An Introduction to Agroforestry

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Alley cropping. Photo: Manfred Mielke, USDA Forest Service

In an earlier post, I introduced the concept of agroforestry.  In this post, I will expand on what agroforestry is, and how it is being used here in Wisconsin.  Although this post may seem very agricultural centered, I should point out a few things.  One, many woodlots are associated with farmsteads, and are not seen as a profit center for the farm, though they could be.  Two, landowners are finding the costs of owning land to be so high that they lease their land to neighboring farms.  Is there a way for both owner and farmer to benefit in ways they each want or need to use the property?  Three, some of these are more forest centered (see forest farming), and can be a new way for woodland owners to spend time in their woods.

To revisit, agroforestry is a system that combines trees and shrubs with various combinations of crops and animals. Some benefits gained from practicing agroforestry include improved soil and water quality, wildlife habitat, and economic and ecologic diversity. Although this is commonly associated with tropical regions, there are applications here in Wisconsin as well.  There is any number of ways to think about an agroforestry system, so let me define a few.

    • Alley cropping is using rows of trees alternated with rows of crops.  The general benefit is seen from a farmer’s view where they can add economic diversity to their farming system by adding Christmas trees or biomass production to crops such as corn, soybeans or forages.  Added benefits include protection against wind and water erosion, and added wildlife habitat.
    • Windbreaks are simply rows of trees or shrubs surrounding large crop areas to reduce and redirect wind from the fields.
    • Silvopastoral systems combine trees and livestock.  The main crop is trees, but forage crops are grown under the trees for grazing livestock.  Although an assumption is cattle, this could include goats and sheep.
    • Agro-silvopastoral adds agricultural commodities to the mix along with trees and grazing.
    • Forest farming is a system that introduces specialty crops into the forest setting.  These could include food (mushrooms, ginseng & nuts), medicinal plants, decoratives (balsam boughs & ferns), and handicrafts (baskets & pine oils)
    • Entomoforestry is the combination of trees and insects.  A common example is bees for honey production.
    • Aquaforestry is the combination of trees and aquaculture.  Trees surrounding fish ponds can enhance the nutrients in the ponds through leaf litter.

I’m leaving out a few of the systems that are more common in tropical and developing countries, such as community forests, but by now you get the idea that agroforestry can mean any number of groupings of tree, animals and crops.

Many of these systems originated not out of a University’s research facilities, rather out of necessity to get the most out of scarce land resources.  Think about a forest garden in a tropical setting where a family needs to raise food and fuel in a small space around the home.  Some of these systems are already being practiced here in Wisconsin.  For example, the Central Wisconsin Windshed Partners was established to promote and install windbreaks and living snow fences to protect farmsteads and highways in central Wisconsin.  These windbreaks can be planted with trees and shrubs that produce a crop along with protecting from soil erosion. This way, farmers don’t lose valuable cropland to what may be a non-commercial use, and instead produce an additional crop.  Hazelnuts are an example of a tree that is being grown in windbreaks, with the commercial crop being the nuts.  Along the same lines, hazelnuts (and other trees) planted along waterways as a buffer can produce a commercial crop along with protecting the shoreline and creating wildlife habitat.

The change in how lands are taxed to reflect their use has encouraged many farmers to graze their cattle in their woodlots.  Unmanaged grazing in woodlots can cause damage to existing trees and compaction to the soil (that prevents new tree seedlings).  However, silvopastoral systems, when managed correctly, can provide all the benefits of a true agroforestry system.  Specific management is needed to integrate grazing into forests so that the benefits from the forest are still gained.

I want to introduce one other system that is becoming more common, and that is edible woody landscapes.  This is the integration of a forest (trees and shrubs) with animals (ourselves and other wildlife).  Many landowners purchase woodlots so that they can live in them and enjoy them for their own uses.  This is a way for us to create a transition zone between the forest and the house, while maintaining the forested feel.  The variety of trees can provide nuts (hazelnuts, walnuts, hickory), fruits (cherry, apple, plum), tea (pine needles, juniper berries, elderberry fruit & flowers), foliage for decorating (balsam boughs), and more.

A valuable resource for more information on agroforestry and the various systems can be found through the National Agroforestry Center.