Eichen im Aargau – eine besondere Verantwortung für das Fricktal | Oak in the canton of Argovia – a special responsibility for the Fricktal
A targeted nurturing of oak in the canton of Argovia goes against the natural development of forest stands where the dominant, naturally occurring species is beech. Because of this, afforestation with oak is both work intensive and costly and is therefore concentrated on sites where silvicultural, economical and ecological aspects have been taken into account. With the help of a simple model showing areas where, above all, oak is nurtured, comprehensively mapped forest stands were classed according to competitiveness and correlated to thermal levels, that represent an important site factor for oak. One important aspect surrounding the issue is the preservation of genetic resources and an adequate supply of appropriate seed from chosen autochthonal, indigenous oak stands. In addition, the endangered population of middle spotted woodpecker, which is tied to widespread sites of aged oak-rich deciduous stands, should be fostered. Taking ecological priorities into account a possible area to nurture oak has bee...
Autochthon oder allochthon? Ein molekulargenetischer Ansatz am Beispiel der Eichen (Quercus spp.) in der Schweiz
Autochthonous forests are considered to be valuable genetic resources, and their conservation is incorporated into many national forest programmes. The methods applied so far often do not allow to distinguish between autochthonous and allochthonous stands. Therefore, alternative methods are needed. In this study, we analyse spatial patterns of variation of chloroplast DNA to estimate the extent of the human influence on oak stands in Switzerland.
Geographic And Environmental Influence On Maya Settlement Patterns Of The Northwest Yucatan: An Explanation For The Sparsely Settled Western Cenote Zone
Most settlement pattern research and GIS analysis of the ancient Maya of the Northern Yucatan have focused on water availability in a dry landscape where cenotes are often the only water source. While water is of paramount importance, permanent settlement secondarily requires farmable soil, a resource often as precious as water in many parts of the Yucatan. The dynamics between these resources reveal areas of ideal settlement and more challenging landscapes for which the Maya developed strategies to overcome environmental conditions. A region of the southwest "Cenote Zone", however, appears to have presented the ancient Maya with insurmountably poor environmental conditions despite abundant water resources. The lack of dense population and stone architecture in this area emphasizes the lack of a simple correlation between cenotes and settlement. This thesis uses GIS analysis to identify and explore such problematic settlement areas to better understand the factors and complexities involved in the more successful settlements of neighboring regions. iv This work is dedicated to my late father, who first introduced me to the Mundo Maya through a visit to the ruins of Tikal at the age of nine, and who instilled in me strength, curiosity, and a love for exploring the world. v ACKLOWLEDGEMENTS I'd like to acknowledge Dr. Arlen Chase and Dr. Diane Chase for providing such outstanding opportunities and instruction, and for leading by example both in the field and in the classroom. Dr. John Walker for his eye-opening perspectives, GIS instruction, inspiring hard-working attitude, and patience in the field. Dr. Clifford Brown and Dr. Walter Witschey for their invaluable correspondence and for their contributions to mapping and GIS data of Maya sites.