US Forest Service International Programs Technical ...

US Forest Service International Programs Technical Assistance to USAID/Cairo IWRM II Project

May 3 - 7, 2009 Egypt

Trip Report

US Forest Service Trip Report May 3-7, 2009 -1-

EXECUTIVE SUMMARY From May 3 – 7, 2009, US Forest Service personnel, John Stanturf, Ron Zalesny, and Chris Soriano, together with Steve Evett of USDA Agricultural Research Service, traveled to Egypt for a technical cooperation mission in support of USAID Cairo’s Integrated Water Resources Management II project (IWRMII). The scope of work for this visit was developed in partnership with USAID Cairo and addressed the technical feasibility of scaling up afforestation efforts that were piloted during the IWRM I USAID project. The team was tasked with determining appropriate species for afforestation in Egypt, and outlining specific components of potential long-term US Forest Service (USFS) technical support. As USAID and the Government of Egypt (GOE) move forward with afforestation activities, certain questions must be addressed at the outset to ensure the selection appropriate tree species: What is the purpose or end goal of growing trees? What domestic/international markets exist for specific species? What favorable traits do specific species possess? How have specific species performed in trials in Egypt? How do the potential afforestation sites correlate to species’ favorable traits and trial performances? The team has grouped the recommended tree species into three classes: versatile species that can be managed for pulpwood or sawnwood (Pinus, Eucalyptus and Populus spp.); high value species (Khaya ivorensis and Tectona grandis); and pulpwood (Gmelina arborea). Yet, at this time it is too early to provide detailed instructions on how to move forward with afforestation activities on these specific species. This is because there is currently a dearth of scientific data regarding the on-going afforestation activities in Egypt’s man-made forests. That being said, as this promising work in the man-made forests continues, rigorous experimentation and record keeping will help articulate the best management practices for continuing afforestation with treated wastewater. Where possible, the team provides guidance on performing such trials and experiments throughout the report. Populus species and hybrids (i.e., poplars) hold much potential for afforestation efforts using treated wastewater in Egypt because of their fast growth and biomass accumulation, quick establishment and extensive root systems, ease of asexual propagation, exceptional growth on marginal lands, and elevated rates of transpiration. Successful afforestation with poplar in Egypt largely depends upon matching allowable irrigation application rates with suitable evapotranspiration demands of the plantations. Failure to combine these components likely will result in plantation failure, as was seen by the team at Ismailia and Groppi Nursery. Nevertheless, the broad amount of genetic variation within the genus Populus increases the likelihood that genotypes with adequate stomatal control can be identified and selected, and cultivated successfully in Egypt. The drawback of having such extensive variability within the genus Populus is that field deployment of unfavorable genotypes may result in inadequate plantation productivity or complete failure, inadvertent leaching of wastewater into ground water aquifers, and/or a US Forest Service Trip Report May 3-7, 2009 -2-

lack of a quality product at the end of the rotation. It is possible to reduce the potential of such impacts with early genotypic screening and selection trials prior to deployment in field-based production systems. Such testing is referred to as “phyto-recurrent selection” and involves the evaluation, identification, and selection of favorable clones using multiple selection cycles. This methodology is also appropriate for many other species recommend in this report. Providing the trees with the amount of water they need, when they need it will be essential for maximizing productivity. Some indications of plant needs are given in the report; but there is little hard data on most of the species under conditions of wastewater irrigation. As plants grow larger and develop more leaves, they will require more water until they reach a plateau with full canopy development and maximum insolation. Windy conditions will increase water needs as turbulence above the canopy increases transpiration potential, as will smaller relative humidities such as in Upper Egypt. Because the sandy soils typical to the afforestation plots have little water holding capacity frequent watering will give best results. Evapotranspiration rates will vary widely from upper to lower Egypt, from west of the Nile to near the Suez Canal (larger relative humidities), seasonally and by species. Successful irrigation of any tree species demands careful irrigation scheduling based on the best scientific knowledge available, probable on-site measurement of weather data, and ongoing maintenance and repair of the irrigation system from pump intake to emitters and/or spaghetti tubing. Maximizing the potential of afforestation efforts requires judicious choice of species, development of quality planting stock, and appropriate methods for plantation establishment and tending, including initial spacing, thinning regimes, and very importantly, appropriate irrigation regimes for the site and species. Commercial inputs for afforestation efforts activities include those associated with site preparation, stand establishment, stand management, irrigation, and timber harvest. While most inputs are similar to or less than those required in other regions of the world, the irrigation component is substantial in Egypt. Potential long-term impacts on the natural resource base are dominated by direct leaching of wastewater into the soil and ground water aquifers as a result of irrigating with volumes of water that exceed evapotranspiraton levels. In addition, pests and pathogens may become a problem; an active monitoring program to detect problems before they lead to total failure is needed. Problems from competing vegetation may also arise, especially after the first rotation. Fire hazards and potential markets must also be considered. Finally, based on the team’s findings and recommendations, the team outlined seven options for follow-up technical assistance with USAID and the GOE. These include: 1. Assistance and support for a Stakeholder Workshop that would address identifying specific and tree species and appropriate irrigation systems.


2. From the Stakeholder Workshop output, specify nursery management, silviculture, and irrigation systems and model yields and develop pro forma business plans. 3. Establish monitoring protocols that would be used by Egyptian scientists and managers, with on-going technical assistance from Forest Service scientists. 4. Design and monitoring of targeted research to improve understanding of water requirements, monitoring of actual amounts of TWW applied, and appropriate silvicultural regimes for each species selected. 5. On-going assistance to develop the most appropriate and best-adapted plant material for conditions in Egypt. The approach is a modification of the phytorecurrent selection system that can be applied to all species, not just Populus. 6. A workshop for nursery managers in Egypt focusing on best management practices and developing an adaptive management strategy that would aim to identify the optimum ideotype of seedling with the best outplanting success and for continuous improvement of nursery practices. 7. Assistance with developing the modeling framework, as well as training and developing capacity, in Egyptian ministries for integrating information, developing and testing growth and yield models, and supporting economic analyses. A more detailed list is included in Section V.


TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................................................- 2 TABLE OF CONTENTS................................................................................................- 5 I.

BACKGROUND ................................................................................................- 6 -

II.

TEAM SCHEDULE ...........................................................................................- 7 -

III.

TRIP OBJECTIVES ...........................................................................................- 7 -

IV.

FINDINGS AND RECOMMENDATIONS.......................................................- 8 -

1. 2. 3. 4.

5.

Identifying tree species suitable for afforestation according to local soil characteristics, water quality, and quantity of water supply Understanding the pros and cons of using different tree and/or crop species Providing recommendations for irrigation based on recommended tree species and local conditions Identifying strategies to maximize the potential of afforestation efforts with regard to: improving water quality, maximizing resource production (timber/pulp/non-timber forest products), increasing biodiversity, and limiting commercial inputs Outlining potential long-term impacts on the natural resource base from afforestation and strategies to mitigate these impacts

-8- 20 - 27 -

- 41 - 48 -

V.

NEXT STEP ACTIVITIES...............................................................................- 50 -

VI.

LITERATURE CITED .....................................................................................- 51 -

APPENDIX I:

Contacts for meteorological information in Egypt. ......................- 58 -

APPENDIX II:

Location of Areas Identified for Reuse of Treated Wastewater ...- 59 -

ADDENDA:….……………………………………………………………………….- 63 -


US FOREST SERVICE TEAM MEMBERS John Stanturf: US Forest Service, Project Leader and Principal Ecologist for the Southern Research Station Ron Zalesny: US Forest Service, Team Leader and Research Plant Geneticist, Northern Research Station, Institute for Applied Ecosystem Studies Steve Evett: USDA Agricultural Research Service, Research Soil Scientist and Lead Scientist of the Crop Water Use and Irrigation Research Team, Soil and Water Management Research Unit, USDA-ARS Conservation & Production Research Laboratory Chris Soriano: US Forest Service, International Programs

I.

BACKGROUND

US Forest Service (USFS) personnel, John Stanturf, Ron Zalesny, and Chris Soriano, together with Steve Evett of USDA Agricultural Research Service, traveled to Egypt from May 3 - 7, 2009 to provide technical guidance to a USAID/Cairo project and examine the potential of using treated wastewater to irrigate afforestation plots in Egypt. The Nile River provides approximately 97% of Egypt’s freshwater supply, which is 55.5 billion cubic meters annually. This amount is allocated to Egypt according to international treaty obligations and fixed at 55.5 billion cubic meters. As a result, Egypt will not be able to meet increasing water demand by increasing its supply of freshwater from the Nile. Rather, strategies for increasing water efficiency and promoting water reuse must be developed and implemented to meet future demands. In the year 2000, about 8 billion cubic meters of wastewater were treated and returned to the water system. This amount is projected to increase to 14 billion cubic meters by 2017. Identifying strategies to utilize this water for productive purposes will be instrumental to ensuring Egypt’s water security. Since 2004, the USAID Mission in Cairo has promoted strategies for water reuse through its Integrated Water Resources Management (IWRM) Project with Egypt’s Ministry of Water Resources and Irrigation. Through this program, the Government of Egypt has developed and since approved guidelines for the reuse of treated wastewater for agricultural purposes. These guidelines represent the legal foundation for farmers to begin cultivating with irrigated wastewater. As a follow-up to the IWRM Project, USAID Cairo is initiating a new project that seeks to improve the economic return of treated wastewater. The US Forest Service has been asked by USAID to examine the potential of using treated wastewater to irrigate afforestation plots in Egypt. Through the IWRM project, USAID has demonstrated the potential of wastewater irrigation at a pilot project in Luxor and is now interested in scaling this pilot up to a commercial level. As a first step in scaling up, the technical US Forest Service Trip Report May 3-7, 2009 -6-

feasibility of afforestation with treated wastewater on a commercial scale needs to be examined.

II.

TEAM SCHEDULE

The USFS team arrived in Egypt on May 2 and began work on May 3. The schedule was as follows: May 3:

May 4: May 5: May 6: May 7:

III.

Introductory meeting with USAID staff and presentation on Tentative Opportunities for Reuse of Treated Wastewater for Agriculture in Egypt by Dr. Ken Swanberg, Deputy Chief of Party, IWRM II. Meetings with Ministry of Water Resource and Irrigation representatives Field visit to Luxor to view Ministry of Agriculture Man-Made Forest and USAID IWRM pilot project site. Field visit to Serabium Man-Made Forest located in Ismailia Meetings with Ministry of Agriculture’s Soil, Water and Environment Research Institute. Field visit to Groppi Nursery in Cairo.

TRIP OBJECTIVES

The USFS technical assistance mission to Egypt assessed the technical feasibility of scaling up afforestation efforts. Prior to the visit the USFS team formulated the following objectives with USAID Cairo: 1. Determine appropriate species for afforestation in Egypt, and; 2. Outline specific components of potential long-term USFS technical support. This trip report: 1. Identifies tree species suitable for afforestation according to local soil characteristics, water quality, and quantity of water supply; 2. Articulates the pros and cons of using different tree and/or crop species; 3. Provides recommendations for irrigation based on recommended tree species and local conditions; 4. Identifies strategies to maximize the potential of afforestation efforts with regard to: improving water quality, maximizing resource production (timber/pulp/non-timber forest products), increasing biodiversity, and limiting commercial inputs; and, 5. Outlines potential long-term impacts on the natural resource base from afforestation and strategies to mitigate these impacts.


IV.

FINDINGS AND RECOMMENDATIONS

The team has organized its findings and recommendations according to the trip objectives as outlined above. At this time, it is difficult to provide detailed instructions on how to move forward with afforestation activities on specific species. This is because there is currently a dearth of scientific data about the on-going afforestation activities in Egypt’s man-made forests. That being said, as this promising work in the man-made forests continues, rigorous experimentation and record keeping will help articulate the best management practices for continuing afforestation with treated wastewater. Where possible, the team provides guidance on performing such trials and experiments. Additionally, certain poplar species may be promising for afforestation in Egypt if lower water use clones can be identified; and the team members have many years of experience and expertise in poplar cultivation. Where appropriate, poplar has been singled out as a sub-set of the team’s general recommendations under each numbered heading and pros and cons of poplar cultivation are discussed.

1.

Identifying tree species suitable for afforestation according to local soil characteristics, water quality, and quantity of water supply

Answers to three basic questions determine the choice of species for a plantation project (Evans 1992): (1) What is the purpose of the plantation? (2) Which species are available? (3) What will grow on the sites that are available? Answers to these questions have not been finalized for the IWRM II project in Egypt using treated waste water (TWW) to grow tree plantations on unused “desert” land. The following attempts to provide some basic information to enable project staff and decision makers to better answer these questions. a) Purpose The main purpose of the IWRM II project is to responsibly dispose of TWW and hopefully produce something of economic value in the process. Because of limitations in the Egyptian Code 205 for use of Class 1 and 2 TWW, non-edible tree crops have been identified, along with two oil-producing shrub species (jatropha and jojoba) as acceptable crops. Thus, economic use of the TWW plantations could be for industrial wood products (pulpwood, sawtimber, panel products), ungraded wood for local construction or craft use, charcoal, firewood, or bioenergy. Given this wide range of potential uses, many species are available and some species could meet all or many of these uses provided an appropriate silvicultural management scheme is adopted. b) Potential markets Egypt meets almost all its wood needs through imports. In 2005, total lumber imports (softwood and hardwood) were estimated at about 3.7 million cubic meters (m3) mostly in the form of kiln-dried lumber (Giles and Ibrahim 2006). Russia and Sweden are the main softwood suppliers, mostly of spruce and fir. In 2005, Russia controlled 68 percent US Forest Service Trip Report May 3-7, 2009 -8-

of the Egyptian softwood market, while Scandinavia, Baltic countries and Canada controlled the balance. Romania, Croatia and Bosnia are the main suppliers of hardwoods to Egypt. In 2005, Romania was the major supplier of beechwood, capturing 70 percent of total Egyptian imports. Tropical hardwood lumber consumption has been stable in the last several years, with a few small shipments being imported from West Africa mostly for the manufacture of luxury furniture. Mahogany is the most preferred tropical wood, but teak (Tectona grandis), samba (Triplochiton schleroxylon from Africa) and sapelli (Entandrophragma cylindricum from Africa) are also imported. Tropical hardwood veneer consumption is also stable due to increased substitution with artificial veneers. In 2005, Egypt’s total veneer imports were estimated at 12,000 m3 with 60 percent (5,000 m3) imported from the United States (mostly red oak). Some veneer importers were said to be considering importing logs from Turkey for veneer production. Softwoods, including some plywood, are used extensively for scaffolding, forming and joinery. Approximately 70 percent of softwood imports are consumed by the construction industry. The remainder is used in making doors, windows and other items, including low quality furniture (Figure 1)

Spruce

17 30 15

20

Other

Joinery

18

Structural Construction Non-Structural Furniture

Fir

12 6

35

8

14 25

Other

Joinery

Furniture

Packaging

Scaffolding

Concrete forming

Figure 1. Percentage of imported spruce and fire used in various construction and manufacturing sectors in 2005 (Source: Giles and Ibrahim 2006). US Forest Service Trip Report May 3-7, 2009 -9-

In 2005, imports were expected to increase for construction wood for new tourist villages and hotels along the coasts of the Mediterranean and the Red Sea. There has also been new residential development adjacent to Cairo and Alexandria. In addition to local consumption, Egypt has developed export markets for its furniture, mostly to Arab countries and to Europe (the following from Furniture Today, accessed June 1). About 25% of the country's $2 billion in furniture production is exported. Many companies anticipate breaking into the North American market and feel they can compete with Chinese manufacturers on design and price. Egypt’s furniture sector is estimated to employ more than 1 million workers. The industry includes 200,000 firms, with work forces that range from five to 800. Long known for intricate marquetry, carvings, inlays and ormolu work, Egyptian furniture makers are now applying those skills in a more delicate manner, enabling their furniture to be compatible with today's modern and classic settings. Until now, most production for export has been furniture of classic Middle-Eastern and French-inspired designs. This is changing as many Egyptian companies are working with designers from Europe to create product that will be more appealing to the U.S. market. Charcoal and firewood uses would be low-value and serve only local markets. Information is not available on the potential for local consumption but we assume that local markets will establish for all thinnings and any wastewood, once reliable sources are established. Bioenergy development has been cited as a reason for establishing large-scale plantations of jatropha (Jatropha curcas) and there has been interest in this species in Egypt for some time (Reyadh 1997). Industrial plantations of jojoba (Simmondsia chinensis) have been established in the Negev desert of Israel (Benzioni 2006) after extensive research starting in 1978. Jojoba currently is the only profitable industrial crop under Israeli agriculture, planted on about 1,000 ha (Benzioni 2006). The Israeli experience is illustrative: “...it was thought that minimal water supplies and limited agronomic knowledge would suffice. It proved to be a very problematic crop and only through intensive research, the dedication of growers, and intensive cooperation between these two groups” made it successful (Benzioni 2006, p. 54). Table 1. Important factors in species choice for industrial end-uses (Adapted from Evans 1992)

Growth and silviculture

Fuelwood

Wood pulp

Sawn timber

Plywood/veneer

Fast growth with early culmination of maximum growth rate. Large size and form not important; set by harvesting

As for fuelwood, but straight stems important for rapid de-barking (which is critical for chip quality)

Moderate to fast growth, ability to grow to large sizes. Good form important, ease of pruning and freedom from butt

As for sawtimber, but growth to very large size may be important. Good natural pruning with rapid wound occlusion desirable

US Forest Service Trip Report May 3-7, 2009 - 10 -

Wood properties

Examples of species chosen for large-scale plantations

economics. Coppicing ability desirable Quick drying, low ash content. Moderate to high density

Casurina Eucalyptus Gmelina arborea Populus

rots desirable

Fiber length, color, extractives content, density, papermaking quality

Pinus patula Pinus caribaea Gmelina arborea Eucalyptus Populus

Strength, dimensional stability, wood uniformity. Good seasoning, working and finishing properties. Acceptance in the marketplace. Pinus patula Pinus caribaea Cupressus lusitanica Tectona grandis Cordis alliodora Eucaplyptus Populus

Peeling or slicing quality. Figure. Knot-free. Good adhesive bonding for plywood.

Swietenia macrophylla Araucaria cunninghamii Populus Eucalyptus

c) Favorable traits Many traits are important when choosing species for various industrial end-uses (Table 1). The following characteristics of what constitutes a desirable species for the IWRM II project are strictly the ideas of the study team. The most important characteristics would be that a species is able to be grown under Egyptian conditions, including tolerance of TWW irrigation; and at maturity, the species provides an economically desirable product. The following list of additional characteristics should be considered in species selection. The first four characteristics are essential, the second four are desirable. 1) Fast-growth, although this is relative to the quality of the wood or other products produced. Generally, fast growth is suitable for pulpwood and materials for panel products but not with sawn wood products because of the often lower density of fast grown wood. Some species (e.g., Populus and Eucalyptus) that traditionally have been fast grown in plantations are now being managed for sawn wood by lengthening rotations, aggressive thinning, and early pruning. 2) Tolerate sandy soils of high reactivity (pH and/or salinity). 3) Tolerate high temperatures/insolation. 4) Ease of propagation, including a reliable seed supply if seedlings are used. This is to insure a supply of material for planting. 5) High transpiration rates could be a positive factor for the IWRM II project, as it would mean more TWW could be applied per unit area of plantation without risking contamination of groundwater. However, allowable application rates on the sandy soils used for these plantations are not large enough to accommodate the very large transpiration rates of some species or clones (e.g., Populus) without US Forest Service Trip Report May 3-7, 2009 - 11 -

complex, automated drip irrigation systems that require continuous pumping plant availability and high maintenance. Thus, species or clones with lower transpiration rates may prove to be more suitable given the irrigation technology available and given that land availability is not problematic. 6) Evergreeness is a plus but not essential; this allows the plantation to utilize TWW year-round. 7) Some drought tolerance or adaptation in order to reduce the risk of failure if water supply is disrupted. 8) Avoid nitrogen-fixing and shallow-rooted species. The TWW should supply enough nitrogen for optimal growth and adding N would increase the risk of groundwater contamination. Shallow-rooting would increase the risk of windthrow and reduce the contact time with TWW, increasing the risk of deep percolation losses and groundwater contamination.

d) Species trials/performance The demonstration projects visited by the study team have shown that some tree crops can be grown under the prevailing site conditions in Egypt using TWW. The water requirements of the species in trials have not been established and because of the seemingly arbitrary irrigation regimes, we have to conclude that experience to date has not established which species can or cannot be grown, or even the most promising. This situation is confounded because of uncertainty about the origin of the plant material. Our conclusion is also based on observations that irrigation regimes have not been adequate. For example, plants at Luxor were irrigated every other day in the nursery and every third day in plantations, without a basis for frequency or volume of irrigation. At Ismailia, we are not certain of the irrigation regime but we were told that Populus was irrigated only until established; these trees subsequently died (Figure 4). Likewise, Populus trees and those of other species were severely drought-stressed at Groppi Nursery. At none of the sites was TWW applied in relation to actual crop requirements, or were data provided on how much water had actually been applied. In all cases, it seemed there was more than enough TWW available for the intended plantation development. Improved understanding of water requirements, monitoring of actual amounts of TWW applied, and appropriate silvicultural regimes for each species are critical needs if the pilot projects are to be scaled up to commercial production. From the literature and the experience to date from earlier projects in Egypt, we offer several species as candidates (Table 2). The species are characterized according to suitability and growth potential. For species rated “Fast Growth” the expected rotation length is 15 years or less. Suitability is evaluated in terms of adaptation to Egyptian conditions, including average maximum temperature of the warmest month (in its native range), evergreeness, economic uses, and ease of propagation. Adaptations to drought and high pH or saline soil are noted. Growth potential is in terms of reported volume growth (m3 ha-1 yr-1) and height (m), as well as form (poor, acceptable, exceptional). A column for notes provides important other considerations for some species. The column for “local experience” notes whether there is local experience in Egypt with this species. US Forest Service Trip Report May 3-7, 2009 - 12 -

In some cases, a question mark (?) means that we were uncertain as to the actual species we observed or that we were told there were plantings but we did not observe them in the locations we visited. e) Sites available Three allocations of land were mentioned that appear to be additive: 160,000 feddans from the Ministry of Housing and Urban Affairs to their Holding Company for tree crops using treated wastewater (IWRM II); 240,000 feddans dedicated for jatropha (the team is unsure which government Ministry would be responsible for this land); and 250,000 feddans to the Horticulture Institute for woody crops (which we presume is for ornamentals and fruit and nut trees). The land allocated to the Holding Company is located on the desert fringes, possibly mostly in Upper Egypt (Annex II). This land is near to the sources of the TWW, with no parcel more than 3 km from a source facility. Soils are sandy, loamy sand and coarse sandy with some sandy loams and a few small areas of finer textures; organic matter content is less than 1% (e.g., IRG, 2005a). Soils in Egypt are generally from slightly to moderately alkaline, with pH values from 7 to over 8. Outside of the Nile valley and the Delta where alluvial soils predominate, soils of the desert fringes have developed from Eocene or Miocene limestone or from Nubian sandstone. Soils developing from limestone will have higher pH than soils developed from sandstone, and may have free calcium carbonate (CaCO3). The pH of the surface soil at the Luxor demonstration site was alkaline to strongly alkaline, 8.0 to 8.45. It is possible that other sites will have soils with somewhat lower pH. Soil reaction is important to species selection and will be discussed further.


Table 2: Candidate tree species with potential for successful afforestation under the hot and dry conditions in Egypt using treated wastewater Species Local Fast- Temp EG Uses Saline Growth Dry Propagation Form Native exp. grow max High adap. o pH C Vol. Ht m3ha-1yr-1 m Azadirachta indica ? Y 38 Y SRFO Y Short viability 5-18 20-25 A SE Asia (Neem) Casurina ? Y 35 Y SRFO Y Stores 1+ 5-18 10-40 A/E Asia, equisetifolia (?) years AUS Cunninghamia ? Y 27 Y SRF Stores 1 yr 36 20-50 E/A China lanceolata (?) Cuppressus ? Y 32 Y SRF Stores 2+ yrs 15-40 25-30 A Mexico lusitanica Eucalyptus Y Y 34 Y SRO Y Stores 2+ yrs 10-21 30-40 E AUS citriodora E. camaldulensis Y Y 36 Y SR Y Y Stores 2+ yrs 15-25 20-40 A AUS

E. grandis

N

Y

35

Y

SRV

Gmelina arborea P. caribbea hondurensis P. caribbea bahamensis P. eliottii

N N

Y Y

35 34

N Y

SRF SRF

N

Y

32

Y

SRF

N

Y

32

Y

SRF

P. merkusii Populus hybrid Taxodium distichum Terminalia brassii

N ? Y

Y Y Y

32 32 30

Y N N

SF SRV SRF

?

Y

34

Y

SRV

Y

Y?

Stores 2+ years Short viability Stores 2+ yrs

24-70

40-55

E

AUS

18-32 10-40

20-30 35-45

P/A A

SE Asia CAMER

Stores 2+ yrs

10-28

15-20

E

Stores 2+ yrs

10-20

20-30

E

Bahama Islands US

Short viability cuttings Short viability

8-18 20-40 4-8

30-40 25-30 30-40

A E A

US, EUR US

Short viability

25-35

30-35

E

Pacific


Notes

N-fixer. Shortlived Coppices Shade tolerant

Provenance variation; northern best

Short-lived Provenance variability

S. Florida provenances are denser deltoides × nigra? Long-lived

Species

Local exp.

Fastgrow N

Temp max o C 30

Araucaria cunninghamii Araucaria hunsteinii Khaya ivorensis Chlorophora excelsa Cordia alliodora Dalbergia sissoo

N

Y

SR

N

N

32

Y

SR

Y N

N N

40 33

N N

SRV SV

N Y

N N

32 45

N N

SRFV SRFV

Tectona grandis

N

N

32

N

SRV

EG

Uses

Saline High pH

Dry adap.

Form

Native

Short viability

Growth Vol, m3ha-1yr-1 10-18

Ht, m 40-70

E

Short viability

20-30

40-80

E

AUS, PNG PNG

3 mos Short viability

5-8

15-40 35-40

A E

AFR AFR

Y

Short viability Stores 1-2 yrs

10-20 5-8

25-30 30

A A

SAMER India

N

Stores 2+ yrs

6-18

30-40

E

India, SE Asia

Y

Y

Propagation

Notes

Wide-spacing Mixed planting best

Bamboo spp. Y Y V (Phyllostachys spp.?) Jatropha curcas Y Y Y O Simmondsia ? Y 45 Y O Y Y Stores 1-2 yrs chinensis (Jojoba) Abbreviations and Notes Fast growth: yes = rotation length less than 15 yrs Temp Max: mean maximum temperature of the hottest month in its native range, an indication of adaptation to Egyptian conditions EG= evergreen character Uses: S= sawnwood; R=roundwood (pulp and panel products); F=firewood, also bioenergy; O=oils; V=veneer Growth: averages at maturity; vol=volume in m3ha-1yr-1; ht= height in meters (these should be used to compare among species, not necessarily as yield predictions) Form: E= exceptional; A= acceptable; P=poor Native: Area where the species is native; AUS=Australia; CAMER= Central America; EUR=Europe; US=USA; PNG=Papua-New Guinea; AFR=Africa, generally western


Climate is hot and dry. The mean maximum temperature for the hottest month ranges from 35.7 oC (96.3 oF) in July at Ismailia (Lower Egypt) in the north; 41.4 oC (106.5 oF) in June at Luxor (Upper Egypt); and 41.0 oC at Aswan (June and July, 105.8 oF) in the extreme south of Egypt. Relative humidity (RH) is often increased by air masses moving in from the Mediterranean and Red seas. This is most pronounced at Ismailia, where RH in June and July averages 50%. This effect is seen less at Luxor (RH in June and July averages 30%). At Aswan, RH in June and July is 20%. In coastal areas of southern Sinai (Egypt in Asia), mean maximum temperature at Ras Nsrany near Sharm El Sheikh is 37.5 o C in July and 37.4 oC in August. RH in July and August is 35 and 36%. (Data from http://www.climate-charts.com/) f) Poplar Populus species and hybrids (hereafter referred to as poplars) may be appropriate for afforestation in Egypt (Figure 2). Poplars grow best on well-drained soils where root penetration to a depth of 1 m is not interrupted. Soil fertility is important, and augmentation with traditional fertilizers or wastewaters with requisite levels of nitrogen and other nutrients is necessary on relatively infertile sites. Optimum pH is 5.0 to 7.5 but some hybrids have been identified that do well on higher pH soils (Lombard et al. 2005). In addition, there is a tremendous amount of genetic variation within the genus Populus (Rajora and Zsuffa 1990, Eckenwalder 1996), which makes these trees ideal for wastewater afforestation systems. From a tree improvement standpoint, this variation promotes incorporation of traits that are necessary for energy, fiber, and other end uses into strategic (selection of parental species) or operational (selection with specific genomic groups) breeding plans (Zalesny et al. 2005). Although selection of specific clones within genomic groups has typically been more effective than selection at the strategic level (Zalesny et al. 2007), both intra- and interspecific selection increases the potential of identifying genotypes that are favorable for afforestation using wastewaters as fertilization and irrigation (i.e., fertigation) sources. The drawback of having extensive variability is that field deployment of unfavorable genotypes may result in inadequate plantation Figure 2. Dr. John Stanturf (U.S. Forest Service) standing productivity or complete failure, inadvertent next to poplar hybrids at Groppi Nursery, Cairo, Egypt. leaching of wastewater into ground water (Photo taken by Ron Zalesny)


aquifers, and/or a lack of a quality product at the end of the rotation. Although it is common in poplar wastewater projects to utilize a limited number of readily-available clones, it is possible to increase system success with early genotypic screening and selection trials prior to deployment in field-based production systems. Such testing is referred to as “phyto-recurrent selection” and involves the evaluation, identification, and selection of favorable clones using multiple testing cycles (Zalesny and Bauer 2007, Zalesny et al. 2007) (Figure 3). Developed specifically for phytoremediation projects, phyto-recurrent selection is directly applicable to wastewater afforestation efforts in Egypt. Information about each clone increases with subsequent cycles, while the number of clones tested decreases. Successful establishment is the first biological requirement for long-term ecological sustainability. Thus, genotypes that are successful in greenhouse, growth chamber, and/or nursery cycles are more likely than those that are erratic to produce adequate biomass for end products; such clones are also effective biological filters for uptake, storage, utilization, or volatilization of potential wastewater contaminants (Hasselgren 1998, Erdman and Christenson 2000, Moffat et al. 2001).

Phyto-Recurrent Selection in Phytoremediation Primary Objectives Choose clones for field deployment that have: 1. Improved phytoremediation potential over original set of clones 2. Adequate genetic variation to guard against insect/disease outbreaks, changes in soil conditions (e.g. flood/drought), & unfavorable genotype × environment interactions

Select Initial Clones for Testing

Continue next cycle with favorables

Discard Undesirables

1. Evaluate Clones when Irrigated with Leachate

2. Select Favorable Clones Based on Phenotypic, Physiological, and Anatomical Traits

Figure 3. Phyto-recurrent selection; adapted from Zalesny and Bauer (2007).


Given the short timeframe in which afforestation efforts are needed in Egypt, as well as the limited amount of resources for detailed testing strategies, we propose a modification to the program described above. We recommend multiple selection cycles within a short time period that can be conducted with limited resources. Rather than conducting initial phyto-recurrent selection cycles ex situ, initial genotypes should be selected based on current growth and favorable productivity in similar climates, stomatal control and other necessary physiological parameters, and that represent a broad range of parental species and clones. Trees should be planted at available field sites in cycle 1. Two European contacts that produce commercial poplar genotypes have been identified and are listed in Table 3, along with genomic groups and clones that are available from each of them. Depending on the amount of material requested, additional genomic groups are available from North America and are listed in Table 4. After two years of field establishment (cycle 2), sites should be inventoried, tree height, diameter, or equivalent surrogate for tree health recorded, and final genotypes selected. The elimination of unsuccessful genotypes at the earliest selection cycle is imperative to the final goal of field deployment of well-suited clones (Zalesny et al. 2007). Thus, those genotypes that are not suitable for wastewater afforestation efforts in Egypt should be thinned out of the plantings, followed by replanting with the favorable clones during year 4 or 5, with cycle 3 lasting until final harvest. Unsuitable genotypes can be replaced at any time during development, and additional cycles can be added, if resources are available. Field testing should include split-plot treatments of four irrigation rates in order to identify clones that use less water. Reasonable irrigation rates for this determination are 50%, 75%, 100% and 125% of the reference evapotranspiration (ET) rate calculated from weather data using the ASCE Penman-Monteith reference ET method (Allen et al., 2005). Production functions (measured yield versus water use) established in this way will allow identification of clones that grow well with less water, which could somewhat ease the requirements for drip irrigation investment and management discussed in Section 3 of this report.


Table 3. Available commercial poplar genotypes from Germany and Italy.

Genomic group

Clone

Contact

P. nigra × P. maximowiczii

Max 1 Max 3 Max 4

P. maximowiczii × P. trichocarpa

Hybrid 275 Androscoggin

P. deltoides × P. trichocarpa

Beaupré

P. trichocarpa

Muhle Larsen

Jan Lüdemann Gust. Lüdemann Baumschulen KG Dorfplatz 1 29568 Wieren-Bollensen, Germany Phone: 0 58 25 81 15 Fax: 0 58 25 82 14 Email: [email protected] Web: www.gustav-luedemann.de

Genomic group

Clone

Contact

P. ×canadensis

A4A

(P. ×generosa) × (P. nigra × P. nigra)

AF3

P. ×canadensis

AF4

P. ×generosa × (P. ×canadensis)

AF7

(P. ×generosa) × P. trichocarpa

AF8

Fabrizio Nardin Alasia Franco Vivai strada Solerette 5/A 12038 Savigliano (CN), Italy Phone: 39 3356907316 Email: [email protected] Web: www.alasiafranco.it

(P. ×generosa) × P. nigra

AF9

*P. ×canadensis = P. deltoides × P. nigra *P. ×generosa = P. deltoides × P. trichocarpa

Table 4. Potential North American poplar genomic groups.

Genomic group

Contact(s)

P. deltoides P. nigra P. maximowiczii P. trichocarpa P. deltoides ×P. deltoides P. trichocarpa ×P. deltoides P. ×canadensis P. ×generosa P. nigra × P. maximowiczii P. deltoides × P. maximowiczii P. alba × P. grandidentata P. maximowiczii × P. trichocarpa P. balsamifer × P. deltoides

Ronald S. Zalesny Jr. U.S. Forest Service, Northern Research Station 5985 Highway K Rhinelander, WI 54501, USA Phone: +1 715 362 1132 Fax: +1 715 362 1166 Email: [email protected] Web: www.nrs.fs.fed.us/people/Zalesny John A. Stanturf U.S. Forest Service, Southern Research Station 320 Green Street Athens, GA 30602, USA Phone: +1 706 559 4316 Fax: +1 706 559 4317 Email: [email protected] Web: www.srs.fs.fed.us/disturbance


The ultimate goal is to select about four clones that can be grown across Egypt to provide economic, ecological, and social benefits to local communities. However, the total number of clones for production depends largely on the relatedness of the selected genotypes (Zalesny et al. 2007). It is important to maintain diversity among clones to guard against insect/disease outbreaks, changes in soil conditions, and wastewater chemistries. Additional testing throughout plantation development should be conducted in order to assess genotype × environment interactions across Egypt. Such testing is important for selection of generalist genotypes that perform well across the country and with many wastewaters or specialist genotypes that perform well in designated production zones with specific wastewaters (Zalesny et al. 2007). Understanding clonal stability across variable sites and waste water chemistries will inform management decisions and help to enhance long-term success of future wastewater afforestation projects in Egypt.

2.

Understanding the pros and cons of using different tree and/or crop species

We recommend a strategy for species selection that first establishes species/provenance trials with 5-10 individual candidates at each major location, stratified by climatic region (high, low, medium relative humidity in the hottest months). To select individuals for the trials, we recommend favoring species for which there is much knowledge internationally, as well as some species with high potential market value. Candidate species should be selected from Pinus, Populus, and Eucalyptus species/provenances; and Khaya ivorensis, Tectona grandis, and possibly Gmelina arborea. There is much local support in Egypt for growing Jatropha curcas in TWW plantations. Because there are plans to dedicate 240,000 feddans to Jatropha in addition to the IWRM II plantations, it seems to the team that it would be prudent to concentrate on other species in this report. Recommended species have been grouped into three classes: versatile species that can be managed for pulpwood or sawnwood (Pinus, Eucalyptus and Populus spp.); high value species (Khaya ivorensis and Tectona grandis); and pulpwood (Gmelina arborea). Eucalyptus and Populus traditionally have been regarded as fast growth species, managed mostly for pulpwood in plantations. Recent interest has turned from pulpwood to solid wood products (Stanton et al. 2002; Flynn 2008). Existing plantations that were established to grow pulpwood are converted to longer rotations and pruned for clearwood to enhance value as sawn wood. Presumably these sawlog plantations will still be established at the same density in order to fully and quickly capture site resources and achieve crown closure to shade-out competing vegetation but aggressive early thinning and pruning will be needed. A growth and yield model developed in Uruguay (Flynn 2008) showed that silvicultural regimes that combined pulpwood and sawlog production did not yield returns as high as management for Eucalyptus sawlogs alone.


a) Pinus Systems such as these have been instituted for Pinus species, including P. taeda and P. elliottii in the Southern US and P. radiata in Australia and New Zealand. In the US, pruning has not been shown to be economical (Alexander Clark, Research Wood Technologist (Retired), US Forest Service, Athens, GA, personal communication, 2008). The Pinus species in Table 2 include two that are tolerant of high pH soils, P. caribbea var. bahamensis and P. elliottii var. densa but it may be that the hondurensis and elliottii varieties will do as well and should certainly be preferred for sites with lower pH (below 7.5). Certainly it will be easier to procure seed from commercial sources for the hondurensis and elliottii varieties. b) Eucalyptus Eucalyptus trees are planted widely around the world, on small-holder plots as well as industrial plantations. With over 500 species to choose from, and several distinct provenances in most, there are many possible choices. Nevertheless, only a relatively few species are grown in industrial plantations although some of these have been hybridized. The list in Table 2 includes only two species of Eucalyptus, E. camaldulensis and E. citriodora, both of which we observed growing in Egypt. Of the two, E. camaldulensis has demonstrated some tolerance of higher pH soils and some salinity tolerance. A species not on the list but one that should be considered for lower pH sites is E. grandis or the hybrids of E. grandis with other species. One side-by-side comparison in India (Hunter 2001) grew E. grandis, E. camaldulensis and Dalbergia sissoo on a lateritic soil with irrigation and fertilizer and the yields after 3 years were illustrative. The dry weight of the two Eucalypts averaged 45.3 Mg ha-1 and Dalbergia averaged only 7.6 Mg ha-1. The stem volume growth rate of the two Eucalypts was 20 m3 ha-1 yr-1. Work in Australia confirms that E. camaldulensis and E. grandis can be grown using wastewater (Stewart and Flinn 1984) although there was some indication of iron (Fe) deficiency on calcareous soils. Irrigation requirement was 1550 mm yr-1 using border/strip flooding. In southern Brazil, Bernardo and others (1998) report similar yields as Hunter (2001) although E. urophylla outgrew E. camaldulensis after 41 months. Also in Brazil, Almeida and others (2007) grew an E. grandis hybrid for pulpwood and reported peak growth of 95 m3 ha-1 yr-1 on a 6 to 7 year rotation. Water use was 1092 mm yr-1. c) Poplar Wastewaters with highly varying inorganic and organic contaminants have been successfully used as fertigation sources for poplar and other short rotation woody crops throughout the world (Shrive et al. 1994, Mirck et al. 2005). Poplars are ideal for these systems because of their fast growth and biomass accumulation, quick establishment and extensive root systems, ease of asexual propagation, elevated rates of transpiration, and exceptional growth on marginal lands (Isebrands and Karnosky 2001). Poplar productivity worldwide typically ranges from 10 to 20 Mg ha-1 yr-1, with values exceeding 20 Mg ha-1 yr-1 being more common in recent years due to growing improved genetic stock at favorable sites. Poplar root systems are dominated by a combination of US Forest Service Trip Report May 3-7, 2009 - 21 -

lateral roots with extensive fine root surface area crucial for water and nutrient uptake and deep sinker roots for anchorage and penetration to zones of saturation (i.e., groundwater) (Negri et al. 2003, Zalesny and Zalesny 2009). In contrast to many tree species that must be propagated via seeds or tissues culture methods, poplars are propagated vegetatively (Stanturf et al. 2001), which is more efficient and cost effective than most alternative techniques. Vegetative propagation also ensures a continuous supply of planting stock once favorable genotypes are identified. Poplars utilize a substantial amount of water, which is beneficial for afforestation systems in need of recycling wastewater (Zalesny et al. 2006), assuming allowable irrigation application rates are suitable for evapotranspiration demands of the plantations (see Section 1.c above and Section 3 below). All of these traits are favorable for wastewater afforestation projects because of the need for quick plot establishment, hydraulic control, and filtering capabilities to reduce subsurface contaminant movement (Ferro et al. 2001); but in sandy soils, required application rates may exceed the water holding capacity of the soil in the root zone, leading to the possibility of deep percolation losses and ground water contamination.


Ismailia, Egypt

Pacific Northwest, USA

Midwest, USA

Figure 4. Seven-year-old poplar growing at three locations: one with inadequate irrigation, severe tree stress, and atypical tree form (Ismailia), two with adequate irrigation (Pacific Northwest) and precipitation (Midwest).

From an energy perspective, the energy per biomass unit of poplar ranges from 1.9 × 1010 to 2.0 × 1010 J Mg-1, which is relatively favorable. The energy returned on energy invested (EROEI) for poplar is also favorable at about 12, which means there are 12 units of energy gained for every one unit of energy used during the conversion of poplar wood to transportation fuels. Overall, using poplars in wastewater afforestation projects in Egypt should provide improved environmental quality and secondary benefits such as carbon sequestration, a harvestable product, aesthetic improvements, improved landscape processes, and erosion control (Isebrands and Karnosky 2001). There are potential limitations to the successful use of poplar for wastewater afforestation projects in Egypt. First, the need for intensive management at sites where weed control may be an issue could result in high costs during stand establishment and management. Loss of funding for such efforts could be very detrimental, especially before crown closure. Second, while elevated water usage is an advantage of poplars for such wastewater projects, it can also be an important disadvantage during times when wastewater is not available. Given the broad amount of genetic variation, some clones can withstand periods of drought while others cannot. For example, Figure 4 shows the US Forest Service Trip Report May 3-7, 2009 - 23 -

health and condition of seven-year-old poplar trees growing in the Serabium Man-made Forest at Ismailia, Egypt following inadequate wastewater irrigation relative to sevenyear-old poplar hybrids growing in the Pacific Northwest and Midwest United States with adequate water from irrigation and precipitation, respectively. Third, as mentioned above, genotype × environment interactions are very important for poplars, with failure to match clones to sites of deployment often resulting in reduced growth or plantation failure. Fourth, as with other species proposed in this report, a disadvantage of poplars is the potential lack of processing facilities and associated markets for the wood. d) Khaya (Mahogany) The biggest drawback to growing Khaya ivorensis in plantations in its native range in Africa has been attack by a shoot borer, Hypsipyla robusta (Ofori et al. 2007). Damage extends from mortality of young seedlings to forking of mature stems at 5 m. Newton and others (1994) suggested the solution would be a combination of resistant populations with an appropriate silvicultural system of mixed species. Mixing the Khaya with another species apparently lowers the detection of Khaya by the borer. Ofori and others (2007) found some progeny to be resistant and it may be possible to develop borer-resistant material by vegetative propagation from superior individuals. Growth in shade also reduces the infestation by the borer but shade also severely reduces growth of the Khaya (Opuni-Fripong et al. 2008). Where Khaya has been planted outside its native range, it seems to be resistant to indigenous borers. The older Khaya we observed in Egypt, however, all seemed to fork between 2 and 3 m, possibly from borer damage (Figure 5).


Figure 5. Khaya ivorensis at Luxor; from local seed source originally from Burkina Faso.

Growth of Khaya (from modeling results from thinned natural forests) is around 31 m2 ha-1 (basal area; Foli et al. 2003). From the modeled crown diameter-bole diameter work of Foli and others (2003) (Table 5), a recommended spacing and silvicultural regime can be developed that appears to be very similar to the system for Tectona grandis used in Costa Rica (Perez and Kanninen 2005). Table 5. Modeled stand characteristics for full site-occupancy of Khaya ivorensis (from Foli et al. 2003)

Bole diameter (cm) 20 25 30 35 40 45 50

Stems ha-1 726 503 370 283 223 181 149

Basal area (m2 ha-1) 23 25 26 27 28 29 29


e) Teak Market demand for Teak (Tectona grandis) has outstripped the capacity of native forests to provide; and plantations have been established far outside its natural range. Costa Rica, for example, has 40,000 ha of teak plantations but these have not reached the expected productivity (Pérez and Kanninen 2005). Recently, Pérez and Kanninen (2005) developed management scenarios for teak plantations using density management approaches and competition indices to develop guidelines for thinning. Their guidelines appear to be applicable to Egypt, although they were not developed for plantations using TWW. They developed guidelines for plantations of 20 and 30 years rotation length, on low-, mediumand high-quality sites. Their results for medium-quality sites would seem to be a conservative estimate for teak plantations using TWW in Egypt. An initial stand density of 1,111 trees ha-1 is assumed. This is a spacing of 3.0 by 3.0 m, which is quite common and reasonable to achieve full site-occupancy quickly. Thinning occurs every 5 years; only the results for 20-yr rotation with the objective of maximum volume are shown here (Table 6). The total volume removed under this scenario would be 364.1 m3 ha-1. Table 6. Stand growth scenario for Tectona grandis on medium site, 20-year rotation, with the objective of maximum volume production (adapted from Pérez and Kanninen 2005).

Age Stems per ha

Thinning DBH intensity (%) (cm)

Total height (m)

5 10 15 20

40 40 33 100

11.5 19.7 25.2 28.7

667 400 300 0

11.5 20.9 27.6 32.1

Basal area remain (m2ha-1) 6.9 13.7 17.9 0

Basal area removed (m2ha-1)

Volume removed (m3ha-1)

4.6 9.1 4.2 24.3

28.4 75.5 35.6 224.6

f) Gmelina Gmelina arborea is among the leading plantation species in the world. Another native of Australia, Gmelina grows well on deep, well-drained and fertile soils but generally develops poor form. Thus, most of the world’s Gmelina is used for pulp or bioenergy. Production rates in Nigeria are typical of Gmelina growth; Onyekwelu and others (2004) report on even-aged plantations 5 to 21 years old where aboveground biomass ranged from 83.2 Mg ha-1 (5 years) to 394.9 Mg ha-1 (21 years). Mean annual biomass increment varied from 16.2 to 20.9 Mg ha-1 yr-1, with an average of 84% of biomass allocated to stems and 13% to branches. Stand densities ranged from 837 to 1275 stems ha-1. In a study in the dry tropical region of western Venezuela, Henri (2001) compared growth of Gmelina, E. grandis, and E. urophylla. Her results are shown in Table 7.


Table 7. Productivity of 60+ plantations of Gmelina, E. grandis, and E. urophylla in western Venezuela (adapted from Henri 2001).

Species

Height (m) Annual Increment (m3ha-1yr-1) 11.8 22.6 Gmelina arborea 14.5 17.0 Eucalyptus grandis 18.6 Eucalyptus urophylla 18.6

Age 4.5 4.5 4.5

g) Other species Three species we observed growing in Egypt are less desirable, in our estimation, than the species described above. Pinus eldarica is adapted to higher pH soils and native to west Asia. As shown by its growth in Egypt, it is of lower productivity than the pines mentioned above. Additionally, it is quite branchy and retains its branches even in dense plantations, producing low quality wood. Casurina species are widely grown in Egypt and are fast growing. Nevertheless, Casurina grown in plantations yields lower quality wood good only for rough construction, although it is used in the Egyptian furniture industry. Casurina is a nitrogen fixing species, which makes it less attractive for using in treated wastewater plantations. Dalbergia sissoo was observed in some of the Man-Made Forests where it grew in typical poor form, with many stems from a central root system that required multiple, early pruning to develop into a tree-form. Although older, straightstemmed Dalbergia have been observed, the necessity and cost of pruning such a slow growth species made it less desirable than other high value species.

3.

Providing recommendations for irrigation based on recommended tree species and local conditions

The use of treated wastewater for tree plantations is expected to take place in the desert areas outside of the Nile River delta and floodplain. Thus, the soil textures are predominantly sandy, loamy sand and coarse sandy with some sandy loams and a few small areas of finer textures; and organic matter content is less than 1% (e.g., IRG, 2005a). Depending on location, rock fragments may be common to rare, but do not present important challenges. Sandy soils with little organic matter are difficult to irrigate uniformly and without deep percolation losses due to their larger hydraulic conductivity and smaller water holding capacity. Providing the plants with the amount of water they need, when they need it will be essential for maximizing productivity. Some indications of plant needs are given here; but there is little hard data on most of these species under conditions of wastewater irrigation. As plants grow larger and develop more leaves, they will require more water until they reach a plateau with full canopy development and maximum insolation. Windy conditions will increase water needs as turbulence above the canopy increases transpiration potential, as will smaller relative humidities such as in Upper Egypt. Because these sandy soils have little water holding capacity (due to their coarse texture and lack of appreciable organic matter) frequent watering will give best US Forest Service Trip Report May 3-7, 2009 - 27 -

results. Evapotranspiration rates will vary widely from upper to lower Egypt, from west of the Nile to near the Suez Canal (larger relative humidities), seasonally and by species. For example ET may be as low as the 6 mm d-1 observed by Tanaka et al. (2008) for natural teak forests in Thailand during the dry season. And ET may be as large as 15 mm d-1 for hybrid poplar (see data below). a) Irrigation application systems The large hydraulic conductivity means that irrigation by surface flooding in basins or furrows will lead to deep percolation losses of water near the inlet to a tree plot if enough water is applied to adequately irrigate the plot areas furthest from the inlet. We observed two responses to this problem in the plantations that we visited: 1) adoption of a “modified” surface irrigation system, and 2) adoption of drip irrigation. The “modified” surface irrigated system consists of keeping tree plot sizes small and conveying water to plot inlets using piping, which prevents conveyance losses between the reservoir and plot. We saw various plot sizes, the larger of which were too large for efficient water distribution. Plot leveling was generally adequate to provide for reasonably uniform depth of standing water at full flooding, though this will not eliminate the deep percolation problem nearer to the inlet. The drip irrigation systems routinely used 18-mm diameter polyethylene tubing of Egyptian manufacture for lateral lines and polyethylene spaghetti tubing of 4-mm diameter for emitters at each tree, one per tree. Compared with even the modified surface irrigation systems, the drip systems are much more water efficient and likely to provide more uniform distribution of water. The fact that spaghetti tubing is used, rather than tortuous path emitters or drippers, should eliminate most plugging problems. Plugging was not observed, but is still possible, which means that routine maintenance of the drip systems will be required. However, the spaghetti tubing has a large flow rate compared to drip emitters and requires a larger pump flow rate and larger lateral line diameter to provide for uniform distribution than would be the case with lower flow rate drip emitters. The irrigation application efficiency of the drip systems we saw was probably on the order of 75%, much smaller than can be obtained with pressure compensated drip emitters. The maintenance required will be both for inspection and cleaning/flushing of the filtering system at the drip system head works, and inspection of spaghetti tubing placement and flow during irrigation. In the older plantations, we observed missing spaghetti tubing and spaghetti tubing that terminated in the interrow between trees, rather than at the base of the tree; both are signs of lack of maintenance. Biofilm formation was observed in furrows and in wells around drip-irrigated trees. This is due to the large amount of organic matter in the treated wastewater. Biofilms can have the effect of reducing infiltration rates; but this effect is not predictable or controllable. The drip irrigation systems that we observed were all adequately filtered with two-stage systems and back flushing. We also saw flush-out lines at the ends of drip laterals, another essential system component since lateral lines should be flushed at the beginning and end of each season (or twice a year for continuous irrigation). We saw a limited amount of GR drip tape, which has in-line pressure compensated emitters. This type of drip tape is common in Egypt and may be a useful alternative to spaghetti tubing if water quality and US Forest Service Trip Report May 3-7, 2009 - 28 -

filtration are good enough to prevent plugging. If the chosen silvicultural system includes thinning, removal of drip irrigation will be required in the thinned row. Because thinning most likely will be by removing entire rows, this will influence the kind of irrigation system used but does not preclude a drip system. There is typically a large capital cost difference between drip and surface irrigation systems, which make surface irrigation appear to be more economical. However, two factors tend to balance out the relative cost of these systems for irrigation of tree plots in Egypt. One factor is that the modified surface irrigation systems must have large diameter (costly) steel piping to each tree plot inlet and valves at each inlet in order to deliver the large flow rates necessary to quickly flood the plots. This reduces the cost differential considerably. The other factor is the expected improved performance of tree growth under drip irrigation due to the better uniformity of water distribution. However, these factors will be rendered of little consequence if irrigation scheduling does not provide water as needed for good tree growth, and if tree cultural practices are not carried out in a timely fashion so that tree boles are free from knots and unproductive growth. Both of these were problematic in one or more of the plantations we visited. Overland flow (surface) irrigation systems tend to lead to deep percolation in at least some part of the system, usually nearer the inlet into the field, due to the increased opportunity time for infiltration. This can lead to nitrate increase in the ground water, even in finer textured soils (e.g., Eade, 2004). b) Irrigation scheduling There appeared to be little rationale for irrigation scheduling in the plantations that the team visited beyond rules of thumb that irrigation should take place every two to three days in summer and every week in winter. One misapprehension that was repeated at more than one plantation is that irrigation could be reduced after the trees had become established. This is not true unless the desired outcome is to establish a minimal tree cover and small growth rate. If the desired outcome is near-maximal growth rates (high production), then irrigation rate must increase as the trees grow until full ground cover is achieved or full crown extension is achieved, after which irrigation rate may become essentially stable. The team observed several cases where tree growth was severely hampered by under irrigation and at least one case where tree death had occurred due to irrigation system failure. In some plots, tree size was quite variable due to variability of application and under irrigation. Irrigation water demand should not be unduly large since wind speeds are not generally large, relative humidities are often increased by air masses moving in from the Mediterranean and Red seas, and elevations are low (e.g. 88 m above mean sea level at Luxor), resulting in considerable reduction in solar radiation due to atmospheric transmission losses despite clear skies. These mitigating factors combine to produce reference evapotranspiration (ETo) rates as small as ~2 mm d-1 in January to as large as 11 mm d-1 in the June-July period at Luxor according to the Central Laboratory for Agricultural Climate (CLAC) (Figure 6). Note that there is considerable discrepancy US Forest Service Trip Report May 3-7, 2009 - 29 -

ETo (mm)

between the values reported by different sources for ETo at Luxor. One report suggests that mid-summer ETo is 2 mm less than the average of CLAC data while matching CLAC data in winter (IRG, 2005a); another suggests that winter ETo is larger than CLAC values, though matching well in mid summer. Experiments with well-watered crops at Ismailia indicated that peak ETc (crop water use or evapotranspiration) for maize was 10 mm d-1, that ETc for winter wheat was