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:

Limestone

Chalk

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

Dep

th (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 than to the trees density

Clay

Limestone

Na+Ca++

Ca++ Ca++

NaCl=Salinity

Na+

Chalk

1012141618202224

0 100 200 300 400 500 600

Trees 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 co

ntac

t th

e ro

ck

Impr

ove

water

sy

stem

Limestone

Deeper soilMore clay

Lower trees

Smaller diameter

Low vitality

Rock

ser

ves

as re

serv

oir

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

Extra slides

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

ʭʩʩʧ ʭʩ̡ʨ̫ʭʩ́ ʡʩʭʩ̡ʨ̫

P = 0.006

ʸ ʥʩʠʤʬʴ ʮʧʥ̋ʩhAnalysysFunction Discriminant(ʡʬʥ́ʮʩ̋ ʡʩʡʱ ʤhʺ ʹ ʮʩɹʬʺ ʥ̫ʬʧ ʤʩ̡ʨ̫ ʯʥʩʮʬ

ʯʤʩyʴ ʱ ʮʥ̋ʥ̫ʬʧʤy ʩʁ

ʡʬʥ́

ʮʤ

ʤhʺ

ʹʮ

ʤyʩʁ

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

ךר

וןטרקי

לרגי

בןא

מוג

רדי porosityב.

= גיר) רך, = 1אבן קירטון3)

stoninessג.

עק

רק

בתיובנ

אוז

חא

א.Soil depth

)"

( מ

סק

מעו

Pair compare T test

החיים המקטעים של עולה סדר לפי חלקות

Living plots

Dry plots

porosity

claysalinity

Menuha fm.

Soil depth

SARNa