There are many oak trees on this mountain; their wood is hard and durable.
Tips
history
栎 is rarely used alone; in modern Chinese it appears in bound terms like 栎树 (oak tree) and 麻栎 (sawtooth oak). It also has a reading yuè used only in the old place name 栎阳.
culture
In Zhuangzi the 栎 social oak (栎社树) is so gnarled it is useless for timber — and so survives untouched. It became a classic image of the value of being 'useless'.
乐 (also read yuè 'music') gives the sound, here read lì. It is the simplified stand-in for the traditional phonetic 樂 in 櫟; it carries no meaning in the oak word.