Why I can't find my mesh in menu? I wrote the script, begining looks in this way:

bl_idname = "mesh.tree_add"
bl_label = "Trees Generator"
bl_options = {'REGISTER', 'UNDO', 'PRESET'}
bl_space_type = 'VIEW_3D'
bl_region_type = 'TOOL_PROPS'


I installed my script from User Pref. menu and checked this box:


but still I can't find my script in menu called by Shift+A. Also I can't find others extra objects. But I can find it by SPACE menu and it work correctly. Any ideas?
You can't find it in the menu because you didn't add it to the menu. Menus don't automatically pick up new entries based on the class properties, you have to write code to add them:

import bpy

def add_menu_item(self, context):
    self.layout.label("Added this line")
    self.layout.operator("mesh.tree_add")

bpy.types.INFO_MT_mesh_add.append(add_menu_item)