Since I decided to draw my inspirations from both Grimm's tales and Slavonic mythology, more research needs to be done. What kind of forest will it be? What plants specifically? What weather?
Slavic lands are basically Easter Europe and I'm going to focus exactly on this area. Climate of Eastern Europe is temperate which means there's a huge variety of vegetation all over the place. The average temperature ranges from 0 °C do 10 °C, and precipitation occurs in different seasons. The most typical plant formation in colder parts is taiga, while warmer parts are covered with deciduous and mixed forest. Seasons are easily distinguishable and determined by temperature (warm, humid spring, warm, usually dry summer, cold, humid autumn and winter, often with snow). What I'm looking for then is a humid environment with a choice of rather common vegetation.
Here's a big fat oak. They get absolutely huge and live for centuries. Their trunks often 'open' creating a sort of a cave inside, which always make people want to peak inside.
Birch would a nice differentiation from brown and green trunks.
Mountain ash has beautiful red berries which will bring some colour to my forest.
...and a pine.
It would be fantastic to make at least those trees. I'd have to speed up. With my attention to detail it will take me awfully loads of time to build five kinds of trees.