"I really do not know how to paint. I also do not have the time to get it right. What can I do to create a good looking forest?"

Get yourself the cardboard or canvas of your choice. Prime the canvas surface with the color of your choice using a sponge. Use the pore site of the sponge. Apply the color without pressing down to hard. Cover the entire surface. Now let it dry.

Melt some wax in the microwave. Wear gloves. No children doing this! Do not burn yourself. Use tealight candle wax or real bees wax. It’s your choice. Tealight candle wax cleans up more easily.

The wax is now fluid inside a container allowing for easy pouring. Lift up the canvas or cardboard. Hold it up so that there is a pleasant angle.

Slowly pour the hot wax over the upper edges of the canvas from left to right and from right to left. Give it some time so that the wax dries slowly as it is dripping down on the picture surface side of the cardboard or canvas. Repeat until your are satisfied.

Wax dries quickly. After the first application you can already see some kind of tree stem structures to appear. Use the sponge and slowly cover the entire surface area with the color of your choice. A pattern appears even stronger because of the treated wax surface and surface or surfaces not yet wax covered.

Repeat the process as often as you like.

Result: Your forest gets growing with more depth each time you are adding a wax or sponge application.

It looks real. It looks even better if you hold the canvas at different angles and let the wax do its gravity movement over only selected areas of the canvas surface to create leaves and twigs for your project.