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Thursday, May 19, 2011

Air layering a redwood

Today's post is going to explain how to air-layer a15 gallon redwood ,  in the beginning of what will be a long term project . I hope to, through several methods, create several trees from this one and eventually plant them together as a group.

This tree has been in a southern California nursery for a number of years. It is in a 15 gallon can and is about 10 feet tall. I got it in the beginning of the year. The first thing I noticed was that it was completely root bound . So the first step was to trim some of the old roots and get it planted in some new soil. This was done in late February and it is now showing lots of new growth so I decided it was time to get started

Air layering is a method used to obtain stock from an existing plant. You can literally make new roots grow in the middle of a plant. Using this method one can obtain fairly mature materials relatively quickly.
Today I'll be using a grafting knife to cut the bark, some rooting hormone, bonsai soil and a plastic nursery can. Another way is to use Sphagnum moss and plastic wrapping instead of soil and a pot.

During the process of air layering, it is necessary to remove the bark, the cambium, and the phloem layer cutting away about a 1-inch wide ring of these tissues from around the circumference of the tree.  After removing a ring of bark  the area is treated with root hormone and either sphagnum moss and plastic or bonsai soil and a pot is placed around the debarked area. I'm using the soil and pot in this case .
After cutting the ring of bark away. I dusted it with rooting hormone. The next step is to fasten the pot to the trunk  around the cut. I used wire to tie the pot together and to hang it from branches above. I then lined the bottom of the pot with sphagnum moss to keep from losing soil.
Next we fill the pot with soil so that the cut area is completely covered. Now we water and wait.

How it works-The layer just under the bark is a layer of actively dividing cells called the cambium, the next layer of cells called the phloem it is responsible for the transportation carbohydrates and other photosynthates down from the leaves to the lower parts of the plant. The layer beneath phloem is called the xylem; it transports water and mineral nutrients from the roots and soil up to the leafy parts of the tree. Removing the bark, cambium, and phloem prevents carbohydrates and photosynthates from flowing down the trunk. It still allows water and mineral nutrients to flow upward to the leaves via the channels in the xylem, thus keeping the leafy portions of the tree from drying out and maintaining them with an adequate supply of nutrients. Removing the cambium layer prevents the regeneration of phloem and healing over of the wound, the carbohydrates and photosynthates flow down the trunk and collect at the girdling site. The presence of this excess of carbohydrates and photosynthates at the girdling site, plus the presence of the water in the soil or sphagnum moss, causes dormant adventitious buds in the area to grow into roots. The most important thing at this point is not allowing the soil or moss to dry.
Redwoods root fairly easy so I anticipate having enough roots to separate the two trees by next spring. In the meantime I will also take cutting from the parent tree. It'll be awhile before there is any more substantial progress on this project. In early June I'll take a bunch of softwood cuttings from the parent tree. Hopefully in the next two years I'll be able to produce enough material from this one tree to create a group planting of Redwoods.
I hope you enjoyed this post, thanks for reading it. If there are any questions or comments please feel free to post them.

Wednesday, May 11, 2011

Hackberry forest revisited

Today I want to revisit the forest planting of Hackberries that we started in February. If you remember we started with 27 Hackberries of various ages and sizes. Here is what they looked like before we started any work.
We trimmed the roots and the tops of the trees very hard and got them all planted into this shallow pot. This is what it looked like when it was first planted on the day before Valentines Day.
In just three short months every tree has exploded with new growth. All 27 tree have survived the bare rooting and transplanting and are growing like gangbusters. Here is the planting before any of todays work.
As you can see the leaves are rather large at this point but after a couple of years in the pot I expect they'll reduce in size to less than a 1/2 inch in length. The goal today is to get all the new growth cut back, cut out any unnecessary branches and to lay out the frame work for the future.
After a little trimming you can start to see the individual trees again. Here is the way it looked about halfway through the trimming.
I'm shortening all the branches, removing any that are crossing or growing into other trunks and generally building the base of the future outline. I'm cutting the branches shorter than I want them to be so that I can build movement and secondary branching through pruning. By paying attention to where I cut I can control the direction of the new growth thereby putting movement into the branches. This is know as the clip and grow method of shaping a tree.  Doing it this way creates very natural looking movement in the branches. Another benefit of the pruning is that it will stimulate buds at the bases of the leaves to start to grow and form secondary branching.
One of the benefits of using  hackberry for a forest planting is that you can build a network of branches and twigs that will reduce in size in a fairly short amount of time.
After the trimming this is what we have.
For the rest of this year I will let things grow until the branches have seven to nine sets of leaves than cut it back to the first or second leaf growing in the right direction.  I'll probably do this another 4-5 times before the growing season ends. This will create movement and branching. It will also insure good root growth so that the trees are all solid and stable in the pot.
Next year I'll start working on healing the scars on the trunks from branch removal and will continue on branch and apex development. If the trees respond to this first pruning strongly I may defoliate the whole forest in late July and force it to grow a new smaller set of leaves. As long as the tree is healthy it can stand total defoliation at least once and maybe even twice in a year. Defoliating not only causes smaller leaves but it also encourages  branching as well.
I'm very pleased with the progress of this planting and can envision it in a winter silhouette show inside of five years.
I hope you enjoyed the update on the forest planting. In my next post I will be doing an air layer on a redwood which is another of my long term projects I intend to chronicle in this blog. If anyone has any questions or  comments , as always I welcome them.

Just a note - on July 1st the price of all Japanese bonsai tools and wire is being raised by my importer 15%. So if you're thinking about buying any tools now is the time before the price increase. Until next time....