Sustainable landscaping
Encyclopedia
Sustainable landscaping encompasses a variety of practices that have developed in response to environmental issues. These practices are used in every phase of landscaping, including design, construction, implementation and management of residential and commercial landscapes.
Issues of sustainability
Sustainability issues for landscaping include:
Non-sustainable practices include:
Effects of non-sustainable practices
Some of the effects of non-sustainable practices are: Severe degradation of the surrounding ecosystem; harm to human health, especially in the case of degraded drinking water supplies; harm to flora and fauna and their habitats; sedimentation of surface waters caused by stormwater runoff; chemical pollutants in drinking water caused by pesticide runoff; health problems caused by toxic fertilizers, toxic pesticides, improper use, handling, storage and disposal of pesticides; air and noise pollution caused by landscape equipment; invasion of wild lands by non-native weeds and insect pests; and over-use of limited natural resources.
Sustainable landscaping solutions
Some of the solutions being developed are:
Background
A sustainable landscape is designed to be both attractive and in balance with the local climate and environment and it should require minimal resource inputs. Thus, the design must be “functional, cost-efficient, visually pleasing, environmentally friendly and maintainable" As part of the concept called sustainable development
it pays close attention to the preservation of limited and costly resources, reducing waste and preventing air, water and soil pollution. Also, compost, fertilization, grass cycling, pest control measures that avoid or minimize the use of chemicals, integrated pest management
, using the right plant in the right place, appropriate use of turf, irrigation efficiency and xeriscaping
or water-wise gardening are all components of sustainable landscaping.
Benefits
The geographic location can determine what is sustainable due to differences in precipitation and temperature. For example, the California Waste Management Board emphasizes the link between minimizing environmental damage and maximizing one’s bottom line of urban commercial landscaping companies. In California, the benefits of landscapes often do not outweigh the cost of inputs like water and labor. However, using appropriately selected and properly sited plants may help to ensure that maintenance costs are lower than they otherwise would be due to reduced chemical and water inputs.
Programs
There are several programs in place that are open to participation by various groups. For example, the Audubon Cooperative Sanctuary Program for Golf Courses
, the Audubon Green NeighborhoodsTM Program, the National Wildlife Federation’s Backyard HabitatTM Program, and the Northeast Organic Farming Association Organic Land Care Program , to name a few.
The Sustainable Sites Initiative, the cooperative effort between the American Society of Landscape Architects
, the Lady Bird Johnson Wildflower Center
and the United States Botanic Garden, began in 2005 and will provide a points-based certification for landscapes, similar to the LEED program for buildings operated by the Green Building Council. The Sustainable Sites Initiative now has a document titled Guidelines and Performance Benchmarks. The credit system is expected to be completed in 2011.
Proper design
The primary step to landscape design is to do a "sustainability audit". This is similar to a landscape site analysis that is typically performed by landscape designers at the beginning of the design process. Factors such as lot size, house size, local covenants and budgets should be considered. The steps to design include a base plan, site inventory and analysis, construction documents, implementation and maintenance. Of great importance is considerations related to the growing conditions of the site. These include orientation to the sun, soil type, wind flow, slopes, shade and climate. The goal of reducing artificial irrigation and reducing use of toxic substances requires proper plant selection for the specific site.
Composting
Composting is a way to recycle kitchen and garden waste while creating inexpensive organic fertilizer for the garden and landscape. (For details about how to compost, see http://sustainablelandscaping.us/Blog_Archive.html). Earthworms, microbes and other soil flora and fauna feast on such organic matter when provided adequate nitrogen and proper temperatures and moisture. The ideal size for a compost pile or bin is one cubic yard (3' x 3' x 3'). It should be placed in a partly shady location to avoid intense sun and drying out, as this will delay the decomposition process. The pile heats up during the decomposition process, then cools as material is transformed, this is a good time to turn the pile, so that undecomposed materials on the periphery of the pile can be moved to the center to complete the process. With adequate moisture, nitrogen, proper temperature and correct timing of turning the pile, compost can be made in about a 30-day period. Left alone this pocess will still occur, but may take three to four months under less-than-ideal conditions.
Compost can be added as an amendment to poorly draining soil, as a fertilizer on flower and vegetable beds, to fruit trees or used as a potting soil for potted plants. Trimmings from lawns, trees and shrubs from a large landscape site can be used as feedstock for on-site composting. Reusing on-site organic materials will decrease the need for purchasing other soil additives.
Irrigation
Mulch may be used to reduce water loss due to evaporation, reduce weeds, minimize erosion
, dust and mud problems. Mulch can also add nutrients to the soil when it decomposes. However, mulch is most often used for weed suppression. Over use of mulch can result in harm to the selected plantings. Care must be taken in the source of the mulch, for instance, black walnut trees result in a toxic mulch product. Grass cycling turf areas (using mulching mowers that leave grass clippings on the lawn) will also decrease the amount of fertilizer needed, reduce landfill waste and reduce costs of disposal.
A common recommendation is to adding 2-4 inches of mulch in flower beds and under trees away from the trunk. Mulch should be applied under trees to the dripline (extension of the branches) in lieu of flowers, hostas, turf or other plants that are often planted there. This practice of planting under trees is detrimental to tree roots, especially when such plants are irrigated to an excessive level that harms the tree. One must be careful not to apply mulch to the bark of the tree. It can result in smothering, mold and to insect depredation.
The practice of xeriscaping
or water-wise gardening suggests that placing plants with similar water demands together will save time and low-water or drought tolerant plants would be a smart initial consideration.
A homeowner may consider consulting an accredited irrigation technician/auditor and obtain a water audit of current systems. In the event that the situation is difficult to manage, drip or sub-surface irrigation may be most effective. If the system has been in use for over five years, upgrading to evapotranspiration
(ET) controllers, soil sensors and refined control panels will improve the system. Oftentimes irrigation heads are in need of readjustment to avoid sprinkling on sidewalks or streets. Business owners may consider developing watering schedules based on historical or actual weather data and soil probes to monitor soil moisture prior to watering.
Building materials
When deciding what kind of building materials to put on a site it is important to recycle as often as possible. Reusing old bricks from sidewalks as patio pavers is one way to provide an aesthetic appeal to an area while reducing what goes to the landfill.
But it is also important to be careful about what materials you use, especially if you plan to grow food crops of any kind. Old telephone poles and railroad ties have usually been treated with a substance called creosote
that can leach into the soils and make any food grown there toxic enough to cause harm to anyone that eats it. In general, you should avoid any kind of treated material, especially wood, that could leach into the soil with rain.
The Forest Stewardship Council
(http://www.fscus.org/) was formed in 1993 "to change the dialogue about and the practice of sustainable forestry worldwide." Sustainably harvested lumber - also called certified wood
is now available, in which ecological, economic and social factors are integrated into the management of trees used for lumber. A chain of custody document is used in the certification process.
Planting selection
One important part of sustainable landscaping is plant selection. Most of what makes a landscape unsustainable is the amount of inputs required to grow a non-native plant on it. What this means is that a local plant, which has adapted to local climate conditions will require less work on the part of some other agent to flourish. For example, it does not make sense to grow tomatoes in Arizona because there is not enough natural rainfall for them to survive without constant watering. Instead, drought tolerant plants like succulents and cacti are better suited to survive. Also, by choosing native plants, one can avoid certain problems with insects and pests because these plants will also be adapted to deal with any local invader. The bottom line is that by choosing the right kind of local plants, a great deal of money can be saved on amendment costs, pest control and watering.
Plants used as windbreaks can save up to 30% on heating costs in winter. They also help with shading a residence or commercial building in summer, create cool air through evapo-transpiration and can cool hardscaped areas such as driveways and sidewalks.
A house surrounded by local trees or bushes enjoys multiple benefits. Plants release water vapor
in the air through transpiration
and water has the ability to reduce temperature extremes in the areas near it (as it boasts very high heat capacity
). The larger and more leafy the plant, the most water vapor it produces. Additionally, the presence of trees is crucial in the creation of stable, healthy and productive ecosystems (such as forests). In fact this is an important principle of permaculture
.
If the surrounding trees are chosen to produce edible fruit they can provide a sustainable food source for the occupants of the house. Even if some are fairly demanding (especially in the summer), irrigation is an excellent end-use option in greywater
recycling and rainwater harvesting
systems, and a composting toilet
can cover (at least) some of the nutrient
requirements. Research suggests that diluted human urine might be as effective as chemical fertilizers. Not all fruit trees are suitable for greywater irrigation, as reclaimed greywater is typically of high pH and acidophile
plants don't do well in alkaline environments.
An intelligent choice for direct energy conservation would be the placement of broadleaf deciduous
trees near the east, west and optionally north-facing walls of the house. Such selection provides shading in the summer while permitting large amounts of heat-carrying solar radiation to strike the house in the winter. The trees are to be placed as closely as possible to the house walls but no closer than 1 meter - otherwise the roots can cause substantial foundation damage. A sustainable house will most likely be equipped with south-facing (north-facing in the S. hemisphere) photovoltaic panels and a large, south-facing glazing
as a result of passive solar heating design. As the efficiency of both systems is very sensitive to shading, experts suggest the complete absence of trees near the south side.
Another intelligent choice would be that of a dense vegetative fence composed of evergreens (e.g. conifers) near that side from which cold continental winds blow (usually north in the N. hemisphere) and also that side from which the prevailing winds
blow (west in temperate regions of both hemispheres). Since north winds are most cold and westerlies blow most often, such choice creates an effective winter windbarrier that prevents very low temperatures outside the house and reduces air infiltration towards the inside. Calculations show that placing the windbrake at a distance twice the height of the trees can reduce the wind velocity by 75%. It then follows that, with some planning, both arrangements (deciduous and evergreen) can be applied simultaneously.
The above vegetative arrangements come with two disadvantages. Firstly, they minimize air circulation in summer (although in many climates heating is more important and costly than cooling) and, secondly, they may affect the efficiency of photovoltaic panels, thus prompting the need for a shading analysis. However, it has been estimated that if both arrangements are applied properly, they can reduce the overall house energy usage by up to 22%.
Maintenance
Pest Problems Maintaining plant health will eliminate most pest problems. It is best to start with pest-free plant materials and supplies and close inspection of the plant upon purchase is also recommended. Establishing diversity within the area of plant species will encourage beneficial organism populations (e.g. birds, insects), which feed on potential plant pests. Because plant pests vary from plant to plant, assessing the problem correctly is half the battle. The owner must consider whether the plant can tolerate the damage caused by the plant. If not, then does the plant value justify some sort of treatment? While pesticide is often chosen to solve the problem, physical barriers and repellents may help. If pesticides are the chosen method, selective organic or natural pesticide is often better because it has less impact on non-target species.
Pruning Proper pruning will increase air circulation and decrease the likelihood of plant diseases. However, improper pruning is detrimental to shrubs and trees. Hedging, topping and shearing of landscape plants causes excessive plant growth. In addition, topping is a hazardous practice which creates a hazardous tree which is highly susceptible to wind damage. Natural pruning techniques during the proper season, on the other hand, promotes healthier, more stable plants. In temperate areas, deciduous plants should be pruned during dormancy. Plants should never be pruned at the end of a growing season because growth is stimulated and such new growth will be too tender to survive winter freezing temperatures.
Pollution Prevention Landscape managers should make use of the Integrated Pest Management (IPM) to reduce use of pesticides and herbicides and reduce non-point source solution.
Campuses with sustainable landscaping projects or programs
See also
Issues of sustainability
Sustainability issues for landscaping include:
- Carbon SequestrationCarbon dioxide sinkA carbon sink is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. The process by which carbon sinks remove carbon dioxide from the atmosphere is known as carbon sequestration...
- Global Climate ChangeClimate changeClimate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
- Air PollutionAir pollutionAir pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....
- Water PollutionWater pollutionWater pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
- Pesticide Toxicity
- Non-Renewable ResourcesNon-renewable resourcesA non-renewable resource is a natural resource which cannot be produced, grown, generated, or used on a scale which can sustain its consumption rate, once depleted there is no more available for future needs. Also considered non-renewable are resources that are consumed much faster than nature...
- Energy Usage
- Native plantNative plantNative plant is a term to describe plants endemic or naturalized to a given area in geologic time.This includes plants that have developed, occur naturally, or existed for many years in an area...
Non-sustainable practices include:
- Soil contaminationSoil contaminationSoil contamination or soil pollution is caused by the presence of xenobiotic chemicals or other alteration in the natural soil environment....
- air and water contamination
- persistence of toxic compounds in the environment
- non-sustainable consumption of natural resourceNatural resourceNatural resources occur naturally within environments that exist relatively undisturbed by mankind, in a natural form. A natural resource is often characterized by amounts of biodiversity and geodiversity existent in various ecosystems....
s - Greenhouse gas emissions
- Invasive speciesInvasive species"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
Effects of non-sustainable practices
Some of the effects of non-sustainable practices are: Severe degradation of the surrounding ecosystem; harm to human health, especially in the case of degraded drinking water supplies; harm to flora and fauna and their habitats; sedimentation of surface waters caused by stormwater runoff; chemical pollutants in drinking water caused by pesticide runoff; health problems caused by toxic fertilizers, toxic pesticides, improper use, handling, storage and disposal of pesticides; air and noise pollution caused by landscape equipment; invasion of wild lands by non-native weeds and insect pests; and over-use of limited natural resources.
Sustainable landscaping solutions
Some of the solutions being developed are:
- Reduction of stormwater run-off through the use of bio-swales, rain gardenRain gardenA rain garden is a planted depression that allows rainwater runoff from impervious urban areas like roofs, driveways, walkways, parking lots, and compacted lawn areas the opportunity to be absorbed...
s and green roofs and walls. - Reduction of water use in landscapes through design of water-wise garden techniques (sometimes known as xeriscapingXeriscapingXeriscaping and xerogardening refers to landscaping and gardening in ways that reduce or eliminate the need for supplemental water from irrigation...
TM) - Bio-filtering of wastes through constructed wetlands
- Landscape irrigation using water from showers and sinks, known as gray water
- Integrated Pest Management techniques for pest controlPest controlPest control refers to the regulation or management of a species defined as a pest, usually because it is perceived to be detrimental to a person's health, the ecology or the economy.-History:...
- Creating and enhancing wildlife habitat in urban environments
- Energy-efficient landscape design in the form of proper placement and selection of shade trees and creation of wind breaks
- Permeable pavingPermeable pavingPermeable paving is a range of materials and techniques for paving roads, cycle-paths, parking lots and sidewalks that allow the movement of water and air around the paving material. Although some porous paving materials appear nearly indistinguishable from nonporous materials, their environmental...
materials to reduce stormwater run-off and allow rain water to infiltrate into the ground and replenish groundwater rather than run into surface water - Use of sustainably harvested wood, composite woodEngineered woodEngineered wood, also called composite wood, man-made wood, or manufactured board; includes a range of derivative wood products which are manufactured by binding the strands, particles, fibers, or veneers of wood, together with adhesives, to form composite materials...
products for decking and other landscape projects, as well as use of plastic lumberWood-plastic compositeWood-plastic composites are composite materials made of wood fiber/flour and plastic. In addition to wood fiber and plastic, WPCs can also contain other ligno-cellulosic and/or inorganic filler materials... - Recycling of products, such as glass, rubber from tires and other materials to create landscape productsLandscape productsLandscape products refers to a group of building industry products used by garden designers and landscape architects and exhibited at trade fairs devoted to these industries. It includes: walls, fences, paving, gardening tools, outdoor lighting, water features, fountains, garden furniture, garden...
such as paving stones, mulch and other materials - Soil managementSoil managementSoil management concerns all operations, practices and treatments used to protect soil and enhance its performance.-Practices:Soil management practices that affect soil quality:...
techniques, including composting kitchen and yard wastes, to maintain and enhance healthy soil that supports a diversity of soil lifeSoil lifeSoil life or soil biota is a collective term for all the organisms living within the soil.-Overview:In balanced soil, plants grow in an active and steady environment. The mineral content of the soil and its heartiful structure are important for their well-being, but it is the life in the earth that... - Integration and adoption of renewable energyRenewable energyRenewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...
, including solar-poweredSolar powerSolar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available...
landscape lighting
Background
A sustainable landscape is designed to be both attractive and in balance with the local climate and environment and it should require minimal resource inputs. Thus, the design must be “functional, cost-efficient, visually pleasing, environmentally friendly and maintainable" As part of the concept called sustainable development
Sustainable development
Sustainable development is a pattern of resource use, that aims to meet human needs while preserving the environment so that these needs can be met not only in the present, but also for generations to come...
it pays close attention to the preservation of limited and costly resources, reducing waste and preventing air, water and soil pollution. Also, compost, fertilization, grass cycling, pest control measures that avoid or minimize the use of chemicals, integrated pest management
Integrated Pest Management
Integrated pest management is an ecological approach to agricultural pest control that integrates pesticides/herbicides into a management system incorporating a range of practices for economic control of a pest...
, using the right plant in the right place, appropriate use of turf, irrigation efficiency and xeriscaping
Xeriscaping
Xeriscaping and xerogardening refers to landscaping and gardening in ways that reduce or eliminate the need for supplemental water from irrigation...
or water-wise gardening are all components of sustainable landscaping.
Benefits
The geographic location can determine what is sustainable due to differences in precipitation and temperature. For example, the California Waste Management Board emphasizes the link between minimizing environmental damage and maximizing one’s bottom line of urban commercial landscaping companies. In California, the benefits of landscapes often do not outweigh the cost of inputs like water and labor. However, using appropriately selected and properly sited plants may help to ensure that maintenance costs are lower than they otherwise would be due to reduced chemical and water inputs.
Programs
There are several programs in place that are open to participation by various groups. For example, the Audubon Cooperative Sanctuary Program for Golf Courses
Golf
Golf is a precision club and ball sport, in which competing players use many types of clubs to hit balls into a series of holes on a golf course using the fewest number of strokes....
, the Audubon Green NeighborhoodsTM Program, the National Wildlife Federation’s Backyard HabitatTM Program, and the Northeast Organic Farming Association Organic Land Care Program , to name a few.
The Sustainable Sites Initiative, the cooperative effort between the American Society of Landscape Architects
American Society of Landscape Architects
The American Society of Landscape Architects is the national professional association representing landscape architects, with more than 17,000 members in 48 chapters, representing all 50 states, U.S. territories, and 42 countries around the world, plus 68 student chapters...
, the Lady Bird Johnson Wildflower Center
Lady Bird Johnson Wildflower Center
The center currently functions as an Organizational Research Unit of The University of Texas at Austin.The Lady Bird Johnson Wildflower Center is a public botanical garden on La Crosse Avenue near the Mopac Expressway, 10 miles SW of downtown Austin, Texas and just inside the edge of the...
and the United States Botanic Garden, began in 2005 and will provide a points-based certification for landscapes, similar to the LEED program for buildings operated by the Green Building Council. The Sustainable Sites Initiative now has a document titled Guidelines and Performance Benchmarks. The credit system is expected to be completed in 2011.
Proper design
The primary step to landscape design is to do a "sustainability audit". This is similar to a landscape site analysis that is typically performed by landscape designers at the beginning of the design process. Factors such as lot size, house size, local covenants and budgets should be considered. The steps to design include a base plan, site inventory and analysis, construction documents, implementation and maintenance. Of great importance is considerations related to the growing conditions of the site. These include orientation to the sun, soil type, wind flow, slopes, shade and climate. The goal of reducing artificial irrigation and reducing use of toxic substances requires proper plant selection for the specific site.
Composting
Composting is a way to recycle kitchen and garden waste while creating inexpensive organic fertilizer for the garden and landscape. (For details about how to compost, see http://sustainablelandscaping.us/Blog_Archive.html). Earthworms, microbes and other soil flora and fauna feast on such organic matter when provided adequate nitrogen and proper temperatures and moisture. The ideal size for a compost pile or bin is one cubic yard (3' x 3' x 3'). It should be placed in a partly shady location to avoid intense sun and drying out, as this will delay the decomposition process. The pile heats up during the decomposition process, then cools as material is transformed, this is a good time to turn the pile, so that undecomposed materials on the periphery of the pile can be moved to the center to complete the process. With adequate moisture, nitrogen, proper temperature and correct timing of turning the pile, compost can be made in about a 30-day period. Left alone this pocess will still occur, but may take three to four months under less-than-ideal conditions.
Compost can be added as an amendment to poorly draining soil, as a fertilizer on flower and vegetable beds, to fruit trees or used as a potting soil for potted plants. Trimmings from lawns, trees and shrubs from a large landscape site can be used as feedstock for on-site composting. Reusing on-site organic materials will decrease the need for purchasing other soil additives.
Irrigation
Mulch may be used to reduce water loss due to evaporation, reduce weeds, minimize erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
, dust and mud problems. Mulch can also add nutrients to the soil when it decomposes. However, mulch is most often used for weed suppression. Over use of mulch can result in harm to the selected plantings. Care must be taken in the source of the mulch, for instance, black walnut trees result in a toxic mulch product. Grass cycling turf areas (using mulching mowers that leave grass clippings on the lawn) will also decrease the amount of fertilizer needed, reduce landfill waste and reduce costs of disposal.
A common recommendation is to adding 2-4 inches of mulch in flower beds and under trees away from the trunk. Mulch should be applied under trees to the dripline (extension of the branches) in lieu of flowers, hostas, turf or other plants that are often planted there. This practice of planting under trees is detrimental to tree roots, especially when such plants are irrigated to an excessive level that harms the tree. One must be careful not to apply mulch to the bark of the tree. It can result in smothering, mold and to insect depredation.
The practice of xeriscaping
Xeriscaping
Xeriscaping and xerogardening refers to landscaping and gardening in ways that reduce or eliminate the need for supplemental water from irrigation...
or water-wise gardening suggests that placing plants with similar water demands together will save time and low-water or drought tolerant plants would be a smart initial consideration.
A homeowner may consider consulting an accredited irrigation technician/auditor and obtain a water audit of current systems. In the event that the situation is difficult to manage, drip or sub-surface irrigation may be most effective. If the system has been in use for over five years, upgrading to evapotranspiration
Evapotranspiration
Evapotranspiration is a term used to describe the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies...
(ET) controllers, soil sensors and refined control panels will improve the system. Oftentimes irrigation heads are in need of readjustment to avoid sprinkling on sidewalks or streets. Business owners may consider developing watering schedules based on historical or actual weather data and soil probes to monitor soil moisture prior to watering.
Building materials
When deciding what kind of building materials to put on a site it is important to recycle as often as possible. Reusing old bricks from sidewalks as patio pavers is one way to provide an aesthetic appeal to an area while reducing what goes to the landfill.
But it is also important to be careful about what materials you use, especially if you plan to grow food crops of any kind. Old telephone poles and railroad ties have usually been treated with a substance called creosote
Creosote
Creosote is the portion of chemical products obtained by the distillation of a tar that remains heavier than water, notably useful for its anti-septic and preservative properties...
that can leach into the soils and make any food grown there toxic enough to cause harm to anyone that eats it. In general, you should avoid any kind of treated material, especially wood, that could leach into the soil with rain.
The Forest Stewardship Council
Forest Stewardship Council
The Forest Stewardship Council is an international not-for-profit, multi-stakeholder organization established in 1993 to promote responsible management of the world’s forests. Its main tools for achieving this are standard setting, independent certification and labeling of forest products...
(http://www.fscus.org/) was formed in 1993 "to change the dialogue about and the practice of sustainable forestry worldwide." Sustainably harvested lumber - also called certified wood
Certified wood
Certified wood and paper products come from responsibly managed forests – as defined by a particular standard. With third-party forest certification, an independent organization develops standards of good forest management, and independent auditors issue certificates to forest operations that...
is now available, in which ecological, economic and social factors are integrated into the management of trees used for lumber. A chain of custody document is used in the certification process.
Planting selection
One important part of sustainable landscaping is plant selection. Most of what makes a landscape unsustainable is the amount of inputs required to grow a non-native plant on it. What this means is that a local plant, which has adapted to local climate conditions will require less work on the part of some other agent to flourish. For example, it does not make sense to grow tomatoes in Arizona because there is not enough natural rainfall for them to survive without constant watering. Instead, drought tolerant plants like succulents and cacti are better suited to survive. Also, by choosing native plants, one can avoid certain problems with insects and pests because these plants will also be adapted to deal with any local invader. The bottom line is that by choosing the right kind of local plants, a great deal of money can be saved on amendment costs, pest control and watering.
Plants used as windbreaks can save up to 30% on heating costs in winter. They also help with shading a residence or commercial building in summer, create cool air through evapo-transpiration and can cool hardscaped areas such as driveways and sidewalks.
A house surrounded by local trees or bushes enjoys multiple benefits. Plants release water vapor
Water vapor
Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
in the air through transpiration
Transpiration
Transpiration is a process similar to evaporation. It is a part of the water cycle, and it is the loss of water vapor from parts of plants , especially in leaves but also in stems, flowers and roots. Leaf surfaces are dotted with openings which are collectively called stomata, and in most plants...
and water has the ability to reduce temperature extremes in the areas near it (as it boasts very high heat capacity
Heat capacity
Heat capacity , or thermal capacity, is the measurable physical quantity that characterizes the amount of heat required to change a substance's temperature by a given amount...
). The larger and more leafy the plant, the most water vapor it produces. Additionally, the presence of trees is crucial in the creation of stable, healthy and productive ecosystems (such as forests). In fact this is an important principle of permaculture
Permaculture
Permaculture is an approach to designing human settlements and agricultural systems that is modeled on the relationships found in nature. It is based on the ecology of how things interrelate rather than on the strictly biological concerns that form the foundation of modern agriculture...
.
If the surrounding trees are chosen to produce edible fruit they can provide a sustainable food source for the occupants of the house. Even if some are fairly demanding (especially in the summer), irrigation is an excellent end-use option in greywater
Greywater
Greywater is wastewater generated from domestic activities such as laundry, dishwashing, and bathing, which can be recycled on-site for uses such as landscape irrigation and constructed wetlands...
recycling and rainwater harvesting
Rainwater harvesting
Rainwater harvesting is the accumulating and storing of rainwater for reuse before it reaches the aquifer. It has been used to provide drinking water, water for livestock, water for irrigation, as well as other typical uses. Rainwater collected from the roofs of houses and local institutions can...
systems, and a composting toilet
Composting toilet
A composting toilet is a dry toilet that using a predominantly aerobic processing system that treats excreta, typically with no water or small volumes of flush water, via composting or managed aerobic decomposition...
can cover (at least) some of the nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
requirements. Research suggests that diluted human urine might be as effective as chemical fertilizers. Not all fruit trees are suitable for greywater irrigation, as reclaimed greywater is typically of high pH and acidophile
Acidophile
Acidophile may refer to:* Acidophile * Acidophile...
plants don't do well in alkaline environments.
An intelligent choice for direct energy conservation would be the placement of broadleaf deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
trees near the east, west and optionally north-facing walls of the house. Such selection provides shading in the summer while permitting large amounts of heat-carrying solar radiation to strike the house in the winter. The trees are to be placed as closely as possible to the house walls but no closer than 1 meter - otherwise the roots can cause substantial foundation damage. A sustainable house will most likely be equipped with south-facing (north-facing in the S. hemisphere) photovoltaic panels and a large, south-facing glazing
Glazing
Glazing, which derives from the Middle English for 'glass', is a part of a wall or window, made of glass. Glazing also describes the work done by a professional "glazier"...
as a result of passive solar heating design. As the efficiency of both systems is very sensitive to shading, experts suggest the complete absence of trees near the south side.
Another intelligent choice would be that of a dense vegetative fence composed of evergreens (e.g. conifers) near that side from which cold continental winds blow (usually north in the N. hemisphere) and also that side from which the prevailing winds
Prevailing winds
Prevailing winds are winds that blow predominantly from a single general direction over a particular point on Earth's surface. The dominant winds are the trends in direction of wind with the highest speed over a particular point on the Earth's surface. A region's prevailing and dominant winds...
blow (west in temperate regions of both hemispheres). Since north winds are most cold and westerlies blow most often, such choice creates an effective winter windbarrier that prevents very low temperatures outside the house and reduces air infiltration towards the inside. Calculations show that placing the windbrake at a distance twice the height of the trees can reduce the wind velocity by 75%. It then follows that, with some planning, both arrangements (deciduous and evergreen) can be applied simultaneously.
The above vegetative arrangements come with two disadvantages. Firstly, they minimize air circulation in summer (although in many climates heating is more important and costly than cooling) and, secondly, they may affect the efficiency of photovoltaic panels, thus prompting the need for a shading analysis. However, it has been estimated that if both arrangements are applied properly, they can reduce the overall house energy usage by up to 22%.
Maintenance
Pest Problems Maintaining plant health will eliminate most pest problems. It is best to start with pest-free plant materials and supplies and close inspection of the plant upon purchase is also recommended. Establishing diversity within the area of plant species will encourage beneficial organism populations (e.g. birds, insects), which feed on potential plant pests. Because plant pests vary from plant to plant, assessing the problem correctly is half the battle. The owner must consider whether the plant can tolerate the damage caused by the plant. If not, then does the plant value justify some sort of treatment? While pesticide is often chosen to solve the problem, physical barriers and repellents may help. If pesticides are the chosen method, selective organic or natural pesticide is often better because it has less impact on non-target species.
Pruning Proper pruning will increase air circulation and decrease the likelihood of plant diseases. However, improper pruning is detrimental to shrubs and trees. Hedging, topping and shearing of landscape plants causes excessive plant growth. In addition, topping is a hazardous practice which creates a hazardous tree which is highly susceptible to wind damage. Natural pruning techniques during the proper season, on the other hand, promotes healthier, more stable plants. In temperate areas, deciduous plants should be pruned during dormancy. Plants should never be pruned at the end of a growing season because growth is stimulated and such new growth will be too tender to survive winter freezing temperatures.
Pollution Prevention Landscape managers should make use of the Integrated Pest Management (IPM) to reduce use of pesticides and herbicides and reduce non-point source solution.
Campuses with sustainable landscaping projects or programs
- Iowa State UniversityIowa State UniversityIowa State University of Science and Technology, more commonly known as Iowa State University , is a public land-grant and space-grant research university located in Ames, Iowa, United States. Iowa State has produced astronauts, scientists, and Nobel and Pulitzer Prize winners, along with a host of...
- Michigan State UniversityMichigan State UniversityMichigan State University is a public research university in East Lansing, Michigan, USA. Founded in 1855, it was the pioneer land-grant institution and served as a model for future land-grant colleges in the United States under the 1862 Morrill Act.MSU pioneered the studies of packaging,...
- Mississippi State UniversityMississippi State UniversityThe Mississippi State University of Agriculture and Applied Science commonly known as Mississippi State University is a land-grant university located in Oktibbeha County, Mississippi, United States, partially in the town of Starkville and partially in an unincorporated area...
- North Carolina State UniversityNorth Carolina State UniversityNorth Carolina State University at Raleigh is a public, coeducational, extensive research university located in Raleigh, North Carolina, United States. Commonly known as NC State, the university is part of the University of North Carolina system and is a land, sea, and space grant institution...
- Swarthmore CollegeSwarthmore CollegeSwarthmore College is a private, independent, liberal arts college in the United States with an enrollment of about 1,500 students. The college is located in the borough of Swarthmore, Pennsylvania, 11 miles southwest of Philadelphia....
- Tufts UniversityTufts UniversityTufts University is a private research university located in Medford/Somerville, near Boston, Massachusetts. It is organized into ten schools, including two undergraduate programs and eight graduate divisions, on four campuses in Massachusetts and on the eastern border of France...
- University of DelawareUniversity of DelawareThe university is organized into seven colleges:* College of Agriculture and Natural Resources* College of Arts and Sciences* Alfred Lerner College of Business and Economics* College of Earth, Ocean and Environment* College of Education and Human Development...
- University of MinnesotaUniversity of MinnesotaThe University of Minnesota, Twin Cities is a public research university located in Minneapolis and St. Paul, Minnesota, United States. It is the oldest and largest part of the University of Minnesota system and has the fourth-largest main campus student body in the United States, with 52,557...
- University of New HampshireUniversity of New HampshireThe University of New Hampshire is a public university in the University System of New Hampshire , United States. The main campus is in Durham, New Hampshire. An additional campus is located in Manchester. With over 15,000 students, UNH is the largest university in New Hampshire. The university is...
- University of PennsylvaniaUniversity of PennsylvaniaThe University of Pennsylvania is a private, Ivy League university located in Philadelphia, Pennsylvania, United States. Penn is the fourth-oldest institution of higher education in the United States,Penn is the fourth-oldest using the founding dates claimed by each institution...
- University of Rhode IslandUniversity of Rhode IslandThe University of Rhode Island is the principal public research university in the U.S. state of Rhode Island. Its main campus is located in Kingston. Additional campuses include the Feinstein Campus in Providence, the Narragansett Bay Campus in Narragansett, and the W. Alton Jones Campus in West...
- University of Wisconsin
- Wesleyan UniversityWesleyan UniversityWesleyan University is a private liberal arts college founded in 1831 and located in Middletown, Connecticut. According to the Carnegie Foundation for the Advancement of Teaching, Wesleyan is the only Baccalaureate College in the nation that emphasizes undergraduate instruction in the arts and...
- Western Illinois UniversityWestern Illinois UniversityWestern Illinois University is a public university founded in 1899 as Western Illinois State Normal School. Like many similar institutions of the time, Western Illinois State Normal School focused on teacher training for its relatively small body of students. As the normal school grew, it became...
See also
- Sustainable gardeningSustainable gardeningSustainable gardening comprises a disparate group of horticultural interests that share, to a greater or lesser extent, the aims and objectives associated with the international post-1980s sustainable development and sustainability programs...
- NaturescapingNaturescapingNaturescaping is a term that refers to a method of landscape design and landscaping that allows people and nature to coexist...
- Landscape ecologyLandscape ecologyLandscape ecology is the science of studying and improving relationships between urban development and ecological processes in the environment and particular ecosystems...
- List of companion plants
- HorticultureHorticultureHorticulture is the industry and science of plant cultivation including the process of preparing soil for the planting of seeds, tubers, or cuttings. Horticulturists work and conduct research in the disciplines of plant propagation and cultivation, crop production, plant breeding and genetic...