The cherry tree is a species that behaves in a particular way from the point of view of its physiological and vegetative development. One of the main characteristics that make it different from other fruit species, is that the vegetative bud-burst in a normal situation is after the floral state, that means all of the reproductive floral states, therefore, although we can recognize that green material and leaves exist in full bloom maybe a little before full bloom which is about 7 or possibly 10 days after the state of full bloom in which it can be visibly recognized in the beginning of the vegetative activity itself.

It’s important to understand all the phenologic states of bract bursting, extension or rosette growth, beginning of the flowering, white bud with full flower and up until petal fall in which the vegetative activity of the cherry tree is not working together with the reproductive processes and that it is more probable that these flowering states are in some way using all the reserves that the plant could store up in the prior period before the post-harvest, the summer before.

Once the vegetative activity of an orchard over two years has started, it has an approximate duration of 70 days from full bloom. Why does it take 70 days or why does the vegetative development take 70 days? There are two reasons that matter. The first is the ecological reason and it has to do with the season change, with the summer solstice that is between December 20 to 22, when the days become shorter and the plant receives this as an ecological sign in which it gives the start to wood growth, the secondary growth, at the beginning of material lignification that could develop in the previous 70 days, this is described as cold tolerance in fruit tree physiology, since this process is the one that assures that the plant comes into the states of pre-dormancy and dormancy and could tolerate the low temperatures, not producing damage in the wood primarily due to cold.

The other important reason of the physiology of the plant is that approximately 70 days after full bloom the important process of flower induction begins which is the biochemical sign to the vegetative buds that indicate that they could be transformed into floral buds, not in the induction process of flowers, but in the later process that is called floral differentiation.

If a month for each of these processes could be determined, the month for flower induction is December and the month for the flower differentiation is January, where in the flower differentiation there are morphological changes, if you can see the floral buds at the base of the wood from the year and the young spurs in the two year wood. These two reasons of importance that these shoots have this development. Within that development, which lasts 70 days approximately, there are two phases, an ascending phase in terms of growth rate and a descending phase. The ascending phase has a duration starting with full bloom of 30-40 days in which the vegetative growth, the vegetative development is very powerful and the second phase, the last 30 days approximately of these 70 since development rate is very low.

It’s necessary to understand that despite the rootstock that is had, being from the weaker to stronger rootstock, the Gisela series, today better known as Gisela5-Gisela 6 we now are getting to know the Gisela 12, considering it as a good alternative for our country and on the other hand the vigor of a Colt or MaxMa 60. No matter the vigor of the rootstock or the ability to generate wood in each of the rootstocks, the yearly wood, each one of the rootstocks has the same 70 days available for the vegetative development. 

 “It’s very important to take into account that the medium to weak rootstocks, like the Gisela series and probably the MaxMa 14 that are in soils in poorer areas which are not so fertile, have a much larger challenge in recuperating their vegetative nature each year with regards to more vigorous rootstocks like the Colt or the MaxMa 60. This has much relation to the nutritional proposal that one makes each year. If I have to analyze it from the point of view of how to recover the orchard it is obvious that the rootstocks with less vigor have to take or demand an annual nitrogen quantity to develop their structure, much more than a Colt, out of necessity, but only the quantity of nitrogen that one could incorporate into the system, and also proportionally as it must be placed. It is important in a concrete example that an orchard above Gisela 6-levels of high productivity have available an important quantity of nitrogen that is within the 30 to 40 days DFFB to assure the ascendant phase of development of vegetative growth. On the other hand, in the Colt at one extreme, like MaxMa 60 at the other extreme, many times it’s not as necessary and there are many cases in which nitrogen is not needed because it can comfortably be developed in this vegetative growth without a problem,” pointed out Carlos Tapia, Avium Director.

A dynamic balance must be assured in this equilibrium between production and vegetation so that it is optimum for high levels of sustainable production in time. That is to say that with a weak rootstock we must always enhance youthfulness to sustain the production that it has and in a vigorous orchard we must consider not allowing the vegetative growth to exacerbate yearly and to fight against the youthfulness of this plant to enhance reproductive and maturity states that are needed to reach a high productive potential. 

 “It’s essential to understand this balance and understand the vegetative condition of vegetative development which has a beginning and an end, and it is important to understand that this end is produced within the season. It must be taken into account that when a water deficit is carried out in post-harvest it doesn’t have any repercussion with the objective, which is to slow down or stop vegetative growth because this has been stopping DFFB and the post-harvest will start 90-100 days after the full bloom, therefore, it doesn’t have a direct repercussion upon it. It’s necessary to consider the different nutritional models for each of the situations in terms of vigor and not only the soil, but also foliar considering root growth as we have explained, not beginning before 14° of soil temperature, and this will not be done before the first week of October,” added the expert.