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1.
Due to the exceptional sweetness of its sap, sugar maple (Acer saccharum Marsh.) is economically exploited at a commercial scale for maple syrup production in northeastern North America. Approximately 80% of world production is realised in the province of Quebec, Canada, where it is economically important for rural communities. Despite important financial investments in industrial infrastructure over recent decades, the maple syrup yield (ml of sap/tap/year) has followed a general declining trend over the last 15 years, presumably because of unfavourable climatic conditions. In this study, the relationship between climate and maple syrup yield by tap for the whole province was investigated. 相似文献
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Michael Farrell 《Agroforestry Systems》2013,87(3):631-641
This paper examines the maple syrup production potential of American forests by analyzing Forest Inventory & Analysis (FIA) data provided by the US Forest Service on the resource of sugar maple (Acer saccharum Marsh.) and red maple (Acer rubrum L.) trees in twenty states. The analysis is based on tree species and size (diameter at breast height, or dbh), ownership category, jurisdiction, the density of maple trees in a stand, and the distance of the stand to an access road. Although there are over 2 billion sugar and red maple trees of tappable size growing in US forests, when narrowed down according to the attributes of an optimal ‘sugarbush’, there are 100 million potential taps from sugar maples alone and 286 million potential taps with sugar and red maples combined. Overall, 45 % of the tappable-size maple trees are found in stands whose density is not high enough to support commercial sap extraction whereas only 6 % are found in stands that are at least 1.6 km from an access road. The ten states with commercial maple syrup industries have a much higher percentage of their maple trees occurring in stands of optimal density and also contain a higher percentage of sugar maple than red maple trees. States that are utilizing the highest percentage of their potential sugarbushes include Vermont and Maine, whereas states that have significant room for expansion include Michigan, New York, and Pennsylvania. 相似文献
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Abbas Banj Shafiei Moslem Akbarinia Gholamali Jalali Mohsen Hosseini 《Forest Ecology and Management》2010
Most of world's forests of different climates have a history of fire, but with different severities. Fire regimes for broadleaf deciduous forests have return intervals that vary from many decades (or less) to centuries (or more). Iran has a total of 1.2 million ha of temperate forest in the north, where fires burn about 300–400 ha annually. This study focused on the impact of fire on forest structure, tree species quality, and regeneration composition (specially beech) in the Chelir forest of northern Iran. The results showed that forest fires changed the structure and had different effects on tree species composition between burned and control areas. Thin barked species such as oriental beech (Fagus orientalis Lipsky) and coliseum maple (Acer cappadocicum Gled.) have been affected more than those with thick bark, like hornbeam (Carpinus betulus L.) and chestnut-leaved oak (Quercus castaneifolia C.A. Mey). The density of oriental beech regeneration in the unburned area was greater than in the burned area, while the quantity of regeneration of hornbeam, coliseum maple and velvet maple (Acer velutinum Boiss) was higher in burned area. Forest fire had a greater effect on oriental beech quality, and changed regeneration composition in the burned area. Fire prevention activities should be considered as a silvicultural treatment for preserving these valuable forests. 相似文献
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21世纪初世界林产工业展望 总被引：2，自引：0，他引：2
文章论述了２１世纪初世界木材资源的变化趋势，各国的森林工业政策和实施措施，介绍了联合国粮农组织对２１世纪初世界主要林产品生产和需求的预测，并对其发展趋势和特点进行了分析。 相似文献
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理顺和建立林区林产工业产品价格体系、制定相关政策、强化价格和行业管理 ,是防止企业内部有害竞争 ,营造公平有序的竞争环境 ,促进行业健康发展 ,提高林区整体经济效益的有效途径 ,是深入实施“天然林保护工程”的必要保证。本文作者着重分析了内蒙古大兴安岭林区林产工业产品销售价格的现状、存在问题 ,探讨和提出了应采取的对策和建议 相似文献
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Differences in sensitivity to soil conditions across tree species and developmental stage are important to predicting forest response to environmental change. This study was conducted to compare elemental concentrations in leaves, stems, and roots of (1) sugar maple (Acer saccharum Marsh.) seedlings vs. mature trees and (2) mature sugar maple vs. mature American beech (Fagus grandifolia Ehrh.) in two sites that differ in soil base saturation and pH. Both sites are located in Huntington Forest, NY, USA; one site (hereafter ‘H’) has higher soil pH and Ca, Mg, and Mn concentrations than the other site (hereafter ‘L’). Sugar maple growth at H (14.8 cm2 year−1 per tree) was much greater than at L (8.6 cm2 year−1 per tree), but the growth of beech was not different between the two sites. Leaves, roots, and stem wood of mature beech trees and sugar maple seedlings and mature trees were sampled for nutrient analysis. Foliar Ca, K, and Al concentrations were positively correlated with soil elements, but Mn concentrations were negatively correlated. Sugar maple differed more than beech between sites in foliar K and Mn concentrations. Root Mg and P concentrations reflected soil chemistry differences, in contrast to foliar concentrations of Mg and P, which were indistinguishable between the sites. In sugar maple, seedlings differed more than in mature trees in nutrient concentrations in roots, especially for Mg and Mn. Although beech was not as responsive to nutrient availability as sugar maple in foliar and root nutrient concentrations, Ca and Mg concentrations in beech wood were higher in H (52% higher for Ca and 68% higher for Mg), while sugar maple did not differ between sites. Sugar maple regeneration failure on acidic soils in the same region is consistent with our finding that sugar maple seedlings were very sensitive to nutrient availability. This sensitivity could ultimately contribute to the replacement of sugar maple by American beech in regions of low pH and base cations if base cation leaching by anthropogenic deposition and tree harvesting continues. 相似文献
8.
Philippe Nolet Sylvain Delagrange Daniel Bouffard Frédérik Doyon Eric Forget 《Annals of Forest Science》2008,65(2):208-208
Two complementary experimental designs at two contrasting scales (landscape/long term; individual tree/short term) were used for an in-depth evaluation of the successional status of sugar maple (AS: Acer saccharum Marsh.). First, forest disturbances during the 20th century and composition were mapped for two landscapes in the Du Lièvre watershed of southern Quebec. Our results show that, as well as dominating stands in the absence of fire, AS often rapidly developed dominance after fire, especially in the south of our study area. Similarly, a majority of AS-dominated stands clearcut in 1928 continued to be AS-dominated 60 years later. Second, we examined AS seedlings planted under two very contrasting light regimes. AS seedlings showed a combination of traits particularly adapted to tolerate shade under a low light regime. However, owing to a surprisingly high phenotypic plasticity, AS also exhibited efficient development under high light. This suggests the classification of AS as a late-successional species should indeed be revised and that generalist or trans-successional would be a more appropriate designation for this species. We discuss the ramifications of such a status revision, with an emphasis on the implications for its silviculture. 相似文献
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Over the last two centuries, logging has caused major, but unquantified, compositional and structural changes in the southern portion of the North American boreal forest. In this study, we used a series of old forest inventory maps coupled with a new dendrochronological approach for analyzing timber floating histories in order to document the long-term transformation (1820–2000) of a southern boreal landscape (117 000 ha) in eastern Quebec, Canada, in response to logging practices. Landscape exploitation became increasingly severe throughout this time period. During the ninetieth century (1820–1900) of limited industrial capacity, selective logging targeted pine and spruce trees and excluded balsam fir, a much abundant species of the forest landscape. Logging intensity increased during the first half of the twentieth century, and targeted all conifer species including balsam fir. After 1975, dramatic changes occurred over the landscape in relation to clear-cutting practices, plantations, and salvage logging, which promoted the proliferation of regenerating areas and extensive plantations of the previously uncommon black spruce. Overall, logging disturbance resulted in an inversion in the forest matrix, from conifer to mixed and deciduous, and from old to regenerating stands, thus creating significant consequences on forest sustainability. If biodiversity conservation and sustainable forestry are to be management goals in such a heavily exploited forested landscape, then restoration strategies should be implemented in order to stop the divergence of the forests from their preindustrial conditions. 相似文献
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《Forest Ecology and Management》1999,114(1):97-106
Historical sources of the use of the forests around the manor Hald during three centuries are used to outline a typical development for many areas on poor sandy soils in Denmark. The balance between forest, shrub, agricultural land, fallow and heathlands in the zone depended on the intensity of land-use for agriculture, grazing and wooden products. The forests at Hald were never totally deforested, and since the forest act of 1805 and first conservation in the early 20th century, the open and shrubby oak woods have developed into oak forest. In a preliminary analysis, data on under-storey vegetation and light conditions from 1916 are compared to data from 1995. Due to conservation of the forest, light penetration has been drastically reduced in the forest since early this century and the reduced light penetration in combination with increased nitrogen deposition has changed the under-storey vegetation significantly. Species diversity and abundance have declined and the typical raw humus species are relatively better adapted to the present conditions. The relative importance of management and air pollution is discussed in relation to succession and preservation of oak forests at a certain successive stage on oligotrophic sandy soils. 相似文献
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The impact of winter harvesting on regeneration 50 years after an experimental diameter-limit cutting was examined in mixed deciduous–coniferous ecosystems of southern Quebec, Canada. The study was conducted in La Mauricie National Park, Quebec, Canada. Regeneration data in two balsam fir (Abies balsamea (L.) Mill.), red spruce (Picea rubens Sarg.), sugar maple (Acer saccharum Marsh.), and yellow birch (Betula alleghaniensis Britt.) ecosystem types were analyzed. Comparisons between uncut and cut stands were obtained from a total of 63 sample plots. For both ecosystems, there were no significant differences between uncut and cut plots for regeneration density and stocking. The most abundant regeneration species were balsam fir, red spruce, sugar maple, red maple (Acer rubrum L.), yellow birch and American beech (Fagus grandifolia Ehrh.). The type of diameter-limit cutting described in the study did not affect regeneration density and stocking but its impact on productivity, timber quality and genetics is still unknown. 相似文献
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This paper discusses determinants of the historical and current spatial extent of the floodplain forest in Leipzig as well as its tree species composition using a GIS-data based delineation model and historical forest inventories for the floodplain forest in the district of Leipzig in Germany from the 19th to the 20th century. We found that the spatial extent of the floodplain forest remained considerably stable in spite of an overall decline in the entire floodplain area from the period where the city first experienced industrialisation in the 19th century to now. However, with river regulations and the alteration of forest management from coppice-with-standards forest to high forest in the 19th century, major changes can be found in the tree species composition of the floodplain forest. Comparing these findings with references from other European floodplain forests we discuss the impact of historical and current forest management as well as the city location's influence on the extent and tree species composition of urban floodplain forests. For urban forest management in particular there is a great need to integrate biophysical, historical and forestry knowledge when predicting future developmental trends. 相似文献
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Theodore T. Salk Lee E. FrelichShinya Sugita Randy CalcoteJames B. Ferrari Rebecca A. Montgomery 《Forest Ecology and Management》2011,261(11):1998-2006
Anthropogenic factors such as elevated deer populations, invasive earthworms or climate change may alter old-growth forests of the Upper Midwest region of the United States. We examined demographic trends of woody species across all size classes over 35 years in a late-successional forest dominated by hemlock (Tsuga canadensis), sugar maple (Acer saccharum) and yellow birch (Betula alleghaniensis) in Michigan's Upper Peninsula using two sets of permanent plots. For the duration of the study period, species that were less-preferred white-tailed deer (Odocoileus virginianus) forage, especially sugar maple, comprised a much higher fraction of all seedlings and saplings compared to overstory trees. The density of small sugar maple declined across the study period, but no other species became more abundant, creating a more open forest understory. By the most recent census, preferred species for deer browse had been nearly eliminated from the understory, and declines in unpreferred species such as sugar maple were also apparent. We found small changes in temperature (<0.5-1 °C rise in minimum and maximum temperatures depending on season) and precipitation (±28 mm depending on season) and little evidence of invasive earthworms impacts. Our results suggest that the sustained elevated deer density is shifting the structure and composition of this old-growth forest. A demographic model showed that if current recruitment, growth and mortality rates were to continue for 500 years the forest would eventually reach a new equilibrium with virtually no hemlock or yellow birch remaining. 相似文献
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As in many parts of the world, rural and forest-dependent communities in Ontario are struggling with a variety of economic
and demographic challenges. Ontario government ministries are seeking to enhance rural sustainable development while at the
same time maintaining forest habitat and preventing forest biodiversity decline. Commercial maple sugar bushes, which in Eastern
Ontario are typically family owned and operated, have the potential to play an important role in biodiversity conservation
and habitat protection, while at the same time contributing to sustainable development. Existing research has shown the social
and economic benefits of small scale maple sugar bushes, but room remains for greater study of the environmental impacts,
particularly in terms of forest biodiversity. In this study, woodlot management practices on twenty-two sugar bushes in Eastern
Ontario were compared against established forest biodiversity conservation guidelines, using information obtained through
detailed interviews with operators. Sugar bush operators reported the presence of many important habitats on their properties.
The interview results show that many standard sugar bush management practices are consistent with biodiversity conservation
principles. Operators were found to be receptive to biodiversity conservation ideals, and could enhance their contribution
to the provincial government’s official biodiversity strategy with additional guidance, incentives, and formal planning. The
findings suggest that through sound management and planning, small scale commercial sugar bush operations generally can be
made environmentally sustainable, and become important components in broader rural development strategies. 相似文献
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中国植物资源广博，植物栽培以及园林应用历史悠久。从17世纪开始，中国植物开始陆续向世界传播，期间对运输保存技术、园林造景方式等都产生较大的影响，以英国园林引种中国植物为例，记述了相关引种栽培历史以及探索了对英国园艺技术的影响。植物的引种栽培促进了英国园林风格的改变，从17世纪早期到18世纪，英国园林中的温室和各式的花坛替代了大面积的草地以及希腊罗马式建筑小品。19世纪后期花境开始在英国园林中风靡，英国园林中草花的应用也成为了植物造景的主流。相较于其他地区引种的植物，中国的植物耐寒性强观赏性高，因此在英国园林中应用频率较高。17—19世纪中国植物在英国园林的发展进程中扮演了重要的角色。 相似文献
18.
We compared the acidity, the external acid neutralizing capacity and the buffering capacity of leaves of four commercially important tree species, largetooth aspen (Populus grandidentata Michx.), sugar maple (Acer saccharum Marsh.), paper birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill), at two sites of contrasting soil fertility in southern Quebec. External acid neutralizing capacity (ENC) of leaves was determined by measuring the change in pH induced by soaking fresh leaves in an acidic solution (pH 4.0) for two hours. The ENC was highest for largetooth aspen (14.3 micro equiv H(+) g(-1)), and lowest for sugar maple and balsam fir (< 5 micro equiv H(+) g(-1)). The buffering capacity index (BCI) was determined by measuring the amount of acid necessary to produce a change of 5 micro equiv H(+) in the leaf homogenate. The BCI ranged from 883 micro equiv H(+) g(-1) for largetooth aspen to less than 105 micro equiv H(+) g(-1) for sugar maple and balsam fir. Leaves of sugar maple and balsam fir had a lower internal pH and a higher percentage of ENC over BCI than paper birch and largetooth aspen. Overall, ENC was correlated with the concentration of all leaf nutrients except Ca, and BCI was correlated with Mg, N and Ca. The site effect was relatively unimportant for all variables. 相似文献
19.
Portugal's forests in the 12th century were dominated by the Fagaceae represented by Quercus and Castanea, and several pine species.From the 12th century onwards, forests underwent changes in their management starting with protection and ultimately leading to intense exploitation. The massive naval construction during the maritime expansion(mainly in the 15th–16th centuries) involved felling of approximately 5 million trees mainly Quercus suber, Pinus pinea and other Quercus species. Cumulative fuel-wood consumption of 959 Mm3 during 1300–1854 was attributed to demographic expansion while the deforestation rate during 1636–1854 accounted for a minimum of 72.6% and a maximum of 96% of total forest cover. The volume of timber used in railway sleepers from 1856 onwards might have reached 0.5 Mm3. The last quarter of the 20th century increased the forest cover of Portugal through the World Bank program of Eucalyptus globulus reforestation. 相似文献
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林业跨越式发展是我国建设现代林业的重要途径，现代林业是跨越式发展战略的目标。以现代林业理论指导我国林业跨越式发展是我国林业健康发展的根本要求。因此，我们要深刻领会现代林业理论的内涵，以可持续林业理论为指导，从林业的多目标经营入手，采取多种经营方式，依靠科学技术进步，动员全社会力量，实现林业的跨越式发展。 相似文献