14 WINTER 2015 ARBOR AGE www.arborage.com
PLANT HEALTH CARE
BY BRANDON M. GALLAGHER WATSON
In the upper regions of Siberia, nearly 450 miles above the
Artic Circle, resides one of the world's toughest tree species.
Larix gmelinii, known as the Dahurian larch, holds the distinct
title of "World's Northernmost Tree Species." Living in this
area, just above the permafrost layer, is not for the faint of
sap. Air temperatures have been recorded at an astonishing
negative 94 degrees Fahrenheit (-70°C) during the winter, and
summer temps climb above the freezing point for just a few
short weeks. The growing season is less than 100 days long
each year with polar night lasting from September to February.
This species has adapted to
low seed germination rates
with the ability to sprout
new trees off its root system,
forming forest colonies of
"creeping larch." This growth
habit is common among
hardwoods, such as aspen,
but uncommon amongst temperate conifers. Their tough
wood and extreme cold keep insect and fungal pests to a
minimum and, of the 268 other organisms that live on this
tundra, there are no other tree species competing for sunlight.
They can survive here for a long time. One individual was
found to be 919 years old, while the root system may be as old
as several millennia. Despite these inhospitable conditions, the
Dahurian larch thrives here.
The Dahurian larch endures the local climate with great
success thanks to a fairly complex series of adaptations we
generally refer to "cold hardiness." Hardiness is a measure of
how well a plant can withstand adverse conditions, and can
include cold, heat, elevation,
drought, flooding and
even wind. The lowest
temperature that it can
survive before freezing to
death determines a plant's
cold hardiness The USDA
has made this fairly simple
"
Hardiness is a measure of how well a
plant can withstand adverse conditions,
and can include cold, heat, elevation,
drought, flooding and even wind.
"
ALL
PHOTOS
PROVIDED
BY
RAINBOW
TREECARE
SCIENTIFIC
ADVANCEMENTS
Just Chill:
How Cold Hardiness Works
