Pruning: The Basics

Pruning is the practice of removing unwanted branches from the tree. Pruning can be broadly categorized to two types of cuts: heading and thinning. Heading cuts remove the terminal bud from the limb. This removes the “control center” and creates a varied response depending on the tree growth stage. Thinning cuts remove an entire limb is removed at a specified junction. This, as long as it is made in a position of low light, will often lead to little regrowth, regardless of when the cut was made. When making heading cuts, the time of the year matters. Dormant heading cuts often lead to an increase in vegetative growth the following spring. They are sometimes considered “invigorating cuts,” and can also be employed to redirect growth of a limb. In-season heading cuts will slow growth and are considered de-invigorating. These cuts slow canopy development as the tree has to redevelop the vegetative buds to push new growth. If timed appropriately, in-season heading cuts can lead to thickening of limbs and reduced breakage from wind and crop. Regardless of when they are made, heading cuts create branching. The growth response from a dormant heading cut depends on “how hard” the tree was cut back. The more proximal the cut (towards the trunk of the tree), the more vigorous the growth response. These growth responses originate out of epicormic buds, or buds that lay dormant within the wood of the tree. When these buds push, they grow without regulation and have very long internodal distances. This leads to very rapid, vertical growth that often has few fruiting positions. Thinning cuts can be made any time of the year. These types of cuts remove entire limbs and are commonly used to remove limbs from the lower canopy. Too many thinning cuts, however, can increase

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Post Harvest Pruning of Mature Orchards

Pruning is one of the subjects that can have ten people explain it in ten different ways. This has to do a lot with the traditional thoughts on how an almond tree should look, the believed benefits of pruning, and personal experiences. It is one of the most important practices of orchard maintenance due to the expense and its effect on orchard yield and longevity. Therefore pruning should be considered more of a science than an art. Pruning can be broken down into two phases: The tree training phase and the maintenance period phase. During the tree training phase, we work to establish and shape the permanent framework of the tree through primary and secondary scaffold selection. This occurs through the first three years of the orchard life. The maintenance pruning phase occurs from the 4th leaf on and is done to maintain the shape of the tree. This post will focus on pruning during the maintenance period of the orchard life. In order to understand the principles of pruning, we need to understand the underlying principle of orchard management: We are farming sunlight. The more sunlight that is intercepted by tree leaves, the more production we can achieve within our orchard. Therefore, trees need to fill the available space as quickly as possible to achieve maximum yields. Along with this, we want to ensure orchard viability by having sufficient fruitwood to produce a sizable crop for the life of the orchard. So, to do this, do we need to prune? The short answer is “no.” Studies by by farm advisors Roger Duncan (Stanislaus Co.), John Edstrom (Colusa Co.), Bill Krueger (Glenn Co.), and Mario Viveros (Emeritus, Kern Co.) have demonstrated that pruning does not increase yield over minimally, or “unpruned” trees (Table 1). As we can see, conventional, annually

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