Chestnut: The Bread Tree

Part 1 of 4: Why Grow Chestnuts

by Akiva Silver

There are legends of a time when manna fell from the sky, and people just had to pick up all the food they needed. Mature chestnut trees are pretty close to making that story a modern day reality. Chestnuts can live for thousands of years and rain down dependable annual crops. They are magnets for wildlife, staples in several cultures, as magnificent as any oak, provide quality, durable timber, and are real epicenters of life.

The Castanea Genus

    There are several species of chestnut stretching around the temperate world. In the U.S., we have the American (c. dentata), the Allegheny chinquapin (c. pumila), and the Ozark chinquapin (c. ozarkensis). American chestnut and Ozark chinquapin are forest canopy trees, while the allegheny is a large shrub. Chinquapins bear nuts singly inside the burs, while chestnuts usually have 3 nuts per bur. Chinquapins generally have much smaller nuts and bear at a very young age. American chestnuts have the greatest cold hardiness and best timber form of all the chestnut species.

    In Europe, it is c. sativa, the sweet chestnut which reigns over the continent. C. sativa is a massive forest tree that was spread throughout Europe by the romans. It is found in large pure stands, as well as in orchards, parks, and along city streets. There is one tree in Sicily that is known as ‘the hundred horsemen chestnut’. Sometime in the 1500’s a princess was traveling with her entourage, when they were forced to take cover under this tree from a thunderstorm. Apparently they could all fit under the massive canopy. This tree, growing at the base of Mt. Etna, is estimated to be 4,000 years old, and it’s trunk is 190 feet in circumference.

    Asia also has several species. Japan is home to c. crenata, the Japanese chestnut, which is a spreading tree with very large nuts and good adaptability to adverse soil conditions. In China, we find c. mollisima, Chinese chestnut, a tree of high variability that makes up forests and orchards. China is also home to c. seguinii, and c. henryii, both of which are small trees/shrubs, they are chinquapins. 

    Around the world chestnuts grow in many different conditions and in several forms. They can be found in both acid and alkaline soils, cold and hot regions, and humid and dry areas. Chestnuts can be massive forest trees, small spreading orchard trees, or tough thicket forming shrubs. There is a chestnut tree well adapted to virtually every bio-region in the temperate world.

Wildlife Value

    What chestnut trees provide to wild animals is truly unparalled. The only tree that comes even close is the oak, but oaks are very different in their fruiting habits, with a profound impact. There are many species of oak found around the world, almost none of which bear regular annual crops. Here in the northeastern U.S., the oaks flower in early May. At this time, we have highly fluctuating temperatures, and it is not uncommon for a freeze to wipe out nearly all the oak flowers. If no frost destroys the acorn crop and the oaks fruit heavily, they will often take the next year off and produce only a very light crop even in the absence of late frosts.

    Chestnuts flower very late here, around the end of June or early July. Their blossoms almost never encounter frost. They bear fairly consistent crops every single year. This is a highly valuable and unique trait among wild fruit and nut trees.

    Chestnuts and acorns are heavy in starch, they are not just staples in the diets of humans, but also in the diets of many species of wild animals. They are the equivalent of rice or potatoes falling out of the sky. If you are a chipmunk or a squirrel who depends on this, then missing a crop every other year is totally devastating. This is why many rodent species (and their predators) in forests of oak and beech will have boom and bust cycles in their populations. The addition of chestnut trees to a forest can significantly temper fluctuations in populations.

    The list of wild critters that eat chestnuts is indeed a long one. It includes bears, wild turkeys, deer, raccoons, jays, o’possums, skunks, foxes, squirrels, chipmunks, and several other rodent species. While it is easy to look unfavorably upon rodents, they are the backbone in the diet of several predator species that we revere, such as owls, hawks, and bobcats.

    It is hard to overestimate just how important chestnut trees can be for wildlife. They create a reliable staple food source that is nutritious, thin-shelled, and easy to consume.

    Chestnut trees have a truly magnetic effect upon wild animals. When chestnuts are fruiting, they are busy centers of activity. Animals will travel from all directions to a stand of chestnut.

Human Value

    The timber value alone makes chestnut trees worth growing. Plantations of pine, spruce, and poplar offer people fast growing timber resources. Chestnuts are another viable option for this with many added benefits. 

    Chestnut trees can grow very fast. They are easily coppiced. This means that they can be cut again and again because they will sprout vigorously from the stump. Coppicing chestnut is an old tradition in the U.K., where trees are put on rotation cycles ranging from one year to 50 years depending on the desired wood products.

     Chestnut wood is highly valued for many reasons. Not only is it a beautiful wood, but it is light and strong. Chestnut is very stable and resists warping and cracking. It is easy to work and it is highly rot resistant. Chestnut wood is a viable alternative to pressure treated lumber, it is certainly more durable in contact with the soil. Rot resistance alone make chestnut timber worth producing, but the wood is also a beautiful straight grained hardwood that has found it’s way into high value items like furniture, trim, cradles, and caskets. All these combined traits make chestnut a truly versatile wood with significant cultural and economic value.

    Add on to the timber, the nuts themselves, and you really have a tree worth growing. Chestnuts can be eaten so many different ways. The most famous way is roasted, but they can also be steamed, boiled, added to soups, ground into flour and made into breads, cakes, cookies, and even noodles. 

    Traveling to cultures outside the U.S., we can find endless recipes calling for chestnut flour, especially in Italy. It is a very tasty, sweet flour that makes excellent desserts, but is also great for thickening stews, or adding to stuffings. The uses of chestnuts is as endless as any other grain.

    Chestnuts have been a staple in such diverse cultures around the world ranging through the Far East, Central Asia, Europe, and early America. They are easily digestible, tasty, and have a similar nutritional equivalent to brown rice. They are the ‘manna’ trees, we really just have to pick up the food.

Chestnut flour cookies in the oven

Chestnut flour cookies in the oven

Earth Value

    Chestnuts are a solution to several problems facing humanity’s role on this planet. Currently almost all of our staple foods come in the form of annual grains (corn, wheat, soy, rice, etc.) In order to grow annual grains, the earth must be plowed and tilled to kill all other plants and prepare a seedbed. Wherever annuals are grown, the entire ecology of that place is totally removed and destroyed. Annual plants require bare soil. This means tillage. Every time the soil is tilled, it is exposed to the elements. The effects of this go far beyond our initial observations.

Changing the color of a field from green to brown has enormous consequences. 

    There is a reason that nature covers the soil. When rain strikes bare soil, it compacts it, changing the structure of the soil into an impervious layer. This leads to runoff and erosion. When bare soil is exposed to air, the organic matter becomes volatilized. Organic matter is essentially carbon, and when carbon meets oxygen, CO2 is formed. CO2 is light enough to float away. Every time a field is plowed, CO2 floats up into the atmosphere. This is detrimental to both the climate and to our soils. 

    Scientists now debate which leads to more greenhouse gasses in the atmosphere, transportation or tillage. It is fully understood and accepted that plowing fields is a huge factor in climate change. When we drive by plowed up acres of brown dirt, we are looking at a piece of land so far removed from nature’s design. The soil structure is being destroyed and massive amounts of carbon are heading up into the sky. 

    There are alternatives, beautiful ones that make economic and ecological sense. By increasing the organic content of our agricultural lands by just 1%, we would return to pre-industrial carbon levels in the atmosphere. The capacity for the soil to store and build carbon is highly under-utilized by our current agricultural system dependent upon annual crops.

 

    Carbon in the soil is known as organic matter. Organic matter holds 4 times it’s weight in water, while at the same time it drains very well through a network of capillaries. Soils high in organic matter can absorb tremendous amounts of rain in a very short time period. They can supply moisture to plants evenly over long time periods. However, organic matter is vulnerable to exposure, it is easily washed away or volatilized into the atmosphere. Early New England soils from the late 1700’s contained about 20% organic matter. These soils were totally resilient in their ability to deal with droughts and floods. As forests were cleared and land was plowed, organic matter was lost into the rivers and the atmosphere. Today, it is common for agricultural fields to contain around 1% organic matter. 

    Carbon belongs in the soil. The cultivation of annual grains leads to carbon moving towards the atmosphere. Chestnuts are a grain, a perennial grain. They pull carbon out of the atmosphere and convert it into leaves, roots, and wood. Chestnuts can be used for all the things we use corn for. They can replace corn and offer tremendous ecological services at the same time.

    Think of the ecology of a corn field, especially a field of roundup-ready corn that has virtually no weeds in it. There’s really not a lot going on, not many places for hawks, butterflies, or honeybees.  A chestnut orchard is buzzing with life. There are 125 known species of lepidoptera that feed on chestnut leaves. The trees provide roosting and nesting sites. In contrast to corn, they have extremely low fertility requirements. Chestnut trees can grow on steep hillsides where bare rock is exposed. They can heal and build soil instead of using it up.

    And of course, the big question people ask is ‘Can an acre of chestnut yield as much as an acre of corn?’

    It seems like a straight forward question that should have a straight forward answer, but it does not. Corn has been intensively bred with the full support of government agencies and universities to boost yields.This has not happened to the chestnut, but despite the lack of breeding, chestnuts may still out yield corn. An acre of chestnut trees can easily accommodate grazing animals, shrubs, and herbaceous plants underneath the canopy. An acre of chestnut trees can exist on a steep rocky hillside, where it would be virtually impossible to cultivate corn. So where is the acre?, is it in the very best fertile bottomland, or is it up in the hills with livestock occupying the same space?

    Chestnuts can easily be grown in conjunction with other crops in the same space, and they can do so in places that corn could never grow. This makes chestnut and corn yields incomparable. They are very different uses of land, and the total amount of food produced will vary considerably depending if you count all the crops grown inside a chestnut planting.

    The technique of grazing animals beneath nut trees is not a new one. Today it is known as silvopasture, in ancient Portugal it was known as the Dehesa system. When done well, by rotating livestock through the orchards, it is a proven sustainable method that has worked for thousands of years.

    Annual grains are just that, annual. They die every year and have to be replanted every year. Chestnuts can live for thousands of years. They can start producing as early as age 2, and will increase their nut production each year. 

    Farmers looking to convert fields of corn to chestnuts can do so with a technique called alley cropping. In alley cropping people plant rows of trees right into the field and continue to grow annual crops in between the rows. As the trees get bigger, the alleys of annuals get smaller, until eventually they are totally eliminated. This method can allow farmers to continue generating income during the transition period.

35 year old hybrid chestnut trees in West Danby, NY

35 year old hybrid chestnut trees in West Danby, NY

If we want to improve wildlife habitat, grow crops with ever-increasing yields, protect and build soils, and reverse climate change, then planting chestnut trees is one way to accomplish all of these wonderful and attainable goals.