Hello. In this case, most likely the deterioration of the tree can be associated with a complex of abiotic factors, such as reduced size of the root system compared to the size of the above-ground parts, unfavorable climatic and soil conditions, high and constant humidity in the soil, stress during transport, handling and planting (Ornamental trees and shrubs - Planting guide) and others, depending on the case.
In one photo, lichens can be seen, which usually grow on old, declining or stressed trees. It is important to mention that although their presence is often associated with the causes of tree diseases, studies have shown that they do not directly affect the trees, but can be hosts for pathogenic fungi and insects. Thus, if lichens are only present on a few lower branches, you may consider removing these parts of the plant entirely (). It is also advisable to remove the dried or drying parts of the plant (if necessary, remove all the lower branches with dry parts – Trimming and pruning ornamental species). Additionally, the removal of gravel from the base of the conifer is recommended, as well as the slight loosening of the topsoil. The stones or any other natural or synthetic material at the base of the plant keeps the humidity high and constant at the soil level and blocks the air circulation at the roots, thus favoring the development and propagation of pathogens. It is important to keep a permanently loose and clear area around the plants.
Since you have already applied root fertilizers, you may consider for the time being the regular application of a foliar fertilizer that is specially formulated for the nutritional requirements of conifers, such as or , by spraying it on the foliage, according to the description of the chosen product. These fertilizers support the resistance of plants to stress factors, increase foliage density and help prevent deficiencies and the browning of foliage.
Afterwards, after the period of action of the root fertilizer has passed, you can also consider using a fertilizer with natural beneficial algae extracts, such as , by watering at the roots, as recommended on the product label.
Also, considering that the activity and proliferation of phytopathogens is stimulated by the high and constant humidity of the soil, watering is recommended to be carried out exclusively at the roots, depending on the recorded temperatures and rainfall, only when the soil is dry on the surface.
More information on this topic can be found in our articles: Fir, planting guide and care work and Conifer diseases: affected needles, branches and cones . Given the current condition of the conifer in the attached photos and those mentioned above, it is not possible to accurately predict its future development.