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1.
Since the early 1980s, Myanmar Forest Department has been recruiting shifting cultivators, establishing plantation villages
and applying the taungya method in establishing teak plantations. From the beginning, there has been an argument about whether
the program is creating ‘forest protective groups’ or ‘forest destructive groups’. A key determinant to that question from
the research viewpoint is the socio-economic situation; knowing the present situation of the plantation villagers can help
to understand their forest management practices. Interview surveys were carried out in three villages in Bago Yoma, the main
region of the special teak plantation program, to examine the current economic benefits to plantation villagers. Questions
were designed mainly to explore the incentives for people participation and the socio-economic situations of the plantation
villagers. Principal component analysis was used to group landholder types. It was found that local people are willing to
participate in the initial establishment of plantations. However, all the incentives relating to plantation projects are temporary,
with no long-term consideration for taungya farmers, which jeopardizes the plan to create forest protective groups. It is
concluded that the time has come for the Myanmar Forest Department to change its main aim of earning foreign exchange from
establishment of teak plantations through the taungya method to redressing deforestation through people participation based
on rural socio-economic development.
相似文献
Tin Min MaungEmail: |
2.
Vindhya Prasad Tewari K. M. Mariswamy A. N. Arunkumar 《Journal of Sustainable Forestry》2013,32(3):213-229
Tectona grandis (teak) is one of the most important timber species worldwide and India is one of the major teak growing countries. Though some volume equations were developed in the past in India, merchantable volume equations (any top diameter or bole length) are not available. Moreover, the models developed were neither quantitatively and qualitatively evaluated nor validated with independent data sets. Hence, the objective of this study was to develop appropriate volume equations to predict total tree volume and merchantable volume for teak in Karnataka. Linear and non-linear equations were used to model the relationship of the volume with respect to diameter at breast height (dbh) and total height. Merchantable volume equations for estimating merchantable volume to any minimum top diameter or bole length have also been constructed. The equations tested mostly fitted well to the data. Other models developed elsewhere tended to underestimate the volume, especially at dbh ≥ 23 cm. The geometric cylinder volume equation, in combination with a stem form factor of .40, is widely used for teak in Karnataka but they were found to be less precise compared to regression equations when applied to the present data set. Model validation indicated that models should be calibrated with local data for greater accuracy in the prediction. 相似文献
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4.
After years of unsustainable logging, dry deciduous dipterocarp forest (DDDF) has become poor in timber stocks and has been converted to industrial crops such as rubber. The objectives of this study were to assess teak (Tectona grandis L.f.) tree establishment under degraded DDDF conditions and to determine factors that influence the suitability of teak as a forest enrichment tree species. A set of 64 experimental plots of 4 900 m2 each was set up and observed for 4–5 years for testing enrichment planting with teak under various combinations of two groups of factors: ecological conditions and forest status. Weighted, non-linear, multivariate regression models were used to detect key factors that influenced the suitability of teak. The results showed that at the age of 4 years the average dominant tree height (defined as 20% of the tallest trees in the experimental plot) reached 11.2, 7.8, 5.3 and 3.8 m for very good, good, average and poor suitability levels, respectively. Survival rates of planted teak from average to very good suitability levels were over 90%. Six key factors that affected the suitability of teak were waterlogging during the rainy season, altitude, stand volume of the degraded DDDF, soil type, percentage of sand and concentration of P2O5 in the soil. Under the extreme ecological and environmental conditions of the DDDF, enrichment planting with teak gave promising results. 相似文献
5.
Forests in north-eastern New South Wales have often been the focus of controversy. The tension between production and preservation
continues and hampers current negotiations for a code of practice for private native forestry. The structure of many private
forests reflects past mismanagement, and silvicultural intervention would benefit both conservation and production objectives,
but such intervention is rarely financially viable. This paper sets out the economic and ecological basis for private native
forestry. Both the timber industry and nature-based tourism are major contributors to the local economy, and both rely in
part on private native forests. Draft regulations currently under negotiation do not offer incentives for improved private
forest management.
相似文献
V. Alex JayEmail: |
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7.
Guillermo Riesco Muñoz Andrés Remacha Gete Manuel Gasalla Regueiro 《Annals of Forest Science》2013,70(7):695-706
Context
The commercial feasibility of sawmilling depends on the expected volume and value of sawn planks. Models that predict the volume of sawn timber of a particular quality and produced from logs of known characteristics are therefore very useful.Aims
The objectives were to study variation in sawing yield and to obtain models that predict lumber volume and grade recovery on the basis of easy-to-measure predictor variables of saw logs.Methods
Forty-six oak trees growing in Galicia (NW Spain) were felled and cut into logs. The logs were visually graded and sawn mainly into quartersawn planks, which were dried, planed and visually graded for structural purposes.Results
The total volumetric sawing yield was 47.6 %. The sawing yield for planks of structural dimensions (cross-section, 70?×?120 or 70?×?170 mm) was 43.4 %, but decreased to 8.4 % for structural sized and quality grade beams because of wane and biotic damage in many pieces. Log grade did not significantly affect sawing yield in the sample analysed, despite the wide range of diameter over bark at the smallest end in the sampled logs (22–77 cm). The sawing pattern affected total sawing yield (F?=?4.913; p value?=?0.001) and the sawing yield for structural planks (F?=?6.142; p value?=?0.0002); radial sawing with one cut and live sawing of half logs provided the highest yields. Three models were proposed for estimating sawn volume in timber products, with the small-end log diameter over bark as the predictor variable and R adj 2 between 0.31 and 0.78 (p value?<?0.01).Conclusion
For the purpose of producing oak timber destined for structural use, the presence of bark and sapwood in planks must be reduced in the sawing process; this would decrease the total lumber recovery but increase the timber value yield. Air drying must be accelerated to reduce biotic damage in sawn planks. Geometric mean diameter over bark at the smallest end (d) outperforms other measures as a predictor variable for total or structural sawn timber volume. 相似文献8.
Stephen Adu-Bredu Daniel A Ofori Anders Ræbild Jon K Hansen Appolinaire Koffi Philipp Vigneron 《Southern Forests》2019,81(1):57-68
Stem straightness, axis persistence, presence/absence of protuberant buds and epicormics, diameter and height have profound influence on timber quality and volume of teak (Tectona grandis). Provenance trials of teak were established in the 1970s in Ghana, as part of the Food and Agriculture Organization (FAO) International Series of Provenance Trials, with the view of selecting teak germplasm for sites with specific environmental conditions. Two field trials were located in dry semi-deciduous (dry) and moist semi-deciduous (moist) ecological zones of Ghana. They consisted of 13 provenances, including four landraces each from Ghana and Indonesia, and two and three provenances from India and Laos, respectively. Trees were assessed at 9, 17 and 28 years to (1) quantify the potential variation in quality and timber volume production, (2) examine possibilities for determining early selection of parameters of superior provenances and (3) select provenances for sites with particular environmental conditions. Production traits were higher on the moist site than the dry site. Mean height was 23.2 and 20.2 m tree?1, stem cross-sectional area at breast height was 0.0896 and 0.0474 m2 tree?1, and stem volume was 0.75 and 0.34 m3 tree?1 for the moist and dry sites, respectively. Nilambur provenance from moist India had the highest mean stem straightness score of 19% above average, whereas Savannakhet from Laos had the best protuberant bud score with 18% of the trees above average. Indonesian landraces performed better in the dry zone, whereas provenances from India and Laos performed better in the moist zone. Phenotypic correlations between age 9 and 28 years were moderate (r 0.54–0.90) to high (r > 0.90) for production and qualitative characteristics, indicating feasibility of early assessment for identification of superior provenances. Nilambur and Savannakhet II provenances proved to be favourable choices for the moist zone, whereas the Temandsang provenance from Indonesia was found to be the best choice for the dry site. 相似文献
9.
Teak (Tectona grandis L. f) has been introduced to reforestation programs in many tropical countries for timber production. The use of teak plantations has changed the supply from large-diameter logs to small-diameter logs featuring a higher proportion of juvenile wood and more knots. Generally, the teak from fast-growth plantation is harvested after 15–30 years of growth, with logs ranging from 12 to 30 cm in diameter. The goal of this work was to review the factors that influence the heartwood formation, variation, quality, color, and durability in teak and to understand which factors should be controlled in fast-growth plantations. Important factors in the heartwood properties of teak trees from fast-growth plantations are as follows: the tree age, longitudinal variation, geographic location, environmental conditions, and silvicultural activities. These factors influence heartwood extractive content, color variation, and durability. 相似文献
10.
John R. Moore Andrew J. Lyon Gregory J. Searles Stefan A. Lehneke Daniel J. Ridley-Ellis 《Annals of Forest Science》2013,70(4):403-415
Context
Information on wood properties variation is needed by forest growers and timber processors to best utilise the available forest resource and to guide future management.Aim
This study aims to quantify the variation in selected properties of Sitka spruce (Picea sitchensis (Bong.) Carr.) structural timber.Methods
Twelve harvest-age stands were selected, ten trees per site were felled and processed into 301 logs. Dynamic modulus of elasticity (MOEdyn) was measured on each tree and log using portable acoustic instruments. Logs were processed into structural timber and its MOE and bending strength was determined.Results
Overall, the timber satisfied the MOE, bending strength and density requirements for the C16 strength class. Approximately 25 % of the total variation in timber mechanical properties was attributed to between-stand differences, with the remaining 75 % attributed to within-stand differences. A series of equations were developed to predict site, tree and log-level variation in timber properties.Conclusion
Knowledge of the site and stand factors that are associated with differences in timber properties can assist with segregation of the current resource. Portable acoustic tools can also be used to increase the stiffness of sawn timber by segregating out individual trees and logs that will yield low stiffness timber. 相似文献11.
The farm forest resource in Ireland: opportunities and challenges for rural development in Ireland 总被引:1,自引:0,他引:1
Niall Farrelly 《Small-Scale Forestry》2007,6(1):49-64
A critical mass of farm forestry and private forestry is now developing in Ireland with over 211,000 ha planted since 1980,
with 190,000 ha of this planted since 1990. Currently, 90,000 ha of private forests are over 10 years of age, with 41,000 ha
over 15 years of age. This paper examines the potential of the farm forest resource in Ireland and highlights some issues
that need to be addressed in order that the full potential of farm forestry is realised. It is estimated that 876,000 m3 of timber is currently available from forests through removals from thinning operations from plantations that are at or have
passed first thinning age. Cumulative volume output from thinning could be as high as 1.9 M m3 by 2010 increasing to 5.9 M m3 by 2015. Farm forestry has the potential to be a financially important farm enterprise with 15% of farmers (16,460) currently
engaged in forestry in Ireland. The development of volume production forecasts will provide crucial supply information for
gearing up of the wood-processing sector for additional volume from farms. However many enterprises face high harvesting and
extraction costs. Solutions to overcoming economies of scale due to the small size of plantations (averaging 9.2 ha) are proposed
using methods to group forestry operations together. The network of small sawmills throughout the country is favourable for
private growers as analysis indicates that 82% of private forests are within 32 km of a sawmill and efforts to stimulate local
processing are being encouraged. Financial analysis indicates that farmers can increase forestry returns by thinning their
plantations. The risk of windthrow to plantations is one of the major factors that can lead to financial losses in farm forestry
in Ireland and can be reduced by adequate management planning. A series of forestry extension programs will provide farmers
with adequate information to help aid decision-making in managing their plantations.
相似文献
Niall FarrellyEmail: |
12.
Pedro Ah Shenga Peter Bomark Olof Broman Dick Sandberg 《Wood material science & engineering》2017,12(4):257-262
The sawmill industry is a very important link in the Mozambique forest products value chain, but the industry is characterized by undeveloped processing technology and high-volume export of almost unrefined logs. The low volume yield of sawn timber has been identified as a critical gap in the technological development of the industry. To improve the profitability of the industry, there is thus a need to develop methods and techniques that improve the yield. In this paper, different positioning of logs prior to sawing and the possibility of increasing the volume yield of crooked logs by bucking the logs before sawing have been studied. A computer simulation was used to study the cant-sawing and through-and-through sawing of the logs to determine the volume yield of sawn timber from the jambirre (Millettia stuhlmannii Taub.) and umbila (Pterocarpus angolensis DC.) species. The optimal position, i.e. the position of the log before sawing that gives the highest volume yield of sawn timber for a given sawing pattern when the positioning parameters, offset, skew and rotation, are considered gave a considerable higher volume yield than the horns-down position. By bucking very crooked logs and using the horns-down positioning before sawing, the volume yield can be of the same magnitude as that obtained by optimal positioning on full-length (un-bucked) logs. The bucking reduces the crook of the logs and hence increases the volume yield of sawn timber. 相似文献
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14.
Edo State teak plantations witnessed unregulated exploitation between 1986 and 2001, which impacted the people, and the environment. This study was undertaken to determine the primary and secondary causes of unregulated exploitation. Ten teak plantations were randomly selected in Edo State with four 25-m × 25-m plots laid out in each plantation, to obtain information on the rates of exploitation based on the assessment of relic trees. Socioeconomic data were obtained through the use of 3 sets of questionnaires developed and administered to 958 respondents comprising 213 forestry staff, 437 farmers, and 308 saw millers/timber contractors in 10 selected communities out of the 28 settlements adjoining these plantations. The results revealed there was significant difference (p < .05) between primary and secondary causes. Poor forest policy implementation had a significant (p < .05) positive effect on teak exploitation. Idale had a dominant 11.16 m3 ha? 1 yr?1 mean annual increment (MAI) which accounted for 17.61%, while the least value was recorded at Udo-Nikrowa. It is imperative that commensurate efforts at reforestation and the use of lesser known timber species need to be encouraged. 相似文献
15.
Further study is needed on loblolly pine (Pinus taeda L.) growth in a systematic array of plantation designs or stocking rates commonly used in temperate forestry and agroforestry
practices. Our objective was to determine loblolly pine growth responses and agroforestry implications of 13 plantation designs
(i.e., stocking rates in trees ha−1 [TPH]) at mid-rotation (14 years old). Survival, diameter at 1.3 m above soil surface (dbh), height, basal area (BA), and
volume (V) were measured in unthinned plantations ranging from 490 to 2,300 TPH. Stocking rate was positively correlated with
BA (r ≥ 0.67) and V (r ≥ 0.55) and negatively correlated with survival (r ≤ −0.83) and dbh (r ≤ −0.83). Plantations with ≥2,000 TPH had closed canopies and excessively high BA and V at mid-rotation. The 4- and 5-row
plantations (≥12 m alley spacing) had small dbh (≤17.5 cm). Single-row plantations with ≥3.6 m within row spacing and ≤700
TPH, and the 3-row multiple-row plantations (1,200 TPH), had acceptable BA (29.4–33.2 m2 ha−1) and V (127–136 m3 ha−1). Basal area was ≥30 m2 ha−1 in most plantations indicating thinning is needed to optimize individual tree growth. Besides timber, an array of design-dependent
agroforestry and forestry products should drive the selection of any one of these plantation designs: pine straw or biomass
production at ≥1,800 TPH, and alley cropping or silvopasture in single-row (≤1,000 TPH) and multiple-row plantations (<1,400
TPH). 相似文献
16.
David Thompson 《Small-Scale Forestry》2007,6(2):157-175
With large areas of public native forests now converted into National Parks and unavailable for timber harvest, private native
forests (PNF) in New South Wales (NSW) are becoming increasingly important in providing timber for the wood processing industry.
At the same time, there is increasing interest in the role that these private forests play in providing and maintaining habitat
for wildlife. Historically, timber production from these forests has been opportunistic, with little or no silviculture to
maintain wood production potential. Market circumstances and policy settings have not favoured sound silvicultural practice,
generating an exploitative and short-term view of the timber resource to maximise short-term returns. This has occurred at
a time when these forests are an important and increasing source of log supply to industry. This paper discusses payment of
biodiversity credits (incentives) to improve both environmental management and timber production outcomes, and examines the
findings of some recent studies on the ‘sustainability’ of PNF. Willingness-to-pay (WTP) and willingness-to-supply studies
reveal a disparity between the demand and supply prices for biodiversity and habitat ‘services’ in many cases. Recent ‘sustainability’
studies indicate forestry operations are relatively benign in their impacts on biodiversity, compared to other land uses.
However, in the absence of increased financial returns from PNF and in the face of increased public demand for greater environmental
outcomes, there seems little alternative to meeting the competing demands of biodiversity and timber production than to implement
a system of incentive payments which reward sound private forest management for a multiplicity of objectives.
相似文献
David ThompsonEmail: |
17.
《Wood material science & engineering》2013,8(1-2):1-11
Abstract Growing markets for chopped firewood have created alternative uses for the by-products of sawmills. Based on empirical data and simulated results, the potential of birch (Betula pendula Roth, Betula pubescens Ehrh.) from commercial thinnings for combined industrial production of sawn timber and firewood billets was investigated. In the simulations, different sawing patterns were used for logs intended to combine production of sawn timber and billets for chopped firewood (‘sawlogs’), and for logs intended only to firewood production (‘firewood logs’). Finally, economical feasibility analysis was done concerning the differences between the sawmills’ traditional business concept and the novel concept combining sawn wood and firewood production. The bucking results for the volume yield of different timber assortments varied only slightly between the different bucking options, i.e. the combinations of timber assortments. The main differences in the volumes of timber assortments were due to the stand type where the birch trees were sampled (planted, naturally regenerated, mixed birch–spruce). In the sawing procedure, the output of sawn timber varied between 24% and 42% of the log volume in the sawlogs, depending on the log diameter class. As the volume yield of sawn timber and firewood billets was counted together in the case of sawlogs, the log consumption was c. 1.75 m3 of roundwood per 1 m3 of sawn timber and firewood billets. In the case of the firewood logs, the log consumption rate was considerably lower, only c. 1.35. The economic calculations showed that using the firewood approach in sawing may increase the net added value of products by €1.9–5.4 m?3 of logs, depending on their diameter class. As a conclusion, parallel production of sawn timber and firewood from logs from the first and second commercial thinning of birch-dominated stands is a concept that could work as an alliance between a sawmiller and a firewood entrepreneur. The concept could be competitive compared with both traditional sawmilling and production of chopped firewood. 相似文献
18.
Markku J. Penttinen 《European Journal of Forest Research》2006,125(4):335-343
This paper analyses timber harvesting in the Finnish economic and wood production environment. Empirical evidence including stumpage prices, silvicultural costs, etc., since 1949 covers all non-industrial private forestry. Stumpage price and volume growth processes are proxied by GBMs. Optimal harvesting age solutions and numerical results recognising price drift, price and growth volatility, volume growth, value growth and stand establishment costs, as well as thinning benefits, are provided for Scots pine. Moreover, comparative static and sensitivity solutions, including numerical results, show the impact of the discount rate, price drift, and price and growth volatilities on optimal harvesting age. Price volatility prolonged harvesting age by some 5–9 years, and growth volatility by about 1–2, but negative price drift for discount rates from 5 to 2% fell by roughly 6–10 years. Ignoring the future thinning benefits prolonged the harvesting age only by 1–2 years, but ignoring future stand establishment costs reduced it by 2–4 years. Including the price drift and volatility violated the 70 year age limit in the Forest Act for discount rates exceeding 3.5%. The recommended harvesting age of 80 years could be established only by ignoring the price drift. In all, this study produces solutions and programs that can be incorporated into a forest management planning software product widely used in Finland (Hynynen et al. in For Ecol Manage 207(1–2):5–18, 2005).
相似文献
Markku J. PenttinenEmail: Phone: +358-10-2112244Fax: +358-10-2112104 |
19.
Liana-dominated forest patches constitute 15–20% of old-growth forests in the Eastern Amazon but are generally excluded from management for timber production. Here we ask if liana-dominated patches may be brought into production by clearing lianas and conducting enrichment planting (EP) of native timber species. We present growth results from 8 years of such EP trials. Rapid growth and low mortality of all species in this study suggest that EP in cleared liana patches can contribute to timber stocks in second and third harvests of managed forests. The most vigorous individuals of Parkiagigantocarpa and Schizolobium amazonicum in each enrichment site grew more than 1 cm diameter per year (rates were initially >2 cm yr−1), and attained dominant canopy positions and diameters equal to those of small canopy trees in the surrounding forest within 8 years of planting (mean dbh ∼18 cm and ∼20 cm, respectively, at year 8). Limited data on Ceiba pentandra plantings indicate a similar trajectory for this species (dbh ∼40 cm in 8 years). The most vigorous Swietenia macrophylla grew at least 1 cm per year in enrichment plots (mean dbh ∼10 cm in 8 years), but take longer to attain dominant positions. Tabebuia serratifolia may take much longer to reach the canopy than other species tested (rates <1 m yr−1). We attribute the excellent performance to light availability; planting in intact soil with minimal compaction and abundant organic material; and low competition rates maintained by periodic thinning of competing vegetation. 相似文献
20.
This analysis suggests important considerations for assessing social impacts of large-scale pulpwood production in Indonesia,
emphasizing the extremely limited conditions under which pulp plantations may complement, rather than threaten, livelihoods
of existing communities in their vicinity. Pulpwood plantations are expanding rapidly in Indonesia to feed major new pulp
mills. Though officially developed on “unproductive forest lands”, pulpwood monocultures are commonly established at the expense
of natural forests and indigenous agroforestry systems in Sumatra and Kalimantan. Based on a South Sumatra case study, this
article analyzes how pulpwood plantations may be combined with more traditional land uses to improve livelihoods for local
populations, considering the potential for “complementary” labor opportunities. This analysis is built on two assumptions:
(1) village smallholder activities represent a first choice for village-based workers and smallholders, with relatively high
financial returns per hectare; and (2) seasonal variations in labor requirements for village-based livelihoods open opportunities
for complementary labor and land uses such as industrial plantations. Applying our model to a Sumatra case study highlights
an upper limit to “complementary labor” for industrial timber plantation land use at a ratio of 5:1 (no more than 5 ha of
pulpwood to each 1 ha remaining in intensified local agriculture and agroforestry). Other conditions required to minimize
risks for local livelihoods include: flexible timing of company operations; priority to local employment; cautious determination
of plantation sites; more transparent government licensing of plantation concessions and pulp mills recognizing local and
customary land and resource rights.
相似文献
Judith MayerEmail: |