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Prevention of Hazardous Tree Defects, Part II

– By Gary R. Johnson,

Richard J. Hauer, and Jill D. Pokorny

(Following is an adaptation of the second half of an article by the authors cited above. 

The first half of this article was presented in the November edition of the Citizen Forester

and can be viewed on the DCR web site at http://www.mass.gov/dcr/stewardship/forestry/urban/citForester.htm

Introduction

In part one of this article, the authors presented long term methods for reducing the

occurrence of tree hazards.  By taking steps to design a species-diverse, uneven – aged

forest, match tree species to site conditions, and purchase high quality nursery stock, the

authors contend that community foresters can reduce the incidence of tree hazards and

the costs associated with mitigation of those hazards.   

In this second half of the article, the authors review proper tree planting and pruning

guidelines and protection of trees from construction damage as further steps to reduce the

formation of tree hazards.  By observing proper planting technique, maintaining tree

structure with appropriate pruning and protecting trees during construction activities,

community foresters can have a positive impact throughout the life span of shade trees. 

Proper Tree Planting Techniques

Trees can be purchased as bare root, containerized, or balled and burlapped specimens. 

Basic planting methods are the same for all specimen types, but handling and special

considerations apply, depending on the size and the type of tree.  (A checklist of basic

planting guidelines for all three types, and planting guidelines for special situations is

provided in the article).  

Basic Planting Guidelines for All Tree Types:  Match the tree species to site conditions. 

Base this on the soil type, soil pH, surface and sub-soil drainage, growing space,

exposure factors (e.g. sun, wind, ice and snow, and de-icing salts), and the tree’s cold

hardiness.  

Prepare the site by removing the sod.  Loosen the soil by tilling or spading an area three

to five times wider in diameter than the width of the root system, and only to the depth of

the root system.  

Dig a hole in the center of this circle that is 1 to 2 feet larger in diameter than the root ball

and deep enough so the root collar is at the soil surface when the tree is planted.  The root

collar is the base of the stem where the primary roots first begin to branch away from the

stem.  The root collar may be buried in balled and burlapped, container grown, or tree

spade dug trees because of the way the trees are dug in the nursery.  If you find the root

collar is buried to 3 inches deep in the root ball, dig the planting hole 3 inches shallower

than the depth of the root ball.   

Maintain undisturbed (not loosened) soil beneath the root ball to prevent the tree from

settling.  Carefully place the tree in the center of the hole and gently remove any excess

soil to expose the root collar flare.  Double-check that the root collar (base of the stem

where the primary roots first begin to branch away from the stem) is at soil surface or

slightly above (e.g. 1 to 2 inches).  Planting trees at the proper depth, and not too deeply,

is a critical step that can help to prevent the development of stem girdling roots and

premature tree failure.  Stem girdling roots can compress and kill trunk tissue, and cause

trees to decline 10 to 20 years after planting or suddenly fail during storms by snapping

off at the stem/root compression area.  

Backfill around the roots with the soil that was removed.  Lightly pack or water the soil

during this process to eliminate air pockets.  Backfill the planting hole to the height of the

root collar, but no higher.  

Mulch with 4 to 6 inches of coarse wood chips or shredded bark.  Pull the mulch back

away from the trunk to prevent direct contact with the root collar and trunk.  Be sure to

avoid creating a mulch volcano by applying the mulch too deeply and placing it right up

to the stem.  

Water is very important to a newly planted tree.  Newly transplanted trees will benefit

from daily watering for the first 1 to 2 weeks, applying approximately 1 to 3 inches of

water per caliper inch at each watering.  Thereafter, water trees every 2 to 3 days for the

next 2 to 3 months and then weekly until established.  Remember, roots need oxygen,

too! Adjust the watering schedule accordingly for rain or very dry conditions.  

Important “Don’t Forget” items and Planting Guidelines for Special
Situations

The planting guidelines given above are general in nature and apply in the great majority

of planting situations.  The complete article includes subsequent sections on specific

“don’t’ forget to” procedures and issues that often arise during tree planting.  Some of

these items include steps for handling girdling roots and the special moisture needs of

bare root stock.  In addition, planting suggestions for dealing with heavy and/ or poorly

drained soils, proper staking methodologies and many other topics are covered in these

sections.  

Proper Tree Pruning Techniques  

Sound arboricultural practices will prevent development of many hazardous tree defects. 

Investing community resources in proper tree pruning techniques is one of the most

effective tree risk management strategies.  Early formative pruning and ongoing

maintenance pruning will prevent the development or eliminate many tree defects that are

leading causes of tree failure.  Early and regular tree pruning will also reduce the costs of

subsequent pruning, tree removal, and replanting.  

Industry standards for pruning trees are published by the American National Standards

Institute in The American National Standard for Tree Care Operations – Trees, Shrubs

and other Woody Plant Maintenance – Standard Practices: ANSI A300 – 1995 (ANSI

1995).  These industry standards can help communities develop pruning specifications

and safety regulations.  Community tree care managers who write contracts and bidding

specifications for tree maintenance work projects should be familiar with them.  

The complete article includes discussion sections related to the following pruning related

topics:

  • Pruning Schedules
  • Pruning Young Trees
  • Basic Pruning Methods
  • Wound Dressings 
  • Timing of Pruning
  • Protection of Trees from Construction Damage

Construction activities impact trees and can create or exacerbate hazardous situations. 

Protecting tree health and mitigating high-risk situations on a construction site is a matter

of recognizing the potential impacts of construction activities, and identifying hazardous

trees or defects that exist on the site.  Avoiding or minimizing construction damage is a

critical step in preventing the development of many hazardous tree defects, and

eliminates the costs of treating construction damaged trees.  Advanced planning and

simple mitigation steps can minimize the risks associated with trees during and after

construction.  These include:

  • Protecting healthy, structurally sound trees 
  • Protecting trees from direct injury
  • Protecting the structural integrity of trees
  • Protecting the overall health of trees throughout construction
  • Street trees and construction damage

Each of these topics is addressed in detail in the complete article.  The section dealing

with street trees includes a comprehensive list of suggestions for avoiding or mitigating

the construction effects that often have such serious negative impacts upon shade trees on

our streets.  

Conclusion

In the urban and community setting, the actions of human beings may have become the

primary influence on the health of the ecosystem and its many elements, including trees. 

While it is impossible to avoid  the development of all tree hazards, it should be clear

from this and the previous related article that humans can use our influence to greatly

reduce the incidence of hazard tree defects.  With thoughtful planning and proper species

selection, consideration of site limitations, careful planting, prudent pruning and

maintenance and effective protection, our urban and community forests will offer even

greater benefits with much reduced costs, risks and liabilities.  

Harvesting Urban Timber:  An Option for Municipal Forest Managers

(Following is an article adapted from “Recycling Municipal Trees: A Guide for

Marketing Sawlogs from Street Tree Removals in Municipalities”  by Edward T. Cesa,

Edward Lempicki and J. Howard Knotts – see full citation below)

Introduction

Many municipalities and local governments are currently experiencing budgeting

problems in meeting community needs.  Street tree management and maintenance

budgets are among those becoming strained.  As a result, the quality of our street trees

cannot help but suffer as economic considerations continue to reduce tree management

budgets.

Presently, much of the wood generated from street tree removals brings little economic

return to tree management budgets.  Because of this, most tree management and

maintenance programs are being run as a cost burden to municipal budgets.  Although

most tree management crews are hardworking and efficient, the products rendered from

street tree removals are usually low-value, which returns little money to municipal

coffers.  In fact, in New Jersey (for example), it is estimated that more than 50 percent of

an average municipality’s tree management budget is spent on the cost of tree removals

alone.  

Tree mortality from natural occurrences like insects, diseases, and storms plus a myriad

of man made circumstances such as roadway widening, right-of-way maintenance, and

utility construction activities, take a huge toll on street trees.  This results in a continuing

need for tree maintenance on a municipal level.  Much of this harvested wood, if

produced and marketed effectively, can generate income for municipalities to help

support tree management and maintenance programs.  

An alternative to disposing of removed trees by cutting them into fire wood or chipping

them is to consider the potential marketability of sawmill-size logs from municipal tree

removals.  Advantages of merchandising salable sawlogs include:

1.    potential income generated from selling logs or developing barter arrangements

2.    reduction in labor cost by reducing the amount of time work crews need to

  process logs into firewood

3.    reduction in amount of woody material going to landfills

4.   reduction in landfill costs for disposal of material 

5.  reduction in volume of firewood material that must be stored in municipal

  maintenance yards until it is sold 

6.    conservation of forestland resources by generating sawlogs from street trees that

  must be removed anyway (note: approximately 3 to 4 billion board feet of

  potential lumber are thrown away every year as green waste1 – this is about equal

  to one quarter of the hardwood lumber harvested from traditional forestry

  operations that the U.S. consumes annually2).  

There must be a better way for street tree management than maximum cost – minimum

return systems.  The removal work itself must be done, but there is a potential

opportunity for changing this cost-burden scenario into one that is more cost efficient. 

Instead of sawing a good log into firewood, leave it “as is” – a readily marketable

commodity.  As a simple illustration of commodity value, the dollar return potential of

selling the log for lumber products exceeds the return potential of selling the log for

firewood by at least two to four times. 

A strategy of “recycling” municipal trees that includes harvesting saw logs involves the

implementation of a carefully designed process.  This process includes:

1.  Identifying one or more sawmills in your area that may be interested in

  purchasing your material 

2.  Learning what their sawlog requirements are and deciding whether your street

  tree logs fit these requirements

3.    Locating and removing metal and other foreign material in the logs

4.    Storing sawlogs until a salable quantity is accumulated

5.  Being flexible and persistent enough to try this concept

 

The Market

The concept of utilizing street trees in sawmills is not new.  Some sawmills have been

sawing products from street trees for many years because they have found a unique niche

for using street tree sawlogs.  From street tree logs, sawmills can manufacture products

such as pallets and pallet stock, landscape ties, truck bed sotck, fencing, heavy timbers,

construction lumber, posts , bridges and park benches.  Furniture grade lumber can also

be produced from these logs which can then be used to make products such as mantels

and decorative moldings.  Sawmills are the market and opportunity to which street tree

logs can be merchandised.  

Some of the wood generated from municipal trees holds special potential for unique and

figurative characteristics.  One example is spalted wood, which results when logs are

invaded by certain fungi.  The fungi produce a highly unique coloration and pattern in the

wood that is very appealing and special.  

The retail price for some of these figurative woods can be as much as four times the retail

price for standard lumber used to produce the same product.  Crafters seek these types of

wood because of the many special effects they give their finished products.  

Generally, the mills using street trees are not typical high-production operations.  They

are smaller in size and may have different markets and product lines compared to

standard production – oriented sawmills. 

Products and Specifications

Street trees that are at least 12 inches in diameter at breast height (4.5 feet from the

ground) and have a log of at least six feet in length have sawlog potential.  Normally, the

most valuable part of the tree is the first eight to sixteen feet closest to the ground.  This

is where the greatest volume of wood is located.  It is also where the most valuable wood

is found.  A sawmill’s raw material requirements are directly influenced by its markets. 

Consequently, the demand and price for your potential sawlogs depends on this

relationship.  Knowing what a sawmill requires is an important first step for successfully

merchandising sawlogs.  

For example, persimmon is listed as “fair” in species desirability because most sawmills

do not have a high demand for these sawlogs.  However, in Tennessee there is a large

market for persimmon, which centers around its use in manufacturing golf club heads. 

You must keep in mind that special markets dictate higher values for particular species,

depending on local market conditions.  (The take home message here is – get to know

your local miller and establish a relationship based upon mutual understanding of the

needs of all parties involved).  

Metal and Other Foreign Material in Street Trees

One of the primary reasons why demand for street tree sawlogs has been low in the past

is because of metal and other foreign material sometimes found in the logs.  The

reputation of these logs having metal in them (i.e. nails, wire, spikes or even car parts) is

common among sawmillers.  

Metal can become a serious problem during log sawing because it dulls and/or damages

saw blades and sawmill equipment.  It can also be a safety hazard for workers in a mill

because of flying debris when a blade hits large metal objects.  

The best way to correct this problem is to scan logs for metal before they go through the

sawing process.  Standard metal detectors are normally adequate.  When metal is

discovered, it must be removed.  If large quantities of metal are detected in a log, it

should not be sold as a sawlog.  If a metal-laden log is shipped as part of a load to a

sawmill, it will probably be the last load you ever see to the particular mill.  Normally,

the most metal is located within the first four to six feet of a street tree.  This is the

section of the tree which people use for hanging signs and securing fencing for yards or

pastures.  This is also the section that children llike to pound nails into.  Consequently,

butt logs (the first log cut closest to the ground is called the butt log) need to be screened

more carefully than logs which come from higher up in the tree.  

Typical metal detection techniques include a visual inspection of the log surface for metal

objects like wire and protruding nails, as well as any discoloration which normally

appears as a black/blue stain on the end of the log.  Following a through visual

inspection, a careful scan with a metal detector is needed.  

Following these steps, metal can be detected and removed or logs can be pulled from the

shipment if they are loaded with foreign material.  The problem of metal and other

materials in street tree logs is serious, but it is not insurmountable if care is taken to

ensure the quality of the logs being shipped to the mill.  (Detailed techniques for

removing metal and debris from street tree logs are given in the complete booklet) 

Conclusion
Being Persistent

“ I look at a log and see revenue, someone in the tree service business looks at the same

log and sees disposal costs,” – Stubby Warmbold, Founder of CitiLog 

This quote summarizes the opportunities inherent in harvesting street trees for lumber;

both the opportunity for increasing revenue and the opportunities currently lost because

street trees (and indeed most other urban trees) are viewed in one particular way.  With a

change in the way we see these trees, a carefully managed procedure to ensure that high

quality and safe timber is being delivered to a local mill and the persistence to keep at it,

lumber from urban trees can be a much needed input to municipal tree budgets.  (check

out the case studies in the complete booklet – they are impressive).  

Prevention of Hazardous Tree Defects – By Gary R. Johnson, Richard J. Hauer, and Jill D. Pokorny

 

(The following is an adaptation of the first half of an article by the authors cited above – an adaptation of part two of this article will be presented in a later edition of the Citizen Forester)

Introduction

The fundamental goal of tree risk management is to prevent development of hazardous tree defects and reduce the risks hazardous trees pose to public safety.  Development of many hazardous defects in trees can be prevented through effective planning, and the implementation of sound arboricultural practices.  Post-storm tree damage surveys document that appropriate species composition, and proper planting and maintenance practices can help prevent the formation of many structural defects that predispose trees to branch and stem failures.(Dempsey 1994, Johnson 1999).  This chapter discusses how communities can prevent development of many hazardous tree defects through effective streetscape planning and design.  Designing a species-diverse, uneven – aged forest, matching tree species to site conditions, purchasing high quality nursery stock, implementing proper planting and pruning techniques, and protecting trees from construction damage help to promote healthy trees and reduce development of hazardous tree defects. 

Designing a Species – Diverse, Uneven – Aged Urban Forest

When many of our older cities were established, there were initially few large trees present.  Tree planting programs lined the streets of many communities with avenues of even – aged trees all of the same species.  While these planting programs eventually resulted in aesthetically beautiful tree-lined boulevards, this practice led to problems that eventually convinced arborists that this practice should be avoided.  The vulnerability of an urban forest to insect and disease outbreaks is much higher where a single species of tree dominates the landscape.  This problem was dramatically illustrated during the Dutch Elm disease epidemic that altered forever the character of so many eastern city streets. 

As many of the avenue trees planted in the early 20th century are rapidly approaching the end of their normal lifespan in an urban setting, urban forest managers have an opportunity to develop a well-designed, species-diverse, uneven-aged management system……. Even in those communities where trees are somewhat haphazardly replanted as they die, the results will be an unavoidable shift from an even-aged management system towards a more sustainable species-diverse, uneven-aged management system. 

Matching Tree Species to Site Conditions

Tree species vary in their nutritional, water, and light requirements, and in their resistance to environmental and chemical extremes.  Match tree species to each site by considering both the silvical characteristics (requirements) of the tree, and the conditions of the site.  The Silvics Manual of North America, volumes 1 (conifers) and 2 (hardwoods) are excellent sources of information on plant/site requirements (Burns and Honkala 1990). 

Site Characteristics that Affect Tree Species Selection 

When choosing a species to fit a site, consider soil and light conditions; exposure to sun, wind, ice, snow, and de-icing salt; space limitations (both above and below ground) and human use of the site.  Soil conditions, especially in urban areas, often drive species selection.  In addition to the site factors listed above, trees in areas that are converted from woodland to urban use through new construction require specific consideration.  (Site characteristics to be considered in species selection are listed and described in full in the complete article – including recommended management strategies for each characteristic; for purposes of saving space, they are listed here briefly). 

1. Soil pH

2. Soil Compaction

3. Soil Drainage

4. Low Light Situations

5. Exposure to Sun and Wind

6. Susceptibility to Ice, Snow, and Wind Damage

7. De-icing Salt Damage

8. Human Use of the Area

9. Space Limitations

Urbanization of Woodlands

Forest trees that have been in relatively protected and undisturbed environments for all of their lives become very vulnerable to exposure when these forests are urbanized, that is, when residential or commercial subdivisions are built in or around the forests.  Suddenly, the trees that were once protected from wind and sun are exposed, in particular those that have now become residents of the forest edge.  Typically, these trees are tall and slender, with very high canopies and very shallow root systems, and are more prone to windthrow. 

Roots of the new edge trees are commonly lost during development of wooded areas, either directly through cutting, or indirectly through exposure, loss of soil moisture, and subsequent death of the shallow network of supportive, fine roots.  As a result, they become less stable and more vulnerable to winds and windthrow.  In addition, they produce more dead wood in the canopies as a result of defensive dieback in reaction to the root loss and death.  So even if they are able to remain vertical despite the increasing wind loads, they often produce a significant amount of deadwood high in the canopies that presents a threat to people and structures below. 

A few simple steps can help to alleviate the stresses that exposure of these trees causes:

1.           Protect the roots of trees during construction – with physical barriers and written              policies

2.           Cover the soil under newly exposed trees with organic mulch

3.           Irrigate trees during and after construction activities

4.           Under-plant the newly exposed soil areas under trees with shrubs and small trees             to reduce the amount of sunlight and drying wind that reach the forest floor.

5.            Do not “clean up” the forest floor by removing natural leaf litter and other

              detritus that serves to protect the soils of the remaining tree covered area.

 Purchasing High Quality Nursery Stock

Just as it is important to select the right trees for the right places, it is equally as important that the trees selected for planting are of high quality.  Planting unthrifty planting stock is money wasted, and sets the stage for future tree health problems and unsuccessful streetscape designs.  Communities that invest in high quality trees and proper planting and maintenance practices will enjoy the benefits of a tree resource that increases in aesthetic and economic value, possesses fewer hazardous defects, and lives longer. 

Industry standards for nursery stock have been established by the American Association of Nurserymen and are published in the American Standard for Nursery Stock, ANSI Z60.1 (ANSI 1996). 

Here are some tree quality characteristics that communities should look for when purchasing nursery stock for tree planting operations:

1.           Single, straight trunk that is free of branches below 6 to 8  feet (for trees to be     planted within a few feet of a sidewalk or street)

2.           A strong form with well spaced, firmly attached branches

3.           A trunk free of stem defects such as mechanical wounds, flush cut pruning            wounds, cankers, insect injuries, or cracks.

4.           Adequate root ball/container/root spread size in relation to tree caliper (see          American Standard for Nursery Stock, ANSI Z60.1).

Consider rejecting trees with the following problems:

1.           Trees with double or multiple leaders

2.           Trees with weak branch unions (e.g. narrow, V-shaped) and included bark in      branch unions

3.           Trees with defects on the main stem – (wounds, cankers, insect damage, cracks)

4.           Trees with serious root related problems – (girdling roots, crushed/damaged roots) 

Conclusion

By taking steps to design a species-diverse, uneven – aged forest, match tree species to site conditions, and purchase high quality nursery stock, community foresters can reduce the incidence of tree hazards and the costs associated with mitigation of those hazards.   As the old saying so correctly admonishes, “an ounce of prevention is worth a pound of cure.”  In part two of this series about preventing tree hazards, we will look at implementing proper planting and pruning techniques, and protecting trees from construction damage. 

 

 

Trees as Biotechnology to Improve the Environment

– Dr. David Nowak, USDA Forest Service

 (The following article is adapted from “Institutionalizing urban forestry as a `biotechnology` to improve environmental quality” by Dr. Nowak, 2006.) 

Urbanization concentrates people, materials and energy into relatively small geographical areas to facilitate the functioning of society.  Urbanization often degrades local and regional environmental quality as natural landscapes are replaced with anthropogenic materials.  Byproducts of urbanization (eg., heat combustion, and chemical emissions) affect the health of the local and regional landscapes, as well as the health of the people who reside, visit and/or work in and around urban areas. 

 

In the lower 48 United States, percent of land classified as urban increased from 2.5% in 1990 to 3.1% in 2000 (44,834 km2), an area about the size of Vermont and New Hampshire combined.  Patterns of urban expansion reveal that increased growth rates are likely in the future (Nowak et. al., 2005 a,b).  Urban land is projected to increase from 3.1 % in 2000 to 8.1 % in 2050, an area (392,000 km') greater than the size of

Montana. By 2050, four states (Rhode Island, New Jersey, Massachusetts, and Connecticut) are projected to be more than half urban land (Nowak and Walton,

200 5).

 

Urban vegetation, through its natural functioning, can improve environmental quality and human health in and around urban areas. These benefits include improvements

in air and water quality, building energy conservation, cooler air temperatures, reduction in ultraviolet radiation, and many other environmental and social benefits (Nowak and Dwyer. 2000). Properly designed and managed, urban vegetation can be used as

a natural "biotechnology" to reduce some of the adverse environmental and health effects associated with urbanization. With the extent of urbanization expanding across the landscape, there is an urgent need to incorporate the effects of urban vegetation on reducing the adverse effects of urbanization into long-term planning, policies, and regulations to improve environmental quality and human health. 

 

Methods

To incorporate the effects of urban trees in meeting environmental standards, the impacts of trees on the environment need to be quantified. The urban forest functions that appear to be most critical to environmental quality and associated regulations are tree effects

on air and water quality, and carbon sequestration. To quantify these urban forest effects in various cities, the Urban Forest Effects (UFORE) model was used. The UFORE model uses standardized field data from randomly located urban forest plots and local hourly

air pollution and meteorological data to quantify urban forest structure, functions, and values (e.g., Nowak et al., 2000, 2001, 2002a, b, 2005a, b; Nowak and Crane,

2000, 2002). The model currently quantifies: (a) urban forest structure by land use type (e.g., species composition, tree density, tree health, leaf area, leaf and tree

biomass, species diversity, etc.); (b) hourly amount of pollution removed by the urban forest, its value, and its associated percent air quality improvement throughout

a year. Pollution removal is calculated for ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide and particulate matter (< 10 um); (c) hourly urban forest volatile organic compound (VOC) emissions and the relative impact of tree species on net ozone and carbon monoxide formation throughout the year; (d) total carbon stored and net carbon annually sequestered by the urban forest, including its value to society; and (e)

effects of trees on building energy use and consequent effects on carbon dioxide emissions from power plants.

 

To date, urban forest structural data (e.g., tree species composition, number of trees, trees size, health) have been or are being collected and analyzed with the UFORE model for about 30 cities, with about one-third of the analyses occurring in cities outside of the United States - e.g,, Beijing, China (Uang et al., 2005); Fuenlabrada, Spain (Lozano, 2004); Santiago, Chile (Escobedo et al., 2004); and Toronto, Ontario, Canada

(Kenney et al., 2001). From this basic field data, leaf area and leaf biomass estimates are made and combined with local meteorological and pollution data to estimate

hourly air pollution removal, total carbon storage, and annual carbon sequestration.

 

Results - urban forest effects
Air quality

 

Urban vegetation can directly and indirectly affect local and regional air quality by removing air pollution and altering the urban atmospheric environment.

Factors that affect pollution removal by trees include the amount of healthy leaf-surface area, concentrations of local pollutants, and local meteorology. In the US,

urban forests are estimated to remove about 711,000 metric tons ($3.8 billion value) of air pollution per year (Nowak et al., 2006). Computer simulations using the UFORE model with local field data reveal that pollution removal by urban trees in selected cities range from 8 metric tons per year in the developed portion of Fuenlabrada, Spain, to over 1500 metric tons per year in Atlanta and New York. Amount of pollution removed was typically greatest for ozone, followed by particulate matter less than 10 um, nitrogen dioxide, sulfur dioxide, and carbon monoxide. Annual value of pollution removal, based on national median externality values for each pollutant (Murray et al., 1994), ranged

from $48,000 in Fuenlabrada to $8.3 million in Atlanta.

 

Average annual pollution removal per square meter of canopy cover was 10.4 g, but ranged between 6.6 g/m2 in Syracuse to 27.5g/m2 in Beijing, China. Excluding Beijing, which has a relatively high pollution concentration, the average is 9.3g/m2. The average annual dollar value of pollution removed per hectare of tree cover was $552 ($508 excluding Beijing), but ranged between $378/ha cover in Syracuse to $1223/ha cover in Beijing. Increasing tree cover in urban areas will lead to greater pollution removal, as well as reduced air temperatures that can help improve urban air quality.

 

Carbon sequestration

Trees can reduce atmospheric carbon dioxide (CO2), the dominant greenhouse gas, by directly storing carbon (C) from CO2 as they grow. In addition, urban trees can also reduce C02 emissions from power plants by reducing building energy use by lowering temperatures and shading buildings during the summer, and by blocking winds in winter (Heisler, 1986). Healthy trees sequester carbon each year; large, healthy trees sequester about 93 kg C/yr as compared to 1 kg C/yr for small trees. Net annual sequestration by trees in the Chicago area (140,600 t C) equals the amount of carbon emitted from transportation in the Chicago area in about 1 week (Nowak, 1994).

 

Urban trees in the coterminous United States currently store 700 million metric tons of carbon (335 million t C to 980 million t C; $14,300 million value) with a gross carbon sequestration rate of 22.8 million t C/yr.  The estimated carbon storage by urban trees in United States is equivalent to the amount of carbon emitted from US population in about 5.5 months. National annual carbon sequestration by urban trees is equivalent to US population emissions over a 5-day period (Nowak and Crane, 2002).

 

Stream flows and water quality

 

To determine the effects of urban trees on water quality, it is important to accurately quantify the effects of trees on stream flows. Urban trees affect stream flow

by intercepting rainfall, transpiring water, affecting evapotranspiration of surrounding areas, and by affecting soil infiltration rates. In addition, urban trees also affect water quality by intercepting atmospheric pollutants, reducing runoff, which indirectly affects water quality, and by increasing infiltration rates in pervious areas. As trees have a relatively large impact on runoff during small frequent storm events and the most water

quality control benefit is derived from the treatment of small frequent storms  (Department of Irrigation and Drainage, 2000), the potential impact of urban trees on water quality is likely to be significant.  To quantify the effects of urban tree and impervious surfaces on stream flow, a simulation was conducted using the UFORE-Hydro model (Wang et al., in review a, b) on the Dead Run watershed (14.3 km2) in the Baltimore, Maryland region. In the watershed, current tree cover is 13.2% with an impervious cover of 29%. Increasing tree cover in the watershed to 71 % (keeping total impervious cover at 29%) is estimated to reduce total runoff in the watershed by about 5% for the simulation period of the year 2000. Increasing impervious area from 29% to 75% (keeping tree cover at 13.2%) increased total runoff by about 50%. These results are annual effects, and variation in tree effects will occur during each season of the year. These types of data can be used to simulate the effects of changes in urban tree and impervious cover on water quality in

future simulations for cities.

 

Urban forests and environmental programs in
the United States

 

In the United States, there are several environmental programs or protocols where urban trees could make a contribution to improving environmental quality: State Implementation Plans (SIPS) of the Clean Air Act; Total Maximum Daily Loads (TMDL) and Stormwater Program for Municipal Separate Storm Sewer Systems of the Clean Water Act; and the Kyoto Protocols aimed at reducing greenhouse gases. The United States, although a signatory to the protocol, has neither ratified nor withdrawn from the protocol (UNFCCC, 2006a; Wikipedia, 2006).

 

State implementation plans

 

The Clean Air Act requires attainment of National Ambient Air Quality Standards (NAAQS) (US EPA, 2006a) for criteria air pollutants that cause human health impacts (e.g., ozone). Each non-attainment state must develop a state implementation plan (SIP) to attain the NAAQS by the applicable attainment deadlines. In September, 2004, the US Environmental Protection Agency (EPA) released a guidance document titled "Incorporating Emerging and Voluntary Measures in a State Implementation Plan

(SIP)" ((US EPA, 2006b). This EPA guidance details how new measures, which may include ""strategic tree planting," can be incorporated in SIPS as a means to help meet air quality standards set by the EPA. Due to the new ozone standards (US EPA, 2006c)many urban areas are designated as non-attainment areas for the ozone clean air standard, and are required to reach attainment typically by 2007-2010 (but up to 2021 for

Los Angeles).

 

As many of the standard strategies to meet clean air standards may not be sufficient to reach attainment, new and emerging strategies (e.g., tree planting, increasing

surface albedo) may provide a means to help an area reach compliance with the new clean air standard for ozone. "In light of the increasing incremental cost associated with stationary source emission reductions and the difficulty of identifying additional stationary sources of emission reduction, EPA believes that it needs to encourage innovative approaches to generating emissions reductions" (US EPA, 2006b). This new

emerging and voluntary measures document opens the door for urban tree programs to get credit within environmental regulations set to improve air quality (Nowak, 2005). Though this document specifically mentions trees, other environmental quality programs

also have the potential to incorporate trees, though current documentation may not specifically mention trees.

 

Total Maximum Daily Load (TMDL) and Stormwater Program for Municipal
Separate Storm Sewer Systems

 

A TMDL specifies the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and allocates pollutant loadings among point and non-point pollutant sources. A TMDL is the sum of the allowable loads of a single pollutant from all contributing point and non-point sources. The Clean Water Act, section 303, establishes the water quality standards and TMDL programs. States should describe plans for implementing load allocations for non-point sources, including reasonable

assurances that load allocations will be achieved, using incentive based, non-regulatory or regulatory approaches (US EPA, 2006d). 

 

Storm water run-off is a leading source of water pollution and can harm surface waters such as rivers, lakes, and streams which, in turn, causes or contributes to non-attainment of water quality standards.  Residential and commercial development substantially increases impervious surfaces where pollutants settle, thereby increasing runoff from city streets, driveways, parking lots, and sidewalks (US EPA, 2006e).  The Stormwater Program for Municipal Separate Storm Sewer Systems is designed to reduce the amount

of sediment and pollution that enters surface and ground water from storm sewer systems.

 

Stormwater discharges associated with Municipal Separate Storm Sewer Systems are regulated through the use of National Pollutant Discharge Elimination System (NPDES)

permits (US EPA, 2006f). Through this permit, the owner or operator is required to develop a stormwater pollution prevention program that incorporates best

management practices (US EPA, 2006e). 

 

As trees can reduce stormwater flow and consequently improve water quality, urban forests have the potential to impact TMDLs and be incorporated in best management

practices to reduce sediment and pollution from storm sewer systems. Though trees have the potential to improve water quality, the magnitude of their effect must still be quantified to determine if the effects are significant enough to warrant inclusion in these programs and to identify what types/designs of tree programs are most appropriate for optimal effects on water quality in particular instances.

 

Kyoto protocol

 

The average temperature of the earth's surface has risen by 0.6 "C since the late 1800s and is expected to increase by another 1.4-5.8 "C by the year 2100. Major contributors of carbon dioxide, a dominant greenhouse gas, are fossil fuel emissions and deforestation. Over a decade ago, most countries joined an international treaty - the United Nations Framework Convention on Climate Change - to begin to consider what can be done to reduce global warming. In 1997, governments agreed to an addition to the treaty, called the Kyoto Protocol, which has more powerful (and legally binding) measures. The Protocol entered into force on February 16, 2005 (UNFCCC, 2006b). As urban trees can both directly sequester carbon dioxide, a dominant greenhouse gas, and reduce carbon emissions from power plants, they have the potential to help reduce greenhouse gases and be incorporated with Kyoto Protocols.

 

Conclusion

 

Urban forests can improve environmental quality in urban areas.  The types and magnitude of these improvements need to be accurately quantified. If vegetation effects are demonstrated to improve environmental quality, then programs/regulations designed to improve environmental quality can and should consider incorporating urban vegetation as a means to meeting established quality goals. Establishment of urban forestry  programs to meet environmental quality standards can be a cost-effective "biotechnological" means to meet multiple standards (e.g., air and water quality,

greenhouse gas emission reduction) as trees provide multiple benefits for a singular cost.

 

Note:  The Kyoto Protocol is an international scale agreement that may seem irrelevant to local urban forest managers.  However, many cities in the US and around the globe are in the process of adopting greenhouse gas emission control and management strategies for local implementation.  As this article points out, urban forestry should be considered as a tactical measure in the development of these local strategic plans. 

 

 

Soil is Not a Dirty Word

- Eric Seaborn, Program Coordinator

 

“….the Earth…where a thin blanket of air, a thinner film of water, and the thinnest veneer of soil combine to support a web of life of wondrous diversity in continuous change.”  - Jack Eddy 1

 

Let’s get one thing straight right off the bat.  Soil is not dirt.  Soil is a complex material comprised of mineral and organic matter, water, air and, many would include, organisms that supports the growth of plant life and, by extension, almost all life as we know it.   Dirt is the “stuff you get under your fingernails and on your pants when you work,” as a college professor of mine used to say. 

 

As “tree people” we can never over estimate the importance of healthy soil and its vital contribution to healthy trees and forests.  In fact, most of the forestry and arboricultural text books that I have read state quite clearly that, “the relationship between tree root systems and the characteristics of the soils in which they grow has a greater influence on tree health than any other single factor,” 2 or words to that effect.  Soil provides critical inputs for tree growth including moisture and oxygen, nutrients, and a medium in which the tree finds stability for growth.  Anything that impairs the ability of a soil to deliver these vital growth factors can lead to serious decline or even death of the tree. 

 

An idealized healthy soil contains about 45% mineral matter, the result of perhaps millions of years of breaking down (weathering) of underlying rock, 5% organic material including organisms and their remains, and 50% pore spaces that contain both air and water.  The mineral matter in the soil determines the soil texture, meaning the relative fineness or coarseness of the soil.3  Texture is the result of the relative amounts of sand, silt, and clay found in the soil and plays a key role in determining the ability of the soil to hold water and to provide oxygen to trees.  This idealized composition of soil is likely more common to the open forest and meadow of undisturbed “natural” areas.  As we shall discuss later, the situation in urban settings is often radically different. 

 

I suspect most people can grasp the idea that the mineral component of the soil provides key nutrients for plant growth and that the breakdown of organic matter also provides enriching nutrient inputs.  Less intuitive is the fact that the soil under your feet is one half pore space.  But, the porosity of the soil is an important characteristic determining the ability of the soil to support tree growth.  In simplistic terms, there are two kinds of pore spaces in soils – macropores, that ideally function to provide air to tree roots and help water percolate throughout the soil and micropores, that hold soil moisture that can then be accessed by the tree roots.  Pore space and the clumping together of soil matter into clusters (aggregates ) determines the soils structure, which, like texture, helps to determine the water and air holding capacity of the soil and has a major effect upon root growth.  Soil structure, particularly formation of aggregates, is heavily influenced by the amount and quality of organic matter contained in the soil.  Roots growing in soils that have good structure will find water accessible in micropores and adequate air in the macropores and will be able to grow into the spaces between the aggregates as the tree matures.  Again, in urban settings, the scenario is often very different. 

 

Another key factor affecting soil health is its relative acidity or alkalinity, or pH.  On the pH scale, a measurement of 7 means that the soil is chemically neutral, less than 7 becomes progressively more acidic and more than 7 becomes more basic.  The pH of the soil is important because at different pH levels, essential nutrients can become bound in chemical compounds that make them unavailable to plants.  Different species of trees have different pH tolerances, but generally, a range of 6.0 to 6.5 is favorable to most plant growth.4 

 

The Reality of Urban Soils

 

Unfortunately for us as urban and community foresters, the idealized soils described thus far are often not to be found where we do our work.  In the “natural” forest, it is Mother Nature who plays the dominant role in determining soil health through her processes of weathering, organic matter accumulation and decomposition, pH buffering and biological activity.  In our communities and urban centers, we are often the principle actor influencing soil health. 

 

Let’s consider just three of the ways that humans can have a negative impact on urban soils. 

 

1.  Compaction – when soils are compacted by construction equipment, road resurfacing projects, or even pedestrian traffic, those all important pore spaces are crushed.  This reduces the ability of the soil to hold water and air and can make it extremely difficult for tree roots to penetrate the soil interface for growth.  Soils comprised of a variety of particle sizes, such as loams, may be more vulnerable to compaction because the smaller particles fill in large pore spaces between coarse particles.5

 

2.  Lack of Organic Material – Urban top soils are often removed for construction projects and, if they are returned, the organic content of the fill is often deficient.  Organic material supports the development of healthy soil structure by providing glue like substances that bind soil into aggregates.  Lack of organic matter interferes with soil structure, leading to a compacted soil that inhibits root growth.  Further, lack of organic matter decreases the activity of beneficial soil organisms and can lead to nutrient deficits as soil nutrients that would be replaced by the breakdown of organics are not restored to the soil.6

 

3.  Contamination -  Urban soils are often disturbed many times over the years for construction projects, road resurfacing work and utility maintenance.  In many of the projects, materials that can change the chemical activity (pH) of the soil or interfere with the soil structure are introduced into the soil regime.  Materials commonly mixed into urban soils include sand, gravel and tarry/oily substances from road projects, concrete and cement as construction debris and hyrdrocarbons (gas and oils) as road surface runoff.  Other contaminants might include glass, metals, trash and substances discarded by individuals directly into tree pits and open soil surfaces.   All of these materials can degrade the health of the soil and interfere with tree growth and vitality.  

 

Now, think of the typical urban setting around a typical urban tree.  That tree is likely growing in a soil from which the organic layer that would be found at the top of the soil in a “natural” setting is minimal or non existent.  How common is it for leaves and other natural organic litter to be left under urban trees?  Think of the impact this lack of organic material will have on the structure of the soil.  That tree is probably planted in a site that has seen at least one and probably several construction projects over the years.  The top soil was probably removed to facilitate these projects and, if it was restored at all, what are the likely impacts to structure of removal and mixing?  Do you think it probable that the aggregates and pore spaces of the soil survived the construction process?  Further, think of the types of activities that commonly affect soils in most construction projects; re-grading, unintentional compaction from movement of heavy equipment or intentional compaction to lay down impervious surfaces, soil removal, the addition to the soil of debris that can affect pH ….. you get the point. 

 

And, even if there has not been construction, think of the impact of things like tiny little tree pits and their tiny amount of soil, heavy foot traffic under the tree, trash and waste thrown on the soil and even little Fido’s daily salute.  Can we really expect the soils to be in good shape?  Can we really expect, given what we know about the intimacy of soil/tree relations, that our urban trees will thrive?   I think we might if we take a few common sense steps. 

 

 

A Few Good Ideas

 

  • Mulch all newly planted trees and refresh the mulch periodically to maintain an organic layer and organic input to the soil. 
  • If practical, mulch older, significant trees occasionally to reintroduce organic matter.
  • Provide adequate protection zones around trees during construction.  This will prevent soil compaction.  Extend the protection zone as far from the stem of the tree as possible.  Some recommend a formula of one foot of protection radius for each inch of DBH or caliper.  I tend to think this is a bit too conservative.  Again, the farther the activities are kept away from the tree, the better. 
  • Ensure that trees to be protected during construction of other projects are surrounded with a fence that clearly delineates the zone of protection.  Fencing is generally recommended over flagging and other non-restrictive markers because fences physically keep people and equipment out.  Protecting the tree will also protect the soil under that tree
  • If you are involved in a construction project that requires the removal of top soils, be sure to see that good, healthy top soil is returned to the site. 
  • Provide natural paths that lead people away from trees and/or reduce scattered foot traffic.  You may be wise to wait before introducing permanent pathways to see where it is that people tend to walk around new buildings and other new features in the landscape. 
  • Test your soils before you plant trees.  If there is a significant deficiency or other problem, consider remedying that problem before you plant.  For example, if the soil pH has been altered by the presence of construction debris, consider whether it is feasible and practical to restore the pH to a healthier range. 
  • Develop strong tree protection ordinances that consider the health of soils as part of the overall system.  Prevention is much preferred to remediation where soils are concerned. 
  • Educate work crews, decision makers and the public about the importance of a healthy soil resource. 

 

In conclusion, let’s all try to expand our vision to see that the line that separates the tree from the soil is much more blurry than might be perceived at first blush.  In effect, the healthy trees that we all admire and work to protect are the upward extension of the healthy soils that lie under them.  They are the thin layer of soil reaching up to touch the thin layer of atmosphere and water that together bring life to this our one and only Earth. 

 

Notes: 

 

1. “A Fragile Seem of Dark Blue Light,” in Proceedings of the Global Change Research Forum.  U.S. Geological Survey Circular 1086, 1993, p.15

 

2.  Arborist’s Certification Study Guide,  International Society of Arboriculture, 2001

 

3.  Arborist’s Certification Study Guide,  International Society of Arboriculture, 2001

 

4.  Arborist’s Certification Study Guide,  International Society of Arboriculture, 2001

 

5.  Arborist’s Certification Study Guide,  International Society of Arboriculture, 2001

 

6.  Soil Science Simplified,  Helmut Kohnke, Waveland Press, 1994

Protecting and Promoting Urban Forestry through Ordinance
Paul Jahnige (The author is a former Community Action Forester with the DCR Urban and Community Forestry Program and is currently the DCR Trails and Greenways Program Coordinator

One of the more valuable, yet often under-used, tools we have in urban forestry is the ordinance. Ordinances can protect canopy, formalize and standardize procedures, raise awareness, and even raise revenues through permits, fees and fines.

While we are lucky in our state to have Massachusetts General Law (MGL) Chapter 87, the Shade Tree Law, which provides some protections for public street trees and outlines a process for removal decisions, a local ordinance can add breadth, depth, and “teeth” to Chapter 87. Although the process of writing and passing an ordinance can be time consuming, a number of Massachusetts communities have successfully developed ordinances, and these can serve as models for you.

What an ordinance can do:

Some existing Massachusetts tree ordinances are available on our web site at http://www.mass.gov/dcr/stewardship/forestry/urban/urbanFAQs.htm#ordinance and they contain a variety of provisions, including:

  • Providing a rationale for community tree, tree management and tree protection,
  • Clarifying unclear provisions of MGL Chapter 87,
  • Clarifying roles for overseeing trees on scenic roads vs. non-scenic roads,
  • Establishing a community tree committee,
  • Detailing tree planting and pruning guidelines,
  • Establishing a system of permits and fees for tree trimming and removal requests,
  • Providing for existing tree protection and replacement during development projects,
  • Promoting communication between various town boards,
  • Detailing a process for hazard tree identification, and
  • Protecting heritage or significant trees.

 

Don’t forget sub-division regulations:

In addition to ordinances, Massachusetts sub-division regulations allow planning boards to pass regulations that govern the development of new sub-divisions. Tree Wardens and advocates should work with their planning boards to pass or enhance tree related provisions.  These regulations can be used to:

  • Limit clearing of private properties for sub-division development,
  • Require a tree / canopy protection plan,
  • Provide for tree replacements or contributions to a tree replacement fund,
  • Require the planting of new street trees, and
  • Provide standard guidelines for tree planting and landscaping.

 

Some suggestions:

Here are some suggestions for developing and passing an ordinance in your community:

  • Bring all stakeholders to the table and communicate well.  The greatest challenge of a tree ordinance is not writing it, but rather getting it passed and more importantly, having it followed.  Consider reaching out to other town agencies, business leaders, developers and residents to get their input early on. 
  • Consider starting small.  It is easier to start with a simple ordinance that everyone can agree on, than go for something detailed and extensive right off the bat.  Remember, it if often easier to add to or amend an ordinance that is in place than it is to pass a new ordinance. 
  • Understand the legal ramifications of your new ordinance or regulation.  Ensure that town/city legal staff have thoroughly reviewed the policy well before it’s brought for a vote.  Also, realize that your new policy may need to be reviewed by the state Attorney General’s office.
Picks and Shovels

Sample ordinances and sub-division regulations from some Massachusetts communities. www.mass.gov/dcr/stewardship/forestry/urban/urbanFAQs.htm#ordinance

Guidelines for Developing and Evaluating Tree Ordinances from the ISA.www.isa-arbor.com/publications/ordinance.aspx.

A Guide To Developing A Community Tree Preservation Ordinance, from the Minnesota Shade Tree Advisory Committee.

http://www.mnstac.org/RFC/preservationordguide.htm

Georgia Forestry Commission’s sample ordinance:

http://www.arlingtonva.us/Departments/ParksRecreation/scripts/parks/ParksRecreationScriptsParksTreesOrdinance.aspxhttp://www.urbanforestrysouth.org/Resources/Library/Citation.2004-04-30.1107/view

Conservation Design Resource Manual: Language and Guidelines for Updating Local Ordinances: http://www.urbanforestrysouth.org/Resources/Library/TTResource.2005-06-08.2338/view.

 

People Have to Know Each Other

- Sherri Brokopp, Urban Ecology Institute

“That’s the thing - people have to know each other. They can’t be strangers. That way when something comes up, we know what to do. We can deal with it together.”  With these words, an Urban Ecology Institute (UEI) volunteer reminds us that our work goes far beyond tree planting. Community plantings are an incredibly powerful tool for community building. As urban forestry professionals, we have the opportunity to use the urban environment as a catalyst to improve the ecological health and functioning of our cities, and simultaneously strengthen social ties as a way of addressing a whole host of related urban challenges.

In 2005, UEI’s community planting and stewardship program, CityRoots, partnered with nine neighborhood groups and over 140 residents in Dorchester, Roxbury, Chelsea, East Boston, and Lynn to transform overgrown vacant lots, underutilized parks, and barren streetscapes into beautiful, cared-for community spaces. The stories that emerge from these community efforts are inspirational.

As residents of Boston’s most underserved communities, many of our partners are constantly facing the overwhelming pressures of living in the urban environment. They sometimes face random violence. They worry about their children, that they will become victims of violence, or join a gang and participate in it themselves. They’re surrounded by drug dealers, and are woken up at all hours of the night by the sound of police sirens. It’s too loud. It’s too hot in the summer. The buses never come when they’re supposed to. Just living, can be a challenge.

And yet, in the face of all these trials, residents are coming together to work toward their vision for the community. Our community partners see trees and open space as critical components of the safer, stronger, more beautiful neighborhoods they want to build for their families and neighbors. Through their work with CityRoots, which works with each group over the course of the summer to design and implement a planting project, they improve the look, feel and condition of their physical environment. By working with their neighbors, residents also build the social ties and personal connections that create true community, and through this, they are better able to work collaboratively for positive change. Here are a few of their stories.

The Boston’s Hope neighborhood in Dorchester worked diligently all season to transform a vacant lot into a beautiful community garden and park space. Last October they harvested tomatoes, corn, and greens from their garden for a fall festival at their site.  Sharing food that was grow by their own labor, binds neighbors to one another.

Teens from the BOLD program developed an outreach campaign to encourage residents of Dorchester’s Spencer-Whitfield neighborhood to plant trees in their front yards. There are a number of older residents in the neighborhood, and some reacted to the teens with hostility and suspicion at first. But the teens persisted.  In the end, they planted with five residents. As the season wore on, the teens developed strong relationships with their older neighbors. One afternoon everyone was talking together on the front porch of a house at which they had planted a tree. As the conversation was drawing to a close, one of the teens said “We need to spend more time together talking about all these good things, instead of just complaining all the time.”

The Jeffries Point Crew in East Boston planted six trees in a waterside park. Several of the women in this group had been in East Boston all their lives, and shared stories about how they used to play in that park as children, and how their children had done the same. As they grew up, they watched the park decline. At one point, a trash barge was permanently stationed just off the park, close enough that children could easily swim to it. Replanting this park with trees – restoring it to the way they remembered it – was an exercise in healing for these women. And by telling their stories, they were able to link the other participants to the history of their neighborhood.

During one of our planting days, someone walked by a group of high school students who were planting a tree and said, “Who cares about all these stupid trees. When are we going to start taking care of people?” In a city facing as many challenges as Boston, this is certainly an understandable sentiment. But we know that healthy trees and strong communities go hand in hand. Just ask any CityRoots participant. Speaking to her Forester, one young woman said, “It’s funny. I walk by these houses all the time and I never knew who lived in them. You know Bill who was here working last week? I walk by his house everyday on my way to school. Now, when I see him and his wife out in the yard, I know who they are.”

 

Preserving Special Trees:

Using an Easement as a Tool for Private Tree Protection

- Hugh Kelleher, Chair, Newburyport Tree Committee

In 2005, the Newburyport Tree Committee was contacted by homeowner Claudette Moore who was selling her family’s impressive property located on High Street.  A massive copper beech stood in Claudette’s backyard, and she wanted to ensure that no one ever cut down that tree.  Not long before, she had seen a developer purchase a nearby home, and then remove another specimen beech in order to build a second home on the property.

How could a homeowner who loved a tree on her property make sure that it was permanently protected?  Was there a way to ensure that, even after Claudette’s property was sold, the historic copper beech would not fall to some future developer’s chain saw?

Claudette herself had done preliminary research, and learned that in the State of Washington, easements had been used to protect individual trees.  Working with the Tree Committee’s volunteer lawyer Anne Dawley, a standard easement was drawn up.  One important question was: Who would hold the easement?  The Tree Committee was an official city body, and if the Tree Committee were to take possession of an easement, many political issues might be raised.  The mayor and city council might need to get involved and grant official approvals. 

Instead, the Committee immediately created a non-profit group.  Those of us on the Tree Committee had been planning, since in our inception in 2001, to create just such an entity in order to solicit funds and carry out activities that could be officially independent of, but work in partnership with, our city government.  The need for a legal entity spurred us to get the paperwork done quickly.  Within weeks, our non-profit Friends of Newburyport Trees (FONT, Inc.) was established with Tree Committee member Ed Taylor as our first President.

Attorney Anne Dawley then drew up an easement.  Keep in mind that an easement to protect a tree (or small group of trees) is not to be confused with a “conservation easement.”  Conservation easements are typically used to protect parcels of land.  Here, the goal was simply to protect a single tree.  This easement is essentially the same type that one property owner might grant a neighbor who wishes to use a pathway across the property.  The easement means that the primary land owner still controls the property, but it grants certain rights to the easement holder.  In this case, it is the responsibility of the property owner to maintain the tree, and periodic visits to inspect the tree may be arranged by FONT.  However, the easement does not grant the public – or even representatives of FONT – the right to use the property.  The sole purpose is to protect the tree. 

When the tree declines, is damaged or becomes a hazard, the owners have the right to remove it.  However, they must give 28 days notice to FONT, who would then inspect the tree.  The easement specifically states that pruning and restoration alternatives are preferable to removal.  It would be up to FONT, as the easement holder, to legally enforce those provisions if ever there were a dispute.

No surveying or sophisticated documentation was required.  The tree was described in the easement, and a simple hand drawing of the area at the base of the tree was added. The easement must be renewed every thirty years. 

In an interesting twist, the documentation was not quite ready when the property was sold.  But the new owners had purchased the property in part because of their own appreciation of the beautiful copper beech.  They enthusiastically signed the easement, and it now is part of the deed registered with Essex County.

We believe that this model can be replicated and used to protect special trees across our commonwealth.  We have posted copy of the easement at www.mass.gov/dcr/stewardship/forestry/urban/urbanFAQs.htm#ordinance.  

Feel free to copy it, and use it. 

We should point out that, like all innovative legal approaches, an easement to protect a tree has not been tested in the courts.  However, since it uses exactly the same type of format that has been in effect for generations, we believe that it would stand up to any legal test.  We hope this approach will be used to protect a number of other trees in Newburyport and many other communities in the coming years.

 

 

The History of Town Tree Management

A case study of Lexington.

- excerpted from a paper by Karen Longeteig

“If you want to understand today, you have to search yesterday.”  ~Pearl Buck

Lexington’s history of tree management probably mirrors many other small towns in New England.  It is a repeating cycle that we can still learn from today.  At times, trees received a lot of attention, but much of the time, they received rather little.

While the problems concerning Lexington’s trees are nearly universal – street widening, labor shortages during the wars, the fight against Dutch Elm Disease, the hurricanes of 1938 and 1954, pesticide spraying, and budget cuts after Proposition 2 ½ – others were unique to Lexington’s growth as a bedroom community and as the guardians of American ‘sacred space’ on the town’s Battle Green and other historic structures. 

The earliest records reported only sporadically on trees.  Street trees were not systematically planted in colonial times.  But by the early 1800s, East Lexington benefactors Stephen and Eli Robbins planted elms along Massachusetts Avenue.  Town records for 1887 contain accounts of the bitter opposition to the loss of trees in front of Robbins-Stone property, in East Lexington, when Massachusetts Avenue was ‘adjusted’. 

Lexington’s Battle Green, with its important history, had been landscaped and planted with trees since about 1875.  It has consistently received careful attention since then, no matter what happened to trees in the rest of the town. 

The administrative structure of those caring for trees has changed many times over the years.  Systematic reports have been kept since 1901.  From 1913 to 1930 the “Moth Department” or “Insect Suppression Department” seemed to take priority over the Shade Tree Department.  Later on, both came under the umbrella of the DPW, and “trees” as a subject matter was sometimes omitted from Town Annual Reports.  Today, the Forestry Division has become part of “Parks, Trees, and Cemeteries,” all headed by the Superintendent of Public Grounds who is also the Tree Warden.  In 2001, the town passed a new tree by-law establishing a formally appointed Tree Committee, whose role is to advise the Warden and the Selectmen on tree matters. 

In the early 1900s, trees began to suffer the indignities of increasing urbanization – wounds inflicted by delivery wagons, being “charged” with electricity from un-insulated wires, or poisoning by natural gas escaping from underground mains.  Large trees were constantly lost to street widening, curb and sidewalk construction, or the “application of oily substances.” A schoolchild was killed in 1919 by a falling limb, and the tree department spent much of the next two years frantically pruning. 

The first known instance of an inventory was in 1920 when the Lexington Field and Garden Club funded a survey showing that 191 new trees were needed to fill vacancies, and that 70 old trees needed removal. 

The estimate of the number of Lexington’s trees has greatly varied over the years since then.  In 1913, the guess was 4,000.  In 1935, the department reported spraying a total of 47,573 trees.  In 1969, the estimate was 10,000, but the very next year they reported 40,000, a number which continued to be used for several years.  By 1992, the guess was back to 9,000 or 10,000 trees.  The Tree Committee today has ambitions to provide a firm number in four or five years, although the precise number is less important than efforts to map tree sites and conditions.

Our love affair with elms is no different than any other New England town.  Wardens in the early days seemed to be quite expressive about the aesthetic value of their trees.  “Lexington owes much of its beauty as an old New England town to the massive elms that border many of its streets,” and further that it was important to “exercise the forethought that a century ago provided these trees for us to enjoy.”  Trees planted in the year 1922 included 48 “mostly elms” inter-planted between older elms on Massachusetts Avenue and Muzzey Street to continue “our elm-arched streets.” 

By 1933, the town took official and uneasy notice of the new elm disease.  The Tree Warden suggested further study of Dutch Elm Disease (DED) “which is becoming quite prevalent throughout certain sections of the country, and we must guard against it as eighty per cent of our street trees are elms.”  He recommended planting 200 Lindens, evidently as a precaution to diversify tree types.

During the Depression, Lexington benefited from several US Government-funded work programs.  Some concentrated on insects, taking measures against gypsy moth and tent caterpillars.  Contests were held for schoolchildren to collect tent caterpillar clusters, and one year over 55,000 were collected.  In 1938, Works Progress Administration projects included a Tree Census – its whereabouts unfortunately not now known.

In 1935, the federal ERA paid for a survey of all the elms.  None were infected with DED although some of the vector insects, Elm Bark Beetles, were found.  In what amounted to a numerical survey of town trees, the warden reported that they sprayed 4,777 elms and 42,796 other species of trees.  This number is far higher than earlier reported tree count estimates.  A cynic would say that perhaps the government reimbursed the town by the tree – so the town was either generous in its estimate, or took the trouble to actually count existing trees.

The hurricane of 1938 added greatly to the Department’s work, as it destroyed 1,500 public trees and injured 17,000 which “now must be repaired.”  In replanting, the Tree Warden said he would continue to plant Elms, which despite all pests was the “world’s greatest shade tree.”  However, the hurricane decimated New England’s elms.  The elm beetle then bred profusely in the dead and dying wood, and hastened the spread of DED.

The Town fought its losing battle against Dutch Elm Disease from the first warnings in the late 1930s to the resigned attitude of the late 1990s.  In 1946, DED was confirmed in Quincy, only 25 miles from Lexington.  By 1947 the Town had a new chemical arrow in its quiver, and began spraying DDT aerially.  In 1948, the warden reported, “We have 5,000 elm street trees and 2,000 elms in parks, cemeteries, and schools.  DED is only 10 miles from Lexington.  Things don’t look too bright.”  By 1949 the wait was over; DED appeared in Lexington where it destroyed 17 trees that year.  Five years later, there was “such a substantial increase in DED that much of our time was spent sampling and removing.”

How many elms were lost over the years, completely altering the appearance of the town?  The town’s Annual Reports contain some gaps in the quality and quantity of information; nevertheless the Tree Department usually reported how many elms, specifically, were removed.  From 1949 to 1999 it was reported that 1,067 public elms and 971 private elms went down.   The actual number removed is undoubtedly higher, due to missing data from reports.  In 1982 the warden estimated that there were fewer than 600 left.

The technical details of planting have often been a concern of the Tree Warden.  He recommended off-berm (setback) planting as early as 1935.  In 1946, the recommendation was made to put utilities underground in new subdivisions, so wires wouldn’t be such a problem.  However, this was inconsistently done at best.

In 1957, Tree Warden Paul Mazerall began 22 years of service through the worst of the elms’ decline.  His tenure also coincided with the rapid “build-out”, following WWII, of remaining farmland.  Lexington became a bedroom community for Cambridge and Boston, with the population increasing from around 10,000 to over 30,000. 

With the construction of new streets and subdivisions, there was a great call for new trees.  Mr. Mazerall ran a town tree nursery from which hundreds of public shade trees were provided for new streets.  He reported in an interview in 2005 that the Tree Wardens in those days had their own budget and authority to use it.  He preferred to plant most trees off-berm.  In that way, the homeowner would take care of the tree.  He noted that he planted mixed varieties on the same street, as he didn’t want to lose them all at once.  At the beginning of his employment he planted sugar maples, but found their survival to be poor at street side.  The best survival record was held by the Norway Maple, but eventually he “shied away” from it as he saw it volunteering in woods and roadsides. 

One disturbing theme that emerged throughout Lexington’s history is the wholesale applications of poisonous sprays.  As early as 1908, and continuing for nearly 40 years, the town spent sums of $6,000 to $8,000 per year in spraying Arsenate of Lead (lead hydrogen arsenate), and other insecticides, two to three times per growing season. 

The Lexington Tree Warden in 1952 had observed that “while spraying is beneficial, it also destroys predators such as the ladybug”.  In 1963, a year after publication of Rachel Carson’s Silent Spring, Warden Mazerall reacted rapidly and reported that “the entire Spraying Program was re-evaluated due to information from the UMass Field Station and the Department of Public Health in regard to the effects of spraying on wild life.”  In 30 years over the entire US, 1.35 billion pounds of DDT was applied, much of it in the fight to save elms.

In 1980, Proposition 2 ½ – a statewide law setting a limit on raising property taxes to less than 2.5% in any one year – was passed and began to affect municipal funding and functioning.  In the 1990s, its effects became noticeable in the reduction of tree planting funds as well as in staffing.  The Tree Warden began seeking state grants and private donations to support tree planting.  In 2000, the divi