What would you call "coniferous tree" and "deciduous tree" in French?
coniferous tree =
deciduous tree = arbre à feuilles caduques
A lot of people would say "conifère" (including me) but if you're looking for a word that has the same value in the sentence the answers would be :
Arbre à feuillage caduc
Arbre à feuillage persistant
And remember that "caduc" is for masculine nouns (feuillage) and "caduque" for feminine (feuilles).
If you are looking for a classification, you probably don't want ambiguous classes. Therefore there might be an issue with your words in English because deciduous coniferous trees exist (e.g. larix decidua). So here are the pairs that you should use:
Coniferous(or needleleaved)/broadleaved trees
--> Conifères/Feuillus (no need to mention "arbre")
--> Arbres décidus/sempervirents
--> arbres à feuillage caduc (arbre caducifolié)/arbres à feuillage persistant
A Coniferous Tree in French is said "Un conifère". This official Larousse definition might help you : Larousse "conifère" définition
If you want to use a complete sentence to design this kind of tree you could say "Un arbre aux fruits coniques", but most of the time the word "conifère" is used directly.