Sefer HaChinuch 327 ספר החינוך שכ״ז

That we also not do work with the trees: That we also not do work with the trees on the seventh year, as it is stated (Leviticus 25:4), “and your vineyard you shall not prune.” And the language of Sifra, Behar, Section 1:6 is “Sowing and pruning” — the understanding [of which is] “you shall not sow and [...] you shall not prune” — “were in the general category,” meaning they were in the category of resting. “And why were they singled out? To compare to them: Just as sowing and pruning are distinct in being work on the land and on the trees, etc.” — as it is [found] there. The content of this commandment is like the previous commandment. And I wrote a few of its laws also in the Parshah of Eem Kessef Talveh (Sefer HaChinukh 84) — you can see it from there.