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1.
Peter Donaghy Steven Bray Rebecca Gowen John Rolfe Michael Stephens Madonna Hoffmann Anne Stunzer 《Small-Scale Forestry》2010,9(4):463-484
Although agriculture generates 16% of Australia’s greenhouse gas emissions, it also has the potential to sequester large quantities
of emissions through land use management options such as agroforestry. Whilst there is an extensive amount of agroforestry
literature, little has been written on the economic consequences of adopting silvopastoral systems in northern Australia.
This paper reports the financial viability of adopting complementary agroforestry systems in the low rainfall region of northern
Australia. The analysis incorporates the dynamic tradeoffs between tree and pasture growth, likely forest product yields,
carbon sequestration and livestock methane emissions in a bioeconomic model. The results suggest there are financial benefits
for landholders who integrate complementary agroforestry activities into existing grazing operations at even modest carbon
prices. 相似文献
2.
Mariana Vallejo Alejandro Casas José Blancas Ana I. Moreno-Calles Leonor Solís Selene Rangel-Landa Patricia Dávila Oswaldo Téllez 《Agroforestry Systems》2014,88(1):125-140
In this study we analysed: (1) the biodiversity conservation capacity of Agroforestry Systems (AFS) in temperate highlands of the Tehuacán–Cuicatlán Valley, Central Mexico, (2) human cultural motives and actions for conserving such diversity and (3) problems endangering that capacity. We evaluated the richness and diversity of perennial plant species maintained in AFS through vegetation sampling of 14 agricultural plots and compared their composition with that of natural forests (14 plots of 500 m2 each). We examined the situations among communities of Náhuatl, Ixcatec and Cuicatec people, documenting through interviews the management practices of plant species and the whole system, reasons why people maintain vegetation cover within AFS, and factors influencing changes in decisions favouring agriculture intensification. In the AFS studied we recorded a total of 79 species of trees and shrubs, 86 % of them being native species and representing 43 % of all species of trees and shrubs recorded in the sampling of the natural forests the AFS derive from. People leave standing on average a total of 40 individual trees and shrubs per agricultural plot. Reasons for leave plant species standing were more frequently associated with their use as fruit trees, firewood, shade, beauty, respect to nature and other environmental benefits. Water availability for irrigation, land tenure, and dependence on agriculture and forest for peasant's subsistence were main decision factors influencing AFS variation in their composition. AFS in temperate zones are important reservoirs of biodiversity and biocultural heritage and should be keystones for conservation policies in the Tehuacán–Cuicatlán Valley. 相似文献
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In July 1992 the Rondônia Agroforestry Pilot Project (RAPP) was launched in two agricultural municipalities (Nova União and Alto Paraiso) in the western Brazilian Amazon State of Rondônia. The purpose of the RAPP was to assess the conditions under which colonist farmers in the western Amazon would integrate agroforestry plantings into their small-scale farming systems and to assess the performance of those plantings over time. An experimental group consisting of 50 small-scale farmers was selected to participate. Plots were designed to accommodate between 3 and 25 different species, each producing one or more commodities with local market potential (hardwood, fruits, nuts, latexes, oils). Farmers planted seedlings typically on a 1-ha plot, located and designed by each farmer with the advice of a professional Brazilian extensionist. During the first phase of the project (1992–1998), the growth performance of the seedlings and changes in household characteristics were monitored on an annual basis. By 2002, 32 (64.0%) of the original 50 agroforest plots were found in place. This paper updates the research findings based on a 2002 follow-up visit to these 32 farms. In addition to growth performance, the authors’ found that 17.95% of the farms in the neighboring control group had planted trees and other agroforest crops between 1992 and 2002, compared to only 5.38% of farms outside the project area, suggesting spontaneous diffusion. The authors also found a potentially synergistic relationship between agroforestry and secondary forest regeneration with the use of satellite image analysis. The experience of the RAPP indicates that colonist farmers in Amazonia can be successful managers of agroforest plots with minimal external inputs over the long-term (10 years). 相似文献
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Small-scale Forestry - Despite claims that plantations both enhance and undermine the quality, valuation and protection of natural forests, plantation forestry continues to expand worldwide. In... 相似文献
6.
Cheikh Mbow Michel M. Verstraete Bienvenu Sambou Amadou Tahirou Diaw Henry Neufeldt 《Journal of Forest Research》2014,19(3):340-347
This paper presents new allometric models for woody savanna of the dry Sudanian zone of the southern part of Senegal and contributes to the needs for accurate and precise carbon estimates through improved statistical models and methods. The results are based on statistical relationships between the total dry biomass and either tree diameter at breast height (DBH) or tree height for a set of 101 individuals of different sizes from 13 dominant species in 6 protected forests. The statistical regression (cubic order 3) generated for DBH (5–41.5 cm) and tree height (2.5–15.6 m) showed significant R 2 of 0.934 and 0.813, respectively. Using the same database, species-based models for the most represented genera (Acacia sp., Combretum sp. and Terminalia sp.) show more precision than the generic model. The model residual standard error and relative errors showed a good fit between observed and predicted data. Species-based models showed smaller errors compare to generic models outputs. 相似文献
7.
The influence of farmers’ mental models on the success of an agroforestry extension program on Leyte Island in the Philippines
was investigated. Knowledge of farmers’ mental models and hence the likely acceptance of technology was used to inform the
design of a hypothetically expanded program. To gain an insight into the reasons behind differing acceptance of extension
assistance, data were collected and analysed from formal interviews, translated conversations and visual observations. The
data provided a chain of evidence and triangulation between farmers’ stated intentions and their actions. Farmers had little
prior knowledge of nursery technology and were highly receptive to extension assistance which enabled them to develop high
self-efficacy in seedling production. However, farmers’ rejection of silvicultural advice to thin and prune existing plantations
was predicated by existing attitudes to forest resource management. Farmers also expressed a strong preference for a low-cost
and low-input approach to establishing timber trees. Visual observations of farmers’ tree establishment practices indicated
the existence of gaps in their knowledge of tree growth processes. This investigation illustrates the need to elicit farmers’
mental models as a parallel enquiry to extension activities. If agroforestry extension is to be constructivist and participatory,
accommodation of farmers’ mental models and modification of program goals may be necessary. Relatively little is known about
the reasons for farmers’ acceptance or rejection of silviculture in Leyte and these results indicate that further research
into the way that farmers’ mental models filter and guide acceptance of advice may be worthwhile. 相似文献
8.
Reducing carbon emissions from deforestation and forest degradation (REDD+) has become central to efforts to mitigate climate change. Approximately 10 % of the world’s forests are managed by local and indigenous peoples. Agroforestry may provide these communities with a means to engage in carbon offsetting initiatives without forfeiting access to, or benefits from, forests. Here, we present an analysis of social and ecological data from a four-year-old, reforestation-based carbon-offset project on the collective lands of Ipetí-Emberá, Panama. Mixed-species agroforests or timber-only plots were established by a subset of community members under voluntary carbon-offset agreements with a private client. We (1) describe how plot carbon accumulation trajectories were related to species composition; (2) determine if established agroforests are likely to meet carbon sequestration targets by the end of the 25-year project period; (3) describe the motivations and experiences of participants who chose to establish agroforests; and (4) compare socio-economics of participants versus non-participants. Our study provides data on early mortality, tree growth and the carbon sequestration capacity of 29 species that are commonly used by small farming households in Latin America and elsewhere. The study highlights strategies for reducing risks associated with agroforestry as a carbon sequestration strategy in the context of carbon offset projects, such as the replanting of dead trees and the establishment of a carbon buffer. We also provide evidence to counter claims that offset projects could amplify inequality in rural communities as participants to agroforestry, when compared to non-participants, were not remarkable in terms of their assets or wealth. Overall, this case study provides an encouraging example of how agroforestry may help forest communities engage with REDD+ in a way that benefits both their livelihoods and the global climate change agenda. 相似文献
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A. Moreno-Calles A. Casas J. Blancas I. Torres O. Masera J. Caballero L. Garcia-Barrios E. Pérez-Negrón S. Rangel-Landa 《Agroforestry Systems》2010,80(3):315-331
The role of agroforestry systems in biodiversity conservation was investigated in the semiarid Tehuacán Valley, Central México.
Richness and diversity of native plant species were compared between agroforestry systems (6 sampling sites) and the following
forests (6 sampling sites) dominated by columnar cacti: (i) “chichipera” dominated by Polaskia chichipe; (ii) “jiotillal” dominated by Escontria chiotilla; and (iii) “garambullal” dominated by Myrtillocactus schenckii. Our information on genetic variation of dominant arboreal species in the study sites was reviewed and included in the analysis.
Factors influencing household’s decisions to maintain vegetation cover were compiled through a survey and interviews and analyzed.
All the samples of the agroforestry systems studied maintained on average nearly 59% plant species and 94% genetic variation
of dominant cacti occurring in the forests, although their ability to preserve endemic rare species is limited. Social factors
favoring maintenance of perennial species in agricultural plots include collective rules, households traditions, use of the
plants maintained in the systems, and the environmental information gathered from NGOs, the local Biosphere Reserve, and researchers.
However, agroforestry systems are losing their capability to maintain vegetation cover, mainly because of (i) decreasing amount
of land managed by households, determined by a progressive fragmentation of the land area given to new families, (ii) adoption
of technologies to intensify agriculture, and (iii) governmental programs penalizing the presence of vegetation patches within
agricultural lands since they are considered “useless” areas. Necessary policies to stop degradation of the agroforestry systems
and to improve their conservation capacity are discussed. 相似文献
10.
The effect of the crosser’s position used for piled lumber on longitudinal vibration was investigated. As a model case, specimens with and without a concentrated mass were compressed in their thickness direction at nodal and antinodal positions of longitudinal vibration, following which, longitudinal vibration tests were conducted. Density and Young’s modulus were unaffected by compression of the specimen at the nodal position but was affected by compression at the antinodal position. By placing crossers at the nodal positions, accurate density and Young’s modulus values can be determined using the vibration method with additional mass without the influence of weight of the upper lumber. 相似文献
11.
W. Keith Moser Earl C. Leatherberry Mark H. Hansen Brett J. Butler 《Agroforestry Systems》2009,75(1):49-60
This paper reports the results of a study that explores the relationship between farm woodland owners’ stated intentions for
owning woodland, and the structure and composition of these woodlands in the states of Illinois, Indiana and Iowa in the upper
Midwest of the United States. Data from two sample-based inventories conducted by the USDA Forest Service, Forest Inventory
and Analysis (FIA) program were combined for this analysis—the FIA forest resources inventory and the National Woodland Owner
Survey (NWOS). We looked for relationships between product value and investment in woodlands, as reflected in volumes and
tree quality. We also examined whether measures of diversity reflected specific management focus. Our results partially supported
our hypotheses. Woodland-focused ownership reasons were found to have larger volumes and individual tree sizes. We found that
a passive woodland ownership reason—that woods were “part of the farm”—generally had lower volumes per hectare. Although we
were not able to differentiate between different forest product classes and measures of volume, we did find that those landowners
who harvested veneer had more volume than those who harvested for firewood. Woodland owners who salvage-harvested their woodlands—a
harvesting reason that is more reactive than proactive—exhibited lower volumes per hectare than those who harvested for more
proactive, product-focused reasons. Biodiversity was also found to be related to the ownership focus and harvest intent. Generally,
there was lower diversity in overstory species when the woodland was viewed merely as “part of the farm,” when the product
harvested was fence posts and when timber was harvested for salvage or land clearing. The small sample size limits our analysis,
but we can conclude that focusing the woodland owners on management of their woodlands—regardless of what the specific management
goals might be—should increase productivity and biodiversity of those woodlands.
相似文献
W. Keith MoserEmail: |
12.
African Americans have historically struggled to retain land that has been held in their families for generations as heirs’ property, or land held collectively by heirs of the original owners without clear title. Ethnographic interviews with sixty landholding African American families in North Carolina, South Carolina, and Alabama reveal the cultural meanings associated with family land, forestland in particular, and the role of heirs’ property in inhibiting forest management, including the threat of land loss, intra-family conflict, and legal limitations on forestry activities. The majority of interviewees have a strong desire to pass family land on to their heirs, but they also need the land to be economically productive. Sustainable forest management offers both an incentive to obtain clear title to heirs’ property land and a means of paying property taxes and generating intergenerational wealth within families. The U.S. Endowment for Forestry and Communities is currently collaborating with local institutions in several states in an innovative program designed to help African American landowners navigate the legal system in order to obtain clear title and provide educational workshops about the financial and ecological benefits of sustainable forestry as well as site visits by consulting foresters. Analysis of the situations faced by African Americans with heirs’ property adds to the diversity of our understandings of the complex relationships between land tenure and forestry, with potential application for other minority communities in the U.S. and elsewhere. 相似文献
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《中国林学(英文版)》2004,6(4):7-7
During a period of almost fifteen years, Danish development cooperation has been involved in the fuelwood supply sector in Niger, first through the World Bank (Project Energie II, 1989-1998), and subsequently bilaterally,through the Household Energy Project (Project Energie Domestique, 2000-2003). Taken together, these initiativeshave contributed to the development of an approach known, in Niger, 相似文献
16.
Selecting the optimum location with attention to conditions and restrictions is one of the most importantfactors in establishing a manufacturing plant. Identification of effective criteria is an important stage in the selection for the location of industrial units. In this study, an analytic hierarchy process (AHP) was applied to select the most effective criteria for the location of MDF (medium density fiberboard) industry in Mazandaran Province, Iran. A consideration in ttaining this goal is that Mazandaran is favored over other provinces because of its resources of raw lignocellulosic ma- erial required for wood and paper industries. The results indicate that the criterion of "materials and products" and the ub-criterion of "reliability of supply of raw material" are the most important factors. 相似文献
17.
To understand the viscoelasticity of wood three dimensionally, a longitudinal tensile creep test for 12 species was conducted
to examine the changes with time in the lateral strain and the viscoelastic, i.e., apparent Poisson’s ratio. The changes in
the lateral strain (ɛ
T and ɛ
R) were similar to those in the longitudinal strain (ɛ
L). That is, during creep, the absolute value of lateral strain continued to increase with the gradual reduction in the increase
rate; immediately after the removal of the load, it recovered abruptly; then, it recovered slowly and finally reached a certain
value. The rate of increase in the longitudinal strain during creep was smaller than that in the absolute value of lateral
strains. The apparent Poisson’s ratio became large during creep because the lateral strain increased more than the longitudinal
strain. The analysis of lateral strain by decomposition into three components, that is, instantaneous strain, delayed elastic
strain, and permanent strain, has revealed that the lateral permanent strain in the transverse direction contributes most
to the increase in the apparent Poisson’s ratio during creep. 相似文献
18.
Rowan Reid 《Agroforestry Systems》2017,91(5):847-865
The Australian Master TreeGrower (MTG) program was launched in 1996 as an agroforestry extension initiative of The University of Melbourne. The program included a short course for landholders that provided knowledge and practical skills but also had a strong focus on developing the information and peer networks that would provide them, and their community, with on-going support as they implement their agroforestry activities. Since 2010 the MTG has been delivered by The Australian Agroforestry Foundation, a not-for-profit organisation, and integrated with the Peer Group Mentoring (PGM) concept developed by a regional farmer group in Australia. The PGM trains, then pays, past Master TreeGrowers to support other landholders as they design and develop their own agroforestry projects. More than 100 MTG courses have been run across Australia involving over 2000 landholders and more than fifty partner organisations. Independent evaluation shows that participants enthusiastically support the program, increase the area of tree cover on their land, adopt more intensive or purposeful management practices, are more inclined to want to grow trees for a mix of both public and private good outcomes, and, actively encourage others in their community to do the same. This paper reviews the development and delivery of the MTG and PGM in Australia and explores whether the models are transferable to developing countries. To date four MTG courses have been conducted in Africa (Uganda (2) and Niger (2)), seven in Indonesia and one in Timor-Leste. Whilst the structure of the international MTG courses was different to that commonly adopted in Australia the content was similar in that they included: information to support the development and implementation of agroforestry designs that reflect their particular interests and aspirations; a review of market opportunities for agroforestry products and services, training in tree and forest measurement, education in tree growth and silviculture; and, encouragement, guidance and support to encourage landholders to share their experience with others in their community. The response suggests that the MTG, originally developed for Australian farmers, may represent a very different model of agroforestry extension to what is commonly offered to farmers in developing countries, and that it may be worth developing in regions where farmers believe they have relatively secure land tenure and are able to make long-term land management decisions regarding tree establishment and management. 相似文献
19.
Teak(Tectona grandis L.f.) is a popular hardwood species native to South and South-East Asia. The possible association of amplified fragment length polymorphism(AFLP) marker with morphological variables of eleven important characters viz. girth at breast height(GBH), height of tree, bole height, branch knots, presence of fluting, spiral stem, leaf hair, leaf length/breadth ratio, branching pattern, bark colour and petiole shape for nine natural populations comprising 180 genotypes of teak(9 populations × 20 trees). The phenogram constructed using Euclidean distances for the eleven morphological characters showed that the populations were not grouped according to their geographical origin. The Mantel's test for pairwise correlation between Euclidean distances of different morphological variables and genetic distances from AFLP data revealed that only petiole character(r =0.269; p =0.046) and height of tree(r =0.200; p =0.001) were significantly correlated with that of AFLP data matrix. The nine populations in this study covered a geographic area of about 1000 km stretch along the Western Ghat of South India. A test of correlation between genetic and geographic distance matrices revealed a significant positive correlation(r =0.475; p =0.009). The lack of perfect congruence between morphological and molecular data except for geographic distance, tree height and petiole character suggested that the morphological system might be useful for the morphotypes management but not appropriate to study the genetic structure of the teak populations. 相似文献
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Hitoshi Nakamura Shigeto Ohgake Norio Sahashi Nobuyuki Yoshikawa Takanori Kubono Tsuyoshi Takahashi 《Journal of Forest Research》1998,3(1):39-42
Seasonal variation of paulownia witches’-broom (PWB) phytoplasma within different organs (leaves, branch and trunk bark and
roots) in paulownia trees was investigated by the amplification of a PWB-specific DNA fragment by the polymerase chain reaction
(PCR). In leaf samples, PWB phytoplasma was first detected in June and the incidence gradually increased. On the other hand,
the PWB was detected at relatively low incidence in branch bark, trunk bark and roots and the incidence did not change among
seasons. A survey of PWB in 27 fields in the Tohoku district of Japan showed that malformed flower buds were observed in paulownia
trees in almost all of the fields. PWB-phytoplasma was also detected by PCR from paulownia trees in almost all of the fields
in Iwate and Fukushima Prefectures. The frequencies of trees in which phytoplasma was detected by PCR were higher than those
in which symptoms were observed. These results indicated that PCR amplification of a PWB-specific DNA fragment is an effective
tool for practical diagnose and that PWB is widely distributed in the Tohoku district of Japan. 相似文献