expressions - Can the phrase "extended all the way up" be used to describe very tall objects?

In “The X extended all the way up to Y”, extended is the simple past tense or the past participle of the verb extend, whose principle meaning is to increase in extent, or to cause to increase in extent. Thus, if you are describing a circumstance where some spruce, fir, or pine trees suddenly grew tall, all the way up to the sky, your original sentence would be perfectly appropriate. If that's not what you mean to say, and want to guard against perverse readings, consider a form like “The X reached clear to Y” or “The X stretched up to Y”. (Of course, like extended in your original sentence, the verbs reached and stretched might be interpreted as expressing active growth, instead of meaning spanned; but such readings with the latter two verbs are slightly less likely than with the first one.)