Tree Bark

Any mixed media or watercolor paper will work great for Nature Journaling. You will develop preferences the more you journal so just start somewhere and go from there. I've painted on all types of paper and it generally all works out just fine.

Here are a couple journal options:

Strathmore Journal

Arches Journal

The erasable blue pencil is the secret sauce to creating beautiful ink drawings you're proud of. My favorite brand is Ticonderoga. You can purchase these at most big box stores and online retailers: Ticonderoga Blue Pencil

You'll need one, optimally two, waterproof ink pens for your drawings. I suggest the Micron brand. There are a lot of thicknesses of these pens. I suggest the 005 thickness for the main drawings and the 003 size for finer detail. To start, you really only need the larger size, 005.

Micron Pens

To paint, you will need a watercolor brush. I recommend starting with a Round watercolor brush. This shape gives you the ability to paint large areas and do fine detail with one brush. Any size between 6-10 is great. Here is an example:

Round Watercolor Brush

The best watercolor paint for Nature Journaling is a set that comes in a travel pallet. Sometimes these are called a sketcher's set. The Winsor & Newton Cotman set is a perfect beginning set. You want a reasonable variety of colors, ~12 is great.

Winsor & Newton Cotman Set

A white gel pen is an extremely handy tool to have in your Nature Journaling kit. You can use it to draw over a painted surface to highlight areas, draw in the eye shine of an animal, and add dimension to nearly any image. This pen does not have to be waterproof since you will use it on top of your painting.

White Gel Pen