There isn't much of a difference between Alliance and Horde in World of Warcraft, they are usually very well balanced regarding gameplay aspects (not necessarily from the lore side). But one minor difference in Warlords of Draenor is that the Horde starting zone has no timber at all (except for one quest tree), while the Alliance starting zone has a full quarter of all small timber in Draenor. As a Horde player you are likely to get your lumber mill before finishing with the starting zone, which means having to go the next zone to find timber. Gorgrond at that point is not only slightly higher in level than you are, but more importantly it isn't the easiest place to navigate. While your character can fell 10 meter high treants, he can't cut through a vine as thick as his arm, creating a lot of impenetrable walls in Gorgrond. (Later you can get the Mechashredder, which allows you to jump over those).

Anyway, I'm the kind of player who thinks that if you playing a MMORPG as intended, you are doing it wrong. :) The obvious solution to the Horde timber shortage is finding your way to the Alliance starting zone. That is easy if you used the level 90 boost, which for no good reason gives you many Draenor flying points without you having to walk there. Your other characters need to walk through Gorgrond and Talador into Shadowmoon Valley to grab the Exile's Rise flight point manually.

Apart from the timber, getting to Shadowmoon Valley as Horde has the added advantage that you get a full new set of level 90 to 92 rare spawns to kill. That is always worth doing, not just for the rare loot, but also because they all drop some garrison resources. The disadvantage of exploring Shadowmoon Valley is that you might run into Alliance defender NPCs which flag you for PvP and attack you. But you'll quickly learn to avoid those settlements.