Philip Juras - MLA Thesis 1997  
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The Presettlement Piedmont Savanna - A Model For Landscape Design and Management - Philip Juras 1997 (pdf format)
Table of Contents - Chapters: One - Two - Three - Four - Five - Six - Seven - Eight - Works Cited - Appendices: A - B - C - D - E

Chapter III - Savanna Landscape Preference

The preponderance of savanna-like landscapes in the human environment suggests that we as a species prefer such landscapes. This section examines potential reasons for and current perspectives of this preference.
 

Bioevolutionary Preference

Once dwelling in the relatively pleasant, colorful, elevated environment of the tree-tops, human ancestors developed enhanced abilities such as excellent color bifocal vision, dexterity of digits for grasping, sense of balance as well as a particular body size and shape. Later on in evolution pre-humans developed another set of abilities that reflected their fall from this forest Eden into the dog-eat-dog world of the open ground. As a result humans have a mixture of the flight responses of the timid forest dweller and the fight responses of the aggressive ground dweller (Kaplan and Kaplan, Humanscape 10-13). The transition of these human ancestors from tree dwelling to ground dwelling would have occurred near water in a zone between forest and grassland. Such areas could be described as a savanna or park, glade, or forest edge, and they would have been rich in variety and numbers of species. These savanna landscapes would have varied in size from expansive areas to narrow zones between grassland and tropical forest (Komarek, Fire Ecology 201). Early humans in this savanna environment would have to have ranged over very large areas of grassland to collect food, facing great danger from predators in doing so. Thus it was that humans developed the abilities to know a great deal about the terrain, their predators, and how to react quickly (Kaplan and Kaplan, Humanscape 5). The biological needs of survival and the ability to be immediately aware of their environment caused humans to prefer environments that could meet these needs.
 

Prospect Refuge Theory

As stated by Jay Appleton in Experience of Landscape, "Habitat Theory postulates that aesthetic pleasure in landscape derives from the observer experiencing an environment favorable to the satisfaction of his biological needs." More specifically, "prospect refuge theory postulates that, because the ability to see without being seen is an intermediate step in the satisfaction of these needs, the capacity of an environment to ensure the achievement of this becomes a more immediate source of aesthetic satisfaction" (73). If such is the case, early humans, and thus their modern day descendants, would prefer the spatial arrangements and visible attributes of the savanna where the open grassland offers unimpeded prospect and forest edge or groups of trees offer the opportunity to take refuge.

The uncertainties of modern life may not be all that different from those that greeted our ancestors when they came down from the trees to live on the danger-filled grounds of the open savanna. People generally prefer what they are familiar with and tend to react cautiously to the unknown (Kaplan and Kaplan, Cognition 77). The role of the unknown or the predator is played now by strangers, fast cars, biting insects, bad weather, and crime, and thus the preference for landscapes affording prospect and refuge is expressed by the landscapes in which we live. This can be seen in the light density of trees and shrubs in arrested succession and the abundance of open space found in both consciously designed landscapes and those that developed without a plan. Institutional settings, suburban landscapes and public parks, often of a picturesque nature, exemplify this, as do many managed forests, orchards and farmyards.
 

Environmental Preference from Kaplan and Kaplan

Another approach to understanding landscape preference that goes beyond the physical need oriented prospect-refuge theory is explained by Stephen and Rachel Kaplan in Cognition and Environment. Investigating human psychology in more depth, they describe preference as "the expression of the evaluation of one's possibilities,." of which the two most important components are making sense and involvement. Essential elements to an individual's well being, making sense and involvement have both a more immediate and a longer range aspect (80). Similarly, Aldo Leopold saw knowledge and experience as key components to the aesthetic appreciation of natural ecosystems (Gobster 68). The Kaplans consider space as having a central role in how an individual perceives a landscape, and that a space can be viewed both in an immediate, two- dimensional way and experienced in a longer term, three-dimensional way (Cognition 82). The framework shown below combines the two basic information needs of making sense and involvement with the dimensional aspects of the immediate and the future. This yields four distinct combinations which can be defined as coherence, complexity, mystery,

Preference Framework
  MAKING SENSE INVOLVEMENT
PRESENT OR IMMEDIATE Coherence Complexity
FUTURE OR PROMISED Legibility Mystery

Figure 3.1 Preference Framework (Kaplan and Kaplan, Cognition 81).

and legibility. Specifically comparing the elements of the preference framework (as described in Cognition and Environment [82-87]) to the savanna helps explain the human preference for savanna-like environments.

Coherence (Figure 3.2) is interpreted as the ease of organizing and structuring parts, units, chunks, blocks or scene elements. Patterns that result from many similar and repeating parts allow for easier human comprehension. Therefore a savanna-like landscape could be said to rank relatively high in coherence because of its few and repetitious types of elements which create easily recognizable patterns. For instance, the ground plain is essentially grassy throughout, and the trees repeat the same general appearance. A landscape low in coherence, such as a forest, might have many forms, sizes, colors, densities, and distributions resulting in less coherent complicated patterns. The prairie or ocean, on the other hand, can be very coherent due to their singularity.

Complexity (Figure 3.3) is a reflection of whether there is enough present in the scene to keep one mentally occupied. It should merit one's making a mental map of it. Too little is boring while too much is overwhelming. Therefore a savanna-like landscape could be said to be within the desired range of complexity. The ground plain and canopy are relatively uncomplicated elements on the whole, but the various patterns of ground layer species, the irregular spacing of trees, the indiscernible gradation into adjacent vegetation types, and the openness to the changing atmosphere creates an appropriate and desirable amount of complexity even at an initial glance.

Mystery (Figure 3.4) occurs when a scene provides partial information about what lies ahead, inviting exploration. Things are obscured in such a way as to reveal their presence but not their full identity. Therefore a savanna-like landscape could be said to be high in mystery. Because of its open aspect, views into the distance would be available, but the obstruction of the unevenly spaced trees, the rolling topography, and the atmospheric effects of aerial perspective enhanced by climatic conditions would prevent full disclosure and invite exploration. Some savanna arrangements might have more mystery than others. Mystery might be greatest in the area where the savanna grades into forest on uneven terrain and lowest where it grades into flat prairie.

Legibility (Figure 3.5) is found in an environment that looks as if one could explore extensively without getting lost. Undifferentiated sameness causes low legibility. Thus a savanna-like landscape could be said to rank very high in legibility. There is enough openness to see where one is going as well as distinct tree formations to provide landmarks. By contrast the open prairie has few landmarks and the forest too many.


Figure 3.2 Savanna Landscape Illustrating Coherence.


Figure 3.3 Savanna Landscape Illustrating Complexity.


Figure 3.4 Savanna Landscape Illustrating Mystery.


Figure 3.5 Savanna Landscape Illustrating Legibility.
 

 Other Preference Studies

In Paul Gobster's article "The Urban Savanna: Reuniting Ecological Preference and Function" in Restoration & Management Notes (pages 64-69), many studies are cited that discuss savannas and savanna elements as they relate to landscape preference. Following is a summary of the conclusions of these studies.

As a landscape, whether in a more natural or cultural configuration, a savanna-like setting is aesthetically preferred. Savanna scenes rated highest compared to coniferous forest, deciduous forest, tropical forest, and deserts. In his own study Gobster found inner city children preferred savanna settings over forests, wetlands, or prairies.

Elements found in savanna landscapes, such as tree form and distribution, are also aesthetically preferred. For instance, studies show mature trees are preferred in park and forest environments, and even-aged stands, without the multiple layering of various aged trees, are also preferred. Stand visual quality is dependent on "visual penetration," seen as a high overstory without any significant understory. The park-like appearance of the savanna is often mentioned as ideal. People prefer between 40 and 65 mature trees per acre in passive use areas, which would be the upper end of savanna density on a forest - prairie gradient. In urban parks people prefer even distribution of trees over tight clumps. Thinning and selective harvests in rural and wild land settings can increase preferences by opening forest canopies.

Savanna landscapes have a broad aesthetic appeal, but ecological integrity can negatively impact aesthetic preference. A survey of inner-city children showed greatest preference for a more formal savanna landscape with elms and lawn, and a lower level of preference for native savanna. Some visitors to the NC Botanical Garden, without special interest in or knowledge of native plants or ecology, viewed the ecological community displays as unkempt and overgrown. In a wild land setting, however, people prefer savannas with high ecological integrity. These preference findings point out the relationship of savanna landscape ecological integrity to site context and ecological awareness of the viewer. Where an ecological aesthetic is developed, people have a higher tolerance and greater appreciation for the more intricate, subtle and complex aspects of ecological integrity.

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The Presettlement Piedmont Savanna - A Model For Landscape Design and Management - Philip Juras 1997
Table of Contents - Chapters: One - Two - Three - Four - Five - Six - Seven - Eight - Works Cited - Appendices: A - B - C - D - E