The publication of this Handbook was supported by the Russian Federation

Fig. E.2. A Quickbird satellite image from 2006 
showing the remaining part of the Stalin Shelter Belt 
on Meadow Chestnut soils at the Dzhanybek Research 
Station ( 49.3928 N, 46.7892 E)
The shelter belt fragments dominated by common 
oak are generally better preserved. Although top 
branches of  both common oak and Siberian elm 
tend to dry out, oak can survive in such condition for 
decades, while elm can not. In the Caspian Lowland, 
some oaks with dried tops are known to live for 
70-80 years. Therefore, dried top of  an oak is not 
necessarily a sign of  approaching death, but rather 
a reaction to periodic drought stress (however, a very 
severe drought can of  course kill common oak as well 
as Siberian elm).
Statistical analysis has revealed a significant correlation 
(r=0.66, p=0.05) between the diameter of  oak trunks 
and the size of  topographic depressions, where these 
trees  grow.  There  is  a  less  significant  correlation 
(r=0.54,  p=0.1)  between  the  height  of   trees  and 
the size of  the area that they occupy. Therefore, the 
diameter and height of  oaks can also be affected by 
other factors such as the shape of  depressions and the 
species composition of  the shelter belt.
Trees that grow within small topographic depressions 
(micro-hollows) are always shorter in comparison 
to trees growing within medium-sized depressions 
(meso-hollows that have areas of  1 ha or more). For 
example, such allometric relationships are found in Malus, Acer, Elaeagnus and Lonicera species that 
are 1.5 times taller in meso-hollows than in micro-hollows.
Meadow Chestnut soils within micro-hollows have been fully colonized by forest vegetation. Tree 
roots can extend slightly beyond micro-hollows into Light Chestnut soils, but they are prevented 
from spreading further to Solonetz due to their high salinity, according to our observations on root 
distribution along a trench across these soil types.
The long lifespan of  trees planted within micro-hollows can be explained by the additional supply 
of  soil moisture (even despite groundwater salinity) that helps the trees to compensate for water loss 
via evapotranspiration. Such artificial plantations have natural analogies, e.g., thickets of  Spiraea 
hypericifolia, Prunus spinoza, Rhamnus cathartica and Rosa cinnamomea that are commonly found within 
small depressions in the Caspian Lowland.
The survival of  such a long-term maintenance-free clusters of  planted trees (including oak) and 

---

123
Annex Е.Innovative methods and technologies of agroforestry on saline and alkaline soils (by the example of the Caspian Lowland, Russia) 
shrubs within small depressions can serve as a basis for recommending the wider application of  
agroforestry in arid zones dominated by Solonetz complexes.