Complex sentence: In 2005, a tree top forest walk was constructed which has attracted many visitors and rises through the forest to a height of about 15 metres (49ft), at a gradient not exceeding 1 in 12.
Split into simpler sentences: In 2005, a tree top forest walk was constructed which has attracted quite a lot of visitors. It rises through the forest to about 15 metres (49ft) high, at a gradient not exceeding 1 in 12.