B: STUDY OF VEGETATION STATUS AND CHANGE

Introduction

Studies of vegetation conditions and patterns of ecological change in natural forests are essential for management decision-making at the state, district, and village levels. Due to the immense ecological and microclimatic diversity found in India, it is necessary to conduct localized studies to understand and respond to the highly varied environmental contexts. Knowledge of the vegetative characteristics of forest ecosystems can be effectively combined with economic and institutional information to develop participatory and locally-adapted management systems based on appropriate resource development strategies. Forest vegetational status and dynamics can be investigated through a combination of conventional ecological mensuration methods and participatory research techniques. The methodologies advocated here differ in certain ways from conventional forest ecosystem studies in terms of approach, time line, and audience. Traditional ecosystem research has been typically directed toward an academic audience and often requires lengthy data collection. In contrast, these methods are designed to generate a rapid understanding of the vegetative conditions in natural forests utilized and/or managed by community groups. The main purpose of study is to help communities generate practical management options that will lead to optimal productivity, while also responding to environmental needs. Resulting management options will be site specific and tailored to local vegetation, economic and institutional factors. Data on vegetation status by itself may not be sufficient to generate viable management options.

The target groups utilizing the vegetation data for generating management options include Forest Departments, NGOs, local institutions and communities. For planning purposes, these groups require timely information that allows them to identify trends reflecting degeneration or regeneration and corresponding productivity levels for important species under current and potential use practices. These groups are not likely to be trained to carry out complex conventional ecological research, and they often do not have the time to wait for lengthy studies. To respond to the requirements of forest managers, whether they be government officers or villagers, vegetative assessment methods should be rapid, simple, user-friendly and applied. The goal is to guide the generation of management options rather than simply describing the forest or grassland ecosystem. These methods also can facilitate community involvement, both capturing the experiences and collective wisdom existing among village members, and bringing families into a dialogue concerning the vegetative state of the forest and how it could best be managed to meet their economic and ecological needs. An exemplary range of participatory vegetative assessment techniques are described in the proceeding section.

1: Management Issues and Parameters

A cross section of examples illustrating common management issues and research parameters, sites, and field methods are presented in Figure 18. Typical issues may include the annual amount of fuelwood or tree leaves that can be extracted sustainably, or the impact of forest protection and increasing canopy closure on fodder grass yields.

Figure 18

Ecological Management Issues, Parameters, and Research Methods

In the context of addressing key forest management issues faced by foresters, NGOs and local communities the aim of the vegetation study is to generate information which will assist in identifying strategies which respond to local resource problems. For example, the research and analysis framework might address such management questions as the current impact of fuelwood extraction practices on wood and biomass productivity described in Box 1.

Box 1: Sustainable Harvest of Firewood
- A Case Study of Moti Pipal Hamlet, Surat District

2: Vegetative Diagnostic Studies at the State Level and Community Level

Indian states are at various stages in designing and implementing JFM systems. At the macro-level, Forest Departments need to assess the biological potential for natural regeneration, targeting areas where coppicing trees and root stock already provide opportunities for rapid regrowth under community protection. If tree root stock and grass seed/slip is dense and healthy, but prone to rapid degradation by overgrazing and cutting, the area should receive priority attention. Vegetation status would be one of the important criteria for consideration in conjunction with indicators of community interest, cohesion, and management capacity in selecting locations to initiate program activities.

The ecological identification of potential and priority areas for JFM should consider soil and water conditions, as well as the type of vegetation present. The potential of any area would be measured with respect to the opportunity for quick natural regeneration. The rate of natural regeneration or net primary productivity of a patch would depend on numerous factors: 1) coppice potential (the higher the percentage of coppicing trees, the higher the rates of regrowth); 2) Stump potential (if stumps or root stock is present, the capacity for coppice growth would be higher); 3) soil status (if the soil is highly eroded, prone to desiccation, low in organic matter etc., the potential for regeneration would be low); and 4) indicator plants (certain plants are keystone indicators of ecological balance or stages of degradation like colonizing weeds).

Several of these factors are shown in the site selection checklist provided in Appendix 1. These assessment tools need to be adapted to the local ecological contexts within respective states. Assessment could be conducted at the Circle and Divisional levels of the FD, relying on secondary data as well as field observations and interviews with field staff who have worked in the area. Preliminary assessments can be recorded on the FD's Division maps, with more detailed descriptions prepared on range or beat level maps. Once approximations have been mapped using existing data, sample ground truth checks should be made to improve the macro-level assessment of natural regenerative capacity of disturbed forests.

3: Local Knowledge of Vegetation Status and Change: A Participatory Approach

The vegetation assessment methods suggested in this manual rely heavily on point-in-time measurements and consequently have limitations in addressing questions related to vegetative change and sustainability. However, given the urgent need for improved management responses to rapidly degrading forests, the proposed methods attempt to partially compensate for the lack of longitudinal information by sampling areas at different stages of degradation and regeneration to reflect the types of changes that occur over time. Since community members have observed these changes and can often recall sophisticated levels of detail, they provide an excellent primary source of information concerning changes in the forest ecosystem. Local informants can identify pressures that have stimulated changes, levels of vegetation removal, responses of species and ecosystems to different methods and rates of extraction, the emergence of new species, seasonality patterns and multiple uses. Because of their specialized knowledge of local forest species, community members can often identify more plants and animals, more quickly and accurately, than botanists.

Participation of the local community in vegetation analysis can be achieved in numerous ways. A proven strategy is to involve one or two members of the community as resource informants in the team from the outset to assist in making observations, and in recording data from transacts and quadrats. Key informant interviews with special user groups such as basket-weavers, mat-weavers or women leaf plate harvesters will also provide insights into collection and utilization practices. Finally, group discussions with women, artisans, farmers, and migrant graziers would also benefit the team by giving them access to specialized knowledge.

As a first step, there is a need to define the issues on which community-generated information should be obtained. A topic for which local knowledge would be useful might include the condition of the vegetation before the current management system was introduced or before a certain intensified period of degradation began. Community members could describe the types and density of species which dominated the forest in the past, and how the size of different tree species, types of ground vegetation, and associated wildlife have changed. Villagers could also describe changes in vegetation due to pressures such as extensive grazing, commercial harvesting of timber or leaves, or fuelwood headloading. This would indicate which species have vanished or declined, which tree species are regenerating, which shrubs, herbs, or pioneering trees have invaded, and which tree species coppice after repeated harvesting. Community perceptions of changes in NTFP availability over time due to modifications in vegetative composition are important indicators. Furthermore, villagers can often describe other related ecological impacts. Communities are usually highly aware of changing ground water levels, flooding and erosion problems, increases in agricultural pests, and microclimatic variations which they sometimes perceive to be related to changes in forest vegetation. Community perceptions and experiences with such environmental impacts need to be carefully documented and assessed.

The research team may also choose to explore labor required for collecting forest products due to changes in vegetation status. This may be reflected in women's hours allocated for collecting a given quantity of fuelwood or leaves (seeds or grass), the part of the tree lopped or collected now, compared to the past, and the number of trees that are lopped or collected to produce a given quantity of forest product. Changes in geographic catchment area for wood or NTFP collection, or distances walked for collection, may indicate changes in availability.

4: Vegetative Parameters: Species Richness and Density, Size Distribution, and Basal Area

A range of vegetation parameters are generally investigated to understand forest management issues. Parameters may include species diversity, plant density in multiple tiers (including trees, shrubs, herbs and climbers), vegetation profiles of forest structure and canopy cover, size distribution of trees (including DBH and height), and basal area of trees, standing biomass, and annual productivity of trees, shrubs, and grasses. Some parameters are simple to estimate (e.g. tree species density or DBH), while others are more difficult to assess (e.g. productivity, standing biomass). All parameters need not be investigated for any given management issue. The investigator must use discretion to carefully select the appropriate parameters for the study given the limited time, resources, infrastructure, and trained manpower available.

Species richness or diversity is assessed by separately listing all plant species (trees, shrubs, climbers, etc.) in the study area. Data on species richness can be estimated in plots under different management/protection regimes and expanded to indicate species uses. Species density explains the dominance of different tree species under various management systems or periods of protection. The tree species density can be obtained by adding together the number of similar species in each quadrat replication and converting the density of each species from the sample area to a per hectare basis. Such information confers important management implications. For example, data from Alahalli in Shimoga district, Karnataka reveals a high density or dominance of Terminalia species, an important indicator of the availability of leaf biomass for manure. Similarly, the dominant presence of the multi-purpose Garcinia species in Hunsur village is an indicator of the availability of NTFP food, oil, and raw dye materials.

DBH class distribution of each tree species indicates the proportion of larger and smaller trees in the forest. DBH, information can be used to indicate tree age, which may reflect potential yields of fruits, seeds, leaves, fuelwood and timber. Basal area is one of the most important indicators of size of the standing stock or volume of trees. By recording the GBH (girth at breast height or circumference) or DBH (diameter at breast height) of all trees in each quadrat, employing a formula, and summing basal areas, the conversion from total basal area for the sample to a per hectare basis in m/ha can be obtained. The following formulae are useful:

Basal area/ha could be used as an indicator of the level of degradation or status of standing stock. If the basal area is declining, it can be safely concluded that the forest is degrading. The dominance and sizes of different tree species in the forest can also be obtained by calculating the basal area of each species in descending order. Since the number of trees of a particular species is not an adequate indicator of tree size or dominance with respect to canopy spread in a given area, basal area of a species can be used as a more accurate indicator.

5: Steps for Vegetation Studies

Vegetation dynamics studies using rapid appraisal methods generally require 4 to 5 days. The first day should be allocated for discussions with local forestry staff and community members concerning vegetative management conditions and problems. Resource persons from the village should be selected to participate on the team and to help identify appropriate study locations and sample plots. These steps were described in the earlier sections of the Manual. As a guide, a suggested activity schedule listing the various steps in conducting a vegetation study is given below.

Steps For Conducting Vegetation Studies

6: Site Selection

Site selection should be determined by the objectives of the vegetation study. These may include establishing benchmark research sites in degraded areas for long-term monitoring of the effects of natural regeneration in degraded forests, or a series of plots under different periods of protection to reflect succession patterns through, a short study. This manual emphasizes rapid assessment methods to diagnose management problems. Consequently, site selection would attempt to represent the impact of existing forest use systems, including: free grazing, controlled grazing and no grazing; removal of only fodder, dry parts, and controlled harvest under JFM programs; and uncontrolled harvest of NTFP. In site locations representing different periods of protection, the vegetation status would differ as tree growth would typically increase and grass production may decrease over time. It may also be useful to select sites at different distances from the settlement. Plots closer to settlements are likely to be more degraded than plots further away. Generally, vegetation exploitation advances in concentric rings around the settlement. Plots in areas up to 2.5 km, 2.5 to 5 km, and 5 to 10 km from the settlement could be selected to cover a range of extraction levels.

It is also important to include a control plot. This will allow a benchmark comparison of the impact of any management practice (or different periods of protection) with plots which are both 1) unprotected open access, and 2) undisturbed natural forests. The second category of control plot is not easy to locate. In this case, only control plots that are not subjected to any management inputs or protection can be studied. For example, the difference in vegetative regeneration can be clearly observed and measured between a plot where grazing is prevented and a control plot where free grazing is practiced. Control plots should be near the study area, and possess similar soil and topography. The size of the plot depends on the purpose Of the study and the condition, heterogeneity, and size of the forest areas (see Figure, 19). The most common method employed for vegetative analysis is the, quadrat technique. Point-centered quarter method is also described for use in highly diverse areas with randomly distributed Species. It is far easier to estimate crucial parameters such as basal area per ha., species diversity per ha., and standing biomass per ha. using equations through the quadrat method than the point-centered quarter or other methods. The mensuration methods described below are designed to allow the researcher to gain an understanding of species diversity and density, basal area, biomass, and productivity.

Figure 19: Decision Chart for Selection of Method for Study

7: Quadrat Method

A quadrat is typically a square plot, however the investigator can select square, rectangular or circular quadrats. In the quadrat method, a specific size quadrat and its replications are marked in the field and vegetation data is recorded for flora falling inside the quadrats. The size and number of quadrats depends on the nature of the study and the vegetative conditions as discussed in the review of site selection criteria. It would vary for different vegetation types because in a given plot, there may be few trees but hundreds of herbs. The investigator may be interested in exploring 0 layers of tree, shrub, regenerating seedlings, and herbs. While the researcher is interested in saving time, the goal is to get as accurate an estimate as possible. Generally, it is Preferable to use more quadrats or quadrats of larger size to provide a better sample. However, statistically even small-sized quadrats or a smaller number of quadrats Property sampled will provide as good an estimate as a fuller census. Keeping in view the limitations on investigators' time and resources, certain quadrat sizes and numbers are generally acceptable as standards as indicated below. Replications of quadrats are necessary to account for variations in soil, moisture availability or topography. In selecting the location of the quadrats, the research team should not choose 'representative' sites, but instead should select randomly in the field to avoid bias. This can be achieved by a random selection on the map in the office, before departing for the field. Also, selection of locations along borders (i.e. of forest and field) should be avoided as be would be subjected to the edge effects and may be larger, more diverse or overused.

After selecting the site and locating the quadrats, the next step is to record relevant observations. In the pre-selected locations, mark the four comers of the quadrat using pegs for the defined dimensions, attaching strings or rope to mark the perimeter of the quadrat. Data to be recorded will vary for trees, shrubs and herbs. Observations should be recorded for all plants lying within the quadrats.

Quadrat Size for Vegetation Studies

Trees:

Data on number of trees, trunk size (DBH), density of coppicing trees, and species distribution are critical for estimating the standing biomass and productivity. Such information is essential to understanding the sustainability of biomass removal, spatial and temporal decisions on extraction, and possible modes for product sharing. Data on the standing biomass, productivity and stump density of coppicing trees would be valuable for decisions regarding economic and institutional aspects of JFM management. Data may be recorded in the format given below:

Tree Quadrat (50m x 20m)

Location: Limbi Quadrat No.: 6 Date: April 4, 1992

(see Appendix 2 for a glossary of terms used in this table.)

Shrubs and Regenerating Seedlings:

The plant types of interest are shrubs and smaller tree seedlings or smaller coppice shoots. Tree seedlings include woody plants with less than 30cm GBH and height above 1.4 m. The presence of a large number of tender coppice shoots is an indicator of future growth potential. The assessment of regenerating seedlings will help in decisions on feasible projected quantities of biomass removal for different uses. The smaller quadrats for shrubs and seedlings should be randomly located inside the larger tree quadrats, and marked using pegs and rope.

Shrub & Seedling Quadrat Size 5m x 5m, 2 plots)