From 00:00 UTC on 9th March to 23:59 UTC on 13th March, collect three tree-themed outfits and combine them to Buy RS Gold make the elite Nature's Sentinel outfit!
How do I get the outfits?

There are three five-piece outfits to collect over this period:

Oaken Sentinel Outfit

Willow Sentinel Outfit

Maple Sentinel Outfit

One outfit will be available on each of the first three days, so check back each day. All three will be available for the final two.

Equivalent pieces from the three outfits can be combined into pieces of the elite version: the Nature's Sentinel outfit. Not only does it look pretty darn sweet, but it comes with a range of amazing benefits for your Woodcutting training.