Fortunately it seems WSU created a written version of the lecture and I found it to be a little easier to comprehend as well as much more concise. Bartlett Pear Pruning | WSU Tree Fruit | Washington State University
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Thatās a useful link. It also serves as a reminder that if you care to notch and/or girdle to induce bud swell itās getting to be the optimum time to do it if your trees are starting to wake up.
Alan, this is the first 10 minutes:
My name is Stefanaki. I am an Associate Professor at Washington State University, and Iām the chair of three fruit physiology and management. Today, Iām here to speak about PR pruning and especially B pruning. We will define how we have to prune a spindle and the relationships among the different organs of the trees that have to be managed with the pruning. Today weāre going to go over some of the principles of pruning high-density Bartlet pears that emphasize rotating wood to develop new fruiting wood to have high volume cropping of good-sized fruit and to renew that fruiting wood. We need to prune the trees because we want a good balance between vegetative and reproductive activity, and pruning is a way to achieve such a result. Trees are a sort of complex of organs that are in competition among them, and every activity interferes with the activity of other organs, for example, shoot growth and flower bud formation. With the pruning, we can really handle this situation. As you can see in this scheme, all the activities are linked, so all the reproductive and vegetative activities can be influenced by how we manage our tree and how we prune the tree.
Before defining the pruning, we need to explain some terms that we will use in the video that probably not all of you are familiar with. Of course, we have some organs in the plant that we call probably in a different way or probably just a different terminology. We are speaking about bindila. Bindila is a one-year-old shoot with a terminal flower bud, and this will be used to describe the habitus of different pear varieties. The second term is Tavia, which is a kind of pruning that we are using to bring the vigor out of the branches. Usually, it is a shortcut with two to three vegetative buds done in one-year-old wood. You will have a very strong response doing this cut, and you will see that all the buds that are close to the stem will have a better size, and we will minimize the effect of blind wood by doing this pruning. The last term is chicken paw, or as we call it in Italy, āZed Gallo.ā This is a very old structure of your trees that usually is very short spurs that grow one over the other for many years, as you can see in the picture. This is really affecting your fruit quality because usually, this structure presents very small-sized fruit, and this is a big point. The size of the bud that we have in our trees will define the size of the fruit, so small buds will provide small fruit. Usually, with bigger buds, you will have much better-sized fruit in your trees.
Now we have to speak about the five different productive habitus of the variety. We have five habitus. The first is type one, which is Bartlet, the variety that we will speak about today. It is mainly on one-year-old wood with bindila especially, and then it becomes good on two-year-old wood or three-year-old wood, and especially for fruit quality, such branches are the best to keep in your trees. The second type belongs to different varieties like AEL or Doyenne, which are mainly producing on two-year-old wood. Itās very rare that you can see fruit on a bindila in these kinds of varieties. The third type is Conference, which is a variety that is productive on old wood, on two-year-old wood, and sometimes on bindila too. Itās a sort of golden variety for pears, as it is able to produce on many kinds of bearing wood. The fourth type is Bosc, which is completely different compared to all the other varieties that we prune and is somehow similar also to Anjou because we need long pruning in this case and not short pruning, which is the model that I propose for Bartlet. The fifth type is Passe Crassane, which is mainly producing on spurs, and in this case, you have to prune very hard to remove the small buds mentioned before. So those are the five different kinds of habitus that you can have in pears.
Today, we will speak in detail about how to handle a spindle, one of the most important systems for pears, and how to manage the branches and establish an orchard for pruning. First of all, the spindle is a conic-shaped tree, which means the first scale of the branch is really strong, and then going up, the branches become smaller and weaker. What is important in pruning pears is that you never bend the branches below 90 degrees, especially at the beginning, because the pear tree doesnāt like to be bent below such a level, as the branch becomes too weak, and you have blind wood, and the branches get exhausted. For this reason, I recommend starting with a crotch angle of 45 to 50 degrees compared to the vertical. To explain why we want to bend the branches at 45 degrees, we can look at this scheme here in the slide that shows how the gradient of vigor will be in different bending situations. If you want to keep your vigor in the top part of the branches, you have to use a 45 to 50-degree angle. If you put the branches horizontally or below 90 degrees, you are reversing this vigor gradient and will have a strong response close to the stem instead of a strong response at the top of the branch. This is really a key point for pear pruning.
Now, we want to introduce the concept of dynamic pruning, which means that in the same time, in the same tree, we need three different kinds of situations. The first situation is the year zero, when we remove branches that are in the wrong position or too big, but we donāt want to make this point blind; we just need a new vegetative point. This new vegetative point in one year will provide some branches, like some one-year-old branches that we can use as renewal. These branches will be good because in one more year, they become productive branches. We need this mix of branches in all the trees that we are growing because otherwise, those branches get old and are not as productive. If we donāt have other branches ready to replace them, we will be in trouble. This is why I always say that pruning is a three-year cycle. There are branches that are productive, branches that will be productive, and branches for the future. If we classify the crop in this case, this will be the crop for 2015, this will be the crop for 2016, and this will be potentially the crop for 2017. This is how I look at the pruning in the trees.
Okay, now here Iām removing the flower buds at the end, always to minimize the problem of blind wood. I did it here and here, because I have the same situation. This kind of pruning is necessary to keep the fruit very close to the stem, and when you are producing fruit on this kind of wood, you will have a very large size. If you donāt prune and those become flower buds, you will have a situation like this: the branch will bend again, and all the fruit that will be produced here will be small. We donāt want small fruit; we want large-sized fruit. This is why we are using mainly two-year-old and three-year-old branches to optimize the quality of our fruit.
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