Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. This has the same reading as 上る which you learned all that time ago in Level 1. If you can remember that, you can remember this one!
Going up this long, steep slope is really tough, eh?
Koichi climbed up the tree as fast as a monkey and came down with bananas without breaking a sweat.
A dream of mine is to climb Mt. Fuji at least once in my lifetime.