You might be highly interested in the new alveary sieve block then, wolfsilver. Everytime a tree would ordinarily be pollinated, the bees instead drop the pollen in the sieve, and you can take it out and rightclick a treeleaf of your choice for instant crossbreeding. It's specifically meant to aid in combining desired traits after you're done mutating the species you want.
Besides, you'll not succeed with a sequoia sized walnut tree anyway, since tree trunk size is not yet inheritable in 1.4.7 versions of Forestry (you'll want 1.5.1 for that). You might succeed with a sequoia bearing walnuts though. Maybe. It'll be no easy feat either way.
Besides, you'll not succeed with a sequoia sized walnut tree anyway, since tree trunk size is not yet inheritable in 1.4.7 versions of Forestry (you'll want 1.5.1 for that). You might succeed with a sequoia bearing walnuts though. Maybe. It'll be no easy feat either way.