Sustainable Harvesting Practices Research Articles

Sustainable Harvesting of Terminalia arjuna (Roxb.) Wight & Arnot (Arjuna) and Litsea glutinosa (Lour.) Robinson (Maida) Bark in Central India

Terminalia arjuna (“Arjuna”) in the family Combretaceae is a well-known medicinal tree whose bark is extensively used in Ayurvedic medicine, particularly as a cardiac tonic. Demand for Arjuna bark, both in India and abroad, has been growing rapidly for over a decade. Litsea glutinosa (“Maida”) in the family Lauraceae is a medium size tree. Its bark is used to treat joint pain, fracture, sprain, arthritis, back pain, and indigestion. Presently the bark of Arjuna and Maida is being extracted through unscientific and destructive harvesting practices. This is the first study on development of sustainable harvesting practices of Arjuna and Maida bark. The stages of bark recovery varied from tree to tree. Age of tree, harvesting method, and season of harvest influenced bark regeneration. This study recommends that for sustainable harvest, mature bark from only one fourth to one third of the total girth of the tree should be stripped by removing only outer and middle bark, leaving the inner bark for regeneration. However, strip harvesting was found to be the best method in younger trees having a girth at breast height (GBH) of less than 60 cm. Sustainable bark harvesting can be done after every 2 yr for Arjuna and 1 yr for Maida by removing opposite quarters of trunk bark.

The effect of harvesting approaches on fruit yield, embelin concentration and regrowth dynamics of the forest shrub, Embelia tsjeriam-cottam, in central India

Embelia tsjeriam-cottam Roem & Schult A. DC. (Myrsinaceae), popularly known as Vaividang, is a vulnerable forest species because of the high demand of fruits for medicinal purposes. It is in great demand in ayurveda and the pharmaceutical industry (>100 t/yr), which has imposed tremendous pressure on some natural populations. The fruits contain embelin (a benzoquinone derivative), which has wide clinical applications. Considering the importance, growing use and decreasing populations in some areas of its natural habitat, a study on development of sustainable harvesting practices of E. tsjeriam-cottam fruits was conducted in Chhattisgarh, in central India. Experiments were laid out in Dhamtari, Marvahi and Bilaspur forest divisions of the state covering both protected and open forests in a randomized design with three replications. At each site, quadrats of 40 × 20 m were laid out to study the effect of two fruit harvesting methods and four harvesting intensities on fruit yield, and regeneration of the species. Fruits were analyzed for their embelin content by HPLC method. This study is the first to experimentally assess the consequences of harvesting of E. tsjeriam-cottam fruits from India. It was found that up to 70% fruits could be hand plucked at the right time of maturity (December) to obtain quality produce without impacting the current population size. Since every year is not a good fruiting year, it is difficult to develop universal harvest regime for sustainable management of E. tsjeriam-cottam. The embelin content increased as fruits ripened, ranging from 1.01% to 5.63%. The adoption of sustainable harvesting practices will be helpful in sustainable management of E. tsjeriam-cottam and also provide income and livelihood opportunities to rural people on a sustainable basis.

Consulting Forestry / Certification and Ecosystem Services

Abstract 45The industrialization of the United States throughout the 19th century resulted in the exploitation of millions of acres of timberland across the country. Logging during that era was described by critics as “cut out and get out” because the land was usually abandoned after the merchantable timber was exhausted. Concern about future timber supplies and the effect of logging on watersheds spurred the development of professional forestry after the Civil War. The first forestry leaders, including Bernhard Fernow and Gifford Pinchot, encouraged private non-industrial forest owners to sustainably manage their woodlands and specifically warned against destructive logging practices—including “cutting the best and leaving the rest”—aka high-grading. During the 1920s and 30s both the Forest Service and SAF spurred initiatives to encourage sustainable timber harvesting practices on private forestland. Although great progress has been made in forest management, logging on most private non-industrial forest land in the east has not changed significantly since the 19th century. Landowners usually sell timber without using the services of a forester, allowing the buyer to selectively cut the most valuable trees in the woodlot. Although this can reduce future value by 70-90%, it remains common practice because both the landowner and the timber buyer maximize short term income. The timber value and productivity of millions of acres of woodland throughout the United States have been significantly degraded as a result. This paper will trace the history of high-grading as described by forestry leaders from the 19th century through the 21st and will show that much work remains unfinished.

Current perspectives on the economic botany of the genus Aloe L. (Xanthorrhoeaceae)

Aloe L. (Xanthorrhoeaceae) is a genus of over 500 species found on the African continent, Arabian Peninsula, Madagascar and eastern Indian Ocean Islands. It is valued by people at many economic scales but verifiable data, with which to quantify the role of Aloe in local livelihoods and commercial trade, are scarce. For a speciose genus of appreciable ethnological value, few taxa have been known in formal and international trade. Leaf mesophyll and exudate from certain Aloe species support sizeable commercial industries that differ markedly in geographical focus, supply chain and taxa used. Leaf mesophyll is primarily sourced from plantations of the well-known A. vera in Mexico, the United States and parts of South America, and is generally used in products made in the same region. By contrast, leaf exudate is principally wild-harvested from A. ferox in South Africa and A. secundiflora in Kenya for export to Europe and Asia. To a much lesser extent, Aloe spp. are used commercially in foods and to produce honey. It is unclear to what degree Aloe spp. are traded as medicinal plants for traditional use throughout their range. Their popularity in horticulture as decorative and/or collectable ornamentals sustains a considerable international trade. Besides habitat loss, wild populations of many species of Aloe are threatened by exploitation for the succulent plant trade and a few species by over-utilisation for natural products, making rare, endemic and utility taxa an obvious priority for conservation. With the exception of Aloe vera, all species of Aloe are protected by the Convention on International Trade in Endangered Species (CITES). There is, nevertheless, considerable potential for commercially-valuable species of Aloe to be employed for rural development and poverty alleviation. The success of the expanded Aloe-based industries will depend on sustainable harvesting and other practices compliant with the Convention on Biological Diversity.

OOS 38: Ecological Dimensions of Biofuel Production

OOS 38: Ecological Dimensions of Biofuel Production

A global meta‐analysis of soil exchangeable cations, pH, carbon, and nitrogen with afforestation

Afforestation, the conversion of non-forested lands to forest plantations, can sequester atmospheric carbon dioxide, but the rapid growth and harvesting of biomass may deplete nutrients and degrade soils if managed improperly. The goal of this study is to evaluate how afforestation affects mineral soil quality, including pH, sodium, exchangeable cations, organic carbon, and nitrogen, and to examine the magnitude of these changes regionally where afforestation rates are high. We also examine potential mechanisms to reduce the impacts of afforestation on soils and to maintain long-term productivity. Across diverse plantation types (153 sites) to a depth of 30 cm of mineral soil, we observed significant decreases in nutrient cations (Ca, K, Mg), increases in sodium (Na), or both with afforestation. Across the data set, afforestation reduced soil concentrations of the macronutrient Ca by 29% on average (P < 0.05). Afforestation by Pinus alone decreased soil K by 23% (P < 0.05). Overall, plantations of all genera also led to a mean 71% increase of soil Na (P < 0.05). Mean pH decreased 0.3 units (P < 0.05) with afforestation. Afforestation caused a 6.7% and 15% (P < 0.05) decrease in soil C and N content respectively, though the effect was driven principally by Pinus plantations (15% and 20% decrease, P < 0.05). Carbon to nitrogen ratios in soils under plantations were 5.7-11.6% higher (P < 0.05). In several regions with high rates of afforestation, cumulative losses of N, Ca, and Mg are likely in the range of tens of millions of metric tons. The decreases indicate that trees take up considerable amounts of nutrients from soils; harvesting this biomass repeatedly could impair long-term soil fertility and productivity in some locations. Based on this study and a review of other literature, we suggest that proper site preparation and sustainable harvest practices, such as avoiding the removal or burning of harvest residue, could minimize the impact of afforestation on soils. These sustainable practices would in turn slow soil compaction, erosion, and organic matter loss, maintaining soil fertility to the greatest extent possible.

Growth history and crown vine coverage are principal factors influencing growth and mortality rates of big‐leaf mahogany Swietenia macrophylla in Brazil

Summary 1. Current efforts to model population dynamics of high‐value tropical timber species largely assume that individual growth history is unimportant to population dynamics, yet growth autocorrelation is known to adversely affect model predictions. In this study, we analyse a decade of annual census data from a natural population of big‐leaf mahogany Swietenia macrophylla King to quantify the strength and duration of growth autocorrelation, and experimentally investigate the role of crown vine coverage, a major predictor of performance. 2. The sample population consisted of 358 trees &gt;10 cm diameter. The relative contributions of predictor variables including diameter, crown vine coverage and growth history to models of growth and mortality were evaluated using Akaike’s Information Criterion. Autocorrelation among trees was incorporated into growth models using generalized least squares. We experimentally removed vines from heavy‐laden trees to test the strength and persistence of their impact on stem diameter growth. 3. Previous growth explained the highest amount of variation in annual diameter growth; the best‐fitting model of autocorrelation was an AR(7) autoregressive model, indicating that autocorrelation persisted throughout the study period. Other factors explaining variation in growth were, in decreasing order of importance: year of measurement, crown vine coverage, diameter, crown illumination and fruit production. The best logistic regression model for mortality retained diameter growth plus crown vine coverage as predictors of risk. 4. The vine release experiment strongly supported these results. Released trees grew faster than control trees but required ≥5 years to approach growth rates of trees with minimal vine coverage. Trees with heavy vine coverage also experienced higher mortality rates. 5. Synthesis and applications. These results indicate that growth autocorrelation is strong, persistent, and an important predictor of future performance; demographic models for tree growth and yield projections can be improved by accounting for growth history. Our results also indicate that targeted silvicultural practices such as vine cutting can increase long‐term growth and timber yield. These findings further current understanding of tropical tree growth and survival, and offer improved management tools for sustainable harvest practices for mahogany and similar species.

The Importance of Taboos and Social Norms to Conservation in Madagascar

Informal institutions governing the use of wild species are present in many societies. A system of prohibitions known as fady is central to Malagasy culture. We examined whether fady that relate to the use of natural resources in the eastern rainforests of Madagascar play an important conservation role. Prohibitions ranged from strict taboos in which a species or area was forbidden by the ancestors to social norms that concerned acceptable behavior when harvesting wild species. Strict taboos offered real protection to threatened species, such as the lemur Propithecus edwardsi and the carnivore Cryptoprocta ferox. Taboos also reduced pressure on some economically important endemic species by preventing their sale or limiting the harvest season. Despite their value for conservation, the taboos did not appear to originate from attempts to sustainably manage resources. Nevertheless, social norms, in which the sanction was social disapproval rather than supernatural retribution, encouraged sustainable harvesting practices for tenrecs (Tenrec ecudatus) and pandans (Pandanus spp.). Unfortunately, the social norms concerning methods of harvesting pandans appeared to be breaking down in villages surrounding Ranomafana National Park, and we suggest that the imposition of external conservation rules is weakening traditional management. Informal institutions are important to conservation because they suggest ways of improving cultural understanding and conservation communication. Food taboos influence societal preferences, which affect the wider demand for a species. Most important, where capacity to enforce external conservation rules is limited, informal institutions may provide the only effective regulations. Informal institutions should receive greater attention from conservation biologists so that local people's conservation roles can be acknowledged fairly and so that potential synergies with conservation objectives can be realized.

An estimation of willingness to pay for asparagus (Asparagus racemosus Willd.) collectors in Makawanpur District, Nepal

The collection and sale of asparagus (&lt;I&gt;Asparagus racemosus&lt;/I&gt; Willd.) is a major source of income for Praja and Tamang castes around the Royal Chitwan National Park (RCNP) in Nepal. However, the forests where asparagus is harvested are becoming depleted threatening the livelihood of collectors. To address this issue, at sustainable harvesting practices, the research reported here applied the contingent valuation method (bidding game) and estimated the average willingness to pay (WTP) of collectors to two asparagus collection scenarios. In the first scenario, if forests under the Department of Forests jurisdiction were managed for sustainable harvesting at 1995 rates, the average WTP of collectors was 4.4 NR/kg. In the second scenario, if the forest in the RCNP is managed in such a way that both the current harvesting rate of asparagus is sustained and they are legally allowed to collect asparagus at the present rate, the average WTP of collectors was 8.35 NR/kg. Consequently, there is a good chance of earning revenue for the government and sustaining the livelihood of asparagus dependents by the sustainable management of the Department’s and the National Park’s forests and giving legal permissions to collect asparagus from the National Park, which would have happened anyway but with financial and legal risks to collectors.

BRIDGING THE GAP: PHYTOTRADE AFRICA'S EXPERIENCE OF THE CERTIFICATION OF NATURAL PRODUCTS

ABSTRACT In the competitive natural products market, product certification is an important mechanism for retailers to differentiate their products. Consumers in this market now seek independent assurances relating to the quality, environmental sustainability and Fair Trade standards of the products they buy. Small-scale producers of non-timber forest products (NTFPs) that feed into this market have found themselves drawn centre stage into often complex, shifting and expensive certification scenarios that, also, may be serving as a barrier to trade. However, certification can increase benefit-flows to small-scale producers and incentives for producers to invest in more sustainable harvesting practices. If the gap between the industry's certification expectations and the small-scale producers' certification capacity is wide, there is a likelihood that small-scale producers will be excluded. This paper presents a case study of the experiences of PhytoTrade Africa, a southern Africa-based natural product Trade Association that has attempted to bridge this gap, overcoming barriers to trade in practical ways to allow entry for small-scale NTFP producers into the global natural products market.

Quantifying and comparing the value of non-timber forest products in the Amazon

The use of sustainable harvest practices in the tropics is often proposed as a way to maintain the environment and address the poverty issues that dominate many tropical regions of the world. In theory, the adoption of these methods can provide win–win solutions to tropical deforestation because they address the environmental consequences of deforestation while increasing the welfare of forest inhabitants. However, there is little reliable data that can be used to test this hypothesis since many of the goods produced in sustainable systems do not have well-defined markets and are most often consumed at home. This paper examines the benefits of collecting and harvesting non-timber forest products in the tropics through various methods using household panel data collected in 1996 and 2000 in the Ouro Preto do Oeste region of Rondônia, Brazil. We estimate the use-value of land under forest, agriculture, and pasture and complement these estimations with census data and regression analysis. Our estimations reveal that households utilizing sustainable practices in the forms of agroforestry and the collection of non-timber forest products have significantly higher levels of diversification. We conclude that directing policy towards “win–win” strategies may not be desirable for reducing both poverty and deforestation in this region since we find no clear evidence that these can successfully be addressed simultaneously. Sustainable development policy should focus on increasing the value of the forest, or reducing the opportunity cost of leaving standing forest on the household lot, if sustainable production strategies are to be more attractive to households in the future.

IMPACT OF CULTIVATION AND COLLECTION ON THE CONSERVATION OF MEDICINAL PLANTS: GLOBAL TRENDS AND ISSUES

IMPACT OF CULTIVATION AND COLLECTION ON THE CONSERVATION OF MEDICINAL PLANTS: GLOBAL TRENDS AND ISSUES

New Tools for Marine Conservation: the Leasing and Ownership of Submerged Lands

Abstract: It has been assumed that strategies for estuarine and marine conservation must be substantially different than those for terrestrial conservation because the seas are all publicly owned. This is an unfortunate misconception. We explored the leasing and ownership of submerged lands as tools for marine conservation and provide examples of the implementation of these tools from The Nature Conservancy's work in Texas, Washington, and New York (U.S.A.). We found that the leasing and ownership of submerged lands are viable new tools for marine conservation. There is a significant amount of submerged land available for lease and ownership in the United States and other countries that includes a diverse array of ecosystems (e.g., kelp forests, marshes, seagrass meadows, oyster reefs, tidal flats, clam beds, scallop beds, sponge, and coral reefs). From our review of policy and experience in practice, we have identified some key benefits and considerations for the use of these tools. Conservation benefits for the leasing and ownership of submerged lands include opportunities to restore ecologically and economically important species, protect diversity in sanctuaries, draw on substantial terrestrial experience in leasing and ownership, buy land cheaply, develop ecologically sustainable harvest practices, partner with fishers and local communities to improve water quality, create control areas for research, and partake in local management forums as a direct stakeholder. Bivalve shellfish are particularly amenable to conservation with these tools because existing policy is well established for leasing and ownership rights to sessile animals that exist on the sea floor. Conservation buyers need to consider that community sentiment does not always favor private rights to submerged lands, conservation interest in submerged lands could affect prices, association with incompatible aquaculture practices will be detrimental, enforcement of restrictions can be difficult, and there may be concerns about setting the precedent of paying for conservation of submerged lands. Policy makers should be encouraged to include more opportunities for conservation and not just exploitation of natural resources on submerged land leases.

Encouraging the application of sustainable timber harvesting practices: A review of policy tool use and effectiveness in the eastern United States

States use a variety of approaches to encourage landowners and loggers to apply ecologically-sustainable timber harvesting practices, the latter generically referred to as timber harvesting guidelines. A survey of 37 state forestry agency administrators in the eastern U.S. (defined as a contiguous region with the northwest and southwest borders being North Dakota and Texas, respectively) was conducted in 2000 to assess the extent and nature of state guideline programs and the various methods by which states encourage their use. The study found states in the eastern U.S. use a variety of policy tools to promote guideline use, with certain policy tools more common for certain target audiences (e.g., loggers) as well as the types of resources (e.g., wildlife habitat) addressed by the guidelines. Eighty-three percent of the programs directed at encouraging forest landowners in the eastern U.S. to use the timber harvesting practices identified in their state guidebooks are technical assistance, educational, or cost-share programs. Technical assistance and education programs are the most common policy tools used to assist loggers in applying sustainable harvesting practices. Technical assistance and cost-share programs consistently rank among the most effective policy tools for encouraging loggers and landowners to apply the guidelines. Comparing the level of program investment to perceived benefits, assistance programs and education programs rank most efficient landowner programs, whereas premium prices for products and preferential access to contracts are the two most efficient programs directed at loggers. The paper concludes with an assessment of emerging trends and additional information needs associated with encouraging the application of sustainable timber harvesting practices.

Policy tools to encourage the application of sustainable timber harvesting practices in the United States and Canada

States and provinces of the United States and Canada have defined practices to mitigate the negative externalities often associated with timber harvesting activities. This paper describes the various methods states and provinces employ to encourage the application of sustainable timber harvesting practices. Information on specific policy tools used to encourage guideline application was obtained through a written questionnaire to state and provincial forestry agency directors. All but one of the 51 responding states and provinces have some form of formally-defined timber harvesting practices. Practices that address riparian zone management, water quality, or wetlands protection are the most common—all but one responding state and province addresses one of more of these areas. Sixty-one percent of the states and provinces implement their practices through predominantly voluntary means whereas the remaining 39% are applied within a regulatory framework. Of the policy tools examined, technical assistance, educational, and cost-share programs account for 88% of all state and provincial programs directed at encouraging forest landowners to use the practices suggested in their guidebooks. Technical assistance and education programs are the most common policy tools used to assist loggers and foresters in applying sustainable harvesting practices. Technical assistance and cost-share programs consistently rank among the most effective policy tools for encouraging loggers, landowners, and foresters to apply the sustainable timber harvesting practices. Comparing levels of program investment to perceived benefits, assistance programs and education programs rank most efficient for landowners and foresters, respectively. Premium prices for products and preferential access to contracts are the two most efficient programs directed at loggers, yet their existence is modest within states and provinces. The paper concludes with an assessment of emerging trends and additional information needs associated with encouraging the application of sustainable timber harvesting practices.

Harvesting and conservation: are both possible for the palm, Iriartea deltoidea?

We consider the mechanism of certification to encourage sustainable harvesting and best management practices of Iriartea deltoidea Ruı́z and Pavón, in the context of current land use and agricultural management in Amazonian Ecuador. Interviews and observations with harvesters, storeowners, and furniture-makers provided information about current and potential markets for goods made from the palm. To understand the demographic variables that are critical for population stability, data from five plots in each of three different forest types (mature, secondary, and dissected) were collected. Matrix models were used to develop harvesting simulations through which biological constraints on sustainable harvesting were explored. These simulations suggest that sparing individuals 5–15 m tall when pastures are cleared and adding this palm to current agroforestry polycultures can improve the likelihood of sustainable harvesting for this species. Results showed that harvesting Iriartea could fit within current land use. Some forest colonists clear pastures to graze cattle, while others devote land to agriculture, including polycultures of annuals and perennials. In either case, palms can be left standing when forests are cleared. Swidden agriculture (slash and burn or slash and mulch) depends on a fallow period during which secondary forest may begin to regenerate. These secondary forests are ideal locations for extraction of forest products that fit within the cycle of fallow regeneration in areas near human settlements. Sparing Iriartea individuals 5–15 m tall could benefit agriculture, encourage the sustainability of future harvests, and help ensure the future of this palm as a part of the Amazonian landscape. Interviews with staff of governmental and non-governmental conservation organizations investigated the policy context for certification as a mechanism for conservation. Establishing guidelines for harvesting requires input from all stakeholders in the decision, not simply an ecological analysis. Such guidelines for certifying good management practices, if they are developed, should include provisions for monitoring unanticipated consequences of harvesting or changes in future environmental conditions. Transportation issues and stem drying processes need to be addressed if efforts to expand markets are to succeed. More generally, guidelines for management of forest resources can be improved by combining ecological and social research perspectives; the potential for carrying out such guidelines can be improved by incorporating the knowledge of local forest dwellers and NGOs.

Sustainable utilization of woodrose-producing mistletoes (Loranthaceae) in South Africa

Pedistylis galpinii and Erianthemum dregei produce woodrose outgrowths at attachment points with host trees. In some rural areas of southern Africa, woodroses are sold as curios. The socio-economics related to woodrose harvesters were investigated via interview schedules and field survey. Harvesting is not detrimental to hosts as only branches infected with mistletoes are cut. Over half the harvesters interviewed reported harvesting both live and dead mistletoes while 20% used only dead ones. The density of dead mistletoes could satisfy present demand. Such sustainable harvesting practices (only using dead woodroses) allow for woodrose harvesting according to calculated quotas. The median gross income per month generated from woodroses was estimated to be between US $38 and 90. Eleven percent of harvesters relied on woodroses as their only source of income. Marketing was relatively haphazard, involving informal selling at roadsides and unscheduled visits to retailers. The market for woodroses can be expanded and the potential exists to increase supply considerably on a sustainable basis.

Spatial distribution, fruit production and seed removal of a rare, dioecious canopy tree species (Aglaia aff. flavida Merr. et Perr.) in Papua New Guinea

ABSTRACTAll mature individuals of Aglaia aff. flavida (Meliaceae) were mapped in a 260 ha study area at the Crater Mountain Biological Research Station in Papua New Guinea. Sixty-four reproductively mature trees were found in an aggregated distribution with a mean inter-tree distance of 88.9 m. The sample consisted of 35 female and 29 male trees with a mean shortest distance between sexes of 232 m. Seed production and seed removal of 22 female trees was monitored throughout the 1992 fruiting season. Female trees with in 200 m of male trees generally produced large seeds crops (&gt; 100 seeds) whereas trees farther than 200 m from the nearest male had small seed crops (&lt; 100 seeds) regardless of female size (DBH). Most seeds (63.2%, n = 3312) produced in a sub-sample of 22 trees came from the five most fecund trees, which also produced 74.1% of the seeds that were removed by vertebrate dispersers. Where a minority of a population of rare tropical trees produce the majority of progeny, sustainable harvest practices would be most effective where highly fecund individuals are identified and conserved.