A three foot wide tree definitely trumps a concrete wall, though it probably loses to a steel beam. Concrete is concrete - an APC can shatter concrete on impact. A living tree, in the same circumstances, is much more likely to get uprooted than broken. Despite being a "basic" building material when cut down and dried, living wood is strong stuff.
Though I wonder, how much strength, impact-wise, do trees even have? In the game, I mean?
edit: and the answer is... none! They're set as unbreakable. Time to alleviate that.
"type" : "terrain",
"id" : "t_tree",
"name": "tree",
"symbol": "7",
"color": "green",
"move_cost": 0,
"flags": ["FLAMMABLE_ASH", "BASHABLE", "NOITEM", "SUPPORTS_ROOF", "TREE", "REDUCE_SCENT"],
"bash": {
"str_min": 8, "str_max": 50,
"sound": "crAAAck!",
"sound_fail": "whump!",
"ter_set": "t_stump",
"items": [
{ "item": "stick", "amount": 5, "minamount": 1 },
{ "item": "splinter", "amount": 6, "minamount": 2 },
{ "item": "log", "amount": 1, "minamount": 0 }
]
}
},{
"type" : "terrain",
"id" : "t_stump",
"name": "stump",
"symbol": "i",
"color": "brown",
"move_cost": 4,
"flags": ["FLAMMABLE_ASH", "BASHABLE", "NOITEM", "TRANSPARENT", "REDUCE_SCENT"],
"bash": {
"str_min": 6, "str_max": 50,
"sound": "crack!",
"sound_fail": "whump!",
"ter_set": "t_dirt",
"items": [
{ "item": "splinter", "amount": 4, "minamount": 1 }
]
}
},{
"type" : "terrain",
"id" : "t_tree_young",
"name": "young tree",
"symbol": "1",
"color": "green",
"move_cost": 4,
"flags": ["TRANSPARENT", "BASHABLE", "FLAMMABLE_ASH", "NOITEM", "YOUNG", "REDUCE_SCENT"],
"bash": {
"str_min": 4, "str_max": 50,
"sound": "crunch!",
"sound_fail": "whack!",
"ter_set": "t_underbrush",
"items": [
{ "item": "stick", "amount": 3, "minamount": 0 }
]
}
},{
"type" : "terrain",
"id" : "t_tree_apple",
"name": "apple tree",
"symbol": "7",
"color": "ltgreen",
"move_cost": 0,
"flags": ["FLAMMABLE_ASH", "NOITEM", "BASHABLE", "SUPPORTS_ROOF", "TREE", "REDUCE_SCENT"],
"examine_action": "tree_apple",
"bash": {
"str_min": 8, "str_max": 50,
"sound": "crAAAck!",
"sound_fail": "whump!",
"ter_set": "t_stump",
"items": [
{ "item": "stick", "amount": 5, "minamount": 1 },
{ "item": "apple", "amount": 6, "minamount": 0 },
{ "item": "splinter", "amount": 6, "minamount": 2 },
{ "item": "log", "amount": 1, "minamount": 0 }
]
}
},{
Find the entry for "t_tree" in your terrain.json and replace everything from it to the apple tree below, with the above. I'll test it out right now, but theoretically it should work.