Attention there is a bug in the 4.10 build that is not related to my pack but creates problems with the foliage in the demo maps of this pack see: https://answers.unrealengine.com/questions/334571/ue-410-foliage-disappearance-bug.html
Everything works in 4.8 and 4.9
You can solve the problem by deleting the foliage instances in the Foliage type list and place them new. This bug only effects the demo maps but has no influence on the use of the package since I assume most of you will be importing height maps and building new maps.