首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A model of public cost-sharing in private forest investment is proposed to describe the substitution between the private financing of investments and public investment assistance. The substitution depends on the curvature conditions of the forest investment function on forest stock. When the second-order investment effects are close to zero or when they do not exist, the funding substitution will not take place. A simultaneous econometric model for private and public funding employing forest incomes, forest income taxes, interest rates, investment scale and market wood price expectations as exogenous variables is estimated. The model estimation based on Finnish regional data in 1983–2000 rejects the substitution alternative. A 10% increase in private investment funding increases the demand for public funding at the same rate, but a 10% increase in public funds will increase the private funds supply by 2.5%. Significant income effects are found only in the case of private funding. In northern Finland, the scale effects are large for public financial assistance. The effects of the income tax reform on the private supply of funds are positive, especially for the new wood-sales profit taxation, whereas the interest rate and price expectation effects are negative.
Mikael LindenEmail: Phone: +358-13-2514225Fax: +358-13-2513290
  相似文献   

2.
Investment in small and large-scale revegetation in Australia is growing in response to concerns regarding the sustainability and productivity of agricultural landscapes. Site preparation and management––such as soil cultivation, weed control, fertilising, mulching, use of treeguards and watering––are major costs associated with small-scale revegetation. The aim of this study has been to investigate local revegetation knowledge and practices to determine the usefulness of each management practice for achieving success and to determine whether some practices are more suited to particular climatic zones. A national online revegetation survey was conducted to ascertain current small-scale revegetation practices and the factors that drive these choices. Management practices were found to be strongly associated with climate. Mulch, fertiliser, weed control and watering were applied more frequently in higher rainfall and higher temperature zones. Soil cultivation and treeguards were used more frequently in lower rainfall and lower temperature zones. These findings suggest that there may be some benefit in modifying existing revegetation guidelines to reflect climatic zones and management flexibility.
Sonia GrahamEmail:
  相似文献   

3.
This paper analyses industrial round wood flows into, within, and out of Northwest regions of Russia. We examine sawlogs, pulpwood, and fuelwood used for industrial purposes obtained from logging, and chips obtained from the wood-processing industry. We attempt to clarify different recent trends in wood harvesting, industrial round wood export, and forest industries development that have an influence on unreported wood in Russia. Our method, which uses wood balance diagrams, provides an interpretation of data from different Russian sources in order to offer better transparency regarding wood flows from forests to mills. It also helps to explain the apparent imbalance between round wood supply and demand and it helps one to assess the possible share of unreported industrial round wood production in Northwest Russia. Based on annual forest-related statistical data available from the Ministry of Natural Resources, the State Committee of Statistics, and the Russian Federation’s Customs Department, unreported round wood flows can be estimated to be 23% of the total industrial round wood production, or approximately 9 million m3 u.b. per year. Unreported round wood flows are more common in export oriented regions that have poorly developed forest industries.
Yuri GerasimovEmail: Phone: +358-102-113253Fax: +358-102-113251
  相似文献   

4.
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.
Niall FarrellyEmail:
  相似文献   

5.
Future harvesting pressure on European forests   总被引:1,自引:0,他引:1  
We provide quantitative insight in the spatial distribution of the future supply of wood as a raw material from European forests (27 countries) until 2060. This supply is tested for two scenarios: ‘projection of historical management’ and ‘new management trends’ and compared against a benchmark scenario. The new management trends scenario incorporates influences of issues as nature-oriented management, carbon credits and increased demand for bio-energy. The results of these projections provide insight in the state of the European forests and indicate that under the ‘new management trends’ supply can still increase to 729 million m3 by 2060 in Europe, whereby almost throughout Europe we allow harvest to be higher than increment for some time. Without linking countries dynamically through international trade, we identify regions where harvesting pressure is highest. Under the new management trends scenario, the harvested volume is reduced with 82 million m3/year (compared to ‘projection of historical management’) because of stricter management constraints. However, the management regimes as parameterised here allow harvesting pressure to remain highest in Central Europe and some Scandinavian countries, notably Finland and Norway.
G. J. NabuursEmail:
  相似文献   

6.
The effects of stocking on wood stiffness (MoE) for three Eucalyptus species are quantified using a 6-year-old trial established in New South Wales, Australia. An acoustic time-of-flight tool measured the velocity between two probes in the outerwood, from which the stiffness was estimated. Four stocking levels (714, 1,250, 1,667 and 3,333 sph) were examined. Stiffness varied significantly between all species, with E. cloeziana showing the highest stiffness (14.2–15.7 GPa), followed by E. pilularis (12.2–13.5 GPa) and E. dunnii (10.7–12.6 GPa). There was a stiffness increase (around 11%) between 714 and 1,250 stems/ha for all species but thereafter differences between stockings were not always significant. Trees were also assessed for basic density, dbh, total height, crown area, green crown height and stem slenderness (height/dbh). Only stem slenderness had a significant association (0.41 ± 0.17) with stiffness. These findings suggest that, where stiffness is a priority, forest managers could reduce establishment costs with low stockings (around 1,250 stems/ha).
Luis Alejandro ApiolazaEmail:
  相似文献   

7.
Die bisher erarbeiteten Ergebnisse lassen sich wie folgt zusammenfassen:
1.  Bei der Fichte korrelieren Jahrringbreite und Holzdichte und damit die wesentlichen Festigkeitseigenschaften, wie Biegefestigkeit, Biege-E-Modul, Druckfestigkeit.
2.  Die Holzdichte als wesentliche Eigenschaft steht in enger Beziehung zum Sp?tholzanteil.
3.  Die Astst?rke korreliert direkt mit der Wachstumsgeschwindigkeit, d. h. ebenfalls mit der Jahrringbreite.
4.  Astst?rkensumme und Jahrringbreite zusammen erkl?ren einen gro?en Teil der technischen Holzeigenschaften.
5.  Durch Wert?stung kann ein Teil der negativen Wirkungen des schnellen Wachstums auf die Festigkeitseigenschaften ausgeglichen werden.
6.  Dies bedeutet allerdings nicht, da? die Holzdichte als wesentliches Merkmal an Bedeutung verliert.
7.  Eine weitgehend zu erwartende Reihung ist also aus holztechnologischer Sicht eindeutig festzustellen:
–  — engringig und wertge?stet auf dem 1. Platz, verspricht also h?chsten Holzwert,
–  — engringig, nicht wertge?stetes Holz steht an 2. Stelle,
–  — weitringig, wertge?stet im Mittelfeld, nur knapp nach Position 2
–  — weitringiges, nicht wertge?stetes Holz verliert, mit Abstand an letzter Stelle stehend.
Results achieved till now may be summarized as follows:
1.  With spruce, annual ring width is correlated with wood density, and thus with the essential strength properties such as bending strength, bending-E-module, and tensile strength.
2.  Wood density as an essential property is closely related to the share of late wood.
3.  There is a direct correlation between knot size and growth rate, i. e. also annual ring width.
4.  The sum of knot diameters and annual ring width together explain a large part of the technical wood properties.
5.  High pruning may compensate for some of the negative effects of rapid growth on strength properties.
6.  This, however, does not imply that wood density is becoming less important as an essential property.
7.  From the wood-technological viewpoint, a largely to be expected ranking can be clearly established:
–  — narrow growth rings and high-pruned stands in first place, thus promising the highest timber value,
–  — narrow growth rings but not pruned comes second,
–  — wide growth rings and high-pruned ranks about in the middle, only slightly behind position 2,
–  — wood showing wide growth rings and not being from pruned trees falls way behind.
  相似文献   

8.
A farm-level financial feasibility was performed to examine the use of shelterbelts as a swine odor mitigation technology. Shelterbelts are purposefully planted rows of trees and shrubs around the main sources of swine odor—swine buildings, manure storage systems, and crop fields that receive land applied manure. By using a series of model pork finishing farms and a number of differing shelterbelt design scenarios, the shelterbelt establishment and long-term (20 years) maintenance costs were calculated using a discounted cash flow analysis. Total costs for examined pork finishing farms, depending upon the shelterbelt design scenario, and whether or not government cost-share programming was used, ranged from $0.01 to $0.65 per pig produced. Study results emphasized the importance of cost-share programs, particularly Environmental Quality Incentive Program (EQIP). In most cases, both with and without cost-share programming, the total costs were well below reported pork producer expenditures for odor management.
John C. TyndallEmail:
  相似文献   

9.
Conservation of biodiversity and mitigation of global warming are two major environmental challenges today. In this context, the relationship between biodiversity (especially plant diversity) and soil carbon (C) sequestration (as a means of mitigating global warming) has become a subject of considerable scientific interest. This relationship was tested for homegardens (HG), a popular and sustainable agroforestry system in the tropics, in Thrissur district, Kerala, India. The major objectives were to examine how tree density and plant-stand characteristics of homegardens affect soil C sequestration. Soil samples were collected at four depths (0–20, 20–50, 50–80, 80–100 cm) from HG of varying sizes and age classes, and their total C content determined. Tree density and plant-stand characteristics such as species richness (Margalef Index) and diversity (Shannon Index) of the HG were also determined. Results indicated that the soil C stock was directly related to plant diversity of HG. Homegardens with higher, compared to those with lower, number of plant species, as well as higher species richness and tree density had higher soil carbon, especially in the top 50 cm of soil. Overall, within 1 m profile, soil C content ranged from 101.5 to 127.4 Mg ha−1. Smaller-sized HG (<0.4 ha) that had higher tree density and plant-species density had more soil C per unit area (119.3 Mg ha−1) of land than larger-sized ones (>0.4 ha) (108.2 Mg ha−1). Soil C content, especially below 50 cm, was higher in older gardens. The enhanced soil-C storage in species-rich homegardens could have relevance and applications in broader ecological contexts.
Subhrajit K. SahaEmail:
  相似文献   

10.
In the European sawnwood markets, competition is tight between producer countries, with the new EU countries gradually gaining larger market shares. This paper focuses on the pass-through of sawnwood prices to supplier countries’ national roundwood prices. Price-change effects on market shares are known to be large, but not so much is known about the timing and duration of price transmission between competitor countries. Our empirical analysis concerns the exports of four large sawnwood supplier countries in Europe (Finland, Austria, Estonia and the Czech Republic) to German markets, using quarterly panel data for 1995–2003. The transmission process was found to differ between countries, and the relationship was most clearly detectable between Finnish sawlog and sawnwood prices. Results based on seemingly unrelated regression analysis indicated that price transmission exhibits similarities between old (i.e. Austria, Finland) and new EU member countries (Estonia, Czech Republic). Overall developments in both sawnwood and sawlog prices displayed convergence in the study period, which indicates that deepening integration in European markets is also detectable in the forest sector.
Ritva ToivonenEmail:
  相似文献   

11.
–  • We present the results of a two-year (2007–2008) greenhouse study investigating the effect of water availability and nitrogen fertilization on the growth, biomass partitioning, and foliar nutrient content of Abies fraseri (Pursh) Poir.  相似文献   

12.
Forest cover and pattern changes in the Carpathians over the last decades   总被引:2,自引:0,他引:2  
This study aims at developing a satellite-based methodology for the implementation of two Ministerial Conference on the Protection of Forests in Europe indicators for the European Alpine Bio-geographic region, and their changes over time: (1) area of forest cover and (2) forest spatial pattern. The northern Carpathians were selected as a study area due to the documented recent increase of forest cover. Changes of forest cover were quantified using Landsat images for the years 1987 and 2000. Single-date forest–non-forest maps were derived by image segmentation and supervised classification, including the use of ancillary data (CORINE Land Cover and a digital elevation model). These maps were an input for the post-classification change detection. The forest spatial pattern maps with four classes (core, patch, edge and perforated forest) were derived with morphological image processing. A simple method to mask uncertainty areas on forest maps and related products was also developed. The accuracy of the resulting forest–non-forest map was assessed with orthophotos and amounts to 93.9%. Uncertainty areas, for which change assessment was judged more difficult and less reliable, were not considered for assessing forest cover change. The annual forest cover change rate of 0.38% was found over the 1987–2000 period. For the 13-year time period, we found a decrease of core forest and an increase of patch and perforated forest. We conclude that the proposed methodology allows to quantify changes of forest cover and forest spatial pattern at ∼1 ha minimum mapping unit.
C. Estreguil
  相似文献   

13.
Der Wald ist für den Naturschutz
–  — aus grunds?tzlichen Erw?gungen,
–  — wegen seines hohen Wertes als Lebensraum für Pflanzen und Tiere,
–  — im Hinblick auf seinen gro?en Fl?chenanteil, auch in seiner Form als Wirtschaftswald von besonderer Bedeutung.
Die naturschutzfachlichen Anforderungen an eine naturvertr?gliche Waldbewirtschaftung lassen sich insbesondere mit Hilfe des Arten- und Biotopschutzprogramms und anderer konzeptioneller Arbeiten immer besser formulieren; es bedarf aber noch weiterer Grundlagenerhebungen, insbesondere einer ?kologischen Werterfassung im Wald.  相似文献   

14.
Carbon sequestration in the woody biomass of shelterbelts has been investigated but there have been no measurements of the C stocks in soil and tree litter under this agroforestry practice. The objective of this study was to quantify C stored in surface soil layers and tree litter within and adjacent to a 35-year-old shelterbelt in eastern Nebraska, USA. The 2-row shelterbelt was composed of eastern red cedar (Juniperus virginiana) and scotch pine (Pinus sylvestris). A sampling grid was established across a section of the shelterbelt on Tomek silt loam (fine, smectitic, mesic Pachic Argiudolls). Four soil cores were collected at each grid point, divided into 0–7.5 and 7.5–15 cm depth increments, and composited by depth. Soil samples were analyzed for total, organic, and inorganic C, total N, texture, pH, and nutrient content. Under the shelterbelt, all surface litter in a 0.5 × 0.5 m2 area at each grid point was collected prior to soil sampling, dried, weighed, sorted, and analyzed for total C and N. Average soil organic carbon (SOC) in the 0–15 cm layer within the shelterbelt (3,994 g m−2) was significantly greater than in the cultivated fields (3,623 g m−2). The tree litter contained an additional ∼1,300 g C m−2. Patterns of litter mass and soil pH and texture suggested increased organic inputs by tree litter and deposition of wind-blown sediment may be responsible for greater SOC beneath the shelterbelt. Further research is needed to identify the mechanism(s) responsible for the observed patterns of SOC within and adjacent to the shelterbelt and to quantify the C in biomass and deeper soil layers.
Thomas J. SauerEmail:
  相似文献   

15.
–  • We aimed to better understand the genetic architecture of growth in E. globulus undergoing inbreeding by comparing families from selfing (SELF), open pollination (OP) and unrelated polymix crossing (POL) of common parents. Stem diameter at breast height (DBH) was assessed at 4, 6 and 10 years after planting in a field trial.  相似文献   

16.
–  • We combined stem volume increment analysis with dendroecological tools to address two unresolved issues concerning oak dieback in Mediterranean areas: early detection of changes in stand growth, and identification of mechanisms for observed growth declines.  相似文献   

17.
There is a widely held view among smallholders that teak timber produced from small-scale agroforestry systems, especially home-garden forestry, fetches a lower price than that from conventional plantation forestry. To examine the veracity of this view, the wood quality attributes of teak from two home gardens in the district of Ernakulam (wet site) and Palakkad (dry site) in India were compared to those of forest plantation in Nilambur. The logs were graded using standard timber trade practices into high, medium and low quality as determined by the potential sawn timber grade-yield recovery pattern. Of 96 home garden teak logs (aged 35 years) from wet and dry sites, 59% belonged to timber Grade II–IV and the rest were classified as poles. Grade I logs (export quality) with a girth above 150 cm were not available from either of the homesteads. Faster-grown teak in the wet site produced large diameter logs (dbh 1.37 m) with average diameter of 39.6 cm, which is comparable to that of best site quality in India. In contrast, the average dbh for teak grown in the dry site was 24 cm as compared to the average dbh of 31 cm recorded from the same aged forest plantation in Nilambur. It was found that only 10% of logs belonged to Grade II timber and the rest fell under grades III and IV with more frequent visual defects. The sawn timber recovery percentage was lower for the dry site (66.8%), whereas there was no significant difference in grade from the wet and forest plantation sites, with recovery rates of 76.5% and 78.8%, respectively. The general notion that home garden teak has a large proportion of sapwood seems to be baseless, no significant difference being found between the heartwood-sapwood ratio of home-garden and forest plantation teak. Lack of appropriate silvicultural practices in home-garden forestry caused the production of more defective logs, adversely affecting the market price of timber.
Puthenpurayil Kumaran ThulasidasEmail:
  相似文献   

18.
Globally, trade in agar-based products is growing rapidly due to their recent adoption as an ingredient in the cosmetics and pharmaceuticals sector. In Bangladesh, people living in some north-eastern districts have been engaged in the production, processing and trading of such products for several decades. These practices, which they consider as the lifeblood of their existence, have been inherited from their ancestors. This paper reports a case study carried out in Maulvibazar district exploring the production and marketing, and industry problems, of agar-based enterprises and their potential contribution to socio-economic development. An exploratory survey was undertaken over 30 randomly selected agar-based factories during December 2005–April 2006, with entrepreneurs of the factories personally interviewed using a semi-structured questionnaire. The majority of the factories of the area were found to depend on local sources of raw materials to produce agar-based products. About 514 full and part-time workers are employed in the factories. Average annual expenditure, revenue and net annual income per factory for three consecutive years 2003–2005 of the study were estimated as Tk 63,980, Tk 111,414 and Tk 47,435, respectively, being highest where attar (agar oil) of superior grade was produced for export. There appears to be a sustainable source of raw materials, availability of technical and financial assistance and opportunity for expansion of market facilities to secure the maximum benefit achievable from this highly promising industry.
Sharif A. MukulEmail:
  相似文献   

19.
Forest owner cooperations (FOC) are bundling wood supply from small-scale forests and some also offer additional services, such as wood harvesting or planting. FOCs are growing throughout Europe in terms of the managed timber volume. The increasing timber demand of forest-based industries as well as the new, rapidly growing demand for energy plants could lead to an under-supply in the following years in Europe. Because of high harvesting arrears in small-scale forests, FOCs are seen as an opportunity to overcome this foreseen timber shortage. The paper maps out timber mobilisation strategies using the SWOT (Strengths, Weaknesses, Opportunities and Threats) approach.
Peter RauchEmail:
  相似文献   

20.
The paper examines the interactions between the demands of society, the restrictions due to recreational and protective functions of forests and the intensity and kind of forest management in the various ownership classes in Switzerland (CH) and Baden–Württemberg (BW) in south–west Germany. A survey was carried out among owners of communal forests, private forest landholders owning more than 200 ha of forest land and small-scale forest enterprises with up to 200 ha of forest land. The survey adopted a two-dimensional approach, using regions and comparable ownership classes in order to identify basic differences and underlying key drivers. It became obvious that there are relevant distinctions between the two countries. The paper highlights the present use of forests, the restrictions perceived by their owners, and the underlying management strategies in terms of structure of the forests, tree species composition and thinning activities. In BW the financial function is the dominant motivation for the majority of the private owners. The communities emphasize both timber and non-timber functions of their forests. Except for the protection function (avalanches, rockslides) the utilisation and importance of the forest in CH is lower than in BW. Profitability of forests continues to be a key-driver of intensity of forest management activities, but there is less influence on the choice of basic silvicultural strategies. The results of this comparative survey are placed in the context of a forest policy framework and the medium-term financial situation in the two countries.
Christoph HartebrodtEmail:
  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号