We used Bunnings flat pack shelving in one of our walk in wardrobes, I'm pretty sure it is Melamine and it is fine. There have been a lot of advances and improvements to these products over the years and they aren't the cheap nasties they used to be. Ours are a matte finish too so look much nicer and classier than a gloss. Have you asked the joiner for a sample of just what he is thinking? This should give you a good idea. Check out Bunnings flat pack products too. You could use just an MDF and paint it, but that is more work and the paint can chip or wear off on shelves. Unless you want to go to the expense of having all solid timber, you will find most products are MDF coated with a timber veneer or a product like Melamine. Going on what I have, and I know Melamine was used internally in my new kitchen cupboards, I don't think you will have any problems. If you are having shelving, do ensure you use adjustable shelving too - it is such a bonus in areas like this when your needs can change over the years and it is so easy to just add or subtract shelves or adjust the height. The wire systems are OK for some things but over the years the plastic coating cracks and breaks off and you could then have difficulty replacing the baskets. You are also more restricted with sizes.

A friend of mine used slices of tree trunk, bark attached. The rounds looked fabulous and were placed just right for stepping from one to the other. They may not last forever, however they should be okay for a few years and would look fabulous in an area of trees.

We've got a gatic style pit lid on our exposed aggregate driveway. You can fill these pit lids with a material like exposed aggregate/concrete and sand etc. to make the pits blend a bit better with the driveway. A couple of driveway people have said that using exposed agg there just doesn't work well due to the inability to get exposed agg even and looking good on the pit lid. Other people have said it looks bad if you don't fill it with exposed agg because that would be different to the driveway. Just wondering if anyone has done this in the past and what they went with? We would've thought exposed agg for the continuity of things but now we aren't sure. Thanks in advance!

Hard to tell from pic if it’s metal ie vertical Matt colourbond or wood-ish ie James Hardie products like scyon, linea or axon. Could also be a batten over a plain cladding. For your purpose have a look at the James Hardie products.