This pattern can be adapted to any size and any kind of yarn. The starting row should contain a Fibonacci number of stitches: that is, those in the sequence
1,2,3,5,8,13,21,34,55,89,….
In the pattern given, I start with 21 stitches but a bigger tree might start with 34 or 55.

The pattern requires some patience as there is a lot of having to join the yarn to begin new branches, and therefore also a lot of weaving in ends.

I am usually surprised by how little wool this tree takes to make. Less than a half-skein of yarn seems to be sufficient, so the project is great for using up leftover wool.