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" The Tree Experiment Lab"
"The Importance of Trees"

As you peruse through the Yellowstone Arboretum website you will find the most important aspect in the history of the collections. That being the 'Accession Records'. How to read an accession record also called catalogue (example-Black Walnut):

0098-100 (year planted-order planted)

Latin: Juglans nigra (latin name)

Family: Juglandaceae (family name)

Origin: North America (location)

Common name: Black Walnut (name)

Location: Old Pond (locate)

Number in accession: 3 (survival)

Notes: (information about specimen)

This valuable information tells us many facts about the tree or shrub that gives us an insight into the make-up and growth of that species and if an experiment was successful or if it needs to be tried again. There are many environmental concerns that affect the outcome of these experiments and what may have happened in the past nurturing of these plants is not necessarily a guide for the future. 

The Old Pond Collection is a perfect example of an experiment in tree life. It represents years of testing, some tests failed but the strongest have survived proving to be a valuable insight into the introduction of future species.

This webpage will help to explain the reasoning behind the survival of existing trees and the demise of past experiments along with a look into future experimentations.


There are some unique features to the Old Pond area of the arboretum that makes it tougher for a particular species to survive. Compared to other parts of the arboretum, this area is in an open environment with drier and more wind-prone conditions. It is also a flat turf area as opposed to a natural grass or native landscape. As a result, it loses some of the protection afforded to trees in these other environments of the arboretum. It's microclimate is one of higher average temperatures, lower humidity and exposed winds.


The other feature that makes the Old Pond more unique is water source. It is  grass irrigated with seasonal water flowing through the adjacent Canyon Creek Canal and a wetlands pond with water levels fluctuating with either drought-like conditions or above average precipitation.


All these factors combine to make this area of the arboretum a natural "tree lab" for testing and experimentation. 


In the coming years the arboretum hopes too establish a healthier community of trees in the Old Pond Collection with the introduction of different species. Priority will be given to a Willow Collection to utilize the benefits of the pond itself. Also planned will be understory plantings of woody shrubs such as Spirea and the introduction of Iris along the perimeter of the Old pond.

The arboretum is planning a microclimate monitoring program to determine the extent of climate on growth habits of present trees and in the decision-making process for future introductions. These stations will be set-up throughout chosen locations in the arboretum. The Old Pond area will be one of those sites as it represents the most average weather site in the arboretum.

If you have any comments about these programs or questions about this collection, you can utilize our contact form found on the information page.


arboretum  [ahr-buh-ree-tuh m] 

noun, plural ar·bo·re·tums, ar·bo·re·ta [ahr-buh-ree-tuh] /ˌɑr bəˈri tə/.
a plot of land on which many different trees or shrubs are grown for study or display.

"Looks can be Deceiving"
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AUGUST 15, 2015



Juniperus virginiana 'Hills Dundee'

Native to Eastern and central North America

Zone: 3 - 9

Accession # 2001-017 (planted in 2001)

Original locations: Old Pond (photos), Sensory Garden (failed), Homestead Collection (survives)

Original curator's notes: Arrived in weakened condition and faced long hot drought summer for establishment. Severely damaged by rutting deer in October of that year. J.chinensis planted nearby not affected.

At first glance from this position there looks to be little growth in the 15 plus years of this tree's existence. Look closer and you will see some improvement in height. The most notable growth is in the body of the tree. It's density has expanded thus experiencing more moisture storage. Compare this specimen with one located on Homestead Hill which is in a completely differing environment.


FEBRUARY 1, 2019

AUGUST 15, 2015 (right)


FEBRUARY 1, 2019 (below)




Pinus nigra 'Austrian'

Native of Europe, from Austria to central Italy, Greece and the Balkan Peninsula

Zones: 3 -7 

Accession # 0098-113 (planted in 1998)

Locations: Old Pond (photos) and throughout the arboretum

Original curator's note: Planted Autumn 1998.Looking extremely winter-burned in May 1999. Three of the original plants (Old Pond) expired but others were thriving in 2003.

Groups of these Austrian Pines are located throughout the Old Pond Collection. Contrary to the Eastern Red Cedar these specimens are thriving and showing growth in density and height in the predicted manner. The Austrian is very drought tolerant and grows well in all soils, except alkaline. Because of it's intolerance to disease in parts of the country it is not recommended but it has been a proven winner in the Billings area.


"Supporting Cast"

Listed below are some of the specimens experimented with over the past decades along with their accession records. Although these specimens did not survive during the early time planted that does not mean they will not be re-ntroduced. There is no definitive proof of their demise as environmental concerns play such a huge factor and those concerns can not always be addressed. No original specimen photos are known to exist.


PERSIMMON A# 0099-053

Diospyros virginiana 'Meader'

Family: Ebenaceae

Origin: Connecticut to Florida, west to Kansas and Texas

Common name: Common persimmon

Where planted: Along entry drive of zoo nr.irrigation pump

Number in accession: 1

Note: Planted April 15, 1999. Mysteriously cut down in June 1999 possibly by ditch rider. Resprouting from base in August 1999. Still surviving October 2002. Seems to resprout from base each year and tends to winterkill. Selected and grown by late Professor Elwyn Meader of New Hampshire. Has been tested to -25 F.


BALD CYPRESS A# 0099-066

Taxodium distichum

Family: Taxodiaceae (or Cupressaceae)

Origin: Delaware to Florida, west to southern Illinois, Missouri, Arkansas and Louisiana

Common name: Common Bald Cypress (dedicious)

Location: In wet area nr.highway entrance pond. Had three spotlights trained on it. Waterways: Waterfowl viewing area, westside of pathway and south of stoned face building

Number in accession: 2

Note: Planted April 22, 1999. Failed to survive the first winter nr.entrance pond and the one nr.waterfowl area survived the winter but then leafed out and died the next spring.


BUTTERNUT A# 2000-010

Juglans cinerea

Family: Juglandaceae

Origin: Eastern North America to the Dakotas

Common name: Butternut or White Walnut

Location: Near front entry pond by inlet bay nearest pavement

Number in accession: 1

Note: Doing poorly in September 2000 (planted in 2000),but still surviving. Died out in winter of 2000/20001

Observation: Here seems to be the case that the specimen was not established enough to survive first winter

"Mystery Guests"

Not all specimens in an arboretum are planned. In a environment like the Yellowstone Arboretum where the planned and the native survive as one, occasionally comes the 'natural'. Whether it's planted by birds or transported by water, these specimens have earned their rightly spot in an arboretum collection. Here's two that fall into that category.


WILLOW A# 2018-NA PL13

3 Unverified (native) Willows are located on the southern side of the Old Pond. None are found in the accession records so are assumed to be naturally occurring specimens. Find out more...



Multiple shrub-style plum bushes were verified along the Canyon Creek Canal adjacent to the Old pond Collection. Assumed to have been transported by water and established they appear to have expanded in growth area and have become quite dense. Read more about the plum...


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