NUTRIENT RETRANSLOCATION INTO THE SOIL IN PURE AND MIXED STANDS OF PARROTIA PERSICA, CASE STUDY: PATOM DISTRICT OF KHEYROUD FOREST

2018 ◽  
Vol 8 (3) ◽  
pp. 561-574
Author(s):  
Maryam Salehi, ◽  
2010 ◽  
Vol 56 (No. 2) ◽  
pp. 58-67 ◽  
Author(s):  
F. Máliš ◽  
J. Vladovič ◽  
V. Čaboun ◽  
A. Vodálová

Natural mixed beech-fir forests were quite widely replaced by spruce dominated stands in Slovakia. Given the demands on the assessment of the forest status as well as on stopping the biodiversity loss it is required to evaluate the influence of <I>Picea abies</I> (L.) Karst. on the species composition. In a case study from the Veporské vrchy Mts. natural beech dominated forests were compared to stands with different spruce proportion. Within three groups of relevés with no, less and more than a half proportion of <I>Picea abies</I> the species diversity and Ellenberg indicator values were compared. The response of particular species to the proportion of <I>Picea abies</I> was evaluated by partial relation in direct gradient analysis. The increasing spruce proportion causes particularly higher occurrence of acidophytes and a decrease in nitrophytes. Species with the highest positive response to spruce are mostly shallow-rooted or characteristic of natural spruce forests. Greater richness along with the highest diversity was found in mixed stands with less than a half proportion of <I>Picea abies</I>. The most significant difference in species composition was between natural and spruce dominated stands. However the proportion of <I>Picea abies</I> does not reduce the species diversity in general, it causes significant changes in the species composition. As the results show, to avoid the negative effect and loss of phytodiversity it is required not to grow spruce dominated stands out of the natural occurrence of <I>Picea abies</I>.


2005 ◽  
Vol 62 (8) ◽  
pp. 807-816 ◽  
Author(s):  
Fyodor Tatarinov ◽  
Yury Bochkarev ◽  
Alexander Oltchev ◽  
Nadezhda Nadezhdina ◽  
Jan Cermak

2018 ◽  
Vol 64 (No. 5) ◽  
pp. 230-244 ◽  
Author(s):  
Basiri Reza ◽  
Moradi Mostafa ◽  
Kiani Bahman ◽  
Babaarabi Maryam Maasumi

The aim of this study was to determine the performance of distance methods in terms of accuracy, precision, bias, consumed time and sampling efficiency in the Maroon riparian forests, Iran. 40 estimators were used to evaluate the density of Populus euphratica Olivier trees in pure and mixed stands. Fifty quadrates (30 × 30 m) were established in each stand. To evaluate the accuracy, precision, bias, consumed time and efficiency of sampling techniques, relative root mean square error – RRMSE (%), coefficient of variation – CV (%), relative bias – RBIAS (%), t × RBIAS<sup>2</sup>, t × E<sup>2</sup>, where t is study time and E (%) is sampling error at a confidence level of 95%, and efficiency ratio between method j and k (Ef<sub>jk</sub>) were used. A compound of three basic distance estimators sampling method and n-tree were the best in both stands according to all criteria for density estimation. Moreover, variable area transect by Parker (g = 3) and quadrat method were the best methods for density estimation only in pure stand, while the angle order-point-centred quarter method was superior in mixed stand. Regarding to the results, we recommend the use of compound of three basic distances (BDAV3) and basic distance-nearest neighbour (BDNN2) for density estimation of P. euphratica stands in riparian forests.


Author(s):  
Māris Laiviņš ◽  
Gunta Čekstere ◽  
Dārta Kaupe

Abstract At the beginning of the 21st century, in extensively managed mature and over-mature conifer stands (Pinus sylvestris and Picea abies) in Latvia, establishment of native deciduous broad-leaved (Acer platanoides, Tilia cordata, Quercus robur and Ulmus laevis), as well as alien broad-leaved species (Acer pseudoplatanus and Tilia platyphyllos) has been observed. The establishment of deciduous broad-leaved species in coniferous stands is a process known as nemoralisation of coniferous stands, which is characterised by a large number of seedlings of broad-leaved species, young trees and the formation of a subcanopy layer in stands. Based on the age measurements of individuals of broad-leaved species trees, the establishment of some individuals into the studied coniferous stands occurred 40–50 years ago — in the 1970s–1980s. However, the predominant age of alien broad-leaved tree species in the study plots was 15–25 years, i.e. the introduction of large numbers of seedlings of these species in the coniferous stands occurred at the end of the 20th century. In this manner, in the final phase of the conifer replacement process, stable, mostly shade tolerant, mixed stands consisting of 3–4 species have formed, in which spruce is often found together with broad-leaved species.


Author(s):  
Marija Cosovic ◽  
Peter Biber ◽  
Miguel Bugalho ◽  
Brigite Botequim ◽  
Jose Borges

Motivation and objective: Because biodiversity conservation in forest management planning is necessary for ensuring regular ecosystem functioning, resilience and sustainability, the specific objective of this research was to quantify biodiversity at the landscape level in a forest plantation. Case study: Vale de Sousa, Forest Intervention Zone (ZIF), is located in the North of Portugal. ZIFs were formed all over the county with the objective to prevent forest fires, desertification and the abandonment of rural areas. The total case study area is 14.773 ha, mainly covered by plantation forests. The predominant forest species are maritime pine (Pinus pinaster) and blue gum (Eucalyptus globulus) either as pure or mixed stands. Methods:Fuzzy-logic system can serve as a platform for bundling expert knowledge on estimating ecosystem services provision and examining the consequences of contradictory expert views. The method was used to evaluate biodiversity as was recently proposed and demonstrated by Biber et al. (2018) in the context of the European Union (EU) project ALTERFOR (Alternative models and robust decision-making for future forest management - https://www.alterfor-project.eu/key-facts.html). In this study, we applied a fuzzy-logic approach for testing three biodiversity indicators: resident birds, heterogeneity of tree species diameter, and tree and shrub species richness. This approach generates scores for the rotation period of each plantation species between 0 (very low) and 1 (very high) for biodiversity categories. It also allows qualitative value rules regarding the above indicators. Scores are established according to stakeholder’s knowledge and validated by experts. Initially, the scores for each indicator are expressed as coloured matrices, but a final fuzzy output of biodiversity is expressed as a score between 0 and 1. Results: Our fuzzy outputs demonstrated low scores for biodiversity in monoculture stands, but medium scores in mixed stands. Tree and shrub species richness and diameter heterogeneity have low scores in analysed plantations but need to be tested in other forest types. However, the score for resident birds had medium values in monoculture forests, but due to the low score of the other biodiversity indicators, the overall biodiversity score is low. Conclusion: The results demonstrate that monocultures have the lowest score for biodiversity due to the zero level of all biodiversity indicators after the clear cut. Mixed stands have different periods of clear cut and this contributes to a higher score for biodiversity in general (fuzzy output). The fuzzy-logic approach is a very useful tool that may contribute to include biodiversity conservation in forest management decisions. This approach can be potentially used for the assessment of other biodiversity indicators (e.g. deadwood, large trees) in other forest types (including semi-natural and natural forests).


2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.


2020 ◽  
Vol 43 ◽  
Author(s):  
Michael Lifshitz ◽  
T. M. Luhrmann

Abstract Culture shapes our basic sensory experience of the world. This is particularly striking in the study of religion and psychosis, where we and others have shown that cultural context determines both the structure and content of hallucination-like events. The cultural shaping of hallucinations may provide a rich case-study for linking cultural learning with emerging prediction-based models of perception.


2019 ◽  
Vol 42 ◽  
Author(s):  
Daniel J. Povinelli ◽  
Gabrielle C. Glorioso ◽  
Shannon L. Kuznar ◽  
Mateja Pavlic

Abstract Hoerl and McCormack demonstrate that although animals possess a sophisticated temporal updating system, there is no evidence that they also possess a temporal reasoning system. This important case study is directly related to the broader claim that although animals are manifestly capable of first-order (perceptually-based) relational reasoning, they lack the capacity for higher-order, role-based relational reasoning. We argue this distinction applies to all domains of cognition.


2019 ◽  
Vol 42 ◽  
Author(s):  
Penny Van Bergen ◽  
John Sutton

Abstract Sociocultural developmental psychology can drive new directions in gadgetry science. We use autobiographical memory, a compound capacity incorporating episodic memory, as a case study. Autobiographical memory emerges late in development, supported by interactions with parents. Intervention research highlights the causal influence of these interactions, whereas cross-cultural research demonstrates culturally determined diversity. Different patterns of inheritance are discussed.


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