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Subsoil properties as the main factors
in drying and mortality of Pinus halepensis at the Yatir
forest
Nir Herr – KKL-JNFYakir Preisler, Eyal Rotenberg - Weizmann InstituteNoam Greenbaum - Haifa University
Medpine5 sept. 2014
Haifa
Tel Aviv
Gaza
Jerusalem
Beer Sheva
Yatir, The biggest forest in Israel3,000 hectare planted forest
Where?
Yatir forest
Galilee
Negev
Limes
tone
Chalk
Eilat
Between the Mediterranean and the desertMean precipitation of 280 mm (with dry summer)
Patches of dry trees,2010
Med
iterra
nean
Sea
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
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?
Methods Digging Trenches in 11 pairs of plotsMeasurement 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
The Rock base
The Soil layer
The Forest properties
Drying and mortality
Stages of research
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:
LimestoneChalk
Na+Ca++
Clay
Ca++ Ca++
NaCl=Salinity
Soil depth
Stoniness
Deep Ca+
Parameters in the soilin relation to rock porosity
Na+
LimestoneChalk
0 3 6 9 12Porosity)%(
C h
a l k
Results
100
80
60
40
20
Dept
h (c
m),
ston
ines
s (%
), EC
(mS/
m),
conc
entr
ation
(meq
/l)
L I m
e s
t o n
e
Deep salinity
Deep Na+
0
20
40
60
80
100
120
140
1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3
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
Na+Ca++
Clay
Ca++ Ca++
NaCl=Salinity
Na+
Limestone
Chalk
Where are the living trees located?Where are the dead trees located?
Why?
WaterMovementFrom the
porous rock
In the winter
In the summer
Na negative influence is balanced by Ca presenceThe salinity is at tolerable concentrationThis shallow soil contribute to root contact with the rock The key factor is the water reservoir of the micro-porous rock
In the limestone environment the roots do not recruit all the soil depth
In the chalk environmentNa .…
Can the tree density be the cause for the mortality?High density of the living trees cause a reduction in their trunk diameterIt does not change the diameter of the low vitality treesthese 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
Limestone
Na+Ca++
Ca++ Ca++
NaCl=Salinity
Na+
Chalk
1012141618202224
0 100 200 300 400 500 600Trees per hectar
Dry plotsalive plots
Trun
k di
amet
er D
BH (c
m)
r2=0.57r2=0.17
Influence of tree densityOn the trunk diameter
Overview
Live forest on shallow soil above chalk Dry patches on deep soil above limestone
chalk
chalk
Limesto
ne
Dry patch
The roots-soil-rock relationsIn deep soil above LimestoneIn shallow soil above Chalk
Salinity
Na+ Ca++
Higher trees
Tolerable factors
Stoniness
Root
s con
tact
th
e ro
ck
Impr
ove
water
sy
stem
Limestone
Deeper soilMore clay
Lower trees
Smaller diameter
Low vitality
Rock
serv
es a
s res
ervo
ir
The dynamic of the factors affecting vitality and mortality
MortalityTree density reduces diameter
Shallow soil
Porous Chalk
Moderate SAR (Na/Ca)
Largerdiameter
• 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
Retention curves of clay soil and chalk rock
Available water in soil
Available water in rock
Soil retention curve
Rock retension curve
Volumetric water capacity
Tension, log H2 O
cm height
Field Capacity
Wilting point
מים עומד
ʠʸ ʷʮ
ʭʩʩʧ ʭʩ̡ʨ̫ʭʩ́ ʡʩʭʩ̡ʨ̫
P = 0.006
ʸ ʥʩʠʤʬʴ ʮʧʥ̋ʩhAnalysysFunction Discriminant(ʡʬʥ́ʮʩ̋ ʡʩʡʱ ʤhʺ ʹ ʮʩɹʬʺ ʥ̫ʬʧ ʤʩ̡ʨ̫ ʯʥʩʮʬ
ʯʤʩyʴ ʱ ʮʥ̋ʥ̫ʬʧʤy ʩʁʡʬ
ʥ́ʮʤ
ʤhʺʹ
ʮʤyʩʁ
ʠʡʬʥ́ʮʤʩ̋ ʡʩʡʱ ʤʤhʺ ʹ ʮʤy ʩʁʬʲ ʺ ʥ̫ʬʧʤʭʥ̫ʩʮr ʸ ʢ
ʡʭʲ ʯʤʬʹ ʺ ʥʩʁʬʸ ʥ̫ʤʥʡʬʥ́ʮʤʤhʺ ʹ ʮʤ̋ ʠʭʩhʥʡʤʭʩh̋ ʹ ʮʤʬʣʥʮʬʭʺ ʮʥy̋ ʺ ʣʩʮʺ ʠʺ ʠʨʡʮʤʤhʺ ʹ ʮʤ
ʠʸ ʷʮ
ʭ ʩʩʧ ʭʩ̡ʨ̫ʭʩ́ ʡʩʭʩ̡ʨ̫
P = 0.006
ʸ ʥʩʠʤʬʴ ʮʧʥ̋ʩhAnalysysFunction Discriminant(ʡʬʥ́ʮʩ̋ ʡʩʡʱ ʤhʺ ʹ ʮʩɹʬʺ ʥ̫ʬʧ ʤʩ̡ʨ̫ ʯʥʩʮʬ
ʯʤʩyʴ ʱ ʮʥ̋ʥ̫ʬʧʤy ʩʁ
ʡʬʥ́
ʮʤʤh
ʺʹʮʤy
ʩʁ
ʠʡʬʥ́ʮʤʩ̋ ʡʩʡʱ ʤʤhʺ ʹ ʮʤy ʩʁʬʲ ʺ ʥ̫ʬʧʤʭʥ̫ʩʮr ʸ ʢ
ʡʭʲ ʯʤʬʹ ʺ ʥʩʁʬʸ ʥ̫ʤʥʡʬʥ́ʮʤʤhʺ ʹ ʮʤ̋ ʠʭʩhʥʡʤʭʩh̋ ʹ ʮʤʬʣʥʮʬʭʺ ʮʥy̋ ʺ ʣʩʮʺ ʠʺ ʠʨʡʮʤʤhʺ ʹ ʮʤ
המשתנה. את הבונים המשתנים באת המבטאות וקורלציות המשולב
למודל תרומתם
רךטון
ירלק
ירןג
אבמ
רוגדי porosityב.
= גיר) רך, = 1אבן קירטון3)
stoninessג.
קעקר
בות
בניא
חוזא
א.Soil depth
)"
( מ
סמק
עו
Pair compare T test
החיים המקטעים של עולה סדר לפי חלקות
Living plots
Dry plots
porosity
claysalinity
Menuha fm.
Soil depth
SARNa