836,536 research outputs found

    Stand Dynamics and Disturbance History of Champlain Valley Clayplain Forests

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    Studies of stand dynamics can explain how species interactions and disturbances drive forest structure and recruitment patterns of tree species. It is difficult to generate an understanding of stand dynamics and successional trends of forests in areas that have a long history of intense land use such as the Champlain Valley of Vermont, where over 230 years of agricultural activity has acutely and permanently influenced the landscape. The valley clayplain forest, a rare natural community containing endangered herbaceous plants and overstory tree species assemblages that are rare in Vermont, has been fragmented by agricultural use of the Champlain Valley. This study used dendroecological methods and assessments of forest structural conditions to describe the tree recruitment history and structural dynamics of two old-growth valley clayplain forest patches. Our results indicate that the valley clayplain forest has a species composition and recruitment history that has been heavily influenced by human land use throughout at least the past 230 years. We found that Quercus spp., typically considered characteristic of the valley clayplain forest, are being replaced by late-successional species such as Tsuga canadensis. Additionally, other human influences such as invasive species threaten to further alter the composition and dynamics of valley clayplain forests in the near future

    Strict Forest Reserve Research in the Margin of the Carpathians, the Vár-hegy Case-Study

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    Sixteen forest reserves are situated in the northern part of Hungary which belongs to the Carpathian region according to EURAC delimitation (Ruffini et al. 2006). These Hungarian forest reserves expand the natural forest remnant/forest reserve net of the Carpathians towards the lower hilly region, representing the deciduous beech and oak forest belts near their lower (xeric) distribution limits. This paper outlines the Hungarian forest reserves belonging to the Carpathian region and the preliminary results of current projects in the Vár-hegy Forest Reserve (Bükk Mts., Hungary) as a case study. The alteration of tree species composition was investigated here based on the reconstruction of forest history in the previous 130 years (management period) and analyses of forest stand inventory. In another project CO2 sequestration changes of these forest stands were modeled since the clear-cutting in the 1880th and carbon stored in the forest ecosystem compartments was estimated. Our results show that the forest reserve stands are presently in a transition state from the managed forest towards a more natural mixed forest with several age-classes

    Classroom on the Mountain

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    Outdoor class studies the history and impact of forest fires in the Cascade mountain range

    Unexpected understorey community development after 30 years in ancient and post-agricultural forests

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    1. Land-use change is considered one of the most radical and extensive disturbances that have influenced plant distributions and diversity patterns in forest understorey communities in much of Europe and eastern North America. In forests growing on former agricultural land, local species diversity and community differentiation among sites are generally reduced compared to ancient forests (i.e. forests with no historical record of agriculture). Yet, no study has determined how the compositional differences created by former land use change over time as the forest sites recover from former agricultural use. 2. Here we resurveyed 78 vegetation plots (half of the plots in ancient and half in post-agricultural forest) to demonstrate how three decades of forest development have changed the compositional differences between post-agricultural and ancient forest sites. The impact of land-use history and survey date was tested on two measures of species diversity and two measure of community divergence. 3. The data indicate that the imprint of former agricultural land use persisted over time, yet not through compositional stability. Parallel and strong vegetation shifts occurred in both ancient and post-agricultural forest: the species diversity decreased and local species cover strongly diverged, which indicates community drift. The observed understorey changes did thus not support the commonly accepted model of community development in post-agricultural forests, i.e. the diversity did not increase and the vegetation did not become more similar to the ancient forest vegetation over time. The changes in species composition were associated with an increase of common, competitive species at the expense of ancient forest indicator species. The source populations of ancient forest species have been gradually depleted, so the recovery of post-agricultural forests becomes even more precarious. 4. Synthesis. While land-use history is likely to persist as the primary predictor of local species diversity and community divergence, other environmental drivers may additionally structure forest understorey communities and lead to biotic impoverishment and pervasive species reordering on the time scale of only decades

    Former land use affects the nitrogen and phosphorus concentrations and biomass of forest herbs

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    The colonization rates of understorey plants into forests growing on former agricultural land differ remarkably among species. Different dispersal and recruitment largely account for the contrasting colonization rates, but different effects of the soil legacies of former agricultural land use on plant performance may also play a role. Seven herbaceous forest species were sampled in paired post-agricultural and ancient forest stands to study whether land-use history has an effect on the aboveground nutrient concentrations (N, P and N:P ratios) and biomass of forest herbs and, if so, whether slow and fast colonizing species respond differently. Results showed that P concentrations were significantly affected by former land use with higher concentrations in the post-agricultural stands. N concentrations were unaffected and N:P ratios were significantly higher in the ancient stands. Nutrient concentrations varied considerably among species, but the variation was unrelated to their colonization capacity. Six out of the seven species had higher biomass in the post-agricultural stands relative to the ancient stands, and the degree to which the species increased biomass was positively related to their colonization capacity, i.e., the fast colonizing species showed the strongest increase. Such differential responses to past land use may contribute to the contrasting colonization capacity of forest plants. Land-use history thus affected both the nutrient concentrations and biomass of forest herbs, and only the biomass response was related to colonization capacity

    Revolution and the end of history: Caryl Churchill's Mad Forest

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    Caryl Churchill’s Mad Forest, written and performed very soon after the Romanian revolution in 1990 and performed both in London and Bucharest, is a dynamic, inter-cultural play that represents a variety of perspectives on the revolutionary events, as well as oscillating between English and Romanian cultural and language coordinates. It has a peculiar topicality in its detailed and specific usages of different aspects of the revolutionary narrative, its sketches of family life before and after the revolution, and the inclusion of the revolution as reported in quasi-documentary-style testimony. The perspective in this article is one that places the play within a framework that thinks through Mad Forest’s relationship to the triumphant, neoliberalist heralding of “the end of history,” most famously argued by Francis Fukuyama in his 1989 article of that name. This discourse gained further confidence from the collapse of Eastern Europe, a collapse that was viewed by proponents of the end-of-history argument as signalling the permanent disintegration of communism and a victory for capitalism. However, Mad Forest is considered here as a play that reflects multiple perspectives on the revolutionary period and, while declining to provide political solutions as such, simultaneously refuses to accede to the implications of the end-of-history argument

    Remnants of the Waikato: native forest survival in a production landscape

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    This paper addresses the issue of conservation of native biodiversity on privately owned farmland in New Zealand. Based on surveys of Waikato dairy farmers as exemplars of intensive agricultural practice, it examines factors that influence the survival of native forest on land with potential for commercial production. Results suggest that a significant proportion of Waikato dairy farmers regard native forest favourably although the proportion of farmers who actively conserve their native forest is small. Factors that assist the persistence of native forest on dairy farms include personal characteristics of the farmer, past accidents of history which have left forest remnants in place, and physical characteristics of the farm such as topography. While the conservation of native biodiversity within this intensively farmed landscape is strongly influenced by political economy pressures that encourage production, non-utilitarian motives such as aesthetic enjoyment and family heritage can serve to counter the production ethic

    Role of plant functional traits in determining vegetation composition of abandoned grazing land in north-eastern Victoria, Australia

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    Question: In the Northern Hemisphere, species with dispersal limitations are typically absent from secondary forests. In Australia, little is known about dispersal mechanisms and other traits that drive species composition within post-agricultural, secondary forest. We asked whether mode of seed dispersal, nutrient uptake strategy, fire response, and life form in extant vegetation differ according to land-use history. We also asked whether functional traits of Australian species that confer tolerance to grazing and re-colonisation potential differ from those in the Northern Hemisphere. Location: Delatite Peninsula, NE Victoria, Australia. Methods: The vegetation of primary and secondary forests was surveyed using a paired-plot design. Eight traits were measured for all species recorded. ANOSIM tests and Non-metric Multi-dimensional Scaling were used to test differences in the abundance of plant attributes between land-use types. Results: Land-use history had a significant effect on vegetation composition. Specific leaf area (SLA) proved to be the best predictor of response to land-use change. Primary forest species were typically myrmecochorous phanerophytes with low SLA. In the secondary forest, species were typically therophytes with epizoochorous dispersal and high SLA. Conclusions: The attributes of species in secondary forests provide tolerance to grazing suggesting that disturbance caused by past grazing activity determined the composition of these forests. Myrmecochores were rare in secondary forests, suggesting that species had failed to re-colonise due to dispersal limitations. Functional traits that resulted in species loss through disturbance and prevented re-colonisation were different to those in the Northern Hemisphere and were attributable to the sclerophyllous nature of the primary forest

    Historical land-use information from culturally modified trees

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    In a global perspective, the human impact on forest ecosystems varies greatly in type, frequency and magnitude. Knowledge of the history of forest use is crucial for understanding the development of forests, which in turn helps to understand how societies react to forest development. Culturally modified trees (CMTs), recorded in the western U.S., northern Scandinavia and south-eastern Australia, are features that can be dated precisely, and they bear witness to unique events of human activity. CMTs are traces from historical uses of forest resources that reflect the activities of local communities and extend far back in time, and therefore offer information not usually available from other sources. In this thesis I argue that CMTs have high potential for assessing human activity and possibly human impacts on forest ecosystems, particularly those concerning local indigenous uses. Periods of increased activity in a certain area are reflected in peaks in the distribution of CMT dates. These also show the time period and speed of abandonment of a traditional forest use in a landscape. The possibility to learn about the people, their behaviour and activities in the forest are good, but their impact on ecosystems will always be difficult to assess when only CMT data are available. Therefore, it is important to learn as much as possible about traditional customs expressed in CMTs, in combination with oral and ethnological sources, and the role of CMTs in the traditional use of the forest. In this way it is possible to estimate what the density and distribution of CMTs in the landscape actually tells us about historical impact on the ecosystem. CMTs contradict the idea of “pristine” forests but symbolize the traditional view that people are part of nature rather than separate from it
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