Regard bushes and trees as soldiers
The regard bushes and trees as soldiers is a defensive stratagem, and it seems fairly useful. Basically the number of troops in the city is exaggerated 5 to 10 times for 24 hours. When a potential attacker see all these troops in the scout report of your city he will probably think twice about attacking it.
Expert Guide to Age 2
To become sucessfull and really do well in Evony Age 2 I really think you should get the Advanced Evony Strategies E-Book. Filled with secret strategies and tips it is definitly worth the cost, cheaper than a holiday package even.
Get it here.

