I'm running Dragon of Icespire Peak, and my PCs are about to fight some NPCs who use the 3rd level spell Lightning Bolt. They will be fighting near a forest and I can see the party looking to use trees as cover. Can anyone advise on how effective this cover would be, and whether the trees should stop the lightning bolt/immediately burst into flame etc?

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    \$\begingroup\$ Are you familiar with the usual rules for cover, and is there a particular confusion about those rules for this situation? \$\endgroup\$ Commented Aug 21, 2021 at 16:23

1 Answer 1


The rules list a tree trunk as an example of 3/4 cover.

The rules for Three-Quarters Cover state:

A target with three-quarters cover has a +5 bonus to AC and Dexterity saving throws. A target has three-quarters cover if about three-quarters of it is covered by an obstacle. The obstacle might be a portcullis, an arrow slit, or a thick tree trunk.

So an character trying to hide behind a tree trunk that happened to be in the area of effect of lightning bolt would get +5 to their dexterity save. Now, as the DM, it's really up to you how much cover the tree actually provides. I once had a player insist that all trees granted 3/4 cover, but unfortunately for him, these were really skinny trees, so I generously gave him half cover. It's up to you to determine the character's size in relation to the size of your trees, but I recommend sticking with 3/4 as the book suggests, unless you've explained to the players that these are really skinny or really thick trees.

Also the tree is now on fire.

The lightning ignites flammable objects in the area that aren't being worn or carried.

Setting the players' cover on fire is a great way to get the players to do something. I don't actually have any experience doing anything to the players with flaming cover, so I can't tell you what to do if they decide to hang around near the flaming tree. This is because my players always freak out when their cover is set ablaze. Whenever I feel like a battle isn't interesting enough because there is too much hiding going on, I set stuff on fire.

Consider the battle in the banquet hall. The ranger and barbarian flipped a wooden long table and were using it for cover. I'm thinking to myself, "I don't want to walk the bad guys over there to get the ranger because the barbarian is chilling with him." Then I remembered my favorite combat seasoning: fire. "The captain of the guard lights an arrow on a nearby sconce and shoots it directly into the table." They think nothing of it, next round I announce, "Some spilled olive oil has caught fire." They think nothing of it. The battle goes on for another round, and I am finally pleased to announce, "The front side of your table has erupted into a raging inferno. This is the part where rational decision making is no longer an option. For no reason at all (except possibly a highly sensationalized fire), the ranger leaps over the table to engage the guards in melee combat.

The point is, when you use lightning bolt you have an opportunity to increase the stakes of the fight a little bit by setting their cover on fire, which I have often seen lead to some pretty epic and funny moments in battle.

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    \$\begingroup\$ Perhaps of note: "The lightning ignites flammable objects in the area that aren't being worn or carried." We just... don't have rules for what that means XD \$\endgroup\$ Commented Aug 21, 2021 at 16:28
  • \$\begingroup\$ @Medix2 I wouldn't really expect the rules to spell out what is and is not flammable. That's pretty much entirely up to the DM. If the forest is under a drought and it hasn't rained in months, then yes, the trees are probably flammable. If it's currently monsoon season and pouring rain, then they probably aren't. \$\endgroup\$ Commented Aug 21, 2021 at 18:21
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    \$\begingroup\$ @Medix2 the non-technical definition of flammable is “easily set on fire”. By that definition, standing trees aren’t flammable. \$\endgroup\$
    – Dale M
    Commented Aug 23, 2021 at 2:21
  • \$\begingroup\$ @DaleM No, living trees are not usually flammable. After a tree dies, it takes a long time for rot to do enough damage that it actually falls over, so you can easily have a large amount of dry wood standing vertically. Sometimes they catch fire, and because the bark isn't really burnable, you get these bizarre looking trees burning from the inside out. And in dry times, it's not unusual for the dry leaves or needles to burn off while the trunk is left mostly unharmed, but that's still plenty of burning to make people get out from under it. \$\endgroup\$ Commented Aug 23, 2021 at 4:53

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