Tuesday, August 4, 2009

Honey Locust as a forage tree

J. Russell Smith proposes the use of several trees to fulfill his vision of a sustainable, permanent, woody agriculture. I thought a good place to start would be to profile each of these trees, and how it could - and should - be used.

The first of these is honey locust, Gleditsia triacanthos. Honey locust is native from New York to Nebraska, and from Louisiana to Minnesota, and is adaptable well beyond that range.

Honey locust produces a large pod that is edible for livestock and people alike. Writes Smith, "I found one man who planted honey locusts that his cattle might eat the beans in the field, and also that he might harvest the beans for winter forage. That man was the late Lamartine Hardman, Governor of Georgia."

Smith lists the qualities of the honey locust tree as follows:

1. It is a beautiful tree that produces strong, durable, beautiful wood. According to Permaculture Plants the heartwood can last up to 100 years untreated in the ground.

2. It is rapid grower (Permaculture Plants co-authors Jeff Nugent and Julia Boniface call it "moderately fast growing"

3. Like the carob and the albaroba, it is a legume... but at the time J. Russell Smith wrote Tree Crops the question of whether or not honey locust can fix nitrogen was unsettled. Honey locust roots lack the nodules common to nitrogen-fixing legumes. Apparently, the question is still unsettled, since a quick search of the web reveals sources that claim that it does indeed fix nitrogen, and sources which state it does not.

I will be doing a lot more research on that topic.

4. It has an open canopy and does not cast a deep shade, making it a great candidate for "two-story agriculture." Pasture can grow well beneath it. (The thorns that commonly grow on the trunks of honey locust trees also help keep them from getting rubs and girdled by livestock - they provide their own barbed wire!)

5. It is a productive tree. Smith maintained correspondence with hundreds of people throughout the world, constantly comparing notes on tree crop yield. Writes Smith, "J. M. Preston of the Branch Experiment Station at Hays, Kansas, gathering seeds for planting, reports a tree with seven- or eight-inch trunk, producing eighty pounds of beans, and another tree in Manhattan, Kansas, from which he gathered 'about four hundred pounds of pods.'"

6. Honey locusts seems to be regular bearers of good crops, as opposed to many trees which produce large mast crops every second or third year.

7. The honey locust bean is very large - often one foot or more in length - which should make it very easy to harvest.

8. It is easily cloned. Once a good honey locust tree has been found, it is easy to propagate either by grafting or by root suckers.

In a country where the vast majority of our annual, soil eroding grain crops are grown for animal feed, the honey locust is an underplanted, under utilized source of animal nutrients.

Permaculture Plants lists the nutrient profile for honey locust as:
Protein - 14.3 - 16%
Sugar - 15.5 - 26.5% (although Smith gives reports of individual trees which yielded 36% and 38.9% sugar)
Carbohydrate - 60.5%
Fat - 7.5%
Calcium - 0.2%
Iron - 0.0038%

Related to my quest to become a dedicated balanoculturist, I also intend to taste test some honey locust recipes this fall and report my results.

Smith then emphasizes the need for better selection & breeding of superior honey locust trees. As with many trees, there is huge variability in the productivity of honey locust trees. With the right genetic selection, incredible yields are possible. Quoting correspondence with a Mr. J. C. Moore, Smith writes: "This year some of the 8-year-old trees produced over 250 pounds of pods per tree. With 35 trees per acre, this would be 8,750 pounds of concentrates or the equivalent of 275 bushels of oats per acre."

So, where can you buy good honey locust trees? A place for great trees and great information is always Oikos Tree Crops in Kalamazoo, MI, a treasure trove of great plant material, information and experience. Oikos' honey locust page is here.

I'll be talking about Oikos Tree Crops a lot both here and at Oak-Watch.

Reading through the Oikos site reminds me of a key point: Many of the grafted varieties of honey locust sold in the nursery trade are sterile to some degree so they produce a very small crop if any at all, and are bred to be thornless - an advantage in a landscape tree, but a disadvantage in a pasture tree.