Beginner - Applying geometry transforms

[my nellie]

Thank you for your time Ofnuts & Espermaschine
I am attaching two photos of the branch in question in order for you to get a clear idea of what I am talking about.
   
   
The branch is on the left and you can see the almost right angle it curves.

And the whole tree
   
Here you can see the said branch is on the right.

As far as realism on the outcome is concerned I am not so eclectic since what I really want is to see how the tree would look after some interventions.
Let me be a little more precise to give you a glimpse of what I am intending to use GIMP for...
Well, I am doing bonsai and in this art (you may be already aware of) we deal with trees which we try to "dwarf" (kind of) and imitate aged trees in nature.
For this purpose we make :

• often repottings (every 1,2,3 or more years)
  
• we remove unwanted branches in order for the tree to fit into the aimed design,
  
• we wire and bend branches or manipulate them using other techniques in order to place them exactly where we want them to be,
  
• we prune the foliage and/or defoliate the tree,
  
• we also change the angle of the trunk in relation to the soil surface and/or the pot,
  
• we change the bonsai pots so that they complement the whole silhouette of the tree and a lot more similar things...
  

So, it is good/helpful for us to be able to look at  and see a photo of what we have in our minds and check how far or within our design the new image of the tree is.

I hope I was able to explain in a comprehensible way...