Forest
Plants in general stand for facts and ideas, so it makes sense that a forest in the Bible represents a collection or system of external, factual, ideas. This can be a collection on its own, or it can be the collected external knowledge of a church. It can also represent the level of a person's mind where he or she deals with such systems of ideas.
(Odkazy: Arcana Coelestia 9011 [1,3-7], 9642 [3,23]; The Apocalypse Explained 650 [26,49])
Ezekiel 31:5-7
5
Therefore its stature was exalted above all the trees of the field; and its boughs were multiplied, and its branches became long by reason of many waters, when it shot [them] forth.
6
All the birds of the sky made their nests in its boughs; and under its branches did all the animals of the field bring forth their young; and under its shadow lived all great nations.
7
Thus was it beautiful in its greatness, in the length of its branches; for its root was by many waters.
