Chestnut trees naturally will grow 18 to 48 inches or more in a year as long
as the growing conditions permit. The trees will continue to grow until they
reach their genetically determined height. Some types of chestnut trees can
reach a height of up to 80 feet. Some types of chestnut trees reach their
maximum height of 40 feet and then only grow out depending on available space.
Chestnut trees, like many other fruiting trees, can be kept much lower than
their natural height through annual pruning. Also, like other fruiting trees,
chestnut trees will produce more nuts per tree or per acre if the trees are
pruned in ways that maximize nut production.
Why even consider pruning a chestnut tree, they seem to grow just fine without
bothering them? There are many reasons to prune trees. The most important
reason is to keep the tree healthy. Removing broken or damaged branches,
diseased sections, and keeping a balanced tree are all important reasons to
prune chestnut trees. If you are a commercial chestnut producer, pruning the
chestnut trees in your orchard will help achieve the highest production. These
are just a few of the motivating factors that brings us to the point where
pruning trees is the best option.
When considering when to prune an orchardist has two times in the annual
growth cycle of the tree, winter and summer pruning. Most of the pruning
occurs in the winter on try days. It is during the winter pruning the shape
and height of the tree is addressed. During the summer pruning only the
growth that is unwanted is removed as well as any diseased portions of the
tree. If any branches break during the growing season these should be removed
as soon as possible. Do not wait for the winter pruning for their removal.
Pruning during or shortly before rain (2-3 days) can provide a path for
disease to enter the tree. Water dripping into the open new cuts is the most
common path of infection. Chestnut trees for the most part do not bleed.
Without the bleeding, new cuts are left vulnerable until the exposed area is
Pruning and Training Tools
Before setting out in to the orchard to start pruning you will need some tools.
High quality pruning tools save time, labor, and make the cleanest cuts that
heal the fastest. Also, always keep cutting edges as sharp as possible. Here is
as short list of the tools you will need.
1. Orchard ladder
2. Pruners (Felco #2)
3. Pruning saw (Felco 600 - 6 inch folding)
4. Bypass loppers (Felco 22)
5. Sawzall - cordless with pruning blade
6. Chainsaw - gas powered
Knowing which tools to use for the job at hand is almost an art form. A few
guidelines are helpful, so here are a few:
- If the tool your are using is not working very well, causing you to exert
to much effort the tool might be to small for the job.
- If the tools is oversized for the job then it will be difficult to properly
place the cut or the tree might get damaged.
- Pruners should be used for cutting branches from 0 to 1-1/2 inches.
- Loppers should be used for cutting branches from 1 to 2-1/2 inches.
- Pruning and sawzall saws should be used for cuts from 2 inches to 4
- Cuts larger than 4 inches should be done with a chainsaw.
- Never operate a chainsaw above the shoulder height.
- Never stand on or above the top two steps on a ladder.
- If working above 6 feet off the ground it would be wise to wear a harness
and be tied off to the tree you are working on.
Sharp tools can be your best friend by helping to make pruning a manageable
task. Tools can also inflict permanent body damage or even death. The best way
to keep from hurting yourself or others is to only use a tool in the way they
were designed for. Also, keep some first aid supplies such as band-aids, 4x4
gause dressing pads, and a roll of 1 inch first aid tape in your pruning bag.
Before cutting on trees there are a few more rules to keep in mind:
1. Never remove more than 1/3 of the tree in any one year
2. Unwanted growth should be removed as soon as it is noticed (this is the
summer pruning). When unwanted growth is allowed to continue the trees
energies are wasted.
3. Chestnut trees produce short little branches that only grow a few inches
long. Never remove these branches because they seem to function as a place for
the chestnut tree to store energies. These small little branches will die and
fall off after a year or two.
4. Chestnut trees do not produce nuts on shaded branches.
5. When cutting branches, leave the sholder at the intersection of the
Pruning and Training, what's the Diff
Pruning is the traditional method of maintaining the tree structure. The more
recent development of training trees focuses on the growth and directs the tree
to the desired shape and form. Winter pruning or dormant pruning of chestnut
trees is done in the dead of winter (late Dec through late Feb). Since the tree
stores its reserved energies in the main trunk and roots, dormant pruning does
not normally effect the vigor of the tree. Summer pruning does effect tree
vigor so summer training/pruning should be limited to removing new growth.
Summer pruning is performed from the time the tree buds out until the end
of July. Any new growth after the first of August will not have time to harden
off before winter. From the first of August until the end of December you
should not be cutting on chestnut trees except if branches break.
If your chestnut tree is no longer balanced then the changes to the trees
structure must be made during the dormant pruning. A balanced tree helps protect
the tree from being blown over in high winds. When preparing to rebalance a
chestnut tree also consider opening up the tree with fewer inner branches. This
does two things for the tree. First, it opens it up to more sunlight helping to
keep the tree healthy. The second thing is an open tree has a lower wind
profile reducing the chances of the wind blowing down the tree.
Training chestnut trees need to be done if the first 5 years in the orchard.
The problem with training a fruiting tree is that it will result in a decrease
in fruit production in the formation years. A properly trained chestnut tree
will far out produce a chestnut tree just left to grow. One has to wonder if
all the additional labor and lower initial production is worth the effort.
Studies done at several research stations have demonstrated that training
fruiting trees has a excellent return on investment. The math gets complicated
when considering the future value of the lost production in the early years.
Aside from the actual lost production there is the fruit quality and size
issues that come into play. Smaller fruits bring lower prices than larger
fruits. There is also possible lost market share and not having a trackable
growth in production making sale of the first few large crops difficult. If
there was an easy answer to all this it would be well documented in most of
the publications about producing chestnuts commercially. Good luch with your
chestnut tree forming and training decisions.
Forming the Chestnut Tree Structure
The Australian Growers Resource Manual discusses four tree form systems. The
most commonly used system is the central leader system. There are many
resources on the web that details how to form a central leader system on trees.
One of the best is
Fruit Trees: Training and Pruning Deciduous Trees. Another one is from the
University of Florida
Pruning and Training Deciduous Fruit Trees for the Dooryard. With either
of these publications you should be able to get a feel for how to get the
central leader system going on a chestnut tree. One major difference between
the fruit trees discussed in these publications and chestnut trees is that
chestnut trees grow much faster than other fruit trees. With fruiting trees
there are dwarfing root stocks. Chestnut trees do not have dwarfing root
stocks so the trees will naturally want to grow tall fast (this depends on
the chestnut cultivar).
In Europe a chestnut tree form system referred to as the Eurovase system has
been developed. This system is also know as open-center is used on peach trees.
One of the best publications on the web discussing the open-center tree form is
Pruning Peach Trees.
This publication is one of the only ones that also discusses fruit loading
on the tree structure. Many chestnut tree cultivars suffer from the same fruit
loading issues so even if you do not use this form for your chestnut trees you
should read this publication anyway. It may save you a lot of broken
The canopy training system is not well documented and little research has been
done in the USA for this system. The tree will end up as a very short tree with
the scaffolding being formed by only two or three branches. Each branch points
in a different direction covering between 120 and 180 degree of the circle
forming the tree canopy. There is a trial using this method under way at the
Univeristy of Missouri agroforestry research center. The trial is under the
guidance of Dr. Hunt. This training system looks promising considering the
relationship between sunlight on the canopy and nut production. The chestnut
cultivars that may work well with this method might be Chinese based and
Japanese based hybrids like Colossal and Qing.
The Y-top forming system is similar to the canopy system in the tree from and
the focus on exposure to sunlight. The main difference is the Y-top uses four
branches in a two layer scaffolding. Each of the branches covers about 90
degrees. This system may be better suited for chestnut trees because it
distributes the load over more branches and provides for a greater vertical
area that chestnut trees prefer to naturally grow to. Some chestnut cultivars
that might work better with this training method are Precoce Migoule, Okie,
Summary of Pruning and Training Chestnut Trees
If your are the type of person who has a tendency to take on too much then
consider just letting your chestnut tree grow on their own. They will do just
fine as long as you are dependent on all your income coming in the form of
chestnut production. Otherwise, put a plan together that includes economic
factors, marketing plans, labor, materials, and equipment requirements around
how your chestnut orchard will be formed. From all the research available
consider "Open is good".
6160 Everson Goshen Rd
Everson, WA 98247
Ph: (360) 966-7158
Fax: (360) 966-7994
Washington Chestnut Company
6160 Everson Goshen Rd.
Everson, WA 98247
Ph: (360) 966-7158