forest (15)

Forests vs. Trees

The other day I attended a very comprehensive talk on the Canopy of Atlanta. The analysis included canopy coverage overlays combined with social demographics like income and race (there was a correlation between income and canopy but not race and canopy). The bottom line is that canopy tells an important story, but it only part of the story. Satellite images, GIS layers, and canopy studies do not tell you the structure of the forest. As an arborist, I look at one tree at a time and I get aggravated with the emphasis on the technology, GIS, and canopy. It is as if we miss the trees for the forests. Municipalities love canopy studies because it lets them avoid difficult questions/conflicts like which trees should be protected and how important are specimen trees.  As long as they replace canopy, they feel they have done their job.  The problem is that specimen trees and the soil around them is not easily replaced. Older trees put on substantially more wood per year than younger trees. If it is native tree, their role in the ecosystem can never be replaced in a human life time. A replant grown in crappy soil, will be a crappy tree. Yet the best trees of the urban forest are removed  because they are inconvenient to our land uses. It is time we started paying more attention to the individual trees and back up the canopy studies with "ground truthing, recognizing the big trees that we need to save to retain the character and function of the forest.  There are ways to build around healthy trees that is win win, but it takes some intention. To destroy the big trees in the forest is the equivalent of polluting upstream, but the price paid is the degradation of the forest and the ecosystems around it. All urban dwellers should care about this, as we are what lives downstream.

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As an Arbor Day Foundation's Tree Planter while I'm preparing to celebrate the National Arbor Day 2014 on Friday April 25, I'm posting and disseminate the following info as a part of CIEDM actions for the celebration:

  • The Animal and Plant Health Inspection Service (APHIS) of the U.S. Department of Agriculture (USDA) has dedicated April as Invasive Plant Pest and Disease Awareness Month. Yesterday USDA proclaimed, as in past years, this month as Invasive Plant Pest and Disease Awareness Month 2014. Each year this time, USDA amplifies its public outreach about the risks that invasive plant pests & diseases pose to America's crops and forests,and how the public can prevent their spread. These non-native, destructive species can seriously harm American groves, thus our economy & environment, even our health & life when our groves die and become fuel for wildfires.
  • Here in California, the California Native Plant Week (CNPW) 2014 is on April 12-20. The California State Assembly and Senate approved Resolution ACR 173 establishing California Native Plant Week in 2011, which proclaims the 3rd week of April, each year, as California Native Plant Week and encourages community groups, schools, and citizens to undertake appropriate activities to promote the conservation, restoration, and appreciation of California's native plants. Specifically, the resolution recognizes that home landscaping and gardening with native plants can cut residential water use from 60 to 90% over conventional gardening. This recognition is specially meaningful with California in drought emergency.   


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The wildfire tragedy in Arizona took away the life of 19 firefighters on Sunday, June 30, the last Day of National Safety Month, is a shocking & hurting news and a deep grieve for all of us, and compels me as a member of American Grove and a urban forester to write about it before July 4th, the day often associates with fires and damages caused by fireworks. The 19 worriers protecting the communities are members of a specially trained outfit, an elite team of "Mountain Hotshots". Their deaths, most of them in the prime of their lives, marked the greatest loss of life from a U.S. wildland blaze in eight decades, since 25 men died battling the Los Angeles' Griffith Park fire of 1933. This deadliest U.S. wildfire tragedy is the nation's biggest loss of firefighters since 9/11. The fire reportly started after a lightning strike on Friday June 28 and spread to at least 2,000 acres on June 30. If it were an arson, in my opinion, the arsonist is a criminal. 
The fire was fused with, as usual in recent years, symptoms of climate change - triple-digit temperatures, low humidity, and windy conditions, and of course fed by dried vegetation caused by drought. As of today, July 3rd, nearly 600 firefighters are battling the mountain blaze, which had blackened about 13 square miles (35 sq. kilometers) and destroyed an estimated 50 to 200 structures, most of them homes, in and around Yarnell, a town of about 700 people. Yarnell and the adjacent community of Peeples Valley, which together are home to roughly 1,000 people, have been evacuated. With a 8% containment, the fire fighting command cautioned that plenty of dense, drought-parched scrub oak and chaparral was left unburned on the ground, providing ample fuel for creeping embers and hot spots to reignite. 
As this sad incident taken place at the very end of June, it should be noted that June is the Great Outdoors (GO) Month, a time when America celebrates its natural resources and treasures such as forests, parks, refuges, and other public lands and waters, and the time to go outdoors to enjoy and protect the nature. June also is the National Safety Month. We at CIEDM supported and participated in both awareness events, held workshops in Arcadia EcoHome on urban forest & toured the home grove, visited Angeles National Forest & met US Forest Services officers, and called for public attentions to the issues such as wildfires. At the eve of July 4, we also want to remind the public that wildfires, mainly caused by human outdoor activities, have become more frequent in recent years all over the world due to longer dry weather resulted from climate change. While we celebrate and enjoy the national holiday especially with fireworks, we also need to be alert with the weather conditions and prevent fire hazards. Let us have a Fire Independence Day tomorrow.

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American Forests, with grant support from the U.S. Forest Service’s Urban and Community Forestry Program, developed the Urban Forest Assessments Resource Guide to provide a framework for practitioners interested in doing urban forest ecosystem assessments. This guide is divided into three main sections designed to walk you through the process of selecting the best urban forest assessment tool for your needs and project. In this guide, you will find the following sections:

  • Urban Forest Management – explains urban forest management and the tools used for effective management
  • How to Choose an Urban Forest Assessment Tool – details the series of questions you need to answer before selecting a tool
  • Urban Forest Ecosystem Assessment Tools – offers descriptions and usage tips for the most common and popular assessment tools available

Over the years, a variety of assessment tools have been developed to help us better understand the benefits that urban forests provide and to quantify them into measurable metrics. The results they provide are extremely useful in helping to improve urban forest policies on all levels, inform planning and management, track environmental changes over time, and determine how trees affect the environment, which consequently enhances human health.

Trees in cities, a main component of a city’s urban forest, contribute significantly to human health and environmental quality. Urban forest ecosystem assessments are a key tool to help quantify the benefits that trees and urban forests provide, advancing our understanding of these valuable resources. That’s why American Forests is providing a step-by-step guide to urban forest assessments with a list of available tools and technologies.

For more information on American Forests’ urban assessments resource guide and other urban forest work, please visit

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Urban Forest Symphony

Sounds of the forest are often overlooked, especially in Urban Areas where airplanes, mowers, and cars can drown out the gentle sounds that emit from the forest. We further limit sounds surrounding us with ubiquitous ear pods or the latest blue tooth connecting us to our devices. Paths II: The Music of Trees by artist Abby Aresty investigates the world through its sounds, creating powerful sonic explorations from the urban forest. Her current installation at the Washington Park Arboretum in Seattle plays back sounds inspired by nature combined with her compositions.  In doing so she bridges the gap of urban and nature and engages you to listen.  Listen to the sounds and the artist being interviewed by Melissa Block on NPR's All Things Considered.

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Shinrin-Yoku--Wood-Air Breathing

In previous blogs I have mentioned Joan Maloof's Teaching the Trees, Lessons from the Forest.  I find her ability to convey and expand upon my understanding of trees and their role within the complex web of the ecosystem to be irresistible. Below is an excerpt from the first chapter with a link to the full chapter below that.  The picture of the forest is Thomas W Whittredge, The Pine Cone Gatherers, 1866

Also of interest is a New York Times Article on Shinrin-Yoku practice and the medical benefits of being exposed to plants.

Old-Growth Air

by Joan Maloof

From Teaching the Trees: Lessons from the Forest by Joan Maloof is a beautifully written and beautifully produced book. Read the first chapter here, which is reprinted by the permission of the University of Georgia Press, then buy the book!
For more information on the book visit

For years I have been explaining to the students in my classes that Maryland's Eastern Shore has no old-growth forests left, whatsoever; that this land the early explorers called Arcadia because of its numerous stately trees has been completely altered, and not a single original forest remains. Depending on my mood the day we discuss it, I relate this fact either with anger or with sadness. Last semester, however, I heard rumors that a twenty-acre remnant of old-growth forest remained. Twenty acres can barely be called a forest, but still I was anxious to see this unique scrap. So one spring morning when I awoke to a "true blue dream of a sky," I knew right away that this was the day I should visit the "leaping greenly spirit of trees."(1)

The forest was more than sixty miles away, and detailed directions were necessary to find it. Even before the car stopped on the isolated dirt road, a sweet, rich, earthy smell filled my senses. I used to think that particular odor was the smell of the mountains, but here I was, still on flat land. Did my own ground once smell like that too--before the grandfather trees were gone, in a time when the trees' breath merged with that of the fungi and the birds and the insects?
When we discuss what we miss about forests after they have been cut, we usually mention the sight or the shade or the species; but now I was breathing deeply of a forest gift I had forgotten: the air! Americans largely ignore this dimension of the forest's allure, but the Japanese recognize it and have a name for it: shinrin-yoku--wood-air bathing. Japanese researchers have discovered that when diabetic patients walk through the forest, their blood sugar drops to healthier levels.(2) Entire symposiums have been held on the benefits of wood-air bathing and walking. I certainly feel better after a walk in the woods, but until I read about it, I didn't know there was a name for my therapy.

What could be in forest air that makes us feel better? Researchers working in the Sierra Nevada of California found 120 chemical compounds in the mountain forest air--but they could identify only 70 of them! (3) We are literally breathing things we don't understand. And when we lose our forests, we don't know what we are losing. Some of the compounds in the air come from the bacteria and the fungi in the soil, but most are given off by the trees. Trees release volatile organic compounds from little pockets between their leaf cells. A number of theories exist about why they release the compounds. Possibly it is to deter insects. Or possibly the compounds are just metabolic by-products, and this is how trees eliminate them, having no excretory system. The scientific community is still undecided.

I like to think of these enticing fragrances as a sort of mutualistic reward for humans--a Botany of Desire scenario where the trees are using one of the few wiles they have that work on humans, (4) although in some cases, such as that of the sassafras tree, having a pleasing aroma is grounds for decimation. Native Americans used the sassafras medicinally, and European explorers were quick to adopt the fragrant leaves for both medicinal and culinary uses. The first shipment of sassafras was sent back to England in 1602, and sassafras remained the largest export for almost a hundred years.

It is not inconceivable that the trees may be altering our perceptions with their chemicals. The volatile molecules evaporate into the air and come into contact with the sensory neurons in our nasal passageways. The olfactory nerves send messages directly to the limbic system in our brains, which deals with instinctive emotions such as sex, memory, and aggression. The limbic system can certainly affect our physical bodies, and all of this can happen even without our perception of having "smelled" anything.

The molecules from the trees don't just go up our noses, however; they are also part of the air that goes into our lungs, and once in our lungs, some of the molecules can enter our bloodstreams. So when we walk through the forest inhaling that sweet air, the wood-air, the forest actually becomes a part of our bodies. No wonder that a forest walk evokes the lines from Rainer Maria Rilke's "Ninth Elegy":

Earth, my dearest, I will. Oh believe me, no more
of your springtimes are needed to win me over--, one,
ah, a single one, is already too much for my blood. (5)

Read Full Excerpt

E. E. Cummings, "i thank you God for this most amazing day," in 100 Selected Poems by E. E. Cummings (New York: Grove Press, 1959), 82.
2. Y. Ohtsuka, Noriyuki Yabunaka, and Shigeru Takayama, "Shinrin-yoku (Forest-Air Bathing and Walking) Effectively Decreases Blood Glucose Levels in Diabetic Patients," International Journal of Biometeorology 41, no. 3 (1998): 125.
3. D. Helmig and J. Arey, "Organic Chemicals in the Air at Whitaker's Forest--Sierra Nevada Mountains California," Science of the Total Environment 112, nos. 2(1992): 233.
4. Michael Pollan, The Botany of Desire (New York: Random House, 2001).
5 Rainer Maria Rilke, "The Ninth Elegy," in The Essential Rilke, sel. and trans. Galway Kinnell and Hannah Liebmann (Hopewell: Ecco Press, 1999), 131; printed in its entirety in the appendix of this book. Hereafter, I refer to quotations from it by line numbers.
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 NASHVILLE, Tenn. — Tennessee’s urban forests, currently valued at about $80 billion, also provide almost  $650 million in benefits such as carbon storage, pollution removal, and energy reduction according to a new U.S. Forest Service report.

The authors of Urban Forests of Tennessee, 2009 found there are 284 million trees in urban areas in the state, with canopies covering 33.7 percent of 1.6 million acres of urban area. Those urban forests provide an estimated $204 million per year in pollution removal and $66 million per year in energy savings. The study is the first of its kind in Tennessee.


“This report, for the first time, puts a face on the urban forest resource and what it means to the state in terms of economic and environmental value, ” said Steven Scott, Tennessee State Forester and head of the Tennessee Division of Forestry, which collected the data for the report. “Perhaps the most significant finding is the immediate impact of urban trees on the use of energy, the savings we get as a result of shade near homes, businesses and industrial areas.”


David Nowak, Northern Research Station project leader and research forester, led the pilot study, which sampled trees in all the state’s urban area and analyzed their value using a model developed by the Forest Service.


“Urban forests make our cities healthier, more vibrant places to live,” said Nowak. “They provide healthy outdoor spaces for our kids, they clean our air and water, and – as this study shows – they provide tremendous economic benefits. We must continue our work to protect these critical natural resources.”

There are more than 100 million acres of urban forest across the U.S., but a recent study shows that many are in decline.

The Tennessee report includes an extensive assessment of urban forest health, providing information about present damage and potential risks. In addition to nonnative invasive plants, Tennessee urban forests face risks from exotic pests that include the recently discovered thousand cankers disease, which impacts black walnut; hemlock woolly adelgid, which kills eastern and Carolina hemlocks; the Asian longhorned beetle, which kills a wide range of hardwood species; and the emerald ash borer, which decimates ash trees. This last insect was recently documented in East Tennessee.

The Forest Service Inventory and Analysis and Community Forestry Programs partnered with Tennessee Division of Forestry and researchers from the Forest Service Northern Research Station and SRS on the project.

To access the full report in PDF format:

To request this publication by mail, send your name and complete mailing address, with report title, author, and publication number (GTR-SRS-149) to:


 Headquartered in Asheville, N.C., the Southern Research Station is comprised of more than 120 scientists and several hundred support staff who conduct natural resource research in 20 locations across 13 southern states (Virginia to Texas). The Station’s mission is “…to create the science and technology needed to sustain and enhance southern forest ecosystems and the benefits they provide.” Learn more about the Southern Research Station at:



Zoë Hoyle


USDA Forest Service

Southern Research Station

Follow SRS onTwitter: @usfs_srs



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One person encouraging a village to make a difference by planting trees- an inspiring story.  It is hard to go wrong planting trees.  Moreover, trees create common ground between partisans, religions, and ethnic groups.      

by Gashaw Tahir | 12:01 pm March 7th, 2012 

Editor’s Note: With the recent release of the movie The Lorax based on the famous Eco-tale by Dr. Seuss, we have a modern day “Lorax,” an American credited with planting 1 million trees in his native Ethiopia. The amazing personal project of Gashaw Tahir (SAY: Gah-sha Ta-ear) is even promoting understanding between Christians and Muslims.

As a child growing up in Ethiopia, Gashaw Tahir lived in a village so dense with majestic trees he couldn’t even see the sky. But, as an adult returning to Ethiopia after years spent abroad, he was shocked to find his native country transformed into a barren land, stripped of most of its forests.

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Alpine Trees Getting Shorter


Below is an article related to using LiDAR and discovering some interesting trends in tree heights.

Link to article:


LiDAR Map Shows Alpine Trees Getting Shorter


A global map of forest height was produced from NASA's ICESAT/GLAS, MODIS and TRMM sensors. The map will advance our understanding of Earth's forest habitats and their role in Earth's carbon cycle.

In a new analysis of Earth’s forest heights, geographers working with light detection and ranging (LiDAR) satellite imagery have found that trees in alpine zones are getting shorter. In contrast, the tropical and boreal forests are getting taller compared with a previous study using the same satellite.

“Our map contains one of the best descriptions of the height of Earth’s forests currently available at regional and global scales,” said remote sensing engineer Marc Simard of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. The Geoscience Laser Altimeter System instrument on NASA’s Ice, Cloud and land Elevation Satellite (ICESat) collected the globally distributed laser pulse measurements, which NASA remote sensing scientists and colleagues at the University of Maryland in College Park and the Woods Hole Research Center in Falmouth, Mass., screened to produce the map.

They used 2.5 million measurements, which the press statement referred to as “sparse,” and coupled the LiDAR data with estimates of the percentage of global tree cover from NASA’s Moderate Resolution Imaging Spectroradiometer on NASA’s Terra satellite, elevation data from NASA’s Shuttle Radar Topography Mission, and temperature and precipitation maps from NASA’s Tropical Rainfall Measuring Mission and the WorldClim database, according to NASA.

The scientists caution that while the new map provides insight on global distribution, it does not distinguish why the trends in forest height are happening and the “accuracy of the new map varies across major ecological community types in the forests, and also depends on how much the forests have been disturbed by human activities and by variability in the forests’ natural height.”

Image courtesy of NASA/JPL-Caltech.

Source: JGR

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In case you missed this interesting article in the NY Times:

In Central Park, more than 1,000 trees in the red oak family were spangling the scenery with the colors of autumn.

But this year, they were failing to do something else they generally do in the harvest season: produce acorns.

“I remember going into areas and you’d get the crunch of acorns under your feet,” said Neil Calvanese, vice president for operations at the Central Park Conservancy. “And this year, you kind of have to search around for them.”

It is a phenomenon happening not only in New York but also throughout the Northeast. While last fall set a recorded high for acorn production, at roughly 250 pounds per tree, this year is seeing a recorded low, with a typical tree shedding less than half a pound of its seeds, said Mark Ashton, a forest ecologist at Yale University. On average, oaks produce about 25 to 30 pounds of acorns a year.

“Scarlet oak, black oak, true red oak,” Dr. Ashton said. “These are the ones that dominate our forest, and these are the ones that aren’t producing acorns this year.”

Coming on the heels of an acorn glut, the dearth this year will probably have a cascade of effects on the forest ecosystem, culling the populations of squirrels, field mice and ground-nesting birds. And because the now-overgrown field mouse population will crash, legions of ticks — some infected with Lyme disease — will be aggressively pursuing new hosts, like humans.

“We expect 2012 to be the worst year for Lyme disease risk ever,” said Richard S. Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies in Millbrook, N.Y. “We are already planning educational materials.”

It will probably turn into a big year for animals’ being killed on highways as well. Deer, in search of alternative sources of food, will leave the cover of the oak trees and wander out closer to roads.

“I would expect that traffic collisions are going to be higher in a year like this year,” Dr. Ostfeld said.

While scientists do not fully understand why this year has produced the lowest acorn crop in 20 years of monitoring, there is nothing unusual about large fluctuations in the annual number of acorns. Fingers are not being pointed at global warming.

Oak trees “produce huge, abundant amounts one year and not in other years,” Dr. Ashton said. “I don’t think it’s bad — the whole system fluctuates like this.”

One theory for why oak trees vary their acorn yield is the so-called predator satiation hypothesis. Under this theory, during bumper years, the trees litter the forest floor with seeds so completely that squirrels, jays, deer and bears cannot possibly eat them all. Then, in off years, the trees ramp down production to keep the predator populations from growing too large to be satiated.

But the variability of weather in New York and New England could also be playing a role in the shortage this year.

“A lot of it has to do with the initial spring,” Dr. Ashton said. Acorn production is high when “everything converges on a perfect spring.”

It takes a red oak 18 months to grow an acorn. The tree is pollinated in the spring of one year, and its acorns drop in the fall of the next year. The rainy spring of 2010 could have dampened the wind-driven transfer of pollen from one tree to another, resulting in the acorn dearth this year.

While acorn fluctuation is normal, what is unusual this year is the abundance followed by the steep drop. “In a sense, it’s just another trough,” Dr. Ostfeld said. “But this is the most extreme pair of years that we’ve seen.”

Dr. Ostfeld describes acorns as an engine that drives the forest ecosystem. “When that engine is cooking along,” he said, “you get these heavy knock-on effects.”


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How fragmented are forests in the Eastern U.S.?

The once unbroken forests that once stretched across vast swathes of North America are mostly gone, broken into pieces by cities, roads and farms. Now a new study attempts to quantify fragmented forests in the Eastern United States – and finds that privately-held lands may play a key role in keeping things together.

“Fragmentation is an ever-present threat to forest communities in the eastern United States,” Kurt H. Riitters and John W. Coulston of the U.S. Forest Service and James D. Wickham of the U.S. Environmental Protection Agency write in Forest Ecology and Management. Forests that get broken into little pieces are more vulnerable to invasive species, for instance, and to losing some species. entirely And past large-scale studies showed that fragmentation in the East was “pervasive,” they note, with one finding that just 10% of forest plots were still “intact.” Those studies, however, were relatively coarse-grained, the trio writes.  View Full Article From Conservation Magazine

photo by Paul Reis

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Autumn Unfolds, With Birdsong and Crackling Leaves

From New York Times


Recently, there were a string of days that felt stolen from summer. Tuesday, the day of my site visit, was the last of these. The warm sun flooded the woods of Inwood Hill Park with light, creating long shadows that foreshortened the scene. Harshly lit patches straddled pockets of deep shade.

Autumn Unfolds

Tracking fall’s progress in a patch of forest in Inwood Hill Park.

There was a high, sweet song above the ever-present din of bluejays, gray catbirds and house sparrows. A bird’s back blends into bark of a tree as it walks straight upward, defying gravity: the palm-sized Northern parula sails through leafy branches, yellow throat and white underbelly melding into the bright light above.

In our urban setting, quiet is elusive and fleeting. And yet, I hear black birch leaves breaking off branches and rasping as they land on the rocks below. Farther afield, successive rolls of gentle drumming are audible; is it a woodpecker?

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Typically old trees are big, but what other characteristics do old trees demonstrate. Neil Pederson of the Department of Biological Sciences at Eastern Kentucky University,  summarizes six characteristics in his abstract. 

(1) smooth or “balding” bark;

(2) low stem taper;

(3) high stem sinuosity;

4) crowns comprised of few, large-diameter, twisting limbs;

(5) low crown volume; and

(6) a low ratio of leaf area to trunk volume.


He concludes, "The existence of old trees in the landscape can also be related to life-history traits or land-use histories. Both professionals and lay folk can be trained to identify these traits and environmental conditions. While these characteristics and settings generally signal the potential for old trees, there is no guarantee that they represent old ages. However, these characteristics should aid in the discovery of old trees throughout the EDF.". 


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Photograph by Kathryn Kolb

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The Secret Forest

The soil was alive, the trees emanated old age, and the shade was prolific with pockets of light bursting through.  All expected qualities of an old growth forest.   The unexpected was the sound of airplanes overhead and cars from a nearby major road.   This was my experience at Big Trees Forest  Preserve located smack dab in the middle of one of the busiest sections of Atlanta.  More amazing is that, of the six million inhabitants surrounding the forest, I saw one person on a walk with their dog and another eating lunch at the entrance.   Adjacent to the forest are office building and strip malls that are full of people.   The contrast of the hot parking lot at the entrance and the cool breeze in the forest was tactile. Entry into the forest felt as if you were transitioning in time and space to a different reality.  The forest was a perfect combination of neglect and love.  Neglected by the general populous but observably cared for by those that love it with fantastic trails, maps, and informative designed viewpoints.   These hidden gems are not as rare as you might think.  I can count ten similar forests that I know of in the Atlanta Region.  Have you discovered the secret forest in your area yet?



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