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The South Dakota
Register of Big Trees is a list of the largest reported specimens of tree
species found in the state, both native and naturalized. The primary purpose
of the Register is to recognize big trees as a valuable natural resource
worthy of conservation. Once identified and located, big trees may provide
sources for superior seed collection and/or vegetative propagation. Through
the Register of Big Trees, uncommonly large trees of any species, especially
those with historical significance, are located and recorded. The owners
and/or locators (nominators) of such trees are recognized through local and
statewide news releases and special certificates.
The South Dakota
Register of Big Trees recognizes champions in 57 different species. A total
of 234 trees, both champions and challengers, are currently listed on the
Register.
How are tree sizes
compared?
Trees are compared in overall size by using a combination of three
measurements. Each tree’s trunk circumference in inches is added to the
height in feet plus one quarter of its crown spread in feet. The tree’s
total point score is used to determine whether the tree is a champion. If
the nominee has more points than the registered champion, then it becomes
the new champion.
Nominees which do not qualify as state champions, but meet minimum
circumference requirements, are classified as Challenger Trees, and are
still registered as big trees. Should something happen to the reigning title
holder, the list of challenger trees will be consulted to select the new
champion.
South Dakota's
Largest Tree
South Dakota’s largest tree has
always been a cottonwood. The current largest cottonwood is located on
a farmstead near Yankton, South Dakota in rural Yankton County. It is 26 feet
5 inches
in circumference, 145 feet tall, and 102 feet in crown spread which results
in a point score of 487.5.
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How are big trees nominated?
An official nomination form can be requested through the South Dakota
Department of Agriculture’s Resource Conservation and Forestry Division, 523
East Capitol Ave., Pierre, SD 57501-3182, or by calling 1-800-228-5254 toll
free in South Dakota. A forester can be requested to measure and document
the required information needed to challenge a spot on the big tree
register.
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How do I measure a
big tree?
For the purposes of the Big Tree Register, a tree is defined as a woody
plant having one erect perennial stem or trunk at least 9 1/2 inches in
circumference at a point 4 1/2 feet above the ground, a definitely formed
crown of foliage, and a height of at least 12 feet. If several stems from a
single root system have grown together to form a trunk, only the largest
stem can be considered.
Three measurements are required: (1) trunk
circumference in feet and inches, (2) vertical to the nearest foot, and (3)
average crown spread to the nearest foot. Trunk circumference is measured at
a point 4 1/2 feet above the center of the base of the tree. If the tree
forks at 4 1/2 feet, measure the smallest circumference below that height.
If it branches below 4 1/2 feet, measure the largest single stem at 4 1/2
feet.
The total height of the tree is considered
to be the vertical distance between a horizontal plane passing through the
center of the base of the tree and a horizontal plane passing through the
top-most twig of the tree. The most accurate measurements of a tree’s height
are made with standard measuring tools such as the Abney hand level, Forest
Service hypsometer, a transit, or other instrument. If such an instrument is
unavailable, a straight stick can be used to obtain a fairly accurate height
measurement. Hold the stick at its base vertically at arm’s length making
certain that the length of the stick above your hand equals the distance
from your hand to your eye. Walk backwards away from the tree, staying on
ground approximately level with the tree’s base. When the stick above your
hand appears to be the same length as the tree, stop. You should be sighting
over your hand to the base of the tree and, without moving anything but your
eye, sighting over the top of the stick to the top of the tree. Measure how
far you have backed away from the tree with a tape measure; a 100’ tape
works best. That measurement should equate to the tree’s height.
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