The following is an excerpt from the world's written histories. It takes
place around 400 AA of the Second Age and is the earliest known recorded
instance of Forest Defenses being used as well as the discovery of
Khandava Forest specifically:

The rebels of Kinsarmar refused to submit to the hostile control of
Stavenn once and for all. Yet again, they rose up against the Stavennite
rulers and expelled the offenders from their city. Stavenn responded by
sending a force of several thousand warriors to subdue the favorably
growing Kinsarmar. While marching through the forests near Kinsarmar the
army was ambushed by an amazing MAGICKAL force, causing the very trees
about them to come alive and attack the army. Survivors returned to
Stavenn with harrowing tales depicting lithe humanoid beings with blades
that danced with blinding speed.

...

Lyria had run for miles until she collapsed in the forest, wounded and
exhausted from the losing battle. The Elves had taken her into their
care and soon she too felt the effects of the Moon of Change. This
forest was named the Khandava Forest and held the strongest MAGICKAL
forces of any wilderness area in Aetherius. One night, when the three
moons were full, she felt the first changes pulse through her veins. The
howl of a wolf was heard
in the distance, and in that lone cry, she felt a bond that would never
be broken from that moment. She had become the first Lycaean, and the
other rebels that had come with her soon changed as well, beginning this
new and ferocious race. It was Lyria who had convinced the Elves and
Lycaeans to take up arms against Stavenn, knowing their forests could
surely have been next in their conquest of the land.


There you go. Research.

The forestal councils use hostile magick to defend the areas surrounding
their home. So do the Wytchen.

Penned by my hand on the 12th of Vita, in the year 463 AD.