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2.2.4 Other procedures
After planting new individuals, some further procedures are necessary, aimed to facilitate the
taking root in the planting site and to reduce failure risks due to collapses, root damages, weed spread,
etc.
A first intervention is mulching, a procedure necessary to avoid weed growth, by covering the soil
surface around the trunk with different kind of materials. In urban forestry interventions, the most
common mulching used are:
•
plastic film, in strips or portion for single plant. This procedure has benefits also for root
growth, because it contribute to keep adequate humidity and temperature of first soil layers
(where root development is maximum), and it supports also microbic activity. Moreover,
maintaining humidity of superficial layers longer allows to reduce irrigation, especially in
areas characterized by hot and dry climate. This kind of mulch, however, is expensive
(especially during the laying and the removal) and unsightly (this problem can be resolved by
covering the plastic film with natural materials, for example straw). This mulch needs to be
removed within first 2-3 years after planting and it should be conveniently dispatched. In
addition to plastic sheetings, mulching sheetings in non woven fabric can be used: they have
the advantage to be made in a breathable material which allows soil transpiration without
creating ponding or asphyctic areas;
•
woodchips or other organic material (shredded bark, lapillus, pine bark, dry leaves, straw, hay,
etc.), applied for a depth of 10-15 cm and, possibly, far from plant collar. Organic mulches
decay over time and are temporary, therefore it is advisable to lay new material every year, in
order to keep mulch layer stable. Costs can vary depending on materials chosen;
•
grass clipping. In this case costs are the lowest, but the yield can be not the best, then it should
be better to choose among other types of mulches.
Finally, it is possible to use disks or squares of various degradable materials (cardboard, plastic,
fibers), but they can be used only in very localized areas due to high costs.
Another procedure quite widespread is the resting of new plants, which consists in placing external
support poles or underground supports (in the root area) during planting (Figure 7). This procedure
allows the normal growth of root apparatus, protecting it from possible damages during rootage.
Furthermore, anchoring to supports prevents plants from being eradicated by atmospheric agents or
collisions. Type of supports depends on plant
59, and also poles’ size (height and diameter) must be
appropriate to those of the trunk. Generally just one pole is placed (of different wood such as chestnut,
black locust, bamboo, etc.), but it would be better to use two or three supports (also if it is more
expensive). Poles have to be placed immediately after the plant, paying attention not to damage it, and
they have to be driven up to the original soil. Support poles should be placed sufficiently far from the
trunk (at least 40 cm) to avoid rubbing in case the tree swings. Anchoring must leave 2/3 of the crow
free to bend in presence of wind. Furthermore, before their use, supports should be treated with
substances that avoid going rotten. Fibres of several materials can be used to join the trunk to the pole
(often rubber, but also coconut filaments or plastic strings). Whatever is the material, the importance is
that it keeps its elasticity for long time in order to allow slight swinging of the plants. Anyway, it is
necessary to verify periodically joining rings (c.f. 2.3). Generally supports should be removed after 1-2
years.
Lately, for trees with big root ball, the use of underground supports is spreading. In this case, three
poles are driven all through hole depth and boards are attached to them, so to form a triangle which
blocks the root ball. This kind of support has the benefit to leave the trunk free, without risks of
damage. Furthermore, unlike external poles, underground supports should not be removed.
In addition to mulching and resting, another procedure which can be necessary is a moderate
planting pruning, that is mainly the removal of damage or dry branches. Finally, for big trees it could
be opportune to realize a pruning which balances crown size with root apparatus dimension.
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For example for some conifers, it is not necessary.