This sign uses ระวัง (rá-wang), meaning 'beware/watch out,' a very common word on Thai warning signs. ต้นไม้ means 'tree' (literally 'trunk/origin of wood'), and กิ่งไม้ means 'branch' (literally 'branch of wood'). หักโค่น combines หัก (to break/snap) and โค่น (to topple/fall down), describing branches breaking and falling.

The English translation 'WARNING LIMBS MAY FALL' is a reasonable translation, using 'limbs' in its arboricultural sense meaning large branches.