(1) ZooWoods: A Naturalistic Landscape
Back to [ZooWoods Index] (2) Naturalistic Plantings: A recognition of ecologyUrban landscapes have traditionally used plants as if they were random assortments of living things, some combinations of which are more aesthetically pleasing than others. We have tended to plant vegetation where we want it and we have rarely thought about whether a particular plant or animal might have its own physiological requirements that might adapt it for some locations better than others. Rather than promoting plants in appropriate environments, we water, use pesticides, herbicides, and fertilizers in an attempt to change the environment in order to keep these "alien" plants growing where we want them. Ecologists tend not to view plants and animals as random assortments of living things. They generally recognize that the occurrence of a particular group of plants in a particular location can be understood in terms of the climatic extremes of the area, the nutrient conditions in the soil and perhaps the nature of animals that may pollinate or even feed on the plants. Ecological understanding has crossed disciplines to influence architects and landscape architects. Rather than continuing to view plants as aesthetic objects in the drab urban landscape, we now tend to recognize that a naturalistic approach to landscaping is environmentally friendly. Plants that are naturally adapted to an area tend to need only the water that is supplied from rain, are suited for the nutrient conditions found naturally in the soils, will survive the extremes of climate of the area and have come to some kind of generally peaceful co-existence with both the other plant species of their environment and with the insect or other pest species that are also endemic to the area. This means that once they are established, naturalistic landscapes should not require large investments in weeding or herbicides (used with exotic plants to reduce competition with "weeds"), should not require fertilizers (used to amend the nutrient composition of the soil), and should not require pesticides (used to keep plant predators at bay). Back to [ZooWoods Index | the Top of this page] (3) The Purpose of ZooWoodsZooWoods is an experiment to test whether native plant species will be a better landscaping choice for the environment on the UofT campus. The assumption is that native plants should be better adapted to the nutrient, water and "pest" species regimes of southern Ontario and hence require fewer chemicals, water or maintenance. However it will be years before these assumptions are fully tested. ZooWoods is a joint venture between staff of Facilities and Services at the University, the people responsible for the landscaping of the University of Toronto campus, and members of the Department of Zoology. A University's mandate is to create and disseminate knowledge and we believe ZooWoods exemplifies our mandate at a number of levels: (1) The Department of Zoology and the Division of the Environment both use the garden in laboratory/tutorial exercises. Several independent projects have already been undertaken by students in the Division, Zoology and Forestry. ENV200Y (Assessing Global Change: Science and the Environment), a large class of 300 students visits ZooWoods in an introduction to the ecosystem concept. (2) ZooWoods serves as an experimental site for Facilities and Services, who use it to learn how to deal with this new approach to landscaping. (3) Finally, ecology tells us that our campus cannot be considered in isolation from the urban landscape of the City of which we are a part. We hope ZooWoods serves to increase awareness of naturalistic landscaping both for other members of the University Community and for the larger public community around us. Back to [ZooWoods Index | the Top of this page] (4) The Beech-Maple Ecosystem4A IntroductionThe Beech-(Sugar) Maple forest is one "type" of eastern temperate forest community. Beech-Maple forests once covered much of southern Ontario including what is now the University of Toronto campus. Beech-Maple forests would have blended into the Carolinian deciduous forests to the south and the continental boreal forests to the north. As you might surmise from the name, beech-maple forests are characterized by an abundance of beech and (sugar) maple trees (in some cases up to 90% of the trees are of these two species). Other trees that are less frequently encountered are ash, oak, dogwood and witch hazel. In contrast to some other forest types, there are no unique shrubs or herbaceous plants that are exclusively characteristic of the Beech-Maple forest and over 500 species of herbaceous and woody plants have been identified in various Beech-Maple communities. You might wonder why two tree types characterize this system. Why for example, don't either Beech or Maple become dominant? The answer provides us with one insight into the nature of an ecosystem. Experiments on tree growth show that young maple trees grow better underneath old beech than they do under old maple trees. The reverse is also true: young beech seedlings grow better under older maple trees than they do under older beech trees. Ecologists call this phenomenon frequency-dependent selection: the more abundant a species becomes in the canopy, the worse its offspring do in the understory. Frequency-dependent selection results in a slow oscillation in the system between beech dominance and maple dominance as the current canopy dominant species is replaced by the understory-dominant species over a cycle that may take 500 years to see the process repeat itself. Beech are extremely long-lived, huge trees. The oldest beech in North America are over 360 years old and over 40 metres (120 feet) in height. They don't even begin to produce seeds until they over 40. Recent research on sugar maples has shown that they grow very slowly in the deep shade of beech trees, sometimes remaining surprisingly small for up to 150 years. Then when a disturbance occurs that permits more light to penetrate the understory, the sugar maple accelerates its growth up into the canopy where is may live for 100-200 years only to be replaced upon its death by more beech. 4B Is ZooWoods really an ecosystem?There are few remnants of Beech-Maple forest remaining in southern Ontario today and ZooWoods will never be a Beech-Maple forest. Instead it is an attempt to echo elements of the natural system that once characterized the site. It is also now home to numerous Beech-Maple herbaceous plants "rescued" from development for housing and the new 407 highway that has obliterated what little remained of beech-maple remnant forest in the GTA. Nevertheless, ZooWoods can be considered an ecosystem. Traditionally, ecologists have considered ecosystems to be energy processing unit whose components have evolved over a long period of time. At a minimum, we expect an ecosystem to have living and non-living parts and to exhibit two basic processes: chemical cycling and energy flow. The biotic community of a system, the living part, generally has at least an autotrophic species (a species that can produced its own food or organic matter from inorganic compounds and energy) and a decomposer species. As units, ecosystems are also expected to have boundaries. Sometimes these are well-defined. In other instances, the transitions between ecosystems can be gradual. There is nothing in the definition of "ecosystem" that excludes the presence of humans or anthropogenic structures. In natural ecosystems, plants serve many functions besides their role as autotrophs. They interact with the soil and its associated microbial community by taking up nutrients and water and by adding organic compounds. They serve as food for an extensive herbivore community that includes a wide variety of insects and other arthropods, amphibians, reptiles, birds and mammals, which are in turn, good for a complex of carnivores and decomposers. ZooWoods is a reasonably clearly defined system, although some would argue that it is made up of several smaller systems, e.g. the pond could be considered an aquatic ecosystem on its own and that it is embedded in the larger landscape that is the GTA. The challenge for us in ZooWoods is to capture as much of the natural function of a Beech-Maple system as we can given our small space. We have had to make choices about the ZooWoods system. The plant community is not a perfect representation of what one would find in a natural Beech-Maple system. We have emphasized plants with more wildlife value over those with less, since we realize that the area available for animals to forage is severely limited. We accept that the plant resources available in ZooWoods will never sustain the animal communities characteristic of large patch of intact Beech-Maple forest. We have added the obviously artificial pond and waterfall to our system to help increase local humidity and provide a close source of drinking water for animals. Sustained life on Planet Earth is a characteristic of ecosystems not a function of any individual species. We have tried to capture as much of that life sustaining function as we can in ZooWoods. In addition we hope we have provided an island of tranquillity where people can relax and enjoy the wonders of nature. At its best, naturalistic landscaping is an attempt to return ecological integrity to a fragmented, urban landscape. 4C ENV200Y Species ListWe are asking you to learn 3 species of trees and 3 other plants. While we have provided the scientific names of the plants or their genus and species names (the parenthetical italized two part names following the common name of the plant), you are only required to know the common name. Scientific names are often used among scientists so that there is no possibility of confusion given the myriad of common names often attached to the same organism in different locations. You can think of a scientific name as similiar to your own name except the last name comes first. The first word in a scientific name is the genus. It is like a last name. The species name comes second and it is unique to a particular organism. Just as there may be more people in your family with your last name, there may be more than one species within a genus. The trees we have chosen to highlight are the sugar maple (Acer saccharum), the Shagbark hickory (Carya ovata) and the green ash (Fraxinus pennsylvanica). The term "tree" isn't particularly definitive, but we all sort of know what a "tree" is - a tall, "woody" plant with a reasonably well developed crown of leaves and a single trunk. The term shrub is usually used for woody plants that are smaller than trees with multiple stems. All three trees we have chosen are deciduous, that is they lose their leaves in winter and all are characteristic of the Maple-Beech ecosystem, although they can be found in other forest types as well. The other three plants are a vine, the Virginia creeper (Parthenocissus quinquefolia), a species of Aster (Aster sp) and a species of goldenrod (Solidago sp.) The use of sp. rather than a species name with the goldenrod and aster simply refers to any species of the named genus. Using the following information, take notes or make sketches on page 31 - the page that is to be turned into your T.A. after the tutorial. These notes or sketches should be sufficient for you to be able to find any particular species in ZooWoods and mark its location on the map on page 31. Please stay on the path in ZooWoods! Sugar MapleGreen ashShagbark hickoryVirginia creeperAsterGoldenrodBack to [ZooWoods Index | the Top of this page] (5) ZooWoods as it was: Summer 1994
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