According to environment factors
Grazing
The architecture can be deeply modified by grazing (especially goats but also sheeps) and first stages of development can be more or less scrubby. Different mechanisms enable the plant to react against such traumatisms. We can separate those using " common " branching processes from those involving dedifferentiation processes (more details should be provided on this aspect in the next report). Along time, some stems can grow without damages and one of them become the new trunk of the individual. When examining such trees, we can easily pick up the trail of passed traumatisms (basal part of the trunk more or less sinuous, presence of many twisted branches)
 .
Forest conditions
In forest conditions, trees local density may modifiy the resulting architecture.
Whatever stand density is, the architectural sequence remains the same .
However stand density may influence the quantitative architecture of the tree. In high density conditions ,
branch shedding is higher, final size of the crown is smaller and trunk straightness is better.
In very low density stands, a strong development of lower branches (that may reach ground level) leads to the development of a huge tree crown .
Extreme envrionmental conditions (cliff, gorge)
In such places, many factors as strong winds or poor soils
(or almost no soil at all! ) result in particular growth habits
.
Soil absence may lead to the formation of a tuber at the base of the trunk ,
wind (and snow
i.e. in Samaria gorge's; Crete) involves trunk bending, asymmetry of branches location and disparition of leaves on all upper parts of branches and trunk.
Nevertheless, according to their precise location, trees can grow quite well (i.e. in lower parts of gorges, young 25 meter high trees are completely straight).
According to genetic factors
Only two places among those we observed have shown populations with specific architecture that we can at first consider as possible endogenous expression.
The first place is located at Profitis Ilias on Rhodes island where reiteration process expresses itself more frequently on branches than for trees of other observed populations :
the resulting crown appears denser and bigger. The second place corresponds to the slopes of Agios Irini ,
in Crete island where tree trunks bear very long, thin and poorly forked branches. Order three axes bear female cones and a great difference between diameters of successive branching order is observed.
Forthcoming studies in provenance's field trials in collaboration with other participants (P1-1) will provide more information about the validation of these possible genetic architectural variations.
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