Each problem has its origins, and the whole problem is that there are a lot of them, and it is difficult to determine a specific one! Apparently, in 3-4 years the root system of a young tree could develop well and reach the level of groundwater. Often trees are neutral to groundwater, but sometimes they do not react very negatively. It could happen to your plum if it got underground water from its roots (it would be desirable to know their level).
Cracking due to growth
Not only a similar problem, but the growth itself, especially sharp and rapid, can give such an effect. The bark, in this case, is cracking for the reason that it does not keep pace with the growth of young wood. Sometimes, the bark is elastic, but not enough to withstand a serious increase. Due to strong pressure, it cracks, which often leads to irreparable consequences. This does not mean that you need to stop feeding trees, worrying about cracks in the bark, you just need to do this carefully and be sure to understand the norms of fertilizer application!
Winter frost bark problems
Each fruit or decorative tree in the country requires special care, and it is a pity when summer residents are skeptical about this. It is clear that everyone performs pruning and cutting, mulching and watering, but the simplest statistics say that more than 70% of summer residents show such care for trees only in the warm season! But you should definitely look after the trees in autumn and winter.
Cracking of the bark could occur for another simple reason - the tree simply froze in the winter or suffered from a February temperature change. During the day, the tree was burnt by the sun's rays, and at night it froze again. As a result, the bark weakened and received similar “injuries”.
Getting rid of cracks in tree trunks
Black cancer - the cause of cracks in the cortex
And not only cracks in the bark, but also the death of the tree, and maybe the whole garden. Black cancer is a really terrible disease, cracks in the cortex are some of the symptoms. You should start treating the tree very on time, otherwise the disease can go all over the garden!
recommends that every summer resident carefully study the agricultural technology of plants that you want to grow in the country. Only attention and understanding will give you the opportunity to get a beautiful garden and harvest from the garden!