Kiawe, Algoroba

Kiawe is a Hawaiian name for the algaroba, or carob, tree. Kiawe is a species of mesquite tree introduced to O‘ahu in 1827 by Father Bachelot, a French Catholic priest. He probably picked up the seeds in Chile on his way to the Hawaiian Islands.

Father Bachelot established a Catholic mission in Honolulu shortly after he arrived. He planted a garden with seeds that he brought from Paris, and the kiawe seeds from South America. Only the kiawe tree survived in his garden.

Father Bachelot was expelled from the Hawaiian Kingdom a few years after his arrival. Protestants had established themselves several years before the arrival of Father Bachelot, and Queen Ka‘ahumanu was an enthusiastic convert to the Protestant faith. Her Protestant prejudices became a barrier to the establishment of a Catholic Church, and she ordered the expulsion of the Catholic priests from the Hawaiian Kingdom. Catholics were allowed to reestablish a mission in the Hawaiian Kingdom after the death of Queen Ka’ahumanu.

Almost ten years had passed since their expulsion. The kiawe tree planted by Father Bachelot continued to grow in his absence. In 1840 kiawe seeds from the original tree planted by Father Bachelot were given to be planted at the Protestant Kawaiaha‘o Church as a sign of religious tolerance. One of the trees grown from these seeds is still in front of Kawaiaha‘o Church.

The Kiawe brought by Father Bachelot (Prosipis pallida or Neltuma pallida) grows to be a large tree with many uses. It is a well loved tree in the Hawaiian Islands. The seed pods are edible, the leaves feed livestock, flowers provide honey, and it is good firewood. It is drought resistant and can grow in very dry places. It has a very deep taproot that controls erosion. Because the entire population of kiawe in Hawaiʻi originated from one tree, there is a lack of genetic diversity and inbreeding. One of the results is that the kiawe thorns are relatively small, or absent.

The more problematic Long-thorn kiawe (Prosipis juliflora) is a more recent introduction from the Gulf of Mexico. It started becoming a problem around 1978. It is moderately salt tolerant, and grows in dry coastal areas as a thorny rambling shrub in dense thickets. It takes away habitat from native plants, and can block beach access. The poisonous thorns, up to 4 inches (10 cm) long, can puncture shoes and even car tires. The deep roots, 150 feet (50m) or more, make it difficult to remove. Fortunately, it shares many of the useful traits of the small thorn P. pallida. The edible seed pods and commercially valuable wood can be harvested. This is another invasive plant that can be exploited to eradication.