Source:dota2.gamepedia.com/Trees

Trees

Trees are a terrain feature in Dota 2. They make up a large amount of the map, and are very prominent in the forests that separate the Lanes and border the map. Trees block vision and are impassable.

Mechanics

Trees cannot be targeted by normal attacks, and can only be destroyed by certain skills, such as Beastmaster's Wild Axes.
Trees will regrow five minutes after they were destroyed except if a Hero is standing where they would spawn.
There are 2662 trees in the Dota 2 map.

Abilities that Interact with Trees

Abilities that Destroy Trees

Batrider - Firefly Destroys all trees Batrider flies over.	Batrider - Flamebreak Destroys trees units are pushed into.
Beastmaster - Wild Axes Range: 1300 Radius: 125	Dark Seer - Vacuum Radius: 250/350/450/550
Elder Titan - Earth Splitter Area: 300 (width) / 2400 (distance)	Enigma - Midnight Pulse Radius: 400
Force Staff - Force 2250 Range: 600	Invoker - Deafening Blast Destroys trees units are pushed into.
Io - Tether Radius: 300 Only destroys trees if cast from over 700 units away.	Jakiro - Macropyre Range: 900 (1350*) Radius: 225
Lina - Light Strike Array Radius: 225	Leshrac - Split Earth Radius: 150/175/200/225
Magnus - Skewer Range: 600/800/1000/1200 Radius: 125	Nature's Prophet - Nature's Call Radius: 150/225/300/375
Phoenix - Sun Ray Destroys all trees Phoenix flies over.	Quelling Blade - Destroy Tree 225
Rubick - Telekinesis Radius: 325	Spirit Breaker - Greater Bash Destroys trees units are pushed into.
Storm Spirit - Ball Lightning Range: Global Radius: 125/200/275	Slark - Pounce Destroys trees in a 200x200 square around Slark's landing area.
Tango - Eat Tree 125	Timbersaw - Chakram Range: 1200 Radius: 200 Chakram automatically returns after Timbersaw moves 2000 units away.
Timbersaw - Timber Chain	Timbersaw - Whirling Death Radius: 300
Tiny - Toss Radius: 275	Tusk - Ice Shards Radius: 300
Tusk - Snowball Range: 1250 Radius: 200 + 40 per sec	Vengeful Spirit - Nether Swap Range: 600/900/1200
Warlock - Chaotic Offering Radius: 600	Windrunner - Powershot Range: 1825

Source:dota2.gamepedia.com/Vision

Vision

Vision describes what a unit can and can't see from its current location and state. Places a unit cannot see are filled with the Fog of War, a dark mist that hides units inside of it. Invisible units can't be seen even when outside of the Fog of War, unless they are spotted by a unit with True Sight. Units can't see through trees or to higher elevations - the only exceptions to this rule are flying units, who have unrestricted Vision, and Night Stalker with an Aghanim's Scepter at night.
All units on your team share Vision, which means that if a unit can see through the Fog of War, all allies can as well. This also applies to Lane Creeps, other controlled Creeps, and Buildings.

Contents 1 Fog of War 1.1 Elevation and Trees 2 Day and Night 3 Buildings 4 Flying Vision 4.1 Sources of Flying Vision 5 See Also

Fog of War

All areas outside of friendly Vision become Fog of War. Any non-friendly units within the Fog of War cannot be seen or targeted (it is effectively invisible), however they can still be hit by non-targeted spells. To reveal units in the Fog of War, an allied unit must gain vision in that area. Observer Wards will provide vision in an area to their team.
If a unit in the Fog of War attacks an enemy that does not have vision of them, they will be revealed temporarily.

Elevation and Trees

Units cannot see areas that are on higher elevations than them, while units on higher ground receive unrestricted vision below. Additionally, any ranged units attacking an enemy on higher elevation have a 25% chance to miss their target. Trees also block vision, and can be used to escape enemies by running through small gaps in them (known as "Juking"). When Trees are cut down or destroyed, they no longer block vision. Targeted abilites also disjoint if in animation phase even if successfuly cast on a enemy that entered fog of war via elevation.

Day and Night

Most units have different vision ranges for the day and night cycles. Generally, units see a lot farther during the day than they do at night. Most heroes have 1800 units of vision during the day, and 800 at night, though there are several exceptions. This makes ganking a lot more viable at night, because Heroes can get much closer without being detected.
Below is a table of all exceptions to the 1800/800 rule:

Hero	Day	Night
Alchemist	1800	1400
Batrider	1200	800
Bounty Hunter	1800	1000
Luna	1800	1800*
Lycanthrope	1800	1800*
Night Stalker	1200	1800
Slark	1800	1800
Sniper	1800	1000
* Luna is granted 1800 night vision range by leveling her Lunar Blessing ability.
* Lycanthrope is granted 1800 night vision range when he uses his Shapeshift ability.

Buildings

Allied Buildings share vision through the Fog of War with their entire team. Below is a table listing the vision ranges of all buildings:

Building	Day	Night	True Sight	Attack
Towers	1800	800	900	700
Barracks	900	600	NA	NA
Ancients	1800	1800	900	NA
Fountains	1300	1300	900	800
Buffer Buildings	800	550	0	NA

Flying Vision

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Flying vision gives unrestricted vision in an area, it is not blocked by trees or obstacles and can see all elevations.

Sources of Flying Vision

Batrider - Firefly Gives Batrider flying vision equal to his current vision distance, 1200 during the day or 800 at night.	Batrider - Flamebreak AoE on projectile: 300
Dazzle - Weave Radius of ability: 775 Duration: 9 Gives flying vision of the area where Weave is cast. Radius is always 775 (Radius of Aghanim's Scepter upgrade) even without scepter.	Kunkka - Ghost Ship AoE on projectile: 400
Medusa - Mystic Snake AoE on projectile: 300	Meepo - Earthbind AoE on projectile: 300
Nature's Prophet - Sprout Radius from remnant: 900 Duration: 3/3.75/4.5/5.25	Shadow Demon - Shadow Poison AoE from Projectile: 190 Radius
Storm Spirit - Static Remnant Radius from remnant: 800 Duration: 12 or until detonated	Sven - Storm Hammer AoE on projectile: 225
Timbersaw - Chakram AoE where Chakram stops: 300	Troll Warlord - Whirling Axes (Ranged)
Tusk - Ice Shards AoE on projectile: 300	Windrunner - Shackleshot AoE on projectile: 200
Venomancer - Venomous Gale AoE on projectile: 400