Mangroves are characteristic littoral plant formations of tropical and subtropical sheltered coastlines. Generally mangroves are trees and bushes growing below the high-water level of spring tides. Their root system is regularly inundated with saline water, even though it may be diluted due to freshwater surface run-offs and flooded only once or twice a year.
Mangrove forests are evergreen. The paucity of tree species occurring in them is due to the peculiar conditions of their existence, few plants being able to tolerate and flourish in saline mud and to withstand frequent inundation by sea-water. They also differ from inland forests in that certain tree species are practically gregarious over extensive areas.
Due to their situation along coastal lines, mangrove formations are constantly controlled by marine and terrestrial factors, such as coastal erosion and accretion, tidal waves, geomorphology, salinity and other edaphic characteristics. These, together with the distance from the sea, the frequency and duration of inundation and tidal dynamics, govern to a great extent the local distribution of species and their succession.
Best developments of the mangroves are found at locations with deep, well-aerated soils, rich in organic matter and low in sand, usually in river estuaries.
The importance of the mangrove forest resource stems from the many products taken directly from the mangroves, both wood and non-wood products, as well as products and amenities provided from within and beyond their boundaries, such as fish, crustaceans and crabs. Wood products range from timber, poles and posts to firewood, charcoal and tannin. Non-wood products include thatch, honey, wildlife, fish, fodder and medicine. In addition, mangrove lands are often converted to salt ponds or to agriculture or aquaculture purposes.
The intangible benefits of mangroves, often taken for granted, include:
The many types of products and the multiple roles of mangrove forests make a multidisciplinary approach towards their management essential, covering the full range of products and services which can be obtained from these areas.
The ultimate goal of managing non-wood mangrove resources, economic considerations aside, is to exploit to the fullest the natural energies and resources available for any given site so as to produce maximum carrying capacity for the production of desired products and services. In this respect, a careful examination of forest site conditions and the collection of all relevant information regarding the objectives for managing the forest will prove to be a worthwhile investment, both in time and effort, for any forester in so far as it portrays the potential stand productivity under ideal conditions. Equally important is the full assessment of the socio-economic benefits and environmental impact of managing these mangrove resources.
The effective management of non-wood resources calls for large amounts of additional information as compared to the kind and amount of data required when managing wood resources only. For most mangrove areas, such primary information needs include: the extent, distribution and dynamics of forest cover and water/river bodies; identification and assessment of the available and potential non-wood forest resources; and assessment of woody biomass, including vegetative and animal production. Due to the particular forest structure, composition and limited accessibility of mangrove forests and the mangrove area in general, the task of collecting this information is complex, time consuming and more expensive than similar assessments in dryland forests.
The implementation of such a survey should result in the classification and mapping of the resources and the potentials of the area, particularly in relation with the non-wood products and services. Studying mangrove ecosystems for management purposes also requires a broader multi-disciplinary approach than dry-land forests. The complex nature of the mangrove resources (covering both aquatic and terrestrial outputs) and the very closely interrelated land-uses mangroves may be allocated to (agriculture, fishery and forestry) call for the concourse of expertise from many disciplines, including forestry, wildlife management, ecology, geomorphology, aquaculture and agriculture.
In order to save time and money, data needs should be clarified in function of the chosen management objectives before embarking on data collection. Data are collected to assist in formulating realistic courses of action, to allow possible courses of action to be evaluated and thus ultimately to facilitate the decision-making process. Five classes of data are required:
For each non-wood resource, the main information required is (a) availability, (b) biological productivity, and (c) economic potential.
There should be an effective demand-forecasting system for the non-wood forest products and forest services expected from the mangrove forests at various levels. This data type is essential for mangrove forests set aside for productive purposes. Even for environmental management areas, the objective may change over time to include production functions. Relevant factors to consider are:
Economic considerations are required over and above purely financial ones, simply because strict analysis of cash expenditure and revenue do not fully account for the real costs and benefits to the community as a whole. In multiple-use management of mangroves, timber production may be reduced or even curtailed to preserve or enhance aquatic and/or terrestrial non-wood products or services. The trade-offs between the alternatives should be compared. As the economic quantification of intangible benefits (and costs) of many non-wood mangrove resources is still at an early stage, estimates may be used instead.
The socio-economic data needed are:
The preferred operational management interventions to enhance the potential of the non-wood resource should be prescribed and the work activities defined as follows: (a) extent covered (ha); (b) the input (man-days, machine hours, materials, etc.); (c) the output (ha/day, km/day, etc.); and (d) the cost per unit area or effort. The anticipated increase in Mean Annual Increment (or any other measurable indicator such as survival rates) are useful benchmarks for measuring performance. The operational data requirement may usefully be summarized as follows:
Institutional factors are generally political by nature, but also include the legal framework. The management plan should include the following statements:
The following principles can be used as a guide in preparing management plans for non-wood mangrove resources.
|A. Mangrove Forest Products
Construction Household items
Fishing Paper products
Textile, leather Fuelwood for:-
Food, drugs and beverages
Source: Adapted from UNEP, 1983.
FOREST MANAGEMENT PLANNING LEVELS AND RESPONSIBILITIES
|Level||Objective||Documentation||Content of Plans||Prepared by|
|National Policy||To provide the policy framework and define the criteria for management actions of forest resource ministries at federal or national level||Acts, Statutes, Regulations, Ministry and Departmental directives||National Policy Objectives and Priorities. Status Report on forest situation or to satisfy defined requirements of the Forest Acts||The Minister in charge of forestry matters based on draft prepared by the Director General of Forestry/CCF|
|Regional Plan||To establish broad resource management and development policies for the development of an entire geographic region or its major sub-areas or any specified region which includes a number of administrative divisions and township zones||Forestry programme of the Director General of Forestry/Chief Conservator of Forests (DGF/CCF) or State/Divisional/ Regional Forest Officers outlining one or more management alternatives based on a resource analysis||A plan where regional goals and priorities for integrated use are identified and production objectives determined (includes socioeconomic opportunities/ constraints)||Divisional Working Plan Officer/Staff
Working Plan Division in consultation with other Ministries/ Departments
|Forest District Management Plan||Prepare plans and development programmes based on defined management unit area needs/goals and land use. (includes a number of Working Circles)||A Forest Management plan approved by the Divisional Forester/SFO with the consent of the DGF/CCF for use by the Regional/District Forest Officers||Long-term: Fix Annual Allowable Cut from
an analysis of demand, inventory and resource use data
Short-term: Schedules on roading; wood and non-wood harvesting, conservation, amenities and silvicultural activities
|Divisional/ Regional/District Forest Officers
Forest Department Working Plan Division together with Divisional/ Regional Forest Officer concerned
|Working Plan||To resolve resource use conflicts and prepare guidelines and prescriptions for forest management implementation at operational level||A Working Plan, approved by the Divisional Forest Officer/SFO and endorsed by the DGF/CCF, providing specific guidelines for resource development and use||Prescription of operating techniques and silvicultural treatments||Usually Regional/District Forest Officer working with Divisional Headquarters staff|
|Local Operational Plan||To identify what site-specific measures will be taken by the timber contractor (permittee/licensee) to ensure orderly extraction conforming to defined resource management objectives and priorities||A detailed plan. In the case of timber, a Felling or Cutting Plan which, when approved becomes an integral part of the license/permit document.||Detailed specifications for on-site operations: e.g. logging systems, road specifications, layout of landings and skid trails, species selection, felling girth, order of felling blocks, etc.||District Forest Officer/Area Foresters and Senior Ranger/Range Staff|