Urban forestry - AbsoluteAstronomy.com

Urban forestry is the careful care and management of urban forest

Urban forest

An urban forest is a forest or a collection of trees that grow within a city, town or a suburb. In a wider sense it may include any kind of woody plant vegetation growing in and around human settlements. In a narrower sense it describes areas whose ecosystems are inherited from wilderness...

s, i.e., tree

Tree

A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

population

Population

A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...

s in urban

Urban area

An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...

settings for the purpose of improving the urban environment. Urban forestry advocates the role of trees as a critical part of the urban infrastructure. Urban foresters plant and maintain trees, support appropriate tree and forest preservation, conduct research and promote the many benefits trees provide. Urban forestry is practiced by municipal and commercial arborists, municipal and utility foresters, environmental policymakers, city planners, consultants, educators, researchers and community activists.

Management goals and objectives

Management goals should be based on an understanding of public attitudes, perceptions, and knowledge, a review of the agents in change, and the expressed needs and concerns of the community. These goals should be compared to a dynamic or temporal description of the resource based from inventory and management objectives (Mudrack 1980).

Functions and values

Function, the dynamic operation of the forest, includes biochemical cycles, gas exchange, primary productivity, competition, succession, and regeneration. In urban environments, forest functions are frequently related to the human environment. Trees are usually selected, planted, trimmed, and nurtured by people, often with specific intentions, as when a tree is planted in a front yard to shade the driveway and frame the residence. The functional benefits provided by this tree depend on structural attributes, such as species and location, as well as management activities that influence its growth, crown dimensions, and health. Urban forest functions are thus often oriented toward human outcomes, such as shade, beauty, and privacy. People develop emotional attachments to trees that give them special status and value. Removing hazardous trees can be difficult when it means severing the connection between residents and the trees they love. For many, feelings of attachment to trees in cities influences feelings for preservation of trees in forests (McPherson 1998).

Urban forests improve air quality, absorb rainwater, improve biodiversity and potentially allow recycling to 20% of waste which is wood-based

The social and even medical benefits of nature are also dramatic. Urban poverty is common to areas lacking green spaces. Visiting green areas in cities can counteract the stress of city life, renew vital energy and restore attention, and improve medical outcomes. Simply being able to see a natural view out of the window improves self discipline in inner city girls

Having regular access to woodland is desirable for schools, and indeed Forest kindergartens take children to visit substantial forests every day, whatever the weather. When such children go to primary school, teachers observe a significant improvement in reading, writing, mathematics, social skills and many other areas.

Various methods are available to capture the value of urban trees, each designed to analyse a specific type of green space (individual trees, parks, trees on golf courses etc). The following are examples of studies that have used these different approaches, along with their respective constraints.

Method	Study	Location	Results	Limitations
Contingent Valuation Contingent valuation Contingent valuation is a survey-based economic technique for the valuation of non-market resources, such as environmental preservation or the impact of contamination...	Tyrvainen (2001)	Joensuu and Salo, Finland	More than two-thirds of the respondents were willing to pay for the use of recreation areas, with mean WTP ranging from 42 to 53 FIM/ month, depending on their location.	Estimated value of environmental amenities is based on a hypothetical market scenario
Choice modelling and survey Choice Modelling Choice modelling attempts to model the decision process of an individual or segment in a particular context. Choice modelling may also be used to estimate non-market environmental benefits and costs....	Salazar and Menendez (2007)	Valencia, Spain	Residents closer to a proposed park had a higher WTP for the park than those further from it.	Bias, protest answers, strategic answers
Direct estimates	Pandit and Laband (2010)	Auburn, Alabama, USA	17.5 percent tree cover on property = 14.4 percent reduction in electricity ($31/month) 50 percent dense shade = 19.3 percent reduction in electricity ($42/month).	Mitigation effects of climate excluded, Aesthetic values excluded
Numerical Modelling	McPherson et al. (2005)	USA	Every dollar invested in urban tree management returned annual benefits ranging from $1.37 to $3.09.	Aesthetic values excluded

Challenges of urban forestry

Urban forestry is a practical discipline, which includes tree planting, care, and protection, and the overall management of trees as a collective resource. The urban environment presents the arboricultural challenges of limited root

Root

In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

and canopy

Canopy (forest)

In biology, the canopy is the aboveground portion of a plant community or crop, formed by plant crowns.For forests, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms .Sometimes the term canopy is used to refer to the extent...

space, poor soil quality

Soil quality

The proposed a definition, stating that ' is an account of the soil’s ability to provide ecosystem and social services through its capacities to perform its functions under changing conditions...

, deficiency or excess of water and light, heat, pollution, mechanical and chemical damage to trees, and mitigation of tree-related hazards. Management challenges include maintaining a tree and planting site inventory, quantifying and maximizing the benefits of trees, minimizing costs, obtaining and maintaining public support and funding, and establishing laws and policies for trees on public and on private land. Urban forestry presents many social issues that require addressing to allow urban forestry to be seen by the many as an advantage rather than a curse on their environment. Social issues include under funding and lack of management. Urban forestry also challenges the tree surgeons that tend the trees. The lack of space requires greater use of rigging skills and traffic and pedestrian control.

History

Tree warden laws in the New England states are important examples of some of the
earliest and most far-sighted state urban forestry and forest conservation legislation. In
1896, the Massachusetts legislature passed the first tree warden law, and the other five
New England states soon followed suit: Connecticut, Rhode Island, and New
Hampshire in 1901, Vermont in 1904, and Maine in 1919. (Kinney 1972, Favretti 1982, Campanella 2003).
As villages and towns grew in population and wealth, ornamentation of public, or common, spaces with shade trees also increased. However, the ornamentation of public areas did not evolve into a social movement until the late 18th century, when private individuals seriously promoted and sponsored public beautification with shade and ornamental trees (Favretti 1982, Lawrence 1995). Almost a century later, around 1850, institutions and organization were founded to promote ornamentation through private means (Egleston 1878, Favretti 1982).

In the 1890s, New England's “Nail” laws enabled towns to take definitive steps to distinguish which shade trees were public. Chapter 196 of the 1890 Massachusetts Acts and Resolves stated that a public shade tree was to be designated by driving a nail or spike, with the letter M plainly impressed on its head, into the relevant trunk. Connecticut passed a similar law in 1893, except its certified nails and spikes bore the letter C. (Northrup 1887).

In the United States, federal urban forestry policy is overseen by the USDA Forest Service, part of the Department of Agriculture

United States Department of Agriculture

The United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...

. Much of the work on the ground is performed by non-profits funded by private donations and government grants.

Policy on urban forestry is less contentious and partisan than many other forestry issues, such as resource extraction in national forests.

Urban forestry in Toronto

Toronto is a diverse city with a mosaic urban forest – a patchwork of unique situations made up of trees growing in the many residential yards, lining the public streets, and beautifying public parks. Unlike the trees that grow in a wild setting, urban trees are faced with harsh conditions that can be detrimental to their health and growing potential. Soil compaction, air pollution, habitat fragmentation and competition from invasive species are some of the hardships city trees endure. Some neighbourhoods have a geriatric tree population; many mature trees that will reach the end of their lifespan very soon, with few young trees to replace them.

Some neighbourhoods suffer a serious lack of species diversity, with mainly ornamental, non-native or invasive tree species such as Bradford pear, Japanese tree lilac and Norway maple. Still other neighbourhoods, most often newly constructed subdivisions, lack tree cover completely.

Simply planting more trees cannot solve the problems faced by the urban forest.
Through creative and innovative approaches the public, partnered with private enterprises can maximize the potential benefits of trees planted, and minimize the stresses they will have to overcome.

Although most people express a concern for urban trees and consider them very important, many lack the basic knowledge and skills needed to address and prevent the issues listed above. Collective action, or inaction, will make or break the future of the urban forest. Through fostering a sense of ownership amongst Toronto residents for this commonly owned resource, residents will enjoy better air quality and reduce their demand for energy.

Constraints to urban forestry

Resolving limitations will require coordinated efforts among cities, regions, and countries (Meza, 1992; Nilsson, 2000; Valencia, 2000).

Loss of green space is continuous as cities expand; available growing space is limited in city centres. This problem is compounded by pressure to convert green space, parks, etc. into building sites (Glickman, 1999).
Inadequate space is allowed for the root system.
Poor soil is used when planting specimens.
Incorrect and neglected staking leads to bark damage.
Larger, more mature trees are often used to provide scale and a sense of establishment to a scheme. These trees grow more slowly and do not thrive in alien soils whilst smaller specimens can adapt more readily to existing conditions.
Lack of information on the tolerances of urban tree cultivars to environmental constraints.
Poor tree selection which leads to problems in the future
Poor nursery stock and failure of post-care
Limited genetic diversity
Too few communities have working tree inventories and very few have urban forest management plans.
Lack of public awareness about the benefits of healthy urban forests.
Poor tree care practices by citizens and untrained arborists.

Urban forestry organizations

Alliance for Community Trees
American Forests
American Forests
American Forests is a 501 non-profit conservation organization dedicated to protecting and restoring healthy forest ecosystems. Their stated mission is to "grow a healthier world with trees". The organization was established in 1875 as the American Forestry Association by physician and...
Casey Trees
Casey Trees
Casey Trees is a non-profit organization established in 2001 to restore, enhance, and protect the tree canopy of Washington, D.C. The organization plants trees, engages volunteers in tree planting and care, offers an education program open to the public, monitors the District’s tree canopy, and...
Friends of the Urban Forest
International Society of Arboriculture
International Society of Arboriculture
The International Society of Arboriculture is an international non-profit organization headquartered in Champaign, Illinois USA. Its mission statement: "Through research, technology, and education promote the professional practice of arboriculture and foster a greater public awareness of the...
International Society of Arboriculture Australia Chapter
Our City Forest
Society of Municipal Arborists
Society of American Foresters
The Tree Council UK
Tree City USA Program
TREE Fund
TreeLink
Trees Are Good
Canopy
Trees Atlanta