In Yatir forest, located at the southern edge of the dry Mediterranean region in Israel, a patchiness mortality pattern of pines was observed after continuous droughts. The objective of the study was to identify the environmental factors that caused the mortality. Our results suggest that the preferable environment for planting pines in this region is chalk overlain by shallow and stony soil. Storage of water in this rock-soil system is the key factor affecting the survival and success of the forests לצפייה באתר ולהורדת הקובץ ראה בקישור הבא: Look in the site: http://nirforestecosoil.com/

1. Subsoil properties as the main factors
in drying and mortality
of Pinus halepensis at the Yatir forest
Nir Herr – KKL-JNF
Yakir Preisler, Eyal Rotenberg - Weizmann Institute
Noam Greenbaum - Haifa University
Medpine5 sept. 2014

2. Haifa
Tel Aviv
Gaza
Jerusalem
Beer Sheva
Yatir, The biggest forest in Israel
3,000 hectare planted forest
Where?
Yatir
forest
Negev
Chalk
Eilat
Between the Mediterranean and the desert
Mean precipitation of 280 mm (with dry summer)
Patches of dry trees,2010

3. The drying phenomenon in the Yatir forest
• After a sequence of 4 drought years
• Drying occurred within a short time in patches
• 8% of the forest
• This patchy pattern looked threatening over the entire forest
• This pattern enables to compare pairs of dry and living plots

4. Aims and research questions
• Understanding the drying and mortality phenomenon
• Understanding the rock-soil system
• Understanding the forest properties
• What is the reason for this patchy mortality ?
• What can we do to prevent it?

5. Methods
 Digging Trenches in 11 pairs of plots
Measurement and sampling
• Trees forestry measurements
• Soil-rock field measurements
and description
• Root and stones measurements
• Soil-rock sampling for chemical and physical analysis
• Stump sampling for anatomical and physiological analysis
Dry stump
Green
tree
stump
living patch dry patch

6. The Rock base
The Soil layer
The Forest properties
Drying and mortality
Stages of research

7. Carbonate (CaCO3) Rocks physical properties
• Hard rock
• Dense
• Fractured
Soil pedogenesis
• Soft rock
• Composed of microfossiles
• Porous
Over the limestone:
• Atmospheric water dissolve the rock
and percolates along the cracks
• Relatively deep soil (90-150 cm) developes
Rock and soil properties and processes
•Over the chalk:
• The water enters the micro-pores of
the rock and remain there
• Shallow stony soil developed
Chalk: Limestone:
Limestone
Chalk

8. Na+Ca++
Clay
Ca++ Ca++
NaCl=Salinity
Parameters in the soil
in relation to rock porosity
Na+
0 3 6 9 12
Porosity (%)
Chalk
Results
100
80
60
40
20
Depth(cm),stoniness(%),EC(mS/m),concentration(meq/l)
LImestone
20
40
60
80
100
120
140
Soil depth (cm)
Deep Stoniness (%)
Deep Ca (meq/l)
Deep Salinity (mS/m)
Deep Na (meq/10 l)
Chart legend r2
0.30
0.54
0.62
0.71
0.56

9. Na+Ca++
Clay
Ca++ Ca++
NaCl=Salinity
Na+
Where are the living trees located?
Where are the dead trees located?
Why?
Water
Movement
From the
porous rock
In the winter
In the summer
Na negative influence is balanced by Ca presence
The salinity is at tolerable concentration
This shallow soil contribute to root contact with the rock
The key factor is the water reservoir of the micro-porous rock

10. Can the tree density be the cause for the mortality?
High density of the living trees cause a reduction in their trunk diameter
It does not change the diameter of the low vitality trees
these trees experienced less forestry thinning
They were already low size previously and without competition influence
Therefore, the small diameter and the small size of the dry trees
is related to the rock-soil conditions rather tan to the trees density
Clay
Na+Ca++
Ca++ Ca++
NaCl=Salinity
Na+
10
12
14
16
18
20
22
24
0 100 200 300 400 500 600
Trees per hectar
Dry plots
alive plots
TrunkdiameterDBH(cm)
r2=0.57
r2=0.17
Influence of tree density
On the trunk diameter

11. Overview
Live forest on shallow soil above chalk Dry patches on deep soil above limestone
chalk
chalk
Dry patch

12. The roots-soil-rock relations
In deep soil above LimestoneIn shallow soil above Chalk

13. Salinity
Na+ Ca++
Higher
trees
Stoniness
Limestone
Deeper soil
More clay
Lower
trees
Smaller
diameter
Low
vitality
The dynamic of the factors affecting vitality and mortality
MortalityTree density
reduces diameter
Shallow soil
Porous Chalk
Moderate SAR (Na/Ca)
Larger
diameter

14. • In Yatir forest a patchy mortality pattern of pines was observed after continuous
droughts
• Living trees are located mainly over slopes of chalky rock overlain by shallow,
stony soil.
•The porous chalk serves as a water reservoir. The shallow soil enables close
contact between the roots and the rock. The stones help to percolate and hold
moisture throughout the dry season.
• Salinity and sodium in soil in this environment are tolerable for pines. Their
influence is minor compared to the water gain from the chalk and the importance
of this habitat to the tree water system.
• Our results suggest that the preferable environment for planting pines in this
region is chalk overlain by shallow and stony soil.
Storage of water in this rock-soil system is the key factor affecting the survival
and success of the forests in this semi-arid Mediterranean Region.
Summary and conclusions

16. Retention curves of clay soil and chalk rock
Available water
in soil
Available water in rock
Volumetric water capacity
Tension,logH2Ocmheight
Field Capacity
Wilting point
‫מים‬ ‫עומד‬

17. ‫מקרא‬
‫חיים‬ ‫עים‬ ‫ק‬
‫יבשים‬ ‫עים‬ ‫ק‬
P= 0.006
AnalysysFunctionDiscriminant(
‫משולב‬ ‫סביבתי‬ ‫משתנה‬ ‫י‬ ‫ל‬ ‫החלקות‬ ‫עי‬ ‫ק‬ ‫למיו‬
‫א‬‫המשולב‬ ‫הסביבתי‬ ‫המשתנה‬ ‫ציר‬ ‫על‬ ‫החלקות‬ ‫מיקום‬ ‫גרף‬
‫ב‬‫עם‬ ‫שלה‬ ‫והקורלציות‬ ‫המשולב‬ ‫המשתנה‬ ‫את‬ ‫הבונים‬ ‫המשתנים‬
‫למודל‬ ‫תרומתם‬ ‫מידת‬ ‫את‬ ‫את‬ ‫המב‬ ‫המשתנה‬
‫ב‬‫של‬ ‫והקורלציות‬ ‫המשולב‬ ‫המשתנה‬ ‫את‬ ‫הבונים‬ ‫המשתנים‬
‫למודל‬ ‫תרומתם‬ ‫מידת‬ ‫את‬ ‫את‬ ‫המב‬ ‫המשתנה‬
‫ב‬.‫המשולב‬ ‫המשתנה‬ ‫את‬ ‫הבונים‬ ‫המשתנים‬
‫למודל‬ ‫תרומתם‬ ‫את‬ ‫אות‬ ‫המב‬ ‫וקורלציות‬
‫ג‬‫ג‬‫ד‬‫ט‬‫ך‬
.porosity
(‫ג‬=1,‫ט‬‫ך‬=3)‫ג‬.stoniness
‫ע‬‫ז‬
‫א‬.
Soil depth
‫ע‬(")
Pair
compare
T test
‫החיים‬ ‫עים‬ ‫המק‬ ‫של‬ ‫עולה‬ ‫סדר‬ ‫י‬ ‫ל‬ ‫חלקות‬
Living plots
Dry plots
porosity
clay
salinity
Menuha fm.
Soil depth
SAR
Na