The Long-Term Ecological Research Site in Martyrs Forest:

Developing a Sustainable Planted Forest Interface in Israel

The Theoretical Basis

Forest management theory in Israel, which is the guiding document for Israeli forestry management, states among other things that KKL-JNF aspires to manage sustainable forests while taking into account all components of the forest system (in addition to planted trees), based as much as possible on natural processes. The purpose of the research area in the Martyrs’ Forest is to develop a plan for a forest interface that will enable KKL-JNF foresters to carry out these principles and make the next generation of Israeli forests sustainable.
 
A sustainable forest is a healthy, vital forest that is tailored to the conditions of its habitat, exists independently and is self-regenerating, provides a habitat to a large variety of species and supports various human activities without harming neighboring ecosystems.

A sustainable forest interface seeks to design the forest as an ecosystem with resilience and adaptive capacity that can fulfill ecological, landscape, and socioeconomic aims optimally, with minimal human involvement.

General Background

Planted forests cover approximately one million dunams (100,000 hectares) in Israel. Approximately 50 percent of the planted forests are based on coniferous species (pine and cypress). Of these trees, the local species, Jerusalem pine (Pinus halepensis, known also Aleppo pine), is the most prevalent.

The Jerusalem pine was the main species used from the 1940s to the 1970s, when most of Israel’s forests were planted. It appears that many forest areas based on this species will reach maturity within the next 20 to 30 years. In these forests, forest managers must deal with the issue of forest regeneration and designing the next generation of forests. In terms of forest interface, this issue is becoming their principal challenge.
Another important process is taking place as the forests age. The objectives of Israel’s forests and the way they are managed are gradually changing as part of a global trend toward the sustainable management of natural resources and taking into account a broad range of environmental, social and economic considerations.
Anne Frank Forest, which forms part of Martyrs Forest. Photo by Yaakov Shkolnik, KKL-JNF Photo Archive
The development of a plan for a forestry interface in order to make the next generation of Israel’s forests sustainable is a complex process requiring comprehensive knowledge. The purpose of the research area in Martyrs Forest is to meet this need. The study is being conducted in the sections of the forest that were planted with Jerusalem pine during the 1960s. The research activity at the site tracks various biotic and abiotic factors that exist in and affect the forest, including the relationships between them. This will enable researchers to arrive at a deep understanding of the ecological system in the forest and the long-term processes that take place there that result from dependence upon interface activity, disturbances and changes in the environment.
The approach of long-term study was born out of the recognition that most ecological processes take place over many years, and the amount of time required to understand them is often much longer than the amount of time that is usually allocated to conventional research programs. The purpose of the study’s long duration is to enable researchers to arrive at a clear distinction between long-term changes that take place in the ecological system and background noise (fluctuations that take place over the short term). Most of the local Long Term Ecological Research (LTER) sites are part of a network of locations whose purpose is to provide comparable data along a large, broad spectrum.

The Goals of the Study

The study in Martyrs Forest researches long-term influences of forestry care activity whose purpose is to encourage and direct the forest’s regeneration. It also researches the effect of thinning of trees in the mature forest, as well as other activity taking place in the regenerating forest layer.

The following components of the forestry care work are being studied:
  • The conservation of the vitality, resilience and scenic value of the forest’s trees
  • The creation of the next generation of the forest, to be based as much as possible upon the forest’s own natural process of regeneration
  • Nurturing the forest’s unique biodiversity
  • Designing the forest as an ecological system that has flexibility (the ability to recover after a disturbance) and adaptability (the ability to adapt itself to changing environmental conditions)
  • Developing tools for a forest interface in an environment with limited water

The Research Area

Type of forest: A mature forest of Jerusalem pine (planted in 1968)

Location: Martyrs Forest is located east of Route 38 (the Sha’ar ha-Gai–Beit Shemesh Highway) and north of the Eshta’ol-Tzova Junction in the Nahal Sorek basin (Nahal Kisalon secondary basin). The research area, which covers roughly 200 dunams, is on the western edge of the forest near Mesillat Zion.

Climate: Typical Mediterranean climate with annual precipitation of roughly 500 millimeters

Topography: The research area, which is 390 to 510 meters above sea level, is typified by a topographical turning point westward on an average incline of approximately 25 percent.

Geology: The geology, which dates from the Upper Cenomanian-Toronian Age, is massive dolomite structures of the Judea Group (Bina formation) on top of hard karstic chalk (Vradim formation) with a small presence of chalk that became nari. The ground is lithologically uniform and mostly covered by rock.

Soil: The soil is shallow brown terra rossa (on top of dolomite), washed red terra rossa (on top of the hard chalk) and rendzina mixed with terra rossa (near nari).

Forestry history: The forest in the research area was planted in the 1960s as part of Martyrs Forest, which was established to commemorate the six million Jews who perished in the Holocaust. As was customary at the time, most of the trees that were planted were coniferous, many of them Jerusalem pine. The planting density was originally 250 trees per dunam, though it seems that a one-time thinning operation was performed in the forest sometime between the planting and the establishment of the research area. Although the area was declared a national park in the 1970s, KKL-JNF continued to manage the forest.

Goats owned by Bedouin were brought from the Negev to graze seasonally beginning in the 1980s, but this was stopped when the construction of the research area began in 2008. Research began in 2009 after completion of a thinning operation.

The Forestry Care Examined in the Study

Thinning of the mature forest: Thinning work is considered the main interface treatment that can be done to improve the health and vitality of the forest’s trees and influence the natural processes of regeneration and development of the second-growth forest. The following thinning operations were carried out in the summer of 2009:

A. Thinning to a density of 30 trees per dunam
B. Thinning to a density of 10 trees per dunam
C. Complete cutting
D. Examination without cutting

Care of the regenerating forest layer: Care of the regenerating forest layer consists of designing the next generation of the forest. A decision regarding the care of the regenerating forest layer will be made in the future based on an interim assessment of the state of natural regeneration in the forest after the thinning operation that was carried out.

Among the possible treatments are the following:
A. Thinning the trees in the regenerating forest;
B. Regulating the growth of competing grasses and bushes in order to encourage the regenerating trees;
Sowing and/or planting tree species in the absence of sufficient regeneration.

The Variables Measured in the Study

The study tracks the long-term effects of thinning on various biotic and abiotic variables, as noted in the following table:
Field Index
Climate conditions in the forest area Rain
Air temperature
Air humidity
Wind speed and direction
Sunlight
Micro-climate Air temperature
Air humidity
Wind speed and direction
Photosynthetically active radiation
Soil Minerals in the soil (NPK)
Organic material in the soil
Water system Soil humidity
Water use by trees
Vitality and productivity of forest trees Trunk diameter
Tree height
Length of green area in canopy
Canopy width
Color of foliage
Width of annual rings
Canopy coverage
Leaf area index
Health of the forest’s trees Matsucoccus josephi (Israeli pine bast scale)
Bark beetle
Pine processionary moth
Crown moth
Natural regeneration of the forest’s trees Seed dispersal
Density of regenerating trees
Development of regenerating trees
Biodiversity Lignified vegetation in the secondary forest
Grassy vegetation in the secondary forest
Living creatures: ants, earthworms, wild bees
Gazelle activity in the forest
Ecosystem-wide activity Needle drop
Grassy biomass
Lignified biomass
Carbon fixation
Evapotranspiration

Study Outline

The Structure of the Experiment
The experiment is structured as a split plot design, with the entire plots separated according to the amount of thinning are split into subsections in which various treatments are administered in the secondary forest.
The area is divided into four blocks, each with four or more experimental plots (five dunams per plot, each one 70 by 70 meters), with various levels of thinning (Figure 1).
Figure 1: Structure of the experimental plots in the LTER site in the Martyrs’ Forest
Figure 1: Structure of the experimental plots in the LTER site in the Martyrs’ Forest

Key:

White circle with numeral = Sample number
Designated treatment
Yellow = Complete cutting
Light pink = Designated 10 dunams
Green = Designated 30 dunams
Blue = Tracking without cutting
Dark Pink = Sanitation
Aerial Photograph of the Research Site in the Martyrs’ Forest
Aerial Photograph of the Research Site in the Martyrs’ Forest
Milestones

1. 2007: The research plan is finalized, preliminary surveys carried out and the research plots planned

2. 2008–2009: The research plan is approved and measurements taken for Year Zero (before treatment)

3. August–October 2009: Thinning carried out in the study plots

4. November 2009: Long-term tracking begins

5. December 2009: The first annual report is submitted

Project Staff

Name Institution Position
Hanoch Tzoref KKL-JNF, Highlands Region Site manager
Dr. Yagil Osem Agricultural Research Organization, Volcani Institute Scientific director
Moish Zuckerman KKL-JNF, Highlands Region Block forester
Jamal Dawiat KKL-JNF, Highlands Region Block forester
Ela Zangy Agricultural Research Organization, Volcani Institute Study coordinator
Yahel Porat KKL-JNF, Forestry Division Ecologist, Forestry Division
Naftali Karni KKL-JNF, Central Region Survey and mapping
Yehuda Nisan KKL-JNF, Central Region Geographic Information Science

Researchers

Name Institution Research Topic
Dr. Yagil Osem Agricultural Research Organization, Volcani Institute Scientific coordinator
Dr. Eli Gruner Ben-Gurion University of the Negev Arthropods
Professor Uri Shanes University of Haifa Gazelles in the forest
Dr. Oren Pearlson Tel-Hai College Earthworms
Dr. Tomas Pavlicek University of Haifa Earthworms
Dr. Itzik Martinez Tel-Hai College Ants
Dr. Yael Mandelik The Hebrew University, Jerusalem Wild bees
Dr. Ori Fragman-Sapir The Hebrew University, Jerusalem Geophytes
Dr. Shabtai Cohen Agricultural Research Organization, Volcani Institute Water management in the forest
Dr. Victor Alchanatis Agricultural Research Organization, Volcani Institute Water management in the forest
Dr. Michael Sprintzin KKL-JNF Forestry Division Water management in the forest
Dr. José M. Grünzweig Hebrew University, Jerusalem Plant-litter decomposition

Students

Name Institution Research Topic
Elon Kalb (master’s degree candidate) The Hebrew University, Jerusalem Trees of the mature forest (Jerusalem pine)
Ela Zangy (doctoral candidate) The Hebrew University, Jerusalem Vegetation in the secondary-growth forest
Ira Mor (doctoral candidate) The Hebrew University, Jerusalem Water management
Oved Gur (doctoral candidate) University of Haifa Gazelles
Uri Meirovich (master’s degree candidate) The Hebrew University, Jerusalem Leaf surface index
Galia Kapp (master’s degree candidate) Tel Aviv University Ants
Mor Ashkenazi (master’s degree candidate) The Hebrew University, Jerusalem Geophytes
Daniel Gliksman (doctoral candidate) The Hebrew University, Jerusalem Plant-litter decomposition