The Forestry mod was removed because it was found that users who could not do a simple forum search had trouble understanding how to play with it.
Due to modifications made to the mod it would begin cutting it self if it suffered the pain of being loaded by the technic launcher. Due to how tragic it was the technic devs decided to put it out of its misery by ensuring it will never need to suffer that pain again. In short its dev never wanted it in technic and added code to the mod to force the technic devs to remove it. Just a note the evil code was removed from the mod and it is now safe to install/use manually if you want. But as stated above it will never be in the pack again no matter what.
Search the internet for Forestry and Technic. You'll find quite a bit of drama on these forums and probably over in the forestry thread if you do a half assed search at worst. Forestry will never be in technic/tekkit. I've reported this post simply based on the fact you are far from the first person to ask this question in almost the exact same wording. Look around before you ask stupid questions.
