This study explores the affect that distribution and growth factors of trees has on the perceived realism of a video game. Perceived realism was analyzed and it was found that the appearance and behavior of a game-object was based on the player's previous experience and expectations. Two independent variables were used to test what extent perceived realism is affected by distribution and by tree growth factors of procedurally generated trees? Two types of distribution were implemented: Random and ecological distribution and two tree generation algorithms, where one was based on the limiting factors that effects tree growth and one didn't. The results showed that there was no significant difference in the test conditions. But there was found an indication that the distribution and growth factors did have an affect on the perceived realism of the tree's shape. It was found that trees that are distributed with ecological distribution and grown with limiting factor have a more realistic shape.