Our heritage is all that we know of ourselves, what we preserve of it, our only record. That record is our beacon in the darkness of time, the light that guides our steps. Conservation is the means by which we preserve it. It is a commitment not only to the past, but also to the future. To secure our records for the future is not an easy task. Libraries and archives all over the world face serious preservation issues. Whatever continent we focus on, we can find cultural heritage of many types, in many forms, each of which requires different preservation methods. It would be very difficult, therefore, to formulate a uniform policy for preservation. However, we cannot afford to sit on our hands. Conservation has not a very long history as a full-grown profession. The world of paper and book conservation became manifest only some 30 years ago. Today conservation is an established profession. Yet, this development is mainly in the developed countries, since the developing countries had more pressing matters to concentrate on. But it is only now that western conservators have started to realize that the problems their colleagues face at the other end of the globe are different and often more complex than their own.
At the same time western institutions needing solutions for mass conservation problems profit the most from the advances in conservation sciences. Let us hope that this will change in the future. Developing countries often suffer from specific threats to their cultural heritage. Extreme temperatures and relative humidity often cause large-scale infestation of country-specific insects and moulds. In addition, non-western written traditions, including the writing materials, are frequently different from western ones. Although individual governments and multilateral institutions give support and aid, it is mainly according to western preservation strategies. National programmers for preservation, including specific research projects, are being established. Care should be taken not to impose the solutions to western conservation problems on developing countries. Preservation research should rather aim at a better understanding of typical non-western conservation problems. To be informed on current conservation affairs will cost money. Many libraries and archives have had to end subscriptions to professional magazines because of cut backs in their budgets. However, with the arrival of the internet a lot of information is becoming more freely accessible and will contribute to a better and cheaper dissemination of knowledge.
Conservation in tropical climates is not a simple job. In 1966 the French archivist, Yves Pérotin said: ‘What an uphill struggle is the work of the tropical archivist’. But let us not forget that failure is the mother of success. The following paragraphs review some basic concepts and approaches that are relevant to conservation problems in the tropics. As there is much talk of tropical climate, attention is paid to what is actually understood by tropical climate. In fact quite a few references come from those fields of conservation. Many surveys have been published on almost all continents. Without this international cooperation the field of conservation remains very limited for both the rich and the poor countries.
Generally the tropical zone is defined as the area of land and water between the Tropic of Cancer (latitude 2 3.5/ N) and the Tropic of Capricorn (latitude 2 3.5/ S). Occupying approximately forty percent of the land surface of the earth, the tropics are the home to almost half of the world’s population. The area may be envisaged as a hot, moist band around the equator, typified by little seasonal change of temperature. There are variations in climate within the tropics; however ninety percent of the tropical zones embody hot and humid climatic regions, whether permanent or seasonal. The remaining ten percent is desert-like and characterized as hot and dry. The climates prevailing around the globe are primarily influenced by the sun’s energy heating up the land and water masses. At regional level the climate is influenced by altitude, topography, patterns of wind and ocean currents, the relation of land to water masses, geomorphology, and the vegetation pattern.
Accordingly, the tropical and subtropical regions can be divided into many different climatic zones, but for practical reasons, usually three main climate zones are considered:
• The hot-arid zone, including the desert or semi-desert climate and the hot dry maritime climate;
• The warm-humid zone, including the equatorial climate and the warm humid island climate;
• The temperate zone, including the monsoon climate and the tropical upland zone.
This division into three climatic zones is much generalized since many areas exist with differing climates or combination of types. Local conditions may also differ substantially from the prevailing climate of a region, depending on the topography, the altitude and the surroundings, which may be either natural or built by humans.
The presence of conditions like cold air pools, local wind, water bodies, urbanization, and altitude and ground surface can all influence the local climate strongly (Gut et al., 1993). As the features of each zone are different it is obvious that this will result in different problems and consequently different preservation solutions. However, the varied forms of tropical climate in different regions make it necessary to generalize in this stud y. Although we acknowledge the importance of the issue it is beyond the scope of this bibliography. Specific climatic zones are mentioned occasionally if the author so indicates. For ease of reference, the definition north-south facing is used in the sense of the northern hemisphere. For the southern hemisphere the terms have to be reversed. For example, where north orientation is recommended, then this is valid for the northern hemisphere only. For the southern hemisphere the orientation would naturally be south.