earthgen.register_tree({
    max_biome_humidity = -0.4,
    min_biome_temperature = 0.4,
    min_height = 4,
    max_height = 40,
    grows_on = c_desert_sand,
    chance = 50,
    grow = function(data, a, x, y, z, minp, maxp, pr)
        -- Cactus
        local ch = pr:next(1, 4)
        for yy = math.max(y, minp.y), math.min(y+ch-1, maxp.y) do
            data[a:index(x, earthgen.REALM_HEIGHT_MIDPOINT + yy, z)] = c_cactus
        end
    end
})

earthgen.register_tree({
    max_biome_humidity = -0.4,
    min_biome_temperature = 0.4,
    min_height = 2,
    max_height = 30,
    grows_on = c_desert_sand,
    chance = 50,
    can_be_in_village = true,
    grow = function(data, a, x, y, z, minp, maxp, pr)
        -- Dry shrub
        if minp.y <= y and y <= maxp.y then
            data[a:index(x, earthgen.REALM_HEIGHT_MIDPOINT + y, z)] = c_dry_shrub
        end
    end
})

earthgen.register_tree({
    min_biome_humidity = -0.4,
    max_biome_humidity = 0.4,
    min_biome_temperature = 0.4,
    min_height = 2,
    max_height = 12,
    grows_on = c_dry_grass,
    chance = 1000,
    grow = add_savannatree
})

earthgen.register_tree({
    min_biome_humidity = -0.4,
    max_biome_humidity = 0.4,
    min_biome_temperature = 0.4,
    min_height = 13,
    max_height = 30,
    grows_on = c_dry_grass,
    chance = 250,
    grow = add_savannatree
})

earthgen.register_tree({
    min_biome_humidity = -0.4,
    max_biome_humidity = 0.4,
    min_biome_temperature = 0.4,
    min_height = 2,
    max_height = 40,
    grows_on = c_dry_grass,
    chance = 1500,
    grow = add_savannabush
})

earthgen.register_tree({
    min_biome_humidity = 0.4,
    min_biome_temperature = 0.4,
    min_height = 1,
    max_height = 40,
    grows_on = c_grass,
    chance = 14,
    grow = add_tree
})

earthgen.register_tree({
    min_biome_humidity = 0.4,
    min_biome_temperature = 0.4,
    min_height = 1,
    max_height = 25,
    grows_on = c_grass,
    chance = 16,
    grow = add_jungletree
})

earthgen.register_tree({
    min_biome_humidity = 0.4,
    min_biome_temperature = 0.4,
    min_height = 1,
    max_height = 25,
    grows_on = c_grass,
    chance = 30,
    can_be_in_village = true,
    grow = function(data, a, x, y, z, minp, maxp, pr)
        -- Jungle grass
        if minp.y <= y and y <= maxp.y then
            data[a:index(x, earthgen.REALM_HEIGHT_MIDPOINT + y, z)] = c_jungle_grass
        end
    end
})

earthgen.register_tree({
    min_biome_humidity = -0.4,
    max_biome_temperature = -0.4,
    min_height = 3,
    max_height = 55,
    grows_on = c_dirt_snow,
    chance = 40,
    grow = add_pinetree
})

earthgen.register_tree({
    max_biome_humidity = -0.4,
    max_biome_temperature = -0.4,
    min_height = 3,
    max_height = 55,
    grows_on = c_dirt_snow,
    chance = 500,
    grow = add_pinetree
})

earthgen.register_tree({
    max_biome_humidity = -0.4,
    min_biome_temperature = -0.4,
    max_biome_temperature = 0.4,
    min_height = 1,
    max_height = 40,
    grows_on = c_grass,
    chance = 250,
    grow = add_tree
})

earthgen.register_tree({
    max_biome_humidity = -0.4,
    min_biome_temperature = -0.4,
    max_biome_temperature = 0.4,
    min_height = 1,
    max_height = 40,
    grows_on = c_grass,
    chance = 60,
    can_be_in_village = true,
    grow = function(data, a, x, y, z, minp, maxp, pr)
        -- Grass 1-4
        if minp.y <= y and y <= maxp.y then
            data[a:index(x, earthgen.REALM_HEIGHT_MIDPOINT + y, z)] = c_grasses[pr:next(1, 4)]
        end
    end
})

earthgen.register_tree({
    min_biome_humidity = 0.4,
    min_biome_temperature = -0.4,
    max_biome_temperature = 0.4,
    min_height = 1,
    max_height = 40,
    grows_on = c_grass,
    chance = 250,
    grow = add_tree
})

earthgen.register_tree({
    min_biome_humidity = 0.4,
    min_biome_temperature = -0.4,
    max_biome_temperature = 0.4,
    min_height = 3,
    max_height = 40,
    grows_on = c_grass,
    chance = 3,
    can_be_in_village = true,
    grow = function(data, a, x, y, z, minp, maxp, pr)
        -- Grass 3-5
        if minp.y <= y and y <= maxp.y then
            data[a:index(x, earthgen.REALM_HEIGHT_MIDPOINT + y, z)] = c_grasses[pr:next(3, 5)]
        end
    end
})

earthgen.register_tree({
    min_biome_humidity = -0.4,
    max_biome_humidity = 0.4,
    min_biome_temperature = -0.4,
    max_biome_temperature = 0.4,
    min_height = 3,
    max_height = 40,
    grows_on = c_grass,
    chance = 20,
    grow = add_tree
})

earthgen.register_tree({
    min_height = 1,
    max_height = 1,
    grows_on = c_grass,
    chance = 10,
    grow = function(data, a, x, y, z, minp, maxp, pr)
        -- Papyrus
        local ph = pr:next(2, 4)
        for yy = math.max(y, minp.y), math.min(y+ph-1, maxp.y) do
            data[a:index(x, earthgen.REALM_HEIGHT_MIDPOINT + yy, z)] = c_papyrus
        end
    end
})

function earthgen.get_spawn_tree_func(treedef)
    return function(data, a, x, y, z, minp, maxp, pr)
        if minp.y <= y and y <= maxp.y then
            minetest.after(0, minetest.spawn_tree, {x=x, y=y, z=z}, treedef)
        end
    end
end

if minetest.get_modpath("moretreesx") then
    earthgen.register_tree({
        min_humidity = 0,
        min_temperature = 0.2,
        min_height = 1,
        max_height = 5,
        grows_on = c_grass,
        chance = 800,
        grow = earthgen.get_spawn_tree_func(moretrees.rubber_tree_model)
    })
end