Grass deterioration

“Animal Tracks” or “Desire Lines” are one of the new features implemented in Animal Crossing: City Folk. The game is able to keep track of your movements throughout town, and will wear down the grass in certain areas. This feature was originally intended to create paths in frequently-traversed areas, which would add to the town’s own unique character. In some instances, the feature has run amok, nearly completely obliterating all of the grass in the entire town. This process which has been dubbed "desertification" by the Animal Crossing community. Many players seek to prevent desertification in their towns, not only for aesthetic reasons, but because the lack of grass can become a game-breaking event, causing some insects, such as the dung beetle to be impossible to collect.

Walking or running over grass will eventually wear it down. Running wears grass more quickly than walking, but any type of treading on grass causes deterioration.

Prevention
While there is no way to play the game without wearing down any grass, players who wish to prevent grass deterioration in their towns can take certain steps to stem desertification. Since the game calculates grass wear at each game load, players can reduce the number of times each day they reload the game. Players can also walk along designated paths to limit wear to only these areas. Placing patterns on the ground as paths is one way to accomplish this. Patterns will not protect the ground, but will establish a path that can be consistently followed. Walking along a path of flowers also negates the deterioration, as a plot of land with a flower will not lose its grass if it is only stepped on once daily.

Repair
Grass regrowth in the game can take up to six months. There are a few ways in which a player can aid this process. Planting trees and flowers all over the trampled area will speed up regrowth. Flowers cause grass to regrow at about five times the normal rate. A flower takes about 30 days to convert dirt to grass on the plot of land on which it is planted, providing the ground there is not walked on more than once a day. Trees cause grass to regrow at three times the normal rate, as well as providing a physical barrier to prevent that particular plot from being trampled. Once these trees and flowers are planted, the player must avoid walking in the affected area other than to keep the flowers watered. Since running is slightly more devastating to grass than walking, a player should be sure to walk through an area if travel there cannot be avoided altogether. For players who are willing to time-travel within the game, the regrowth process can be further accelerated by advancing the game clock forward one day at a time, being certain that all flowers are kept watered each day.

The time of the year also affects grass regrowth, with spring and summer months being the best time for recovery. The regrowth rate is at its maximum in June. In December, the opposite is true: grass wears the fastest and regrows the slowest.