A Positive Experience With Eucalyptus

Missionary Rodney Babe heads a project in Haiti that has had an impressive impact on the community. It is based on reforesting extremely eroded mountain soil with eucalyptus, a tree that is often maligned by farmers and development workers because of its supposed competition for water with food crops. While there have been problems with eucalyptus in some situations, is it being too quickly overlooked? We interviewed Rodney at an ECHO Conference held in Haiti in January.

“The soil is severely eroded and sandy and often there is very little of this poor soil on top of bedrock. There is a severe problem with goats running loose. Less than 10% of the land can be farmed because of the erosion. Most of the soil has no plant covering. Perhaps 2% of the land was covered with trees when we began. (There were a few coconuts and mature mangoes but no young mangoes.) The area receives about 60 inches of rain each year in two rainy seasons. The maximum altitude is 2500 feet. The average farmer owns less than a hectare of land. Slopes up to 60% are considered farmable. Soil pH is neutral.”

“The local farmers said that eucalyptus dried the soil and casuarinas poisoned the soil. They thought that leucaena produced too many seeds and that neem would take over. Livestock will not eat casuarina, but they will bite the terminal leader and turn the tree into a bush. They preferred fruit trees.” Rodney suggested planting trees as a “crop,” with the idea of harvesting them later. This was a new idea to them and they liked it. In the past he has seen farmers accept free tree seedlings but throw them in a ravine rather than plant them on their land.“

Of the trees Rodney planted, no fruit trees survived. Goats killed off the leucaena. Neem trees died in transplanting. They decided to try eucalyptus because goats would not eat it. They also planted several other popular native trees, including mahogany. After the first year 75% of the eucalyptus trees had survived but essentially none of the other trees. The average height was 3 feet [.9 m]. After a year and a half the trees ranged from 6 to 15 feet [1.8 to 4.5 m], depending on soil conditions. "We decided to put ¼ pound [.11 kg] of fertilizer in a semi-circle one foot from the trunk on the up-hill side of the eucalyptus trees that were 6 feet [1.8 m] tall or less. While fertilizing we made a small hole to hold rainwater, and cut any grass near the trunk. During the next rainy season the trees doubled in height in 2 months. So in future plantings we began using 1/3 pound [.15kg] of fertilizer one month after planting. The fertilized trees reached 12-15 feet [3.6 - 4.5 m] in a year; unfertilized trees reached about 3 feet [.9 m]. We felt that this initial rapid growth rate was worth the cost of the fertilizer.” This was in part because even though animals did not eat the leaves, animals staked near small trees during the cropping season drag their ropes over smaller trees and damage them.

“We fertilized some sections a second time with 1/3 pound [.15 kg] per tree of 15-15-15 fertilizer after 5 months. These trees reached about 20 feet [6 m] in one year.”

“After 2 ½ years people were able to grow pigeon pea under the trees. Pigeon pea growth was not spectacular. The plants reached only 3 feet [.9 m] in a year rather than the normal 9 feet [2.7 m] and bore few peas. The second year the pigeon peas were cut and left on the ground and a new planting was made. This time the height and yield were about the same as in their home gardens. This might be because nitrogenfixing rhizobia were present in garden soil but not in the eroded soil. So the next year we inoculated the pigeon peas under trees with rhizobia in some areas and not in others. Inoculation caused a 300-400% increase in yield.”

“After growing pigeon pea for 2-3 years, people began growing sweet potato, peanut and some black beans. Trees were 10 feet [3 m] apart and gave a very diffuse shade. Now they are planting mango, citron, barbados cherry and a native lumber tree and are seeing about 25% survival.”

“When the trees are 6 inches [15 cm] in diameter people are cutting them and making chairs. Quite a lot of chairs are being sold. We teach them to thin the new sprouts that come from the stump.”

“Now there must be a few million trees in a 12 square mile [31 km²] area. The largest are 50 feet [50 m] tall and 8-10 inches [20-25 cm] in diameter. Some are even starting to plant eucalyptus in their good gardens. Meanwhile we’ve attended dozens of seminars which tell us that eucalyptus trees hurt gardens. The project has been going for 6 years. The ultimate goal is to get mango and the native Catalpa longissima trees growing again.”

We contacted Ido Kerpel, the nursery manager at Double Harvest in Haiti which grew the trees for Rodney’s project. He has visited the project often. The species used was Eucalyptus camaldulensis, or `river red gum.’ He told us that it can be planted from the “mountains down to the coastal plains,” withstands both waterlogging and drought, and reportedly can reach 60 feet [18 m] in 10 years under a 10 inch [250 mm] rainfall. The tree does not make a dense shade, thus allowing other crops to be grown in its vicinity (grass grows up to the trunk).

Ido commented, “It is often quoted that eucalypt leaves contain etheric oils which remain in the soil below the tree and serve as a herbicide. If planted around fields and yards, the concentration of the leaf residues is much too small to be of any effect to crops and grass. If large-scale eucalyptus plantings do indeed have this herbicide effect, I personally would still rather see mountains covered with eucalypt forests, useful for their wood supply, than useless bare mountains slowly disappearing into the ocean due to soil erosion. In my opinion, it is a much under-appreciated tree for community tree planting."