grseb9s/cellular_forest

Cellular Automata simulation of a forest

Cellular Automata simulation of a forest

This is a simulation of a forest populated by trees, lumberjacks, bears and the occasional forest fire.

Erik Sjöström

How it works, (1 iteration = 1 month)

The Grid

• The grid is an NxN square
• 50% of the grid will be populated by trees at the start of the simulation.
• 10% of the grid will be populated by lumberjacks at the start of the simulation.
• 2% of the grid will be populated by bears at the start of the simulation.

Trees

There are three types of trees

• Sapling, the mini tree. A sapling turn into a normal tree after 12 months.
• Normal tree. Has a 10% chance to spawn a sapling at an adjacent cell.
• If a normal tree survives for 120 months it turns into an elder tree, which has a 20% chance to spawn a sapling.

Lumberjacks

Every month the lumberjack takes a random walk for a maximum of three cells. For every cell it reaches it checks if the cell contains a tree. If the cell does contain a tree the lumberjack cuts it down and stays in that cell for the rest of month. If it does not contain a tree, the lumberjack tries to move on to the next cell unless it is at the end of its walk (third cell). For every tree a lumberjack cuts down, lumber is collected. A normal tree is worth 1 lumber and an elder tree is worth 2 lumber.

Hiring and firing

At the end of a year (12 months), all the lumber is counted up and compared to the amount of working lumberjacks according to amount = (lumber/(scale_factor) - lumberjacks), if amount is positive that many lumberjacks are hired, otherwise that many lumberjacks are fired.

Bears

Every month each bear takes a random walk for a maximum of five cells. If a bear runs into a lumberjack, it brutally savages the lumberjack and sends it out of the simulation, and stays in that cell for the rest of the month.

Animal control

If there is one or more accidents during a year, one bear is taken around the back of the simulation. If no accidents is encountered during a year, a new bear is spawned.

Forest fires

A forest fire happens during one single month, so during a forest fire, only one month elapses.

There are some factors which determine the spread of the fire: Chance of catching fire and duration of fire, these differ between trees.

• Sapling: Has a 1/8 chance to catch fire and burns for 1 iteration
• Tree: Has 1/4 chance to catch fire and burns for 2 iterations
• Elder tree: Has 1/2 chance to catch fire and burns for 4 iterations

After the fire, the ground remains scorched for 5 years, until any saplings can spawn on the ground.

Fun keyboard commands

• F = Starts a fire at random cell containing a tree
• K = Removes 50 lumberjacks from the simulation
• B = Spawns 100 new bears
• L = Spawn 50 lumberjacks

TODO

• The lumberjacks are currently taking over, this should probably be fixed
• It seems like there are some stray dots of color, look into this

Credit

Credit goes to reddit user /u/Coder_d00d for coming up with the idea as a challenge in /r/dailyprogrammer