Grafting pine on thick trunk

I wanted to learn how to graft small pine scions on a thick trunk. Last October, I grafted seven Radiata Pine scions on a 6-cm-thick trunk. By the end of November 2012 two of them had new shoots. By January 2013 all scions were alive and six out of seven had new shoots. I removed the plastic protecting the grafts from drying in mid-March this year. Unfortunately, the plant died last month because I chopped off the upper trunk. I wanted to direct all the plant’s energy into the grafted branches, but my plan turned out to be deadly to the plant. Yes, I know. What was I thinking?! Anyway, below are a few images showing this plant’s progress.

A – The rootstock plant after repotting in August 2012;
B – The plant on completion of grafting in early October 2012;
C – Close-up of the grafted scions on the day of grafting in October 2012;
D – Close-up of grafted branches with new shoots in mid-December 2012.

Here are a few things I learned from this experience:

• Advice from bonsai practitioners and the Internet was useful;
• Peeling bark off the trunk, before making incisions, was helpful;
• A grafting chisel is better for making incisions in the trunk;
• Aligning cambium was easier because on a thicker trunk it is a wider band, which can be recognised by its dark orange colour;  
• Enclosing the whole area with clear plastic with some moist sphagnum moss worked really well;
• Once the grafts have new shoots, the plant needs more sun;
• Don’t do anything drastic to the plant for at least a year.