using digit analysis procedure provide spatial change maps by image differencing methods and logical operations. The study carried out using multi-temporal satellite data of 1983 & 1993 in parts of Andhra Pradesh of Adilabad District showed the area decreased upto 25% of the total area studied whereas improvement in the quality of the area is only 6-7% out of the 1,512 sq. km area studied, The methodology recommends for detailed investigations at district level for accounting forest changes over the years within the reserved forests areas.
Forest Fire Damange
The use of multi-mission IRS data has demonstrated amply the feasibility to identify forest ground fire damaged areas with the combined use of IRS 1A and IRS 1B. The studies carried out during 1991 in parts of Nagarghole wild life sanctuary facilitated accounting damage of an area of 68 sq. km. Quite recently in the month of March 1994 the central part of the India in the Simplipal reserve forests the extent of fire damage was assessed using IRS 1B and estimated the ground fire damage to an area of 600 sq. km against 200 sq. km reported. The use of in season data would enhance capability in identifying hot spot areas which are annually prone to fires could be of use to the forest management for mounting fire operation measures during the vulnerable periods.
GIS Applications in Forestry
The scientific and effective forest management information could be operationalised using the GIS approach at district level as a functional unit. The organization of data base, data inputting, updating, retrieval and analysis for specific purposes and to obtain outputs apparently is feasible cost effectively at the district level rather than aiming at state level as a central facility. The data base in GIS should necessarily preceded by generation of reliable spatial maps preferably on 1:25.000 scale to begin with which can be later inputted to GIS for proper data utilization and to obtain outputs with greater degree of accuracy relevant for district level management decision. The organization of data feasibility adopting micro scale to macro scale may be a viable approach rather than adopting top to bottom approach stasr6ting with coarse resolution data which may fail to reveal any meaningful outputs required at the working level. The organization and aggregation of data base at district level would enhance efficient forest working most needed in the district level. The use of GIS at taluk level for preparation of zonation map revealed micro scale details without sacrificing accuracies for management decisions.
While the GIS data base is being parallel evolved simultaneously with the improved spatial maps the requirement on development of forest resources information system at the district level in the form of MIS should form a major management aspect which facilitate aggregation at the state level for strategic decisions The concept of National Natural Resources Information System (NRIS) as part of NNRMS activity of Dept. Of Space would be the fore runner in evolving a reliable operational forest management information system.
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