i want to recreate the trunk of this plant with shaders, but I don't have that much experience how i could do this. Could someone show me a node setup to emulate the trunk? I would be really happy! So it's more or less about how I can make the different color rings and the transitions, which aren´t quite perfect.
I would use a Gradient Texture, isolated on the Z-axis, as well as scaled with a Mapping Node and repeated using a Fraction (Math) Node. This way, the "taper" starts at the bottom of each "segment" and can be used as the basis for a Bump as well as a ColorRamp:
However, for added realism, I would suggest warping the input vectors with a Noise Texture first, which will both distort the "seams", as well add some "organic" bumpiness to the surface:
Here's a setup that better replicates your sample image - I added a bit of "plant subsurface" (low value) and changed the subsurface radius values to slightly favor green (0.2,0.6,0.4). Notice the pattern is different on all of the "sticks - this is because I duplicated them in Edit Mode) - if you duplicate them in Object Mode , the pattern will be identical because the texture is using Object Texture Co-ordinates which are relative to the object's origin - A workaround is to use Generated Texture-Coordinates, but that will require some slight alterations to the Mapping Node (to avoid distortion):