104:8 Planting is forbidden on chol hamoed. If one has seeds that will be completely ruined if not put in water, then one may water them. (“Completely” appears to be the Kitzur Shulchan Aruch’s addition. Compare OC 537:7.)
104:9 On chol hamoed, it is prohibited to pull or cut any plant matter from where it is attached unless the fruit will be ruined if it waits until after yom tov. The exception to this is what one needs to eat on the holiday itself. One doesn’t need to be stingy then; he may pull off a generous amount and if it’s more than he needs, that’s fine. (One may pick fruit in such a case even if he could buy what he needed, or borrow it from a neighbor – Mishnah Brurah 533:1. This is true even if he could have picked the fruit before yom tov and chose to wait – MB 533:2.)
The same is true regarding wood that one needs for fire on the holiday: one is permitted to cut them off from where they are connected. If one is doing it to feed an animal, he should do so with some change from how it’s normally done. One may not, however, collect wood from a field in order to improve it for plowing. If it’s obvious that one’s intention is for his needs, i.e., that he needs the wood – for example, he takes the larger pieces and leaves the smaller ones – it is permitted. Similarly, it is prohibited to cut the branches of a tree in order to prune it but if it’s obvious that he’s doing it for the branches to feed his animals rather than to prune it – such as if he cuts only from one side – then it is permitted.