Forestry possibilities in Ethiopia

By E.H.F. SWAIN, FAO TECHNICAL ASSISTANCE ADVISER IN FORESTRY

AFTER a six month's sojourn in Ethiopia one does not speak with authority on forestry for a land as large as France and Germany combined. One can do little more than present an impressionistic sketch of information absorbed and of deductions tentatively reached, and pay tribute to the two preceding pioneers and reporters of forest explorations in this little known country, namely W.E.M. Logan, Assistant Conservator of Forests for the Gold Coast, whilst on war service in Ethiopia, and Glen Russ of the U.S.A. Technical Mission of 1944-1946.

The general background

Forest conditions are largely shaped by the interaction of men and trees. The elements of the Ethiopian interaction appear to have been as follows.

1. A people, contented and courteous, who have dwelt apart from world influences in highlands of rarefied air surrounded by lowland deserts.

2. The preoccupation of this free and independent people with agricultural and pastoral production, for simple subsistence from red and black soils on which famine and malnutrition are unknown, and which now support about 15,000,000 people.

3. Free selection of land from the outset of colonization, without benefit of surveys or title-deeds; dispossession and changed possession as the outcome of wars; Imperial grants of entailed freehold (gultrist) and of unentailed free-hold (rists); Imperial leaseholds and tenancies.

4. The tradition that useable trees are "royal trees" belonging to Emperor and Government but not yet registered in written laws and still uncertain of application to rist lands.

5. The settlement practice of leaving "royal trees" standing, but of clearing the land around them and burning the trash so that the "royal trees" also succumb.

6. Forest denudation, spreading from the drier north into the moister south, leaving soils stripped of forests, from which the humus has vanished and the surface soils have been washed away.

7. The survival of virgin forests among the hills of the south and south-west, where carnivora, malaria, wars, topography and the general absence of roads have reduced population pressures upon the land, and where the forests are commercially quite inaccessible.

8. The annual clearing by fires on the southern forest fronts, to mark the continuing advance of an agricultural people in pursuit of new farms for old.

9. Traditional satisfaction with local production for local "wayside markets."

10. The relative unimportance, to this indigenous economy, of roads and highways.

11. Historic independence of the world's economy, not significantly affected by the narrow-gauge railway from a political capital across an unproductive desert to a foreign-held port. Trade mainly consists of an exchange of coffee and hides for cotton and paper (which Ethiopia could itself produce), and motor cars and modern goods largely for the governing group and the small foreign population.

12. The dawning of a new era of stationary administration in a permanent capital, superseding a history of shift from center to center in search of fresh stands of trees for fire-wood and building timber for the needs of the Imperial community. This new era was made possible in 1906 by the introduction and planting of Eucalyptus globulus on the Entotto hills, whence the stands of native juniper (often called cedar) had been quickly stripped.

13. A still unfinished unification of Ethiopia pending:

(i) the development of modern roads through difficult country to all parts of Ethiopia;

(ii) the maturing of administrative organization and the perfection of laws and systems in a new center of Government; and the extension of like organization to the provinces.

14. A post-war Ethiopian renaissance, under the personal inspiration of His Imperial Majesty, Haile Selassie, Emperor of Ethiopia, who has been quick to perceive that the pressures of a multiplying world population oblige Ethiopia to make adequate dispositions for the future.

15. Lingering doubts of modern ideas of economics and of the political systems of the outer world.

This, then, is the background to forestry in Ethiopia. In the face of many difficulties, in the teeth of ancient rights and customs, in a multilingual medium which delays any form of action, the Ministry of Agriculture is attempting, with FAO assistance, to shape Ethiopia's first forest policy out of these diverse elements.

Before, however, one can write the recipe for a forest policy, one has first to study the ingredients, Climates, Forests and Economic Routes.

Ethiopia (Map)

Climates of Ethiopia

Ethiopia lies near the Equator, at 3° to 18° Lat. N., resulting in warm temperatures with narrow seasonal differences. The country, however, drops to 100 meters below the level of the Red Sea and then lifts sharply to 2,250 meters, to provide a rugged base for mountain peaks some 4,000 meters above the sea. From these mountains the rainfall then creates the torrents which have dissected the rugged base itself by riverine gulfs 500 to 1,300 meters deep.

On this terrain we find a stratification of seasonally narrow climates, modified by regional variations in rainfall resulting, according to the elevation, in everything from torrid deserts up to winter-frosted peaks on which hailstorms take the place of snow.

In none of this series do temperatures of themselves inhibit the development of forests composed of appropriate species. The limiting factor of a country which helps to fill the Nile with water is drought.

The mean annual rainfalls of Ethiopia range from 25 to 2,500 mm., yet what determines the distribution of vegetation is not the isohyet, but the duration of the annual dry season, which may be measured by simply counting the number of months in the year in which the monthly rainfall average is less than 60 mm. or 2 inches.

Thus, Adamitullo and Shashamana, in the Ethiopian Rift, each registers around 600 mm. mean annual rainfall, but vegetation at Adamitullo has to survive six dry months in the year, whilst that of Shashamana must endure seven or eight.

Gambela and Bure, in the rainy south-west, each record a mean annual rainfall of 1,270 mm., but Gambela has five dry months, and Bure only three. The flora of Bure, if called upon to outlast five dry months instead of three, would be much reduced in composition and yield. Gambela and Bure are in different rainfall regimes as well as in different temperature regimes, and each has its own flora frequency. Throughout the country there are many parallel examples of this and it is in fact the length of the dry season which decides the forest distribution. Unfortunately, there are at present only 10 meteorological stations in Ethiopia and these are the sole source of data on climatic conditions. Knowledge of the vegetation and the altitudes must be drawn upon to fill in the details, as for example by considering the distribution of coffee growing.

Coffee is a plant decreed by nature to be a denizen of lands without frost or drought. Of the three commercial species in the world, C. robusta and C. liberica cannot survive even in the rainiest parts of Ethiopia. C. arabica has the most endurance of the three and special strains have been developed for Ethiopia. These strains are only successful (without irrigation) where the number of dry months does not exceed three, and is more than one. Thus, we have the Ethiopian coffee belt climatically defined as below the frost-line of about 2,240 meters altitude, in a rainfall regime of 2-3 dry months.

The Landolphia rubber liane and the broad-leaved trees of East Africa, (but not of drought-free Central Africa) are within this coffee-rainfall regime. But Juniperus procera is suited instead to higher, colder and drier elevations, where it puts on an inch of diameter growth in ten years. Between these two extremes, or in the shelters of the lesser heights, grows Podocarpus gracillior.

So, despite meagre meteorological data, we can still construct a climatic pattern for Ethiopia-Eritrea, as the basis for consideration of the area's forest problems. This pattern is shown in the accompanying table.

Between coldest and hottest month, the modal range is 57 degrees Centigrade. In the dry lowlands, it widens to 8-10 degrees - except in the south-western desert of Ogaden, where the higher winter temperatures narrow it. It reaches its maximum range on the Eritrean Highlands, where summer drought permits the fullest play of sun heat. Elsewhere, the rule is that rains and cloudiness depress the summer thermometer and leave it to the drier spring to provide the hottest month of the year, as the "Ethiopian Summer."

Whilst seasonal differences of temperature are abnormally small differences of temperature between day and night are abnormally great. Judged by day temperatures only, the wet-cloudy summers are colder than the dry winters, and Ethiopians regard the calendar summer as "winter time." But the night temperatures of the calendar winter are low enough to give that season the mean temperature of the coldest month, both on highlands and lowlands.

Ethiopians do not appreciate adherence to the calendar seasons in preference to their own sense of heat and cold, and it must be accepted that exotic trees appear to incline to the Ethiopian view. These are some of the difficulties of understanding the climatic whys and wherefores of the Equatorial Highlands.

Forest types

If you place your left hand upon the table with the fingers closed and the thumb extended, you have a rough outline of Ethiopia set upon its deserts, and sloping from right to left. The fingers are the northern highlands, the knuckles its peaks, and the interstices the river-cut gulfs. The back of the hand is the southern belt of lowest drought period and of highest productivity. The thumb continues as a bridge to the desert borders of the seaport of Berbera in British Somaliland.

Obviously, the forest climates of Ethiopia are those of this highland hand, with Regime No. 4 of 5 dry months along the fingers and Regime No. 5 of 2-4 dry months on the back. The forests of Regime No. 4 have been reduced to remnants by a thousand years of southward march from Axum. The forests of Regime No. 5 are experiencing the same reduction in the south-east. In the remote and inaccessibile south-west, they linger intact and as yet unused.

Nevertheless, the forests which survive the hand of man in Ethiopia to-day measure approximately 500,000 hectares. That is three times the extent of the high forest of adjoining Kenya, whence exports of manufactured timber of identical East African trees find their way to overseas markets over 600 miles (965 km.) of railway - whilst Ethiopia can export none, for want of access routes.

A number of attempts have been made to classify tropical woody vegetation types. In 1938, T. Burt Davy, mainly on the basis of Indian data, defined six principal types, as follows:

1. High Montane Conifer Forest 
2. Upper Montane Rain Forest 
3. Lower Montane Evergreen Rain Forest 
4. Moist Deciduous Forest 
5. Lowland Evergreen Forest 
6. Semi-Evergreen Forest

In spite of their 1,300 to 6,300 mm. of mean annual rainfall and their general title of "rain forest," the essential limitation of these six tropical woody vegetation types is their annual drought period.

There is definite correspondence between Davy's High Montane Conifer Forest type (Champion's Dry Coniferous Forest of India) and the type of Ethiopian coniferous forest of Regime 4 (c), with its five dry months and its 700-1,300 mm. of mean annual rainfall. The Ethiopian indicator species are Juniperus procera, mixed with Hagenia abyssinica, Olea chrysophylla, Rhus, Ilex, Allophylus, Bersama and Schefflera. The same Juniperus type, with Olea and Widdringtonia, frequents the 2,000-3,000 meters altitudes of Kenya in an equivalent climatic regime. It is found again towards sea-level in the Union of South Africa far to the south, but drought periods and temperatures again indicate the reasons for its occurrence there, with latitude compensating for altitude.

Regimes 4 (a) and 4 (b) of Ethiopia have similar temperatures to those of Davy's Lower Montane Evergreen rainforest, but their diminished rainfalls and doubled drought period exclude his wood vegetation type. Regime 5 (a), however, admits it, but with reduced mean annual rainfall.

CLIMATIC REGIMES IN ETHIOPIA

Area	Altitude (m.)	Mean Temperatures Cold Months °C	Mean Temperatures Hot Months °C	Mean Annual Rainfall (mm.)	Number of Dry Months
1. Regimes of 11 - 12 dry months
(a) Ogaden Desert (S. E. Ethiopia)	300-1000	24-29	29-34	50-125	12
(b) North-western Eritrean Uplands	300-1670	23-28	32-36	50-200	12
(c) Eritrean and Danakil Coastal Deserts	0-1000	21-26	31-36	25-200	11
(d) Awash Desert	1-1000	20-24	29-33	150-250	11
2. Regimes of 8 - 10 dry months
(a) North-west (Sudan) Slopes of Ethiopia	500-1000	23-26	30-33	400-650	8
(b) Low Somali Slopes (S. E. Ethiopia)	1000-1670	19-23	24-28	250-500	8
(c) Eritrean Highlands	1000-1670	18-22	28-33	350-500	9-10
(d) Eritrean Highlands	1670-2240	16-18	21-27	500-750	8-9
(e) Eritrean Highlands	2240-3000	8-16	14-20	450-550	10
3. Regimes of 6 - 7 dry months
(a) West (Sudan) Slopes of Ethiopia	500-1000	23-27	30-34	800-1000	6-7
(b) Rift and the Harar Escarpment	1000-1670	17-22	24-29	500-800	5-7
(c) Low Somali Slopes of S. E. Ethiopia	1000-1670	17-20	24-27	500-600	6-7
(d) North-east Escarpment of Ethiopia	more than 2240	11-13	16-18	1000-1500	6
4. Regimes of 5 dry months
(a) Harar Tableland	1670-2240	16-19	19-22	750-1000	5
(b) North-west Highlands of Ethiopia	1670-2240	14-17	20-22	1200-1450	5
(c) North-east Highlands of Ethiopia	2240-2760	13-15	18-19	700-1300	5
(d) South-west (Sudan) Slopes of Ethiopia	500-1000	22-26	28-31	850-1300	5
5. Regimes of 2 - 4 dry months
(a) Galla Highlands	1670-2240	17-19	22-26	1300-2000	2-4
(b) Arussi-Bale Highlands	1670-2240	-	-	1200-1750	2-3
(c) Arussi-Bale Highlands	more than 2240	-	-	1200-1750	2-3
(d) Eritrean Escarpment	500-1000	18-20	20-31	700-900	3
(e-f) Eritrean Escarpment	1000-2240	-	-	-	-
(g) Eritrean Escarpment	2240	13-14	20-21	1000-1200	3

A drought prolongation and diminished rainfall changes Davy's Lower Montane Evergreen Forest into his Moist Deciduous forest, as represented by the Teak and Terminalia Forest of India and the Padauk of the Andamans. That section of the Ethiopian Regime's No. 5 (a) of highest rainfalls and least drought period, however, barely admits this type - excluding the deciduous trees and converting the type to his Lowland Evergreen Forest, as recorded for India and Ceylon from sea-level to 900 meters.

Davy's Semi-Evergreen Forest is only a differentiation of his Lowland Evergreen type, registering the period of inadequate soil moisture. It exists as an ecotone between closed forest and parkland, or as a connecting link between moist deciduous and dry tropical forest. Regime 4 (d) of Ethiopia approximates to Davy's Semi-Evergreen forest, but it is hotter and drier, with corresponding effect upon the indigenous woody vegetation.

Davy's High Montane Rainforest approximates to the Temperate Rainforest of Shantz and Marbutt, who, however, group Juniperus procera and Podocarpus gracilior forests together. Yet both are Drought Period forests. The Tropical Rainforest of Shantz and Marbutt, recorded for the Ivory Coast and the Cameroons, has no place in Ethiopia, because Ethiopia has no such moist climatic regime.

W.E.M. Logan applies the name of Tropical Upper Montane Rainforest to both the Ethiopian Podocarpus forest and to the Ethiopian broad-leaved forests of regime 5 (a) combined. He uses the High Montane Conifer Forest type of Davy for the Juniperus forests, but precedes it with the adjective "tropical," though the type extends from the Sudan edge of Northern Eritrea southwards to Cape Province.

Glen Russ dismisses all the extant rainforest classifications as incompatible with the forest types of Ethiopia and adopts, instead, the differentiations:

1. Coniferous Mixed Forest 
2. The Broad-Leaved Forests of the South-west and West 
3 The Gallery Forests

This is a simple and direct classification, but oversimplified.

All these classifications lack essential correlation with their climatic regimes, of which their forest types are true vegetational expressions. Nor would 1, at this stage, wish to attempt this fundamental but complex task for a territory where climates are confused by a complicated topography.

It does not take long to perceive, however, that Juniperus procera can tolerate five dry months per annum on the thin-soiled, frosted backbones of Ethiopia, and that this Temperate Mixed Juniper Forest deserves distinction from the Temperate Mixed Podocarpus Forest which Glen Russ groups with it.

Podocarpus gracilior cannot ascend the hard heights of the dry hills nor reach the desert edges, nor can it spread as far north or south as Juniperus. Its growth-rate is almost as slow, but its drought-resistance is lower. It seeks a milder habitat and the companionship of less hardy broad-leaved species. It finds its place in lower, sheltered vales where it is joined by the more venturesome broad-leaved trees of the narrow drought period regimes, such as Ekebergia ruepellianum, Celtis kraussianum, Olea hochstetteri, Syderoxylon acantha and Apodytes. Though the Podocarpus vales interlace with the Juniperus hill-crests, and though both species mingle at the margin (but with Podocarpus always sheltering under the Juniperus) their characteristics, and habitats and types are different.

The Temperate Mixed Podocarpus Forest is really the link between the Temperate Mixed Juniperus Forest and the Sub-Tropical Broad-leaved Forests of the 2-4 dry months climatic regime - a type which Logan styles the Pouteria-Albizzia Association of his Tropical Upper Montane Rainforest, and which Russ disposes of as the Broad-leaved Forests of the South-west and West, of the Ethiopian Highlands.

Between them, they record for these broad-leaved forests the following timber trees with no Central African species among them:

Pouteria (Sersalina) ferruginea 
Albizzia schimperiana 
Sapium ellipticum 
Allophylus abyssinica 
Gallineria coffeoides 
Schefflera abyssinica 
Dracaena steudneri 
Polyscias ferruginea 
Milletia ferruginea 
Teclea nobilis 
Maesa lanceolata 
Pygeum africanum 
Ficus sp. (at their optimum) 
Cordia abyssinica 
Croton microstachya 
Mitragyna sp. 
Erythrina sp.

It is the forest types of the forest climates cited above, which give to Ethiopia its now man-reduced forest area of 500,000 hectares; an area which yet might be doubled by reforestation.

These, however, do not exhaust the forest potential of Ethiopia. Climatic Regime 3, which registers 6-7 dry months per year, is the habitat of Logan's Tropical Savannah Woodland, Russ's High Grass Savannah, or Shantz and Marbutt's Tropical Dry Forest. Annual grazing fires have degraded this dry forest type, reduced its constituent species to the most fire-hardy and widened their spacing to that of an orchard. The surviving species are of such genera as Combretum, Terminalia, Schrebera, Zizyphus, Syzgium, Lonchocarpus, Iannea, Faurea, Stereospermum, Gardenia, Cussonia, Hymenodicton, Hauswolfea, Gymnosporea, Acacia, Vitex Ehretia, Bauhinia, Protea, Grewia and Dodonea. The last seven genera are represented in Australia in an equivalent climatic regime.

Given fire-protection and a sand-mulch, the Australian Callitris glauca, cousin of the East African Widdringtonia, could make a forest stand here. Several Australian Eucalyptus could also distinguish themselves; thornless Australian Acacias would find themselves at home - more so than Acacia senegal, the producer of gum arabic which flourishes in the 6-7 dry months zone of Eastern Sudan, with 650 mm. mean annual rainfall on black, cracking clays, or 450 mm. on sand (and provides the Sudan with 20,000 tons of exports per annum).

The latter species, however, demands a higher summer heat than most of the Ethiopian 6-7 dry months regime affords. It reappears therefore on the coastal and lakeside lowlands of Kenya where it can keep warm enough to make gum arabic - yet with enough dry months to exude its gum from its cracking bark.

Russ describes this dry forest type as the most widespread of Ethiopia, covering half the country. It develops below the high forests, and descends the slopes, through lengthening drought periods, until it has to give place to Russ's Desert Acacia Savannah, Logan's Tropical Thornland, or Shantz and Marbutt's Thorn-Forest - where the dry months range from eight to eleven per annum, and the forest potential of Ethiopia comes to its end in perennial drought.

Exotics

Thus we get a glimpse of Ethiopia's forest situation. The behavior of exotics throws more light on the subject.

Towards the end of the last century Menelik II brought his court to that place where his empress thought to build the "City of the New Flower" in the shadows of the broad, high hills of Entotto. Those hills were thick Juniperus-Podocarpus forests and gave promise of wood provision for all time to those whom forest denudation had driven out of the place from which they had just come.

Menelik II thought to make assurance doubly sure by re-declaring, as oral law, the ancient tradition of imperial ownership of full grown trees. He failed to realize that this could be insured only by safeguarding the younger trees to maturity. Thus, he missed becoming the founder of Ethiopian forest policy. He permitted the continuance of clearing younger trees for cultivation, and they in turn provided the fuel for the fires which brought both Imperial trees and Imperial law to nothing.

The Entotto hills became completely stripped. It appeared that the gardeners of this "City of the New Flower" would be expelled once more from their would-be Eden to seek wood in the underlands of Galla.

At this juncture there arrived M. Mondon-Vidaillet, a French forester, with seeds of Australian Eucalypts. One of them was a tough tree from the hard Australian hills, accommodating enough to take both winter and summer rainfalls in its stride, as well as snow. It grew prodigiously. It was planted at 20,000 per hectare, and thinned for its produce in the fourth, seventh, fifteenth and twenty-fifth years. The 800 trees left per hectare had a standing volume of 570 cubic meters in the 26th year and 1080 cubic meters in the 40th.

The thinnings gave staves for fences, slim sticks for wattle and daub toukouls, and finally, tall poles for the scaffolding of the Imperial masonry. There was also firewood in plenty, even to the bales of foliage lumbered to the toukouls for the cooking of the ingera pancakes of the people.

Anyone who wanted to make good his future planted a plot of this Bahaar Zarf, this "Strange Tree from across the Sea." Now, forestry is the chief industry of the environs of the capital city of Addis Ababa with its 300,000 population. On any market day you will see the forest owners converging on the city, and on their backs and heads and overwhelming their tiny donkeys the produce of their investment. They provide 90 percent of the market traffic. All this is owed to one species of tree.

Now, there are others on trial. Grevillea robusta flaunts its sprays of old gold in the dry Ethiopian autumn, similar to the dry Australian springtime. The Australian blackwood gum grows with the Australian blue Gum; the Australian black wattle of the tanneries flourishes as do the Casuarinae. Mexican, Californian and Mediterranean Cypresses thrive, although the sudden drought period mortally splits the bark of weaklings. A Norfolk Island Pine grows strongly, and you may see the Californian Pinus radiata top-blighted by the north-east winter heat on the her of hills, yet thriving in sheltered valleys.

The significant thing about these exotic successes ix that they all came from drought period habitats, and have had to survive the primitive techniques of sowing in February at the scant commencement of the rains and open-root planting six months later in the deluges that herald the long drought from October back to February again.

With a more scientific approach and techniques, therefore, Ethiopia might well come to be able to grow a vast new forest estate.

Conclusion

It does indeed seem from a cursory survey that Ethiopian forests might provide means of development of the country's economic life. An obvious first step forward is the diversion of trained youth into the creation of a forest service and forest industries. There is still, however, a lion in the path of such a forest policy, and, indeed, in the path of the entire Ethiopian Renaissance. No country was ever developed except along with economic transport routes.

Neighboring countries have had to do it, and Ethiopia can do it - and more profitably, because no neighbor x ever had such a continuous belt of potential productivity through which to project its main road to development.