Grafting

Soildoc

Ok, I desperately need a crash course in grafting. One of my pine trees (bonsai) was hit by a falling branch from one of my other pine trees. Unfortunately the pine that dropped the branch was a 75ft 32in girth loblolly. I have split the trunk and wedged the top portion down in the trunk, wrapped it in raffia and sealed it up with epoxy (it was the only think I had handy). Is there anything else I need to do and what are my chances of having this graft take?

(P.S. I am cutting the loblolly down this weekend)

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TreeBay

Soildoc, I feel for you! _

I had a similar experience occur a few years ago when an unsecured _: garden arbor fell on top of a 35 year-old white pine. _It cracked clean off one very nicely positioned branch and split the trunk down the center.

The broken away branch was a total loss. _Generally this will be the case because even a graft depends on a large contact area vs. a very small foliage load to develop the initial union.

I hate to say, it but I strongly suspect your inserted branch will remain green for a few weeks at most and then brown back. _It is simply too large a branch to use as a scion, and the timing is not optimal.

You can recover from this, although it may take a bit longer than expected. _First, you want to clean up any torn edges with a grafting knife and close the wound as much as you can with raffia. _Once the tree is healthy and pushing growth, you can look at grafting a new branch in place.

Generally speaking, a successful graft depends on

• very clean contact areas with intimate direct cambium-to-cambium contact
• maintaining moisture in the scion (the grafted-on part) throughout the period of its union
• using strong healthy scions that are not actively growing
• some experience or a good bit of luck.

I will be putting together an article on grafting in the near future. _Here are some notes to get you started.
Timing is critical

• For pines, grafting it is best done in very early spring to late winter, before the buds begin to move. _In Japan grafting is sometimes done in the heat of summer when growth shuts down, but their climate is VERY humid and hot during this period. _I wouldn't advise it._
• Scions made up of one-year-old newly opened candles are placed in the fridge for a few weeks in a plastic bag with a bit of damp sphagnum until the weather has warmed and the trees are coming out of dormancy.

In this way, a dormant twig, with little demand for water can be inserted right into the actively growing tree.
[img]http://www.treebay.emerchantpro.com/vendorimages/treebay//photos/azalea/gra
ftknife_sm.jpg[/img][size=1]image courtesy TreeBay.com


[b]preparing the scion

• A chisel shaped bevel cut, again with a grafting knife is made at the end of the twig to expose a nice line of green cambium.
• A shallow cut is made in the trunk of the tree or in a branch where the graft is to be inserted. _the length of the cut is usually at least 1/4 to 1/2 inch, so the cut may be rather shallow indeed. _The depth of the cut needs to undermine the cambium, yet penetrate the cork. _So the actual depth will vary with the age of the tree and the type of bark it has. _Grafting chisels are sometimes used if you are introducing a scion right into the trunk of the tree. _You can see such a chisel on the far left in this tool set:
  [size=1]image courtesy TreeBay.com[b]
  
• Next, the scion is inserted as the new cut is held open with the tip of the knife. _Then the knife is removed and the cut area is bound with raffia. _
• A plastic baggie is placed over the wound area, completely enclosing the new scion _This is closed over the branch and secured with raffia. _
• A syringe is used to inject just a couple cc's of water into the bag, which hangs down just enough to contain the water. _Alternatively a bit of sphagnum may be applied to keep the scion damp.
• Sometimes a bit of tape is placed over the top of the bag to keep the scion out of direct sunlight.
• The bag is cut open a little only when the scion has grown far enough to press against the bag.
• The bag is cut away entirely after growth continues.

My experience - do not repot in the same season that you graft. _You need to keep the pressure in the tree's vascular system to drive healing, and cutting roots will relieve it.

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