Inaugural Addresses (Forest and Wood Science)

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    Remote sensing : a window to/on our world?
    (Stellenbosch : University of Stellenbosch, 2005) Katsch, Christoph
    Inaugural address delivered by Christoph Kätsch on 15 November 2005. The relatively young scientific field of remote sensing deals with one of the oldest principles applied for orientation and evaluation of the surrounding environment developed during evolution on our planet. Beginning on a very simple level, the first organisms used electromagnetic radiation (mostly the daily sunlight) to raise energy and to collect information on the environment. Evolution finally led to the high end of natural remote sensors, the eye, which forms one of the most important senses for several creatures such as mammals. The eye, along with a high-performance organ, the brain, produces images from the environment, images which allow the individual to interact with others, to react to threats and to look for food. For human beings images, of course, mean much more than a real-time controlling and early-warning system. Images are important aids to seeing, analysing and understanding our world. Together with input from the other four senses, images enabled early scientists to discover, analyse and to define the first scientific principles.This may have started with the first human beings roaming the southern African bushveld and deserts, such as the San, who painted their views, thoughts and experiences on rocks several thousands of years ago. Images can of course show much more than our daily environment only. They can be used to make things visible that are not visible to the eyes, because of the limited perspective of a human being or the limited physical sensitivity of our eyes. Beyond that, they may come from the invisible virtual world of our minds and remain invisible until someone takes a pencil to draw them as images. And that is where the title for this presentation comes from. By analogy with the words of the German poet Rainer Maria Rilke (1875-1926), a contemporary of Albert Einstein, who proposed that poetry and the arts should open up a window on our world, scientists recently demanded that science should help to open this window even wider in special ways in order to help mankind to understand what is going on in the world and how global threats to civilisation may be overcome (cf. Fischer 2004). Obviously the idea of remote sensing will cross one’s mind when thinking about a window on our world. A look through a satellite’s camera or from an aeroplane window onto the earth opens up a really huge window, giving an impressive view onto oceans, land and cities. Rilke’s proposal was, of course, not that simple. He wanted poetry to open a window, and not a mirror, to our world, which allows deep insights into the functioning of the world for the benefit of human beings and for their welfare. He was deeply convinced that the arts and poetry could play a key role in understanding the new world which had been opened by science during his lifetime. It may be presumptuous to say that remote sensing really opened this second dimension of Rilke’s window to our world, but there is no doubt that this discipline contributes much to open a window through which we gained a lot of our current knowledge on our natural environment on earth and even beyond this of the universe. After more than 35 years remote sensing has developed into a complex system which incorporates three main components: first, electromagnetic radiation dealing as the medium for transporting data from remote objects; second, technical components for receiving, registering and storage of data; and finally, the data processing and evaluation of the data in order to derive relevant knowledge – information – from them. This paper aims to demonstrate how this technology has helped to open the window on our world significantly wider. It will give a short overview on the historic developments which led to a booming scientific field; it will then provide some examples on what is possible with today’s knowledge and, finally, present an outlook for specific research needs. Due to the very broad orientation of remote sensing that covers nearly all aspects of our natural, social and economic environment, it will be impossible to consider all relevant fields. The focus will therefore lie on natural resources and the disciplines dealing with them.
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    Impact of harvesting machinery on soil physical parameters : evaluation of ProFor model in three main forestry regions of South Africa
    (Stellenbosch : University of Stellenbosch, 2007-12) Kachamba, Daud Jones; Ackerman, P. A.; Rozanov, Andrei Borisovich; University of Stellenbosch. Faculty of Agrisciences. Dept. of Forest and Wood Science.
    Timber harvesting operations in plantation forestry in South Africa are rapidly being mechanised. However, movement of forest machines over the soil increases the potential for soil compaction and disturbance. In an effort to prevent forest soil damage, the Technical University of Munich developed the “ProFor” software. This software enables the calculation of critical soil water content for a given machine and physical soil characteristics. The applicability of ProFor in the South African forestry industry was assessed through the comparison of the evaluation of the impact of forest harvesting machines on soil properties with ProFor predictions. The study was conducted in four harvesting sites located in three of the major plantation forestry regions of South Africa namely: KwaZulu-Natal; Eastern Cape and the Western Cape. The impact of forest harvesting machines on soil physical properties was assessed through the evaluation of changes in soil saturation, soil bulk density and rut depth. The impacts of machine movements on soil physical properties were then compared with ProFor’s predictions. The study has indicated that ProFor gave good predictions of the critical water contents for most of the studied soils except for sandy soils. The study has also indicated that in more than 75% of the observed cases (r = 0.76) ProFor gave valid predictions of rut formation. However, ProFor predictions poorly correlated (r = -0.1) with the observed soil compaction. The model can be adopted for the South African forestry industry for use in the management of wet spots of a plantation. However, ProFor can be of even greater importance if a separate algorithm was built to be used for the prediction of soil compaction which is a common hazard in most South African forestry.