Page 36 - PowerE-L05-F

Lesson 9

Old growth or Virgin Forests

Virgin forests are also termed as old-growth
forest. It is a forest type existing for many
years. It exhibits unique biological factors.
Old-growth forests are composed of large

and old live trees, large dead trees (also
called “snags”) and large logs. The presence
and penetration of light in the main canopy
layer is attributed to the gaps created by the

individual deaths of old trees. This contri
butes to the favorable condition for photosynthesis. Structurally diverse, virgin forests pro-
vide higher diversity habitat than forests in other stages. This allows different animals and
plants species to live symbiotically in this forest type. The unique biological features of

virgin forests also provide protection for humans such as the penetration of ultraviolet rays
from the depleted ozone layer and the possible occurrence of flashfloods. However, many
virgin forests are in great danger due to excessive and abusive logging. This has created a
decrease in biodiversity, affecting not only the forests itself but the indigenous and endemic

species relying on the forest for their habitat. Severe disruptions such as clear cutting or fire
allow regeneration of virgin forests into secondary growth forests. It may take a century or
millennia just like the Hardwood forest in the eastern United States to wash away any signs
of disturbance made to the forest. If destructive human activities such as logging will not be

stopped, all virgin forests of high biodiversity will no longer exist.

Comprehension

1. Do virgin forests provide higher diversity habitat than secondary growth forests?
2. Name things that can be found in old-growth forests.

Questions

1. How can humans preserve the existence of virgin forests?
2. What will happen if all virgin forests no longer exist?

Vocabulary & Expressions

snags - a partly or completely dead tree still standing
canopy - the uppermost layer of a vegetation
symbiotic - a mutual association among animals and plants
diversity - multiplicity in things
endemic - having traits if being confined to a certain geographic region

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