Each tree plays an even greater role, the larger the size. Many years of waiting for the effects of planting trees in many newly built housing estates are known. This period, very disproportionate to the length of the construction period, can only be partially shortened, among others, by planting larger trees, so usually older. However, the creation of vegetation from older trees is limited by many factors and is still of little use in our conditions. This is mainly due to the significant cost of replanting larger trees (it is 30-50 times greater than the cost of planting young trees), no trees prepared for this purpose, significant technical difficulties, resulting from the low level of mechanization of the transplanting process, etc.. Therefore, planting larger trees is usually limited to cases justified by special reasons. Perhaps the most important of them is the need to improve the health conditions and aesthetic value of a given area and the need to use trees, which must be removed from various places. For example, it is necessary to replant suitable valuable trees that are removed to widen the streets, when building enters, in the event of collisions with various elements of the environment, etc..
The basic criterion for making a decision to replant a tree is the assessment of its overall value and suitability for replanting. Specifically – the overall plastic value and health are assessed, value as a species; sizes and expected weight, conditioning the quality of transport. An important factor, which should be considered when deciding to replant, it is necessary to provide the nurturing required by the tree. Transplanted trees should be of as much decorative value as possible, because they are more and more often planted to enhance the aesthetic value of various places. The most valuable in this respect are trees with normally built crowns, and therefore of the right shape. Trees growing in close or one-sided shade, they often have distorted crowns and are usually of lower value. Trees that are disproportionately tall planted in exposed areas require special supports to prevent them from being knocked over by the wind. Choosing larger trees to plant, it is necessary to avoid specimens with various mechanical damages, especially with open wounds and progressive decay of the wood. Also, large trees controlled by diseases or pests should not be planted until they have been eradicated.
Transplanting in old age is not the same for every tree species. The ability of trees to regenerate the root system and to adapt to the conditions of a new place decreases in trees of almost all species as they age. However, there are such among them, who endure the transplanting procedure at the age of a dozen or even several dozen years much better than others. These trees include, first of all, linden trees (Tilia), clones (Acer), sycamore (Platanus), ash trees (Fraxinus), chestnut trees (Aesculus) and others less frequently cultivated. However, they do not tolerate transplanting well over the age of over 4-6 years of willow (Salix) and poplars (Populus). In exceptional cases, old conifers are also transplanted. Planting very large trees is a limiting factor, even well tolerating transplanting, their sizes may be. The reason for this is too much weight of the tree and the root ball and its size (width) crown in relation to the technical possibilities of transport.
The weight of the tree transplanted with the root ball consists of the weight of the aboveground part (trunk, branches) and underground (the roots) and the weight of the earth forming the lump. Determining the lump size for the replanted tree, is accepted, that its radius should approximately correspond to the circumference of the trunk, measured in the ground-level part. Thickness (height) root ball, depending on the quality of the root system, may range from 1/3 do 3/4 the diameter of the body. The weight of a cubic meter of earth can vary from 1200 kg (humus soil) do 2400 kg (sandy, loamy). The table shows approximate diameters and thicknesses of the block as well as the weight of trees with a block for trees with different trunk diameters. The volume and weight were calculated according to the formula:
π • r² • height of the solid • weight of the earth
Weight assumed 1 m³ of land – 2000 kg, the weight of the tree – 25% the weight of the earth.
Table. Approximate diameters and thicknesses of the lumps and weights of trees together with the lump depending on the diameter of the trunk.
As can be seen from the presented examples, the weights of trees with lumps are heavy and increase progressively depending on the diameter of the trunk. Any transport of trees with a trunk diameter above 10 cm already requires the use of mechanized equipment. Transporting very large trees requires heavy cranes and specially prepared vehicles. Trees, even of considerable size, transplanted over short distances (e.g.. during the widening of streets), may be moved on the ground surface with a tractor after proper preparation and securing of the lump. For longer distances, trees must be transported in a horizontal position due to the cables found over roads. This, of course, requires appropriate technical measures.
Transplanting large trees is always a very costly undertaking and should be carried out in this way, so as not to endanger them. You should also remember about the necessity to provide the planted trees with very careful care, at least during the first growing season.
