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ECOLOGICAL ASPECTS: INVENTORY FOR SUSTAINABILITY
ECOLOGICAL AND ECONOMIC ASPECTS OF NTFPs
By Gerald E. Wickens
Unfortunately there is a conflict between sustainable development of the world's natural resources to meet an ever increasing global population and that of sustainable conservation to safeguard genetic resources for the future. The developed countries expect the less developed countries to maintain flora and fauna forest services regardless of the local economy. The situation is not helped where the less developed countries occur in regions inherently poor in natural resources, especially in the arid and semi-arid tropics.
These arid ecosystems well illustrate the problems that inevitably arise between managing the environment and social needs. Improved health care from the 1930s onwards has led to a dramatic increase in human and livestock populations which were formerly held in check by wars, famine and disease. This has resulted in ever increasing requirements for locally grown food, grazing and fuelwood and has led to over- cultivation, over-grazing and deforestation, i.e. desertification, a situation that has been even further aggravated by drought associated with climatic change. Over-cultivation results in lower productivity.
"Whereas 30 years ago farmers were able to grow sufficient crops for subsistence plus a surplus for sale, they are now often cultivating from three to five times as much land in the uncertain hope of a yield that will provide enough for their subsistence" (Cross & Barker, 1993, cited in Wickens, 1997). Later and poorer sexual maturity, fertility and meat production from livestock arise from over-grazing, leading to more and more animals being required in order to meet the demands for meat.
Deforestion has forced people to travel further and further afield for their fuelwood and other tree products. All three factors have led to increased wind and water erosion, lower water tables, etc. It is a degradation cycle that the present population pressure and economy is unable to control.
The changing use of NTFPs by the Mbeere of Embu District, Kenya, between 1970 and 1987 has been documented by Riley and Brokensha (1988). It is a scenario that represents the changes also found in other developing countries. Over-utilization and the degradation of the vegetation, soils, water resources, etc., have imposed changes on the use of NTFPs and even their substitution by, for example, imported products including their chemical analogues in medicine, dyes, pest control, etc.
The use of NTFPs follows the rule of supply and demand. Supplies depend on seasonal or annual availability in terms of quantity and quality and the presence of suitable alternatives. Since the dawn of agriculture, cultivation has been the response to wild sources being unable to meet demand. For example, 2 tons of fresh leaves from Catharanthus roseus (Madagascan periwinkle) are required to produce 1 g of the anticancer alkaloid needed to treat a leukemia patient for 6 weeks. Supplies are now from cultivated plants (Sukh Dev. 1989; Robbins, 1995).
While demand can be related to actual need, a product is not necessarily utilized throughout its distribution range. For example, the field mushroom, Agaricus campestris, is often the only edible fungus people will gather in the UK and even then it is eaten with extreme caution, yet in Europe a wide range of wild fungi are consumed. For example, in the Garfabnana region of Tuscany the local people use 19 species for food (Pieroni, 1999). Many of these edible European fungi also occur in the UK and are readily eaten when imported. The reasons for such different attitudes to wild fungal food sources are obviously complex and poorly understood but certainly involve education, urbanisation and local customs.
For the list of references
please contact the author.
Gerald E. Wickens
The Triangle
Buxton Road
Aylsham, Norfolk
NR 11 6JD, United
Kingdom
GROWTH AND PHYSIOLOGY OF IRVINGIA GABONENSIS SEEDLINGS UNDER DIFFERENT ENVIRONMENTAL CONDITIONS
By Christiane Then and Wolf- Ulrich Kriebitzsch
Introduction
Irvingia gabonensis
(Irvingiaceae) or bush mango is an arbuscular mycorrhizal tropical rain
forest NTFP- producing tree which is widely distributed and abundant all over
Central Africa. The fruits are used by local communities for subsistence and
for sale on local and regional markets.
As pressure on natural resources has been increasing, attempts have been made to include this species into programmes for domestication or for enrichment planting inside the forest. To ensure success, basic information on the species' light and nutrient demands, as well as the drought resistance of the seedling stage, are needed. In this greenhouse experiment we germinated seeds from Irvingia gabonensis from SW Cameroon and grew seedlings in a poor sandy soil (pH 4.8) under controlled conditions. Three different light intensities and fertiliser levels were used:
The response of the plants to the various treatments was evaluated by gas exchange and growth parameters.
Characterization of
Irvingia gabonensis
This species has
very large leaves and generally produces extremely high leaf areas (LA). The
total dry weights (DW) as well as the DWs of leaves, shoots and roots are also
high. In the shade (2%) this is already visible, but total DW is tripled in
slight shade (17%). In full light (100%), total and leaf DWs and total leaf
area (LA) decrease significantly because of leaf fall caused by light damage.
In fact, both leaf damage and numbers of fallen leaves rise from slight shade
to light. Actual leaf number as well as the totally formed leaf number (including
fallen leaves) follow the same patterns as the DWs. Only the +P treatment increases
leaf number at 100%, by providing, among other parameters, better resistance
against leaf fall. At 100% light there is a decrease of the totally formed leaf
number with time. This proves that the decrease in DWs from slight shade to
light, mentioned above, are not only caused by leaf fall but by a growth preference
for the 17% light intensity. This finding is supported by shoot-DW, as well
as height growth and internode lengths, which are significantly higher with
+P, and have their growth maxima at 17% decreasing to 100%. As a consequence,
the shoot/root (S/R) ratio is greatly reduced from shade to light. This means
an improved water uptake from the soil. Specific leaf areas (SLA) and branching
patterns react the same way. The generally low specific leaf area in all three
light treatments indicates a good adaptability of I. gabonensis to dry
conditions. In this context the abscission in light must be considered as a
protection against high water loss.
The species demonstrates generally low maximum photosynthetic capacity rates (Pnmax) - typical for shade adapted plants - with an increase from shade (2%) to slight shade (17%) by 20%, and a decrease to light (100%). In comparison to other investigated rainforest species, however, Pnmax is relatively high. In conjunction with the high leaf area mentioned above, this allows for fast biomass production in the seedling stage. Pnmax is tendentially higher with -P. Quantum efficiency (Q) values prove that I.gabonensis can make use of very low light intensities - a characteristic adaptation for seedlings on the very shady forest floor. Values typically rise from light to shade, with maximum at 17%. Maximum Pnmax at 17 % and the high quantum use is also reflected by a high productivity of DWs and LA especially at this light level (see above). +P nutrient supply increases the light demands of the plants as proved, for example, by the light saturation point (IS) which is significantly enhanced with +P.
Transpiration rates (Tr) are particularly low and tendentially higher at 17% shade. Water use efficiency (WUE) also tends to increase with light. Relatively high Pnmax rates together with low water losses produce a high WUE, which results in particularly effective biomass production relative to water loss. Tr significantly increase with the fertilizer treatments. The increase of photosynthesis caused by a higher nutrient supply raises water use efficiency (WUE) values in the fertiliser treatments which are tendentially highest with +P.
As for drought resistance, water demands are high. Drying out experiments to examine the development of Pnmax under water shortage over several days, show a positive relationship between increasing light and the initiation of drying out, survival rate and recuperation. Experiments indicate that the danger of drying out is most pronounced at the 17% light level and lowest for 100%. This suggests that I. gabonensis is limiting transpiration - in addition to leaf abscission - by closing stomata at higher light levels to avoid water loss. The closing of stomata is also indicated by the decrease in Pnmax and DWs from 17% to 100%. A negative fertilizer effect is most pronounced for +P and -P whereas the controls are less susceptible to drought . This may be a consequence of wider opened stomata for the fertilizer treatments than for the controls as also indicated by Pnmax (see above).
Conclusions
We resume that
all investigated parameters show a great impact of irradiance on I. gabonensis
seedling development. Seedlings of I. gabonensis are very well adapted
to the shady conditions in the understory of rainforest. Water demands are high
and there is a good adaptability to dry conditions. I. gabonensis is
distinguished by a high productivity, which is conform with the high nutrient
and water demands.
Recommendations
Based on the above
results, we recommend partial shading similar to our 17% treatment (which corresponds
to 8.5% of natural radiation) for this species at the seedling stage to achieve
optimal growth and leaf development. Regularly applied fertilizer including
+P would be useful but is costly. We recommend arbuscular mycorrhizal inoculation
as experience points not only to increased growth and nutrient uptake but also
to improved water supply (as indicated, for example, by higher SLA). This would
stimulate even further the above-mentioned high adaptability to dry conditions.
For further information
and available data please contact:
Christiane Then
Institute for World
Forestry
Leuschnerstr. 91
21031 Hamburg,
Germany
Tel:+49 40 73962136,
Fax: +49 40 73962
480
Email: then@holz.uni-hamburg.de
Wolf- Ulrich Kriebitzsch
Tel: +49 40 73962-
103
Email:
kriebitzsch@holz.uni-hamburg.de
OPPORTUNITIES AND CONSTRAINTS FACED BY RESOURCE-POOR FARMERS IN INVESTING IN THE PLANTING AND IMPROVEMENT OF INDIGENOUS TREES FOR INCOME GENERATION
By K. Schreckenberg, RRB Leakey and Z. Tchoundjeu
The domestication of indigenous trees for the production of non-timber forest products within agroforestry practices has been suggested as a sustainable means of promoting the reduction of poverty in tropical countries (Leakey and Simons, 1998). This DFID-funded project was established in Cameroon and Nigeria, to:-
Project sites (4 in Cameroon and 2 in Nigeria) were selected to represent a range of agroecological conditions, species abundance, market access, population pressure and land availability. Biophysical and socio-economic studies were carried out at each site and market studies implemented in adjacent or other relevant markets.
The socio-economic team implemented community level work in the Cameroon communities and household interviews in all six communities. The principal findings are that out of the average of 80 fruit trees per 3-6ha farm, D. edulis is the most commonly planted species, accounting for 65 % of all planted trees. Half of the planted species are indigenous, the vast majority being located within other perennial tree crops (eg. cocoa and coffee), with indigenous exceeding exotic species. Land tenure, which is commonly perceived to be a constraint to planting tree crops, was found not to be and preliminary data analysis found no clear differences between the tree stocks of wealthy or poor farmers, although male headed households had twice the numbers of female-headed households. Labour was not found to be a major constraint for tree planting or maintenance, but bottlenecks may occur at harvest time.
Income from indigenous fruits was the primary source of income for 11% of households, especially in August - October, when other income is scarce. It is also seen by farmers as an important buffer against other financial risks and against falling prices for major commodities, like cocoa and coffee.
The biophysical studies were particularly targeted at an understanding of the variability of fruit and kernel characteristics. Thirteen different characteristics (fruit, nut and kernel mass; fruit length and width; flesh taste and fibrosity; skin and flesh colour, fat content of kernels, and the viscosity and elasticity (drawability) of food prepared from kernels) were measured. The relationships between tree height and dbh showed that the population structures of D. edulis were similar in both countries, both were populations planted on farm, while the I. gabonensis population in Cameroon was a mature relic of a natural population and that in Nigeria a relatively young planted population.
As expected, very considerable tree-to-tree variation was found, indicating the appropriateness of a village-based tree domestication programme (being implemented by ICRAF / IRAD), that also conforms to the Convention on Biological Diversity, by promoting the rights of farmers over their indigenous knowledge and germplasm. For example, a few I. gabonensis trees in Nigeria were found to be considerably bigger than those in Cameroon, while in Cameroon, a few trees had better kernel traits. From the results so far, it is possible to identify the traits that should be selected for cultivar development in both species. In I. gabonensis in particular it will be important to select a combination of traits that form either a fresh fruit ideotype, or a kernel ideotype in response to consumer preferences.
In an attempt to quantify the extent of domestication already achieved by farmers' own tree selection activities, there is evidence that in both species traits of little importance to farmers are normally distributed, as in wild populations, and that others of importance to farmers may form a separate sub-population outside the curve formed by wild populations. This illustrates the way in which such data can be used to identify the best individual trees for cultivar development using vegetative propagation, so taking the domestication process forward more rapidly.
For farmers to really benefit from the further domestication of these species, it is important that the trade recognises the genetic variation between cultivars in terms of the market price. Attempts to ascertain market preferences have identified that traders favour skin colour as a trait in D. edulis, while consumers prefer taste. The odour of I. gabonensis kernels seems also to be a factor of importance to consumers. The market analysis to date has not yet, however, taken into account the apparent differences between the requirements of wholesalers and retailers.
A recent stakeholder workshop in Cameroon, was very enthusiastic about the results of the project and the new emphasis being placed on the domestication of the traditionally important, and previously-ignored, indigenous fruits. In particular the results were seen to be a major contribution towards the work of ICRAF and IRAD to develop land use systems that also provide a step towards poverty reduction and sustainable livelihoods.
Outputs from this project will include 4 already submitted MSc theses, 10-20 peer-reviewed research papers (the first is published), policy guidelines, a synthesis in book form, posters and media presentations.
This publication is an output from a research project funded by the United Kingdom Department for International Development (DFID) for the benefit of developing countries. The views expressed are not necessarily those of DFID. [Project R7190, Forestry Research Programme]
For more information,
please contact the authors at:
Dr. Kate Schreckenberg
Overseas Development
Institute
111 Westminster
Bridge Rd
London SE1 7JD,
UK
Email: k.schreckenberg@odi.org.uk
Dr. Roger Leakey
Centre for Ecology
and Hydrology
Bush Estate, Penicuik
Midlothian EH26
0QB, Scotland
Email: rrbl@ceh.ac.uk
Dr. Zac Tchoundjeu
International Centre
for Research in Agroforestry
PO Box 2123, Yaoundé,
Cameroon
Email: z.tchoundjeu@camnet.cm
APPLICATION OF MOLECULAR MARKER TECHNOLOGIES FOR THE GENETIC CHARACTERISATION OF NON-TIMBER SPECIES
By Marie Baucher, Sylvia Burssens, and Marc Van Montagu
The stability of an ecosystem is largely determined by the intraspecific genetic diversity of the different interacting species, because this diversity holds a reservoir of potential adaptations to changing environmental conditions. A low genetic variability as a consequence of biodiversity loss may lead to the disappearance of endangered species. Although measurements of visual traits reveal the existence of genetic variation, they do not give a good indication of the structure of diversity within populations or how this population is maintained.
Biotechnological advances in the analysis of genetic variation can revolutionise our ability to conserve and improve forest species by accelerating knowledge gathering. The use of molecular markers technology, such as Amplified Fragment Length Polymorphism (AFLP) (Vos et al., 1995), associated with the measurement of quantitative characters, enables the measurement of the genetic variation of a species or a population. As DNA analysis allows for the direct visualisation of genetic information, independent of environmental factors, tissue development or developmental stage, these methods can be used for species identification and the development of general sets of molecular markers with which to assess genetic diversity. Furthermore, the genetic mapping of quantitative traits closely linked to molecular markers is a very efficient tool to analyse the outcomes of crosses in marker assisted breeding programmes.
The Institute of Plant Biotechnology for Developing Countries at the Department of Molecular Genetics, Ghent University, is participating in an INCO-DEV project, supported by the European Community since 1999, to assess the levels and dynamics of intra-specific genetic diversity of tropical trees with molecular tools. In addition to studying the biodiversity within 10 different species from Central America, Costa Rica, French Guiana, Brazilian Atlantic rain forests and the Carribean Islands, the aim of the project has been to assess human impact on the genetic diversity of tropical trees. For example, the AFLP technique was used to study biodiversity within and among three neighbouring natural populations (Guaritiba, Grumari and Barra) of Eugenia uniflora (pitanga), each of which has experienced different degrees of human impact (Margis et al., in preparation). E. uniflora is a colonizing plant species endemic to the Brazilian Atlantic rain forest. It plays an important role in the maintenance of the woody coastal ecosystem, especially in disturbed sites. Its ecological importance is reinforced by the fact that pitanga fruit are a feeding source for a wide variety of birds and mammals. Because of the sensitivity and high resolution of the AFLP method, significant genetic variation could be detected between populations which are geographically very close together. Intra and inter genetic diversity analysis showed that more than 86% of diversity resided on the intra population component, suggesting that gene flow among the populations is intense (Margis et al., in preparation).
The same partners plan a continuation of the project, focusing on the impact of different human activities (e.g. logging, fragmentation and land degradation) on the genetic diversity and gene flow within several tropical plant species in Latin America.
Thanks to the development of methodologies such as HPLC, capillary electrophoresis and mass spectrometry, it is now possible to obtain information on metabolite levels in individuals of a population (Fiehn et al., 2000). These high throughput technologies allow the study of the effect of the genetic background, but also of environmental conditions, on the production of secondary metabolites in medicinal plants and can be applied to capture the value of biodiversity of tropical forests. Other applications of the use of molecular approaches in non-timber species are gene engineering of desired traits, such as the modification of particular phytomedicinal pathways. This might include manipulation of both the quantity and quality of metabolites produced through the introduction of targeted genes.
For references and further
information please contact:
Marc van Montagu
and Sylvia Burssens
Instituut Plantenbiotechnologie
voor Ontwikkelingslanden
K L. Ledeganckstraat
35
9000 Gent,
Belgium
Tel: + 32-9-2648727,
Fax: +32-9-2648795
Email: mamon@gengenp.rug.ac.be
Marie Baucher,
Université
Libre de Bruxelles
Laboratoire de
Biotechnologie Végétale
1850 chaussée
de Wavre
1160 Bruxelles,
Belgium
DEVELOPING NEEDS-BASED INVENTORY METHODS FOR NTFPs
Report of the ETFRN
research workshop held 4-5 May 2000 at FAO in Rome
By Jenny Wong
The ETFRN workshop was one of the activities in a pre-project supported by the Forestry Research Programme of the United Kingdom Department for International Development. The pre-project was intended to examine the biometric basis of current resource assessment methods used for NTFPs. The background paper for the workshop represented a review of English language NTFP literature. The workshop was asked to comment on the review and to assist in the identification of key areas where biometric research is needed.
Biometrics can be defined as the 'application of statistical methods and principles to the study of biological organisms'.
Not all disciplines use the term 'NTFPs' and so the criterion for including a study was that it should be concerned with human harvesting of some forest-based plant or animal resource. Resource assessment was here interpreted as the quantification of some characteristic of the resource, e.g. its abundance, growth rate or yield or as a description of quantitative monitoring methods. In all, 126 case studies were identified from a wide range of disciplinary approaches (see Table 1).
In order to examine the biometrics of these studies it was first necessary to establish a set of criteria to define biometric quality. These are all concerned with statistical aspects of the design of the studies and are:
In addition, in order to be able to judge these criteria it is necessary for the protocol used to be clearly reported, so this was included as a further factor. The results of the evaluation are shown in Table 1.
Generally, it would appear that most (60%) NTFP studies have some biometric shortcomings. Many of the 56% that did not report their protocols could, of course, be well designed studies but without the details it is impossible to judge. Also, to be fair, some of these studies may not need to be biometrically rigorous. As in all forms of inventory the methods used should be matched to the information needs of the management system and need not be biometrically rigorous as long as objectives are met.
What is perhaps of more concern is that 43% of resource inventory and 90% of yield studies failed in some way. These are studies that usually have quantification as a primary objective and it seems clear that there is a serious problem in the methods currently used for NTFP resource quantification.
The review concluded that the principal difficulties with NTFP quantification are:
The workshop itself was concerned with identifying priority research areas from the perspective of different 'needs' for NTFP quantification.
At the species level, information is needed to guide appropriate management of individual products. Here the main difficulties are technical as little is known about the best methods to use to sample, measure, monitor and analyse (including yield determination) individual products. Research is needed into all of these aspects for most products though emphasis was given to resource inventory as other studies build on sound initial inventory of the resource.
At the community level any improved methods for studying a specific product will need to be participatory in that they should enhance and build on local knowledge to be effective. Much NTFP management is traditional and based on local knowledge but often this is not formally acknowledged by regulatory authorities. The workshop identified an urgent need for the development of participatory techniques which are accessible and meaningful to local communities and which will produce results acceptable to regulators, that is, usually, government agencies.
At the macro level the difficulties of studying individual species are compounded by the expense of undertaking studies on individual species forcing the use of a single design for a range of products. This severely restricts the ability to tailor designs to the peculiarities of individual products and there needs to be some investigation of the implications of this in the context of multi-purpose resource inventory. A further consideration is that there needs to be some means of integrating information from all NTFP studies within a country. Such information is required for government level strategic planning for the regulation of harvesting, issuing of export permits, incentives for NTFP livelihoods etc.
The workshop concluded that there is a need for focused research on NTFP biometrics. In particular, the urgent need for a source of biometric advice for fieldworkers and for better reporting of protocols by those publishing NTFP resource studies were emphasised.
For further information and to download the workshop review paper and proceedings visit the workshop web page at: http://www.etfrn.org/etfrn/workshop/ntfp
This publication is an output from a research pre-project funded by the United Kingdom Department for International Development (DFID) for the benefit of developing countries. The views expressed are not necessarily those of DFID. [ZF0077 Forestry Research Programme]
Jenny Wong
Ynys Uchaf
Mynydd Llandegai
Bangor, Gwynedd
LL57 4BZ, United
Kingdom
Tel: +44 1248 602124
Email: 105456.3316@compuserve.com
COMMUNITY-BASED WILDLIFE POPULATION ASSESSMENT IN THE KORUP PROJECT AREA, SW CAMEROON
By Lien, M Waltert, K Faber, K von Loebenstein, M Mühlenberg
The Korup Project Area (KPA) is made up of the Korup National Park (1260 kmē) and the Support Zone (5360 kmē), which includes three Forest Reserves (Ejagham, Nta Ali and Rumpi Hills Forest Reserve) situated to the north, east and south of the National Park, respectively. The human population is 45,000 people in about 180 villages. The global objective of the Korup Project is to conserve the biodiversity of the KPA. Its purpose is that the different actors should protect, develop and use the natural resources in an ecologically and economically sustainable and socially acceptable way.
The majority of the people living in and around the protected areas depend on animal wildlife, which is one of the main sources of protein. Vertebrates also play an active role in the ecology of the forest, e.g. as important seed dispersers. Moreover, the Support Zone still harbours populations of some highly endangered and range-restricted species such as Drill (Mandrillus leucophaeus) and Preuss's Red Colobus (Piliocolobus preussi). Up until now, there have not been enough data to assess the sustainability of human pressure (hunting and poaching) on animal wildlife or the impact of logging activities and changes in land use. Based on experiences from Ivory Coast, the Korup Project, in collaboration with the Centre for Nature Conservation (CNC, Göttingen University, Germany), has therefore developed a methodology involving the local communities in the assessment of wildlife. This programme intends to assess the densities of key species in selected areas and their changes over time. The focal species are duikers (four species), primates (seven species) and three groups of birds (hornbills, touracos and selected understorey bird species). The key species are surveyed from permanent line transects covering the forested parts of five village areas, in the northern and eastern part of the Support Zone. In the near future, a similar programme will be carried out in parts of the National Park.
Transects are surveyed by carefully selected and trained local staff. Direct observations and indirect cues (tracks, dung) are recorded both for diurnal and nocturnal key species. The personnel of the programme consist of 15 Eco-staff divided into five teams (three staff per team), one field supervisor, one co-ordinator, one advisor and non-permanent consultants. Data collection and analysis follow standard Distance Sampling procedures. The collection of data started in February 1999. In one year of biomonitoring, four teams have covered 379 km during morning observations, 311 km during night surveys, and 350 km during footprint surveys, collecting 9827, 185 and 4294 data-sets, respectively. For most focal species this has provided sufficient data for calculating densities.
The community-based approach ensures long-term monitoring and is financially affordable. It also increases the level of awareness on conservation issues of local communities and some key stakeholders such as the Government of Cameroon. The programme is a member of the Cameroon Biomonitoring Network (CBN), the objective of which is to exchange experiences among its members.
For further information,
contact:
Lien
Biomonitoring Co-ordinator
Korup Project
B.P. 2417 Douala,
Cameroun
Tel./Fax: +237-43.21.71
Satellite Tel.:
00873761627170
Email: ngutikp@aol.com
Dr. M. Waltert
Centre for Nature
Conservation (CNC)
University of Göttingen
Von-Siebold-Straße
2
37075 Göttingen,
Germany
Tel.: +49 551 392313,
Fax.: +49 551 399234
Email: mwalter@gwdg.de
http://www.gwdg.de/~ubns/mw.htm
ASSESSMENT OF NTFPs IN COMMUNITY FORESTRY: EMERGING PARTICIPATORY INITIATIVES FROM THE HILLS OF NEPAL
By Hemant R Ojha
Introduction
Nepal has a
very rich floral and faunal diversity due to its topographical, climatic and
edaphic variations. About 100 NTFPs are extracted for trade, and 800 more find
subsistence uses as foods, spices, herbal medicines, incenses, oils, fibres
and construction materials (Edwards, 1996). Increasing subsistence as well as
commercial expectations from non-timber forest products (NTFPs) has necessitated
more careful assessment of the resource base and sustainable harvesting schemes
in the hills of Nepal. This paper reviews some participatory NTFP resource assessment
initiatives with commercial medicinal herbs and fibre-yielding shrubs.
Currently most of the operational plans (OPs) for managing community forests (CF) lack provisions for NTFPs. However, Forest User Groups (FUGs) are not authorized to use and manage NTFPs unless they are included in the OP. Growing awareness of the value of NTFPs has now highlighted the need for better NTFP resource assessment and their incorporation into OPs.
The fundamental parameters that need to be assessed while planning sustainable management of NTFPs at operational level are: existing growing stock, productivity, quantity of sustainable yield that can be prescribed for harvesting, and sustainable harvesting techniques. In Nepal, very limited documented knowledge on species as well as ecosystem level is a major constraint in seeking appropriate answers to these questions. In view of this, FUGs and foresters are increasingly required to work together to generate more information, often using indigenous knowledge and beliefs as a preliminary basis.
Case Examples
Binayak FUG in
Bajhang in the western hills of Nepal was formed in 1995 and a patch
of 25 hectares of community forest was handed over primarily for the fulfilment
of timber and fuelwood needs. In 1999, the Asia Network for Small Scale Bioresources
(ANSAB) assisted the FUG to expand the community forest area to include NTFPs.
The participatory planning exercise identified Lokta (Daphne spp.) as
one of the main commercial products. Lokta (a 3-4m high shrub) is one of the
main sources of traditional Nepali handmade paper, and has an attractive local
as well as international market.
The participatory resource assessment started with preliminary mapping of Lokta resources in the forest. The forest was divided into various blocks following boundary survey and area calculation. Sample plots were then laid systematically in each of the blocks, and counting of Lokta plants by diameter class was done and the total growing stock was projected. Using secondary information, cutting cycle and the minimum size for cutting were determined to estimate annual sustainable harvest levels.
Bhitteri Pakha FUG in Dolakha district in central Nepal offers another example of NTFP assessment. Argeli (Edgeworthia gardeneri), which is a fast growing shrub with a unique triangular branching pattern, was identified as the main commercial NTFP. Whiteskin is extracted from Argeli stems and exported to Japan, where it is converted to a high quality paper that is also used for currency making.
As argeli is not uniformly distributed in the community forest, habitat mapping was carried out to determine the sampling frame. From this, an estimation of number of clumps as well as stems was made. It was very time consuming to count individual stems as a clump contained as many as 80 stems. To expedite the process, stem diameter distribution was assessed from a sample of 1000 stems across several clumps, and the estimated number of clumps was combined with a diameter distribution curve to estimate the number of stems across various diameter classes. Participatory wisdom suggested 30% mortality from one class to another, and based on this, population size was projected for 10 years. Annual sustainable yield was calculated on the basis of a predetermined minimum size of cutting.
In the western Himalayan district of Humla, communities had long experiences of collecting plant products for local as well as commercial use. ANSAB staff wanted to verify whether indigenous harvesting practices were optimal in terms of productivity and conservation impact. To address this, ANSAB (1999) designed a participatory action research plan to identify best harvest intervals and collection methods for four commercially harvested medicinal plants, including Jatamansi (Nardostachys grandiflora). This is an erect perennial rhizomatous herb growing 10-60cm long and used both locally for medicines and commercially for medicines and perfumery.
For the purpose of quick assessment, patches harvested in 1993/94, 1994/95, 1995/96 were discernible, and two more patches were identified for subsequent harvest treatments. By applying the same level of harvesting, the five patches were harvested on a five, four, three, two and one year rotation. Yields of fresh Jatamansi roots and rhizomes from these harvests were recorded. The results were analysed to assess the effect of harvest intervals across the two habitat types. A harvest interval of five years was found to be optimal.
Experience with Jatamansi and other high value NTFPs in Humla has indicated new dimensions of sustainability and management of medicinal plants. In addition to quantity of harvest, methods, seasons and techniques of harvesting were found to be equally important.
Discussions and Conclusion
A wide range of
assessment techniques for NTFPs has to be considered to address variations in
terms of plant form, life cycle and product type. The examples presented demonstrate
that Lokta and Argeli, although similar shrubs, were assessed using two different
techniques. Methods of assessment have to be site and product specific. Understanding
ecological regularities of species as well as ecosystems can facilitate speedy
inventory of NTFPs. Mapping Argeli habitats minimised the sampling frame, and
hence the costs, while maintaining accuracy. Indigenous knowledge may provide
a basis for scientific inquiry as well as for provisional harvesting plans.
Thus both the Jatamansi experiments, and determination of the cutting cycle
and mortality of Argeli were achieved through participatory wisdom. The diversity
of techniques needed for NTFP assessment can be designed, tested and refined
through the use of local as well as scientific knowledge.
For further information
please contact:
Hemant R Ojha
ANSAB
P O Box 11035,
Kathmandu, Nepal
Tel: +977 1 497547,
Fax: +977 1 487916
Email: hemant@infoclub.com.np
ANALYSIS OF THE SPATIAL DISTRIBUTION OF NTFPs IN THE TROPICAL FOREST OF GHANA
By Emmanuel Tabi-Gyansah
Introduction
In Ghana, NTFPs
are an important source of income to the majority of rural dwellers. Main products
are cane (Calamus spp.), rattan (Lacosperma spp.) and chewsticks
(Garcinia afzelii). These products contribute 2 % (in comparison with
the forestry sector's 6%) to the country's GDP. Furniture production and other
processing activities from cane and rattan have expanded. Cane-processing enterprises
were actively promoted.
Although the development of NTFP-based industries has helped economic development, it has also caused an increased demand for raw materials. The growing depletion of forest resources has generated interest in conservation-oriented projects, but these cannot successfully be implemented without knowledge of the current status and rates of change in the spatial distribution of the principal species.
In Ghana, 'conventional' forest inventories generally have been based on stock surveys of compartments. Such inventory data are essentially non-spatial. At best, the results are combined with remote sensing data to display forest patterns and produce forest maps. Because the smallest mapped unit is a compartment (often several hundreds of hectares in area), detailed information on the local spatial distribution within map units is not presented in maps. Recent research (Acharya, 1999) has shown that geostatistics offers a promising method for characterising large and small scale variations of both species richness and forest structure parameters. This paper describes further research to investigate whether geostatistical methods can be used to produce reliable information about the spatial distribution of NTFPs - cane, rattan, and chewstick - in part of the Subri River Forest Reserve, one of the largest forest reserves in Ghana (Tabi-Gyansah, 2000).
Geostatistics
Most people know
intuitively that two values that are close together in space tend to be more
similar than those far apart. Such variables are known as regionalized variables.
A regionalized variable y(x) is considered at all pairs of location x and x
+ h, i.e. at locations separated by the distance vector h. Geostatistics
allow the correlation between any two values separated in space to be quantified
and used to predict the values at unsampled locations. Geostatistics are therefore
a powerful tool for the study of spatial distributions.
In geostatistics, a so-called variogram is used to model the way two values are spatially correlated. The spatial variance usually increases with distance, and levels off at a certain distance beyond which observations appear independent (Figure 1). This is the so-called range, beyond which the variogram value remains constant. Between locations separated by a distance smaller than the range, the regionalized variables are dependent. When the variogram is extrapolated back to zero distance, it may approach a non-zero variance or non-zero y-intercept. This is known as the nugget variance, and represents unexplained spatial dependent variation or purely random variance.
Some general results
A multi-level sampling
design was used to collect data on various tree parameters and on the abundance
of NTFPs in 500 mē sample plots along 1200m transects on either side of a predetermined
base-line. Subsequent analysis involved two main steps: i) analysis of
the observations, without considering their spatial locations, and ii)
estimation of variograms and contour mapping to provide information on spatial
dependence and variations in the distribution of timber and NTFPs.
In summary, the research revealed that timber and NTFPs have some inherently different spatial characteristics:
Conclusion
Although further
work is required, this research suggests that geostatistics may play a useful
role in the survey of NTFP resources which, by their very nature, can only be
studied on the ground. Not only may geostatistical methods help forest resource
managers to better understand the spatial distribution of NTFPs but they may
also support the selection of appropriate sampling designs to inventory this
increasingly scare resource.
Further information
The research described
in this paper was undertaken in partial fulfillment of the requirements for
an MSc degree in Geoinformation for Forest and Tree Resources Management at
the International Institute for Aerospace Survey and Earth Sciences (ITC), in
the Netherlands. The work was supervised by Prof. Dr. A. de Gier and Dr. M.
Weir, and is one of several research projects dealing with applications of geostatistics
carried out by ITC's Forest Science Division. For further information, contact:
weir@itc.nl.
For the list of references,
please contact:
Emmanuel Tabi-Gyansah
Forestry Commission
PO. Box M434
Accra, Ghana.
Email: tabi@forestrycommission.com
EPIPHYTIC BROMELIADS: TOWARD THE SUSTAINABILITY OF YIELD FROM NATURAL POPULATIONS IN THE HIGHLANDS OF CHIAPAS, MEXICO
By Jan H.D. Wolf and Cornelis J.F. Konings
Direct economic benefits of conservation efforts may be attained when forest products can be harvested for commercial purposes while at the same time maintaining the ecological integrity of the forest. Recently, a concept known as canopy farming© has been proposed for this purpose. Vascular epiphytes are just one of the potential NTFPs in the canopy and of these the bromeliads are often the most abundant, particularly in areas with a pronounced dry season.
Bromeliads are traditionally used by highlanders of Mayan origin in Chiapas, Mexico, for ceremonial purposes and for the decoration of sacred sites. The western world has only recently 'discovered' the potential of bromeliads for (home-) decoration, and species in the genus Tillandsia are now regarded as a valuable cash-crop in several countries. Thus, between 1993 and 1995, Guatemala exported 14.5 million Tillandsia plants annually. Rauh, a specialist in Bromeliaceae, estimates that at least 75% of the plants in Tillandsia farms are collected from the wild and holds such activities responsible for a decline of bromeliads, casting doubts upon the sustainability of this harvesting practice.
In a study in pine-oak forest of the highlands of Chiapas we aimed to obtain criteria for the sustainable harvesting of a natural population of bromeliads. For details, we refer to Wolf & Konings (under review).
Two approaches may be followed to attain sustainability of yield. By means of demographic and/or genetic studies and modelling we may attempt to establish the minimum viable population size and propose management interventions accordingly, based on population viability analysis. A reliable analysis, however, requires observations over a long period of time and has no universal value. For the immediately threatened forests and bromeliads in Chiapas we therefore suggest an empirical approach in which we start with an arbitrary definition, though based on generally accepted principles, of the most strict criteria for sustainable removal. Exploited species must then be monitored over time to see whether the initially stringent thresholds may possibly be lowered. We propose that harvesting should only be permitted from populations (i) with a high population density, (ii) that are evenly distributed in space, and (iii) for which the reproductive potential will not be affected by the removal.
Harvesting from a small population might negatively affect the local survival of a species, since small populations may experience reduced offspring fitness and a loss of genetic variability through inbreeding or genetic drift. In addition, they are considered to be more vulnerable to demographic and environmental stochasticity, and to natural catastrophes. We suggest the use of a minimal population density limit for exploitation of 10.000 large rosettes/ha, a threshold ten times higher than that applied in a stable Tillandsia circinnata population in Florida.
We consider that populations that are spatially evenly dispersed within a homogeneous habitat are at carrying capacity, for which the extinction risk is also smaller. We presume that for three-dimensional epiphytic populations at capacity this implies that over the entire forested area the abundance of epiphytes on trees of a larger inhabitable size is nearly proportionally greater than the abundance on smaller trees. On the basis of a pilot study in three forest stands at 'La Florecilla' along a disturbance gradient, we propose to employ the squared correlation coefficient (r2) of a linear correlation of Tree Size against epiphyte abundance as an index of spatial homogeneity (ISH) of the population. The variable Tree Size is a linear combination of DBH and number of branching points. At the least disturbed stand, the ISH was 0.901 and accordingly we suggest that at La Florecilla harvesting should be limited to populations with an ISH >0.90 (p<0.001).
To assure that the removal of rosettes does not affect the reproductive capacity of the population, we propose exploiting only that part of the bromeliad population that grows in the lower stratum of the forest, including the forest floor. Population densities in the lower stratum of the forest are likely to depend on a seed supply from the canopy. In contrast, canopy colonisation by wind dispersed seeds from lower strata seems unlikely and plants that grow near the forest floor are not likely to play an essential role as providers of progeny for populations of bromeliads that seem best adapted to survive in the canopy.
For a second study at 'La Florecilla' we developed a user-friendly transect method that aimed to identify populations of bromeliads that may be harvested sustainably (Table 3). We found one species, Tillandsia vicentina, with both a satisfactory average population density of about 24,000 rosettes of over 20 cm/ha on oaks and an ISH of 0.91, after excluding oaks (40%) that sustained few Tillandsia plants. We allow the exclusion of up to half of all host trees that support few bromeliads, since in the structurally heterogeneous forest we expect a high variability between trees due to the random sampling design. Less than 20% of the population occurred in the lower stratum of the forest, up to a height of 6 m. In compliance with the proposed prerequisites and taking into account certain quality considerations, we estimate that it is possible to sustainably harvest about 700 rosettes of T. vicentina /ha/yr from the understorey and forest floor, in a 4-year rotation cycle; equivalent to an annual yield of 112,000 rosettes from the entire forest at La Florecilla. The implementation of a monitoring programme that makes use of the transect method is a necessity for any management plan. We hope that the exploitation of bromeliads as an alternative NTFP will contribute to community economic development and conservation of both the bromeliads and the forests they grow in.
Acknowledgements
We are grateful
to the community of La Florecilla and the Hermanas Misioneras Clarisas for their
co-operation and for granting us access to their forests. We thank Prof. Dr
R.A.A. Oldeman for permitting free use of the term Canopy Farming©.
For further information,
contact:
Cornelis J.F. Konings
El Colegio de La
Frontera Sur,
C.P. 29290, San
Cristóbal de Las Casas
Chiapas,
México
Jan H.D. Wolf
University of Amsterdam
Institute for Biodiversity
and Ecosystem Dynamics
Hugo de Vries-laboratory
P.O. Box 94062
1090 GB Amsterdam,
The Netherlands
Tel: + 31 20 5257840
Email: wolf@bio.uva.nl