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1.
This paper uses the earliest colonial records for Essex County to establish and map the ingredients of the forest at European contact. It does so in the context of the work both of P. F. Maycock, the modern botanist, and the records of the colonial surveyors. It uses Maycock's thesis of the relationship of individual species to the soil moisture series. The paper establishes what the surveyors considered “good” and “poor” land, maps vegetation areas which the settlers may have discerned and offers statistical evidence for the idea that they, using the prevailing forest lore, could identify the better lands with a minimum knowledge of tree species. Specific references in the historical record suggest that these relationships were valid.  相似文献   

2.
Cadastral maps from the 17th and 18th centuries of villages in southwest Finland and Ostrobothnia have been used in this study to map the variations in land organisation that existed before the first enclosure ( storskiftet ). Settlement structure and land division in particular were found to vary regionally, a fact that can be explained by topographical circumstances but also by the different historical background of the historical provinces. The aim was to distinguish between the cultural influences on the use and ownership of land from Sweden (the west) and Finland (the east) respectively. Through the Swedish colonisation of Finland a feudal social organisation was introduced which affected village organisation all over the investigated area but to a varying degree, resulting in several types of settlements from planned villages with regular strip parcelling to villages developed through piecemeal colonisation and with an unsystematic division of the land.  相似文献   

3.
We consider the history of woodland clearing in central western New South Wales, Australia, which has led to the present highly cleared and fragmented landscape. A combined approach is used examining available historical land‐use data and using regression analysis to relate the pattern of cleared and wooded areas in the recent landscape to environmental variables, taking into account the contagious nature of clearing. We also ask whether it would be possible to apply a simple simulation modelling approach to reconstruct a credible historical sequence of clearing in the study area. The historical data indicate that annual clearing rates have varied substantially in the study area and selective tree removal (ringbarking and thinning) has been common. These findings make it unlikely that a simple simulation approach would replicate the spatial and temporal sequence of woodland loss. Our regression results show that clearing patterns can be related to environmental variables, particularly annual rainfall and estimated pre‐European vegetation type, but that patterns are dominated by contagion.  相似文献   

4.
In the context of an archaeological survey of the southern Argolid, Greece, studies have been carried out to elucidate the evolution of the landscape since its earliest known human occupation about 50,000 years ago. One of these studies was a detailed geological mapping of the late Quaternary alluvium and soils in the area. Dated by means of thorium-uranium disequilibria, archaeological finds, and historical information, seven periods of alluviation were identified, each of short duration relative to long intervening periods of stability and soil formation. The three earliest alluvial phases, falling before and during the last glacial interval, range from about 330,000 to 32,000 years in age. No alluviation accompanied the last glacial maximum around 20,000 years ago. In fact, a stable landscape persisted until about 4500 years ago, when debris flows and widespread aggradation in the valleys resulted from major slope destabilization and soil erosion, probably as a result of extensive land clearance in the Early Bronze Age. A subsequent stable period lasted through the many upheavals of the later Bronze Age, the Dark Ages, and the early historical period. It came to an end with a brief phase of alluviation between about 300 and 50 BC. Stability returned through the late Roman period, notwithstanding considerable expansion of the settled area. Another period of destabilization, this one marked by debris flows and hence major soil erosion, is poorly fixed in time, but probably coincides with expanded maquis clearance accompanying the resettlement of the area around AD 1000. Subsequent events of soil erosion and aggradation vary in nature and timing from one drainage to the next and, in some areas, continue today.Nature and chronology of the soil forming and alluviation events show that simple correlations with climatic events do not suffice to explain them. For the latter ones, past about 2500 BC, human activity seems to be the dominant cause, but once again the relation between cause and effect is not straightforward. Land clearing, or neglect of soil conservation efforts during economic downturns, appear to have a more devastating effect upon the landscape than do intensive land use or total land abandonment.  相似文献   

5.
西安地区全新世土壤的演变   总被引:1,自引:0,他引:1  
野外调查和室内实验资料表明 ,西安临潼全新世发育了 4层土壤。其中有两层发育在较温湿的气候条件下 ,两层发育在较冷干的气候条件下。温湿条件下发育的土壤为棕色土与淋溶褐土 ,冷干条件下发育的土壤为典型褐土与粘化黑垆土。临潼与长安全新世土壤结构及粒度成分指示 ,自全新世中期的大暖期以来 ,西安地区气候环境呈明显的变干趋势。  相似文献   

6.
A soil classification based on the genetic principles of Russia's Dokuchayev school is proposed for the tropical setting of Cuba. In view of the heavy degradation of the island's original forest and savanna soils, leaving fully developed soil profiles only in a few areas, such a genetic classification of Cuban soils must incorporate both the few fully developed soils proper and the various types of subsoil, consisting both of parent material and of its products of redeposition. The following types of parent material are distinguished: (a) quartz-allitic-ferritic, on acid crystalline rocks; (b) kaol-inite-allitic-ferritic, on schists; (c) zeolitic, on basic volcanics; (d) ferro-zeolitic, on ultrabasics, and (e) terra rossa, on crystalline limestones. These primary types of parent material, developed on crystalline rocks, have their secondary equivalents on sedimentary rocks.  相似文献   

7.
Falling trees commonly turbate soils in primary forest, creating characteristic edaphic patterns related to pit and mound topography. Vernal ponds with associated mounds were observed in mineral soils on a treeless plain in subalpine Tasmania, Australia. The hypothesis that paired ponds and mounds on the plain originated as pit and mound features in forests that were later destroyed by fire was tested by comparing the soils and landforms caused by recent tree falls in adjacent forest with those on the plain. The soil characteristics, orientations, and dimensions of the ponds and mounds were consistent with a tree fall origin, although rare secondary ponds on the tops of mounds may derive from the burrowing activities of the medium‐sized marsupial, Vombatus ursinus (common wombat). The characteristics of pond and mound soils suggested that most were hundreds to thousands of years old, with the ponds persisting because of differences in deflation, deposition, and organic matter formation between themselves and adjacent persistently dry land.  相似文献   

8.
历史上祁连山区森林的破坏与变迁考   总被引:13,自引:0,他引:13  
祁连山区宜林面积为2000余万亩,但现有林地面积仅700多万亩(食蔬林、灌木林面积),森林覆盖率不足15%,其减少的原因盖在于历史上的乱砍滥伐人为破坏之故。本文考索有关文献资料,对历史时期祁连山区林草资源的破坏状况作了系统探讨,以期为今天本区林草植被的保护和河西绿洲的可持续发展提供历史惜鉴。  相似文献   

9.
Relict arable soils dating fromc.AD700 provide an opportunity to identify early arable land management practices in the agriculturally marginal landscapes of the Lofoten archipelago, northern Norway. Synthesis of field survey and soil thin section micromorphology supported by image analysis suggests that there was deliberate management of erodible sandy soils in sloping locations to create small areas of cultivation terrace, with a range of materials used as soil amendments to stabilize the accumulated soil and enhance fertility. Small areas of sandy soils in more gently sloping locations were also cultivated, again with a range of materials used as amendments and which contributed to a significant increase in soil thickness. The last phase of cultivation commenced during the late 1800s and involved the reclamation of wetter, peaty soils by spade. These patterns of arable land management are repeated in different parts of Lofoten and indicate that despite the climatic and economic marginality of arable activity in Lofoten, land management practices were developed and applied to permit barley production from small areas.  相似文献   

10.
Soil investigations have been carried out at an Iron Age farm site lying under natural vegetation. The soils of the area were mapped and described, and soil samples analysed for pH, organic carbon, total nitrogen, acid‐soluble phosphorus, and available sodium, potassium, calcium and magnesium. Two soil types were distinguished on the mineral soils ‐ Brown Podzolic Soils and Iron Humus Podzols. The former are associated with a higher pH, higher phosphorus contents, and a lower carbon‐nitrogen ratio. These differences arc difficult to explain by natural causes, and arc ascribed to cultivation and manuring of the soil during the occupation of the site.  相似文献   

11.
Vegetation structure and composition during the pre‐ and early‐European period in Australia is often proposed as a benchmark against which to measure the effects of modern landscape management practices. However, little quantifiable information exists for that historical period. One potential source of information is the land survey record, used in this study to provide estimates of tree densities that existed during the period 1870 to 1900 in part of central New South Wales. Estimates were obtained for 23 parishes in the north Lachlan River valley, between the towns of Condobolin and Tottenham. Densities were calculated from portion corner to nearest tree data obtained from historical survey plans, using the plotless, closest individual method. Densities ranged from 6.0 to 31.4 trees per hectare for parishes with enough data points for reliable calculation. These figures would account for trees of a diameter large enough to be blazed with a survey mark. Any smaller trees would be additional and, although no quantitative data existed for this, qualitative evidence suggested that the figures obtained were more likely to be underestimates due to the presence of such small trees. The study area was predominantly covered by woodlands which varied in density across the landscape, in comparison to the modern landscape where much of the native vegetation has been cleared for agriculture. Although the tree density figures should be considered to be indicative rather than precise, they provide quantifiable historical figures for past conditions in an area where the historical record is otherwise sparse. Such information is valuable for interpreting ecological changes brought about by modern land management.  相似文献   

12.
山西省农业土地资源可持续利用研究   总被引:4,自引:0,他引:4  
郑国璋 《人文地理》2002,17(5):93-96
农业土地资源的可持续利用是实现农业可持续发展的基础和保证。本文通过分析山西农业土地资源的特点,开发利用现状及存在的主要问题,提出了山西农业土地资源可持续利用的主要措施:加快退耕还林步伐,调整农业用地结构,优化农业生态环境;加强生态农业建设,合理利用土地资源,提高土地生产率;加大农业生态环境整治力度,防止土地退化,减轻自然灾害;强化土地管理,规范土地市场,保护农业土地资源。  相似文献   

13.
Abstract

Monitoring and understanding of land use/forest cover dynamics as well as the factors affecting the changes in land use/forest cover are necessary for the sustainable management of natural resources. This study analyzes the spatial and temporal changes in land use and forest cover patterns in a typical mountain forest area in the Torul State Forest Enterprise area of Northeastern Turkey. The investigation evaluates the temporal changes of the spatial structure of forest conditions through the spatial analysis of forest-cover type maps from 1984 and 2005 using GIS and FRAGSTATS. The evidence presented here showed that there were drastic changes in the temporal and spatial dynamics of land use/forest cover, and between 1984 and 2005 there was a net increase of 19.9% in total forested area. Productive forest area increased by 3161 ha, although degraded forest area increased 9216 ha. In examining the changes of crown closure and development stages of the forest ecosystem during the study period, the forest stand area with low crown closures increased. The regenerated area increased because of regeneration activities while the other development stages were left to grow to older development stages in the period. These results regarding the crown closure and development stage show that forest quality has increased, and this is partly due to emigration of the rural population in Torul. In terms of spatial configuration, the landscape structure in Torul, the State Forest Enterprise area, changed substantially over the 21-year study period, resulting in fragmentation of the landscape as indicated by large patch numbers and smaller mean patch sizes, owing to heavy timber subtraction, illegal cutting, and uncontrolled stand treatments.  相似文献   

14.
利用科学测绘技术绘制的近代地图作为一类珍贵的历史地理资料,不同程度上反映着过去的地表覆盖情况,数字化则是复原地图所载地表覆盖信息的重要途径。以《华东·上海》地图为例,实现并验证一种基于机器学习和图像形态学的彩色近代地图数字化方法。结果表明,该方法能够充分挖掘地图中的颜色信息和形态结构信息,以半自动方式快速准确地将彩色近代地图中的地表水体信息提取出来。该方法对数字化一类彩色近代地图具有参考价值,有望为精准复原近代以来地表覆盖变迁,深入理解人地关系变化提供数据和方法基础。  相似文献   

15.
There is more woodland in Britain now than for many centuries and considering many international climate change mitigation policies, woodland cover, both in Britain and internationally, is being promoted. However, neither the management of existing woodlands nor their expansion should be at the expense of important archaeological evidence. Due to the large number of known archaeological sites, the large areas of land with uninvestigated archaeological potential and the expanding woodland cover, suitable mitigation strategies need to be developed to allow preservation in situ of important sites. An understanding of how woodland soils and the buried archaeological resource interact is, therefore, essential. This paper utilises ongoing environmental research into the mineral weathering rates in forest soils and considers its application to artefact preservation. The study concludes that soil water pH, its movement, and the saturation of dissolved ions in the soil solution are major factors determining both mineral and artefact longevity. A simple guide to artefact longevity based on these properties is proposed and a geochemical model for predicting loss is tested. These tools could be applied to any soil or individual horizon irrespective of land-use.  相似文献   

16.
Several parts of Binh Phuóc Province, southern Vietnam, suffer from degraded soils and vegetation as a result of both natural erosion of weak mud rocks and sandstones and intensive human activity, especially through land clearing for agriculture on unstable slopes, deforestation, and abandonment of poor farmland. The underlying cause of this land degradation has been the farming habits of migrants of varying ethnic groups who have settled in the area since 1980. The indigenous farming knowledge of these people and the role of that knowledge in soil erosion were examined by a series of household surveys. They enabled farming practices to be related to ground cover established from a 2002 Landsat 7 ETM (Enhanced Thematic Mapper), and erosion data from a series of erosion bridge measurements. A GIS (Geographical Information System) approach was piloted as a means of identifying areas vulnerable to erosion. This could then be combined with the understanding of farming practices to reveal the relative roles of farmer behaviour, crop cover, and slope and soil characteristics in the erosion process. Land use, local people's knowledge and economic realities are the main factors, as well as natural conditions, that drive this land degradation.  相似文献   

17.
Mont Lozère, located in the French Massif Central region, provides an exceptional context in which to research the impact that charcoal production and metallurgy had on woodlands, along with the role that these activities played in changing the mountain landscape. This study provides an insight into the land use, forest management methods and metallurgical practices in the area during the Middle Ages (11th to 15th centuries). Medieval charcoal burning platforms, archaeological remains that have often been neglected in the past as a source of historical information, along with nearby smelting sites, were identified, sampled and analysed. In this paper, spatial analyses, radiocarbon dating and anthracological and dendro-anthracological studies have been combined in a unique manner. The results reveal that charcoal burners practiced beech coppicing, where the species and diameter of wood used remained the same over a period of four centuries. It is proposed that this form of metallurgical forest management be considered an early example of a sustainable utilisation of natural resources.  相似文献   

18.
19.
对2000年、2005年及2010年的遥感影像图进行解译,得到3个时期的土地利用分类图,运用景观指数法和空间分析法等方法,对长株潭地区聚落的空间演化特征及动因进行分析,并分析了聚落与耕地之间的空间关系。结果表明:长株潭地区聚落的面积、数量规模和分布密度加速扩大,集中分布在高程200 m以下;聚落空间演化的自然动因是低地平原指向,而社会动因是人口规模的变化;提出耕地与聚落面积比指数(K)概念,根据K值的大小可以将耕地与聚落的空间组合关系分为3类地区:耕地资源紧缺区、耕地资源平衡区、耕地资源盈余区;聚落与耕地的空间转移关系可以分为两大类:持续稳定型和动态变化型;长沙市周边耕地转为聚落的趋势十分明显;聚落空间扩张对耕地的影响存在一个空间临界点,城市化速度越快,临界点的位置距离聚落越远。  相似文献   

20.
The archaeological record of dry rockshelters in the Red River Valley of eastern Kentucky contains botanical remains of several weedy annual seed-bearing plants that point to the independent development of agriculture during the Late Archaic and Early Woodland Period. The objective of this study is to gather quantitative data through the chemical and physical analysis of soils collected within a valley transect to gain insights into landscape processes and soil fertility that may have played a role in the early development of plant domestication and the location of garden plots in relation to rock shelter sites in the upper Cumberland Plateau region of eastern Kentucky. Soils on upland benches formed in limestones have soil fertility values that are comparable to fertile floodplain soils. Upslope outcrops of calcareous bedrock are contributing basic cations to these bench soils. Additionally, in comparison to other landscape positions these upland soils have high levels of organic carbon, available P and greater C:N ratios. Soil morphology, radiocarbon dates, and archaeological evidence indicate that many of the numerous earthflows and debris flows within the region are Early to Middle Holocene in age. These slides were likely generated by Mid-Holocene climatic shifts in which the frequency and intensity of summer precipitation increased across the southeastern United States. These slope failures may have contributed to the development of plant domestication by creating forest canopy gaps and disturbed soils in which weedy plants thrived.  相似文献   

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