Wooden items less than three inches in diameter, which are fixed, splinter...
The Cleric's wooden Holy Symbol, firmly fixed to the thong about his neck, is splintered. The Cleric cannot cast spells! Same for one in a pocket, pouch, etc. Bags of Holding I am unsure of, but extraplanar and/or extradimensional storage places (Heward's Handy Haversack, Portable Hole) are unaffected.
(Note here, as I have said innumerable times before, that ALL Clerics and Paladins need multiple copies of their Holy Symbol, in multiple materials, as
Turn Wood,
Warp Wood,
Heat Metal, and
Shatter for the stone crystal, and more exotic ones, will render him or her a second-class Fighter with only a few Verbal/Somatic/Non-DF spells!)
Cast down the center of a corridor, at archers, they lose all their arrow, and are dragged back 40 feet by their bow (unless they drop it). IMO, all arrows would be "pushed" out of the quiver, requiring them to get more, or go 60 feet, to where the spell ends and wait for them, or try to "pick some up" while being pushed back... Even if they did, and fired a shot along the path, the arrows would be pushed back, as well. Hence, no missile attacks along that line, save by all-metal weapons.
Most shield are made of wood, banded by iron. Hence, either drop shield (losing at least 2 AC, in MOST cases), or be pushed back 60 feet over two rounds, and have no ability to attack with missile, unless all-metal. This is very bad, for most mook armies!

It will also pretty much block a 10 foot wide corridor, if cast down the middle (2.5' on either side, with (N)PCs needing 5' to get through).
Backed up by a Wizard/Sorcerer/Bard with some magical attacks, it seems pretty effective, to me!