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                                 PB 1766

Saving Trees and
Making Money
in Residential Development
  Saving Trees and Making Money
  in Residential Development
  Garry Menendez, Associate Professor
  Plant Sciences

                               We all know it. Saving                  the yard than is customary.              of site-sensitive design and prof-
                                                                       Eventually, the owner looks up           it. Also, consider these statis-
                               trees during construc-
                                                                       and sees the tree in serious de-         tics regarding the value of veg-
                               tion is not easy.                       cline (usually dieback along the         etation prior to developing a site
                               It’s a common sight in develop-         ends of the branches).                   plan:
                               ments that are 3 – 5 years old. A                                                1. The average base value for a
                               homeowner had initially pur-            As a professional in the housing
                                                                                                                10-inch diameter tree is $179.
                               chased a property for its wood-         or construction field, you can
                                                                                                                A tree with a 30-inch diameter
                               ed and natural aesthetic appeal         have a major impact on how
                                                                                                                has an average base value of
                               and thinks he or she has suc-           site-sensitive your company is
                                                                                                                $15,554. (These values are ad-
                               ceeded in preserving this beau-         perceived to be by the practices
                                                                                                                justed based on species, loca-
                               ty. When the home is finished           you employ. Preserving existing
                                                                                                                tion in relation to the house and
                               and the nearby trees still cast         vegetation does indeed take
                                                                                                                condition. See section on “What
                               shade, the owner considers the          time and thought, but it can also
                                                                                                                Is a Tree Worth” for formula).3
                               trees to be past the critical           increase your profit. “Trees are
                               stage. It isn’t until after the inte-   aesthetically pleasing and are           2. “Quality of product ratings”
                               rior is furnished and the lawn is       well known to increase real es-          was 30 percent higher in shop-
                               established that the homeowner          tate values by as much as 15             ping districts with trees rather
                               soon notices he or she is picking       percent.”1                               than those with barren side-
                               up a few more fallen branches in                                                 walks.4
                                                                                   The Economics                3. Studies have shown that
                                                                                   of Vegetation                wooded areas add $5,000 to
                                                                                    Given the finite            $10,000 to the value of a resi-
                                                                                    amount of land that is      dential lot. The added value is
                                                                                    available for con-          higher where wooded areas are
                                                                                    struction, developers       adjacent to other protected ar-
                                                                                    often feel pressure to      eas of woodlands.5
                                                                                    maximize the usabil-
                                                                                    ity of a property by        4. According to other research,
                                                                                    completely clearing         prices for products sold in a
                                                                                    the site. Initially, this   well-landscaped district com-
                                                                                    may appear to be a          pared to the same products in a
                                                                                    viable approach.            “no-tree” district were 1 per-
                                                                                    Many builders and           cent higher.6
                                                                                    developers interpret
                                                                                                                5. Healthy, mature trees add an
                                                                                    real estate solely as
                                                                                                                average of 10 percent to a prop-
                                                                                    dollars acquired per
     A common approach to development is to implement                                                           erty’s value.7
                                                                                    square foot, but two
predesigned site plans with minimal regard to existing vegetation.
                                                                       case studies by the National As-         6. In one study, 83 percent of
                                                                       sociation of Home Builders ex-           realtors believe that mature trees
                                                                       amined smart growth issues that          can have a “strong or moderate
                                                                       clearly illustrate the relationship      impact” on the salability of

homes listed for less than           $1,000 and $10,000.11
$150,000. On homes valued at         Always consult with a certified
more than $50,000, this per-        arborist for more information
ception increases to 98 percent.8    regarding tree appraisal values.

These are just a few of the eco-
nomic benefits of adding and/or
                                     Deciding What to Keep
                                     In a perfect world, development
preserving trees on a property.
                                     and tree preservation would co-
Other benefits include savings in
                                     exist with no sacrifices to either.
both heating and cooling costs
                                     In residential situations, buyers        Figure 1. Typical residential lot with several existing trees.
(using deciduous trees to cast
                                     of homes sometimes pressure
shade in summer while still al-
                                     builders to save trees that sim-
lowing solar radiation to warm
                                     ply do not stand a chance of
the structure in winter), improv-
                                     surviving past 3 – 5 years. It is
ing air quality through pollution
                                     best to be honest and tell them
absorption, improved water
                                     that with the footprint of the
quality via less runoff, and the
                                     home they have chosen, mature
often difficult-to-measure quality
                                     trees within close proximity of
of life improvement that comes
                                     construction or soil disturbance
from living in such a setting.
                                     (approximately 0 feet) cannot
                                     be saved without the construc-
What Is a Tree Worth?                tion of retaining walls or other
Tree appraisers use a basic for-     means of grade alteration. While
mula when calculating what a         they may not want to hear this
tree with greater than 1 inch       initially, you may back up your
caliper is worth. While there are    claim by providing them with an
some variations, this is the basic   estimate of costs to remove
formula:                             tree(s) early in the construction
                                                                           Figure . Constructing a home on the property with little thought
Value of Tree = Size (cross-sec-     process and an estimate of what                         given to existing vegetation.
tion trunk area in square inches     it may cost to remove the same
or 3.14 x radius squared) x Value    tree(s) after all construction is
per square inch x Condition x        complete. If they mention a
Location.9                           competitor’s promise to save
                                     large trees, you may advise
For an 18-inch diameter Willow       them that they would be wise to
Oak in good condition and lo-        visit a 3 – 5 year-old develop-
cated on a residential lot, the      ment that same builder has
calculation is as follows:           completed and look up in the
                                     canopy of vegetation to note the
54 sq. in. (3.14 x 9 squared) x
                                     amount of decline or die-back in
$ x 95% x 80% = $3185 10
                                     some of those “saved” trees.
A mature tree (one that is larger
                                     Not all trees can or should be
in stature, greater than 4 inches
                                     saved. Smaller, more vigorous
in diameter and possesses a
                                     trees with a strong leader may
sizeable canopy) can often have
                                     be much more beneficial in the
an appraised value of between
                                                                             Figure 3. By mirroring the floorplan and repositioning house
                                                                                   slightly, all trees could be saved in this scenario.

                                 long term than an older, more        fort it takes to do
                                 mature tree that sits in a high-     so might easily be
                                 risk zone. You may also mention      regained in a high-
                                 to a buyer that some very mar-       er selling price for
                                 ginal trees (those that look un-     a more attractive
                                 stable or spindly with poor          lot. Building up
                                 branching structure) may be bet-     rather than out
                                 ter replaced with younger trees      (multi-story vs.
                                 that display attractive foliage at   single-floor de-
                                 a more appreciated eye level.        sign) provides the
                                 Ultimately, a property should        same amount of
                                 possess both diversity of spe-       usable floor space
                                 cies and maturity of vegetation.     while making less
                                                                      of an impact on
                                 When deciding which trees to
                                                                      a site.                     This dozer filling is an example of detrimental grading.
                                 keep during new construction, a
                                 balanced and well-thought-out
                                 approach may prove to be the
                                                                      How to Protect Trees                    filling within the root-zone, phys-
                                                                                                              ical or mechanical injury and
                                 most profitable. For example, if     During Construction
                                                                                                              trenching in the root zone. While
                                 well-established trees can be        The four major causes of decline
                                                                                                              some trees are more sensitive
                                 preserved through alternative        and eventual death of trees dur-
                                                                                                              than others, a general rule is to
                                 site-design practices, the money     ing and after construction are
                                                                                                              not add any soil over the root
                                 invested in the extra time and ef-   compaction of soil, cutting and
                                                                                                              zone of a tree.

Figure 4. Protective silt fence located beyond tree’s dripline.        Figure 5. Temporary root zone bridge constructed of cross-ties
                                                                                   and steel plates to prevent compaction.

Compaction                            Trenching
Compaction occurs when con-           When routing underground utili-
struction equipment (even stan-       ties, it is critical to avoid any
dard-sized trucks) makes mul-         trenching within the drip line of
tiple trips or is stored on the       trees to be preserved. There are
ground over the tree root-zone        many special tools available to-
for an extended period of time.       day to help. If the utilities to be
This can also occur with the ad-      buried are fairly minimal in size,
dition of soils or construction       air excavation (a tool that uses
materials.                            compressed air to blow soil
                                      away from roots) may work well.
To protect a tree from this haz-
                                      Most irrigation and utility con-
ard, construct a temporary fence
                                      struction companies possess
around the entire perimeter of a
                                      tunneling or auguring devices
tree’s drip line and let all con-
                                      that can be used to literally bore
tractors and sub-contractors                                                  Figure 6. Traditional trenching devastates a tree’s root system.
                                      a tunnel beneath the critical
know that this is off limits to all
                                      zone in which trees’ roots grow.
equipment and disposal of any-
thing other than clean water.         Installing such high-impact ele-
Since the bulk of a tree’s roots      ments as drain fields is another
are a mat of finely meshed feed-      issue. The amount of trenching
er roots that fan out well beyond     needed to accommodate these
the drip line of a tree and occur     will eventually kill any tree in this
primarily within the top 1           area. Therefore, it is best to re-
inches of soil, this protective       move any affected large trees at
zone may extend well beyond           the time of construction, while
the drip line.                        the costs will be relatively small
                                      compared to post-construction
Detrimental Grading                   removal.
Altering the amount of soil within
                                      Being creative with construction
a tree’s root zone either by add-
                                      practices can go far in saving a
ing or removing that which was
                                      large tree. Using a post and len-
there prior to construction can
                                      tel system to build over a portion
cause a tree to die a slow death.
                                      of a tree’s roots may allow soil to
Additional soils can lead to com-
                                      remain relatively undisturbed.
paction and prohibit the flow of
                                      Therefore, the roots are able to
water and oxygen to the roots.
                                      get oxygen and water. Although
Removing soil from this area
                                      roots in this zone may not re-          Figure 7. Boring beneath root zone saves tree’s root system.
exposes roots, which will cause
                                      ceive any water, as long as this
them to dry out, also prohibiting
                                      area is less than 5 percent of
this exchange. Existing contours
                                      the total root mass and the re-
on grading plans should be un-
                                      mainder has access to water,
altered in a protected tree’s
                                      this tree may stand a much
root zone.
                                      higher chance of survival than if
                                      trenching for a foundation had

    Mechanical Injury                     relatively inexpensive and            Large-leaved trees such as Syc-
    Mechanical injury occurs when         non-threatening but offer little in   amore and Tulip Poplar will be
    construction equipment bumps          the way of shade and longevity.       better off planted in a setting
    and scrapes tree trunks or dam-       The second category includes          where they may be permitted to
    ages and breaks branches. This        some species that are often           drop their leaves without having
    is probably one of the most           classified as “legacy trees.”         to be collected. Smaller-leaved
    avoidable of all practices. Proj-     These are shade trees that are        trees such as Willow Oak or
    ect managers and contractors          typically slower growing but          Dawn Redwood produce rela-
    may simply construct the high-        stronger and much longer-lived.       tively little debris when fall ar-
    visibility plastic fencing men-       Since they will be around for a       rives and are less of a threat to
    tioned earlier around trees to be     long time, placement is critical.     clog gutters and drain inlets.
    protected. Any undesirable un-
                                          If a lot size allows, larger-grow-    An abbreviated list of trees to
    derstory brush within the drip
                                          ing trees should be planted at        consider planting in the South-
    line of the tree should be re-
                                          least 0 feet away from struc-        east is shown below. Do not
    moved by hand, rather than us-
                                          tures. Choose strong trees with       plant trees that will grow large
    ing machinery, to avoid soil
                                          good branching habits and of          under utilities or in areas where
    compaction and mechanical in-
                                          the appropriate foliage texture.      they may potentially block park-
    jury. The larger the area fenced
    off, the better. Although a tree’s
    roots are often equal to the             Recommended Legacy Trees
    mass of its canopy, it may be
    difficult to preserve 100 percent        Common Name                          Scientific Name
    of this area and still perform any
    construction. A rule of thumb is         Scarlet Oak                          Quercus coccinea
    to fence 1 foot of radius per inch       American Linden                      Tilia americana
    caliper (for a 1-inch tree, a 1-
                                             Tulip Poplar                         Liriodendron tulipifera
    foot radius or 4-foot diameter
    circle is marked and fenced).            Swamp White Oak                      Quercus bicolor

                                             Bald Cypress                         Taxodium distichum
    Post-Development                         Gingko (male)*                       Ginkgo biloba (male)
                                             Autumn Blaze Maple                   Acer x freemanii
    After a property has been devel-
    oped and has stabilized, it is           Sugar Maple                          Acer saccharum
    time to plan(t) for the future. The      Black Gum                            Nyssa sylvatica
    benefits of planting trees are
    lengthy, but there is an impor-          Willow Oak                           Quercus phellos
    tant question to ask: How much           White Ash                            Fraxinus americana
    of your site-planting work will be
                                                                                  “Rose Hill” or “Autumn Purple”
    around for your grandchildren to
    enjoy? There are two classifica-         Japanese Zelkova*                    Zelkova serrata
    tions of trees to consider. The          Lacebark Elm*                        Ulmus parvifolia
    first is the smaller, flowering,
    decorative trees, which are very         * Non-native species that are not invasive
    popular. They are attractive,

ing lot lighting from illuminating      Fact Sheet Series – www.tva.         ments and knowledgeable about
dark, higher-risk zones. With           gov/river/landandshore/stabiliza-    beneficial landscape practices
regard to care, select trees that       tion/plantsearch.htm).               can result in higher profits, while
are self-sustaining in the envi-                                             also earning one the reputation
                                        Our landscapes are far from
ronment after a couple years of                                              of being an individual or com-
                                        static. They will always change
watering. If irrigation is needed                                            pany who cares about much
                                        and hopefully mature. Develop-
to keep a tree alive, it shouldn’t                                           more than just dollars per
                                        ers, builders and realtors with an
be considered in the first place.                                            square foot.
                                        appreciation and respect for
For a complete list of native
                                        land and the landscape will be in
trees, contact the Tennessee
                                        high demand as the general
Valley Authority (TVA) and ask
                                        public’s knowledge of ecology
for the publication, “Native
                                        and environment increases.
Plants of the Tennessee Valley”
                                        Being attuned to natural ele-
(no. 5 in Riparian Restoration

       National Association of Home Builders – NAHBNET issue summary, February 1990.

       “Smart Growth Case Study: Newpoint” and “Smart Growth Case Study: The Preserve at
       Hunter’s Lake” www.nahb.org/generic.aspx?genericContentID=437

       “Growing Greener Cities, A Tree Planting Handbook” (Global Releaf, Living Plants Press,
       Los Angeles, 199).

       Washington Community Forest Council. “TreeLink 1999.

       The Maryland-National Capital Park and Planning Commission. Prince George’s County
       Planning Department.

       Research performed by Kathy Wolf. www.treesforyou.org

       USDA Forest Service

       American Forests, Arbor National Mortgage

       Guide for Plant Appraisals, authored by the Council of Tree and Landscape Appraisers

         Guide for Plant Appraisals, authored by the Council of Tree and Landscape Appraisers

        Council of Tree and Landscape Appraisers

                   07-0031           PB1766-3M-10/06                   E1-5115-00-003-07

                          Programs in agriculture and natural resources, 4-H youth development,
family and consumer sciences, and resource development. University of Tennessee Institute of Agriculture, U.S. Department of
 Agriculture and county governments cooperating. UT Extension provides equal opportunities in programs and employment.

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