Content uploaded by Virginia I. Lohr
Author content
All content in this area was uploaded by Virginia I. Lohr on Oct 03, 2014
Content may be subject to copyright.
● July–September 2005 15(3)
472
YOUTH IN HORTICULTURE
Children’s Active and Passive Interactions
with Plants Infl uence Their Attitudes and
Actions toward Trees and Gardening as
Adults
Virginia I. Lohr1 and Caroline H. Pearson-Mims2
ADDITIONAL INDEX WORDS. benefits of trees, community forestry, environment,
human issues in horticulture, human well-being, people–plant interactions,
response to nature, survey, urban forestry, youth
SUMMARY. A nationwide phone survey of attitudes toward urban trees, partici-
pation in civic or educational activities, and memories of childhood experiences
with gardening and nature was conducted with 2004 adults in large urban areas.
We analyzed the infl uence of 11 childhood experiences and fi ve adult demo-
graphic characteristics on three items: “Trees in cities help people feel calmer,”
“Do trees have a particular personal, symbolic, or spiritual meaning to you?”
and “During the past year, have you participated in a class or program about
gardening?” Growing up next to natural elements such as fl ower beds, visit-
ing parks, taking environmental classes, and gardening during childhood were
associated with stronger adult attitudes and more actions. Growing up next to
urban elements, such as large buildings, had a small, but opposite, infl uence.
Demographics played a role in adult attitudes and actions. While both passive
and active interactions with plants during childhood were associated with posi-
tive adult values about trees, the strongest infl uence came from active gardening,
such as picking fl owers or planting trees. These results indicate that horticultural
programs for children raised in urban surroundings with few or no plants can be
effective in fostering an appreciation for gardening in adults.
Department of Horticulture and Landscape Archi-
tecture, Washington State University, Pullman, WA
99164-6414
This research protocol was approved by the WSU
Human Subjects Institutional Review Board. Financial
support was provided in part by the U.S. Department
of Agriculture Forest Service Urban and Community
Forestry Program on the recommendation of the
National Urban and Community Forestry Advisory
Council.
1Professor.
2Research Technologist.
Historically, gardening has been
an important part of fam-
ily life; children have helped
plant, weed, and harvest. Today, formal
children’s gardens are very popular
in the United States, being found in
elementary schools, arboretums, and
community gardens (DeMarco et al.,
1999; Eberbach, 1990). Programs to
promote interaction between children
and nature are also popular, with nature
camps, tree planting programs, and
environmental projects being plentiful
(Waliczek et al., 2003). Sponsors of
such programs hope that these chil-
dren will develop a “sense of kinship
and respect for the natural world” that
they will still have when they are adults
(Lewis, 1996).
More than 80% of the U.S. popu-
lation now lives in urban areas (U.S.
Census Bureau, 2000). Europe and
Latin America are also highly urban-
ized, at 75%, and worldwide almost
50% of the population lives in urban
areas (United Nations, 2001). More
and more children today are being
raised in these areas, which offer few
easy opportunities for interactions
with nature or gardening. This has
increased the call for formal gardening
programs with inner-city children (Relf
and Lohr, 2003).
Nature education and outdoor
experiences help children gain a
respect for living things, stimulate
their curiosity, and provide them with
meaningful life experiences (Cooper
Marcus, 1992; Bullock, 1994). Gar-
dening and environmental education
programs promote positive attitudes
toward the environment in elementary
school children (Jaus, 1984; Skelly and
Zajicek, 1998; Waliczek and Zajicek,
1999). These programs also offer op-
portunities for hands-on, or active,
learning experiences that encourage
higher-order thinking and problem
solving (Athman and Monroe, 2001;
Waliczek et al., 2003). Little is known
about the long-term effects of such
programs, because longitudinal studies
are costly and time consuming.
The goal of this project was to
examine the relationship between
childhood contact with nature and
adult attitudes toward plants. Are chil-
dren that have extensive experiences
with nature more likely to understand
and appreciate the values of garden-
ing when they are adults? Will early
interventions with plants translate into
positive adult responses to nature? The
objective of this project was to deter-
mine the relationship between adult
memories of childhood contact with
plants and adult attitudes toward trees
and gardening among residents of large
metropolitan areas in the U.S.
Methods
A nationwide telephone survey
was prepared by the authors with assis-
tance from John Tarnai and Don Dill-
man of the Washington State University
Social and Economic Sciences Research
Center (SESRC). Participants were
surveyed about their attitudes toward
urban trees, participation in activities
such as community service, and child-
hood experiences with gardening and
nature. Demographic information was
also gathered.
The population was respondents
18 years old and older in households
with telephones in the 112 most-popu-
lated metropolitan areas in the conti-
nental U.S., including Los Angeles,
Calif.; Chicago, Ill.; and Atlanta, Ga. A
sample combining randomly generated
and directory listed telephone numbers
was purchased from Genesys Sampling
Systems of Fort Washington, Pa. The
survey was administered by the SESRC
using a computer-assisted telephone
interviewing system. A pretest of the
survey was administered to respondents
to assess reactions to the questions,
estimate the length of the interview,
and determine how diffi cult it would
be to reach respondents. Following
the pretest, the number of questions
was reduced to shorten the time for
the interview and to remove confusing
items. For the full survey, call attempts
alternated day of the week and time of
the day. The survey was completed in
13 weeks, and the response rate was
51.8%. The fi nal sample consisted of
2004 completed interviews, averaging
23 min long. The sampling error was
±2.2% for binomial variable questions.
Bias in the sampling was examined by
July05HT.indb 472July05HT.indb 472 6/8/05 2:23:43 PM6/8/05 2:23:43 PM
473
● July–September 2005 15(3)
comparing demographics of the sample
to known characteristics of residents of
metropolitan areas; they were similar,
indicating that the sample was a good
representation of the population.
We analyzed the infl uence of 11
childhood experiences on adult re-
sponses to three survey items: “Trees
in cities help people feel calmer” (a
social value), “Do trees have a par-
ticular personal, symbolic, or spiritual
meaning to you?” (an intrinsic value),
and “During the past year, have you
participated in a class or program about
gardening?” (an action). The 11 child-
hood experiences included being raised
next to natural or urban elements,
participating in environmental action
or education, interacting passively
with plants, such as visiting parks, and
interacting actively with plants, such
as picking fl owers. Comparisons of
adult responses with fi ve demographic
variables were also examined. A child-
hood experience or adult demographic
was compared with an adult survey
item using a chi-square statistic from
a two-way frequency table. The rela-
tive strength of childhood experiences
and adult demographics in predicting
adult responses was examined using a
logistic regression analysis, a form of
multivariate analysis (SAS Institute,
1999). For the logistic regression, the
11 childhood variables were combined
into fi ve composite variables.
Results and discussion
Respondents ranged from 18 to
90 years old with a mean age of 42
years, and 56% were female. Less than
half had completed a 4-year college
degree, 60% had an annual income of
$50,000 or less, and a majority identi-
fi ed themselves as White/European.
Most respondents had lived next to
trees or gardens as children, while one-
third grew up next to urban elements,
such as large buildings. As adults, most
respondents continued to live near
plants, but more than half now lived
next to urban elements.
CHILDHOOD EXPERIENCES: HOME
SURROUNDINGS. Respondents were
asked about natural elements that sur-
rounded their childhood homes. Of
those from a childhood home “next
to a garden or fl ower beds,” 65%
strongly agreed that trees are calming,
while only 56% of those from a home
not “next to a garden or fl ower beds”
strongly agreed (Table 1). This showed
that childhood surroundings could
infl uence adult attitudes on the social
benefi ts of trees. Respondents with
a childhood home next to a garden
were more likely than those not next
to them to say that trees had “a par-
ticular personal, symbolic, or spiritual
meaning,” thus showing that adult
attitudes toward the intrinsic value
of trees could also be infl uenced by
raising children next to gardens. This
fi nding provides support for the value
of inner city planting projects such as
Philadelphia Green (Lewis, 1996).
Attitudes may be strongly held
and resistant to change, or they may be
weakly felt and subject to fl uctuation.
Strongly held attitudes are more likely
to be expressed in actions or behavior
than weak ones (Schwarz and Tesser,
2001). Being raised next to a garden
affected adult actions as well as attitudes
(Table 1). Of the respondents who lived
in homes by gardens during childhood,
11% reported taking a gardening class
in the last year, while only 6% of those
whose childhood home was not by a
garden reported doing so. This clearly
showed that living near a garden during
childhood was a signifi cant predictor of
interest in gardening in adulthood.
Being raised “next to woods or
forest” did not infl uence adult attitudes
on the calming value of trees, which
was a social benefi t, or the likelihood
of taking a gardening class (Table 1).
It did infl uence adult attitudes on the
personal meaning of trees, which was an
intrinsic value. Perhaps being around
woods or forests is a more solitary way
of interacting with nature while garden-
ing is more social, and this may have
been refl ected in these results.
We next examined the infl uence
of being raised near urban elements.
Living “next to large buildings” or
“busy streets” as a child did not affect
adult attitudes toward the calming
nature of trees, but did affect feelings
about their intrinsic value, with fewer
of these respondents saying that trees
had personal meaning than those whose
homes were not next to large buildings
or busy streets (Table 1). Being raised
“next to large buildings” did not af-
fect adult participation in gardening
programs, but being raised “next to
busy streets” reduced the likelihood of
taking a gardening class. These results
indicated that being raised near urban
elements could affect adult attitudes
and actions.
CHILDHOOD EXPERIENCES: ENVI-
RONMENTAL EDUCATION AND ACTION.
Most of us assume that childhood
education about gardening or nature
favorably affects adults’ attitudes
toward plants. We looked at this rela-
tionship by asking people if they had
participated in such programs. For
adults who had participated in “nature
or environmental education in elemen-
tary school,” the effects on attitudes
toward the social and intrinsic values
of trees and on taking a gardening class
were strong (Table 1). Participating
in “organized activities to improve
the local environment” as a child also
infl uenced attitudes toward the social
and intrinsic values of trees, but not
the likelihood of taking a gardening
class.
CHILDHOOD EXPERIENCES: PAS-
SIVE INTERACTION WITH PLANTS. We
looked at relationships between passive
childhood exposure to trees and adult
attitudes by asking people how often
they spent time in outdoor places with
trees or visited parks as children. Adults
who very often were outdoors with
trees appreciated the calming value of
trees more than those who did so less
often, but visiting parks had no effect
on this (Table 1). Both spending time
around trees and playing in parks were
signifi cant infl uences on people’s per-
ceptions of the personal meaning of
trees. These results are consistent with
previous studies of adult environmen-
talists, who overwhelmingly reported
that childhood experiences contributed
to their concerns for the environment
(Palmer, 1993; Tanner, 1980). The
results of this study, which was not
restricted to environmentalists, con-
fi rmed that formative experiences with
nature also infl uence values among the
general public. Spending time around
trees and playing in parks often were
associated with an increased likelihood
of taking gardening classes as an adult
as well. These results demonstrated that
passive childhood nature interactions
could have a strong impact on adult
attitudes and actions.
CHILDHOOD EXPERIENCES: ACTIVE
GARDENING. To examine whether adult
attitudes or actions might be affected by
gardening during childhood, we asked
adults how often they had spent time
“picking fl owers, fruits, or vegetables
from a garden”; “planting trees, seeds,
or plants”; or “taking care of indoor or
outdoor plants” as children. Increased
frequency of each of these activities
had a strong infl uence on the three
adult attitudes and actions (Table 1).
July05HT.indb 473July05HT.indb 473 6/8/05 2:23:44 PM6/8/05 2:23:44 PM
● July–September 2005 15(3)
474
YOUTH IN HORTICULTURE
For example, 71% of adults who often
planted trees, seeds, or plants as a child
felt that trees had personal meaning,
while only 45% of those who never did
so felt this way about trees. Adults who
had often cared for plants when they
were children were twice as likely to
have participated in a gardening class
or program during the past year than
those who had never done so. These
results show the important infl uence
of active childhood involvement with
plants on adults.
ADULT DEMOGRAPHICS. Demo-
graphics infl uenced the responses to
some of the survey items (Table 2).
Age was a factor in all three items, with
older people usually having stronger at-
titudes than younger people. The more
education a person had, the more likely
they were to have taken a gardening
class during the past year. Ethnicity
was a factor in appreciating the calm-
ing value of trees. While respondents
of all ethnicities held positive attitudes
toward trees, with nearly 50% in each
ethnic group strongly agreeing that
trees helped people feel calmer, Asian
and African Americans generally felt
this less strongly than Whites or Native
Americans. Earlier studies have also
documented differences among ethnic
groups regarding the value of nature
(Kellert, 1996). Ethnicity was not a
factor in attitudes toward the personal
meaning of trees, but was a factor in
participation in gardening classes or
programs, with Native Americans being
the most likely to have participated.
Gender and income were factors in
attitudes, but not actions. Women
were more likely than men to express
appreciation for the social and intrinsic
values of trees, as were respondents
with annual incomes between $30,000
and $50,000 compared to respondents
in other income categories.
RELATIVE IMPORTANCE OF DIFFER-
ENT VARIABLES. Among the 10 variables
selected to compare the relative im-
portance of childhood experiences and
adult demographics on adult attitudes
and actions, both childhood experi-
ences and adult demographics were
shown to be important in explaining
people’s responses about the calming
nature of trees (Table 3). In this analy-
Table 1. Proportion of respondents agreeing that trees in cities are calming, that trees have personal value, or that they had
taken a gardening class or program during the past year, based on childhood experiences with plants.
Response to Trees are Trees have Took gardening
Childhood childhood experience calming personal value class/program
experience question (%) (%) (%)
Home with natural surroundings
Garden or fl ower beds No 56*** 49*** 6**
Yes 65 61 11
Woods or forest No 63NS 55*** 9NS
Yes 63 63 11
Home surrounded by urban elements
Large buildings No 63NS 60* 10NS
Yes 63 52 9
Busy streets No 63NS 60@ 11@
Yes 63 56 8
Environmental education and action
Participated in environmental No 62@ 54*** 8***
education in elementary school Yes 66 69 13
Participated in organized activities No 61** 55*** 9NS
to improve the local environment Yes 67 68 12
Passive interaction with plants
Spent time around trees or plants Not ver y often 53*** 47*** 6**
Very often 65 61 11
Visited or played in local parks Never 59NS 51*** 10*
Rarely 62 53 6
Occasionally 62 57 9
Often 65 63 12
Active gardening
Picked fl owers, fruits, or vegetables Never 53*** 44*** 5***
Rarely 55 50 4
Occasionally 62 54 9
Often 69 69 14
Planted trees, seeds, or plants Never 55*** 45*** 7***
Rarely 61 56 7
Occasionally 63 58 10
Often 71 71 15
Cared for indoor or outdoor plants Never 57*** 42*** 7***
Rarely 57 53 6
Occasionally 62 59 10
Often 71 71 14
NS, @, *, **, ***For each childhood experience, numbers within the column are not signifi cantly different or are signifi cantly different based on a chi-square statistic at P ≤ 0.10,
0.05, 0.01, or 0.001, respectively.
July05HT.indb 474July05HT.indb 474 6/8/05 2:23:45 PM6/8/05 2:23:45 PM
475
● July–September 2005 15(3)
sis, the order in which a variable enters
the model indicates its importance rela-
tive to the other variables in explaining
responses to that item. Participation
in active gardening during childhood
was the most important variable in
explaining respondents’ perceptions of
the calming value of trees, indicating
that early experiences with plants had
a greater infl uence on adults’ attitudes
toward trees than any other variable
examined. The next most important
variables in explaining adult attitudes
on the calming value of trees were
ethnicity, gender, and age, respectively.
While those teaching gardening classes,
obviously, cannot change these demo-
graphics, the results could be used to
predict who might respond most to
such activities or to target those who
are less likely to appreciate the calming
value of trees. The fi nal variable to enter
the model was childhood participation
in environmental education or action.
This indicates that children’s garden-
ing classes that include environmental
education or activities to improve the
local environment, such as planting
trees to reduce erosion, should be
benefi cial in contributing to adult
values toward plants.
Participation in active garden-
ing during childhood also was the
most important variable in explaining
respondents’ feelings that trees have
personal meaning (Table 3). Gender
was the second most important vari-
able, followed by environmental educa-
tion and age. The childhood variables
of passive interaction with plants and
being raised in a home with natural sur-
roundings, such as fl ower beds or trees,
were the last two variables to enter the
model. These results indicated that
any involvement with nature during
childhood, whether active or passive,
had positive value, but actively caring
for plants had a stronger infl uence on
adult attitudes than did passive involve-
ment. The strong infl uence of active
interaction with plants has long been
suspected and assumed by people in this
fi eld, and these results verify it.
The most important variable
to explain the likelihood of an adult
participating in a gardening class or
program was participation in active
gardening as a child, the same variable
that entered fi rst in the models for the
other two survey items (Table 3). This
indicates the great importance and role
of childhood active gardening, such as
planting trees and picking vegetables,
in promoting adult appreciation for
gardening and the environment. The
second most important variable was
age, which also was a factor in the
other models. Passive interaction with
plants was the third most important in
explaining the likelihood of taking a
gardening class, showing that simply
being around plants could infl uence
adult actions. Education and a child-
hood home with natural surroundings
were the least important infl uences for
this item.
Current income and being raised
Table 2. Proportion of respondents agreeing that trees in cities are calming, that
trees have personal value, or that they had taken a gardening class or program
during the past year, based on adult demographics.
Trees Trees have Took
are personal gardening
Adult calming value class/program
demographic Response (%) (%) (%)
Age 18–21 years 53*** 49*** 8***
22–30 years 55 51 4
31–40 years 63 57 9
41–55 years 68 62 14
Over 55 years 66 62 9
Education High school or less 61NS 57NS 6*
2-year degree or less 63 58 10
4-year degree or less 65 59 12
Some graduate school or more 64 62 13
Ethnicity Asian American/Pacifi c Islander 54*** 56NS 12@
Black/African American 48 55 10
Hispanic/Latino 60 57 9
Multi-ethnic/Other 60 60 7
Native American 68 60 22
White/European American 65 59 10
Gender Female 67*** 65*** 11NS
Male 58 50 9
Annual Under $20,000 60* 57 * 8NS
income Over $20,000 up to $30,000 63 57 9
Over $30,000 up to $50,000 69 65 11
Over $50,000 up to $75,000 62 57 11
Over $75,000 62 54 11
NS, @, *, **, *** For each adult demographic, numbers within the column are not signifi cantly different or are signifi cantly
different based on a chi-square statistic at P ≤ 0.10, 0.05, 0.01, or 0.001, respectively.
Table 3. The relative infl uence of selected childhood experience and demographic
variables in explaining responses to items that trees in cities are calming, that
trees have personal value, or that respondents had taken a gardening class or
program during the past year.
Trees are Trees have Took gardening
calming personal value class/program
Variable Order in the modelz
Childhood experiences
Home with natural surroundings --- 6 5
Home surrounded by urban elements --- --- ---
Environmental education or action 5 3 ---
Passive interaction with plants --- 5 3
Active gardening 1 1 1
Demographics
Age 4 4 2
Education --- --- 4
Ethnicity 2 --- ---
Gender 3 2 ---
Income --- --- ---
z Variables that met the 0.05 signifi cance level for entry into and removal from the model, based on a multivariate,
stepwise logistic regression. Variables with (---) did not meet these criteria.
July05HT.indb 475July05HT.indb 475 6/8/05 2:23:45 PM6/8/05 2:23:45 PM
● July–September 2005 15(3)
476
YOUTH IN HORTICULTURE
in a home surrounded by urban ele-
ments were never important in explain-
ing adult values or actions (Table 3).
These factors, when analyzed alone,
were shown to infl uence adult values,
but not adult actions (Tables 1 and 2).
The fact that they were not signifi cant in
the multivariate analysis indicates that
their infl uence was easily overcome by
other factors, such as participating in
activities involving plants. This is an
encouraging fi nding, indicating that
children being raised in urban sur-
roundings devoid of nature can benefi t
greatly from positive interventions with
plants and gardening.
Conclusion
Childhood experiences with
nature infl uence adult sensitivities to
trees and that infl uence is very strong.
Both active and passive childhood ex-
periences with nature, such as picking
vegetables and living next to a garden,
had positive infl uences on adults’
perceptions of the social and intrinsic
values of trees and on their likelihood
of taking a gardening class. Under-
standing this infl uence is particularly
important, given that, in the future,
more children will be raised in urban
areas where chances to interact with
nature may be limited. These results
show that gardening and tree planting
programs for children in surroundings
devoid of nature can be effective in
fostering the positive values that come
from living with plants.
Participation in active gardening
during childhood was consistently the
most important infl uence in explaining
adult attitudes and actions. Adults who
spent more time during childhood in
gardening activities were more likely
to agree strongly that trees help people
feel calmer and have personal value and
to have taken a gardening class during
the past year. Childhood participation
in environmental education and pas-
sive interaction with plants, such as
visiting parks, were also factors, but
were less important in explaining these
responses.
By understanding the relation-
ships between childhood nature ex-
periences and adult attitudes, we can
better understand the value of tree
planting and gardening programs for
children on the perspectives of those
same children as adults. These results
indicate that horticultural programs
for children can have great worth
in helping children raised in urban
surroundings with few or no plants.
This information could be used to
tailor children’s environmental and
gardening activities more effectively
to engender appreciation for nearby
nature in our adult citizens.
This research only begins to ad-
dress these important relationships. It
was based on memories of childhood
nature contact and was designed to
point the way to promising further
studies, such as longitudinal ones.
Many additional analyses of these
data are possible (Lohr, 2004; Lohr
and Pearson-Mims, 2002, 2004; Lohr
et al., 2004a), and the raw data are
available to other researchers for this
purpose. More information on this
project, its results, and the raw data
are available at our web site (Lohr et
al., 2004b).
Literature cited
Athman, J.A. and M.C. Monroe. 2001. Ele-
ments of effective environmental education
programs. Eric Document Reproduction
Serv. No. ED 463 936.
Bullock, J.R. 1994. Helping children value
and appreciate nature. Day Care Early
Educ. 21(4):4–8.
Cooper Marcus, C. 1992. Environmental
memories, p. 87–112. In: I. Altman and
S.M. Low (eds.). Place attachment. Plenum
Press, New York.
DeMarco, L.W., D. Relf, and A. McDan-
iel. 1999. Integrating gardening into the
elementary school curriculum. HortTech-
nology 9:276–281.
Eberbach, C. 1990. School children:
From recipients to participants. Public
Garden 5:14.
Jaus, H.H. 1984. The development and
retention of environmental attitudes in
elementary school children. J. Environ.
Educ. 15:33–36.
Kellert, S.R. 1996. American society, p.
37–63. In: The value of life: Biological
diversity and human society. Island Press,
Washington, D.C.
Lewis, C.A. 1996. Green nature/human
nature: The meaning of plants in our lives.
Univ. of Illinois Press, Urbana.
Lohr, V.I. 2004. Effect of childhood ex-
periences with nature, including planting
trees, on adult understanding of trees in
cities. Acta Hort. 643:183–187.
Lohr, V.I. and C.H. Pearson-Mims. 2004.
The relative infl uence of childhood activities
and demographics on adult appreciation
for the role of trees in human well-being.
Acta Hort. 639: 253–259.
Lohr, V.I. and C.H. Pearson-Mims. 2002.
Childhood contact with nature infl uences
adult attitudes and actions toward trees
and gardening. p. 267–277. In: C.A.
Shoemaker (ed.). Interaction by design.
Iowa State Press, Ames.
Lohr, V.I., C.H. Pearson-Mims, J. Tarnai,
and D.A. Dillman. 2004a. How urban
residents rate and rank the benefi ts and
problems associated with trees in cities. J.
Arboricult. 30:28–35.
Lohr, V.I., C.H. Pearson-Mims, J. Tarnai,
and D.A. Dillman. 2004b. A multicultural
survey of the infl uence of childhood envi-
ronmental experiences on adult sensitivities
to urban forests. 1 Oct. 2004. <http://
www.wsu.edu/~lohr/hih.nucfac/>.
Palmer, J. 1993. Development of concern
for the environment and formative expe-
riences of educators. J. Environ. Educ.
24:26–30.
Relf, P.D. and V.I. Lohr. 2003. Hu-
man issues in horticulture. HortScience
38:984–993.
SAS Institute. 1999. The logistic pro-
cedure, p. 1903–2042. In: SAS/STAT
user’s guide, version 8. SAS Institute,
Cary, N.C.
Schwarz, N. and A. Tesser. 2001. Blackwell
handbook of social psychology: Intra-
individual processes. Blackwell, Oxford,
U.K.
Skelly, S.M. and Zajicek, J.M. 1998. The
effect of an interdisciplinary garden pro-
gram on the environmental attitudes of
elementary school students. Hor tTechnol-
ogy 8:579–583.
Tanner, T. 1980. Signifi cant life experi-
ences: A new research area in environmental
education. J. Environ. Educ. 11:20–24.
U.S. Census Bureau. 2000. Metropolitan
area population estimates for July 1, 1999
and population change for April 1, 1990 to
July 1, 1999. 12 Dec. 2001. <http://www.
census.gov/population/estimates/metro-
city/ma99-01.txt>.
United Nations. 2001. World urbanization
prospects: The 1999 revision. Dept. of
Economic and Social Affairs, Population
Div. United Nations, New York.
Waliczek, T.M. and J.M. Zajicek. 1999.
School gardening: Improving environmen-
tal attitudes of children through hands-on
learning. J. Environ. Hort. 17:180–184.
Waliczek, T.M., P. Logan, and J.M. Zajicek.
2003. Exploring the impact of outdoor
environmental activities on children us-
ing a qualitative text data analysis system.
HortTechnology 13:684–688.
July05HT.indb 476July05HT.indb 476 6/8/05 2:23:46 PM6/8/05 2:23:46 PM
