As measured by social media site buzz and search engine keywords employed, agroforestry, as a topic of interest and discussion is trending higher. And forest farming, the deliberate integration and/or cultivation of non-timber crops (NTCs) in a forest setting is also on the rise. Much of the discussion and available practical information relating to forest farming centres around forest gardens. Forest gardens, patterned after home gardens in southeast Asia and popularized by Robert Hart’s book, are structured assemblages of food trees, shrubs and ground crops, arranged to leverage positive ecological interactions and make efficient use of small spaces. There are however, forest farming options suited to more extensive forest management situations, and by adopting these practices they can contribute to simultaneous demands for more food, fibre and conservation.
Throughout the world there are large tracts of managed forest that, through some creative silviculture and integrated planning and management, can be converted to forest farms. And because the methods for setting up forest farming are the same that may be employed in intensive silviculture to improve wood quality and value, they have the dual benefits of diversifying production and generating incremental income, without sacrificing either wood products or the ecological goods and services afforded by forest ecosystems.
The options outlined below include some general logistical considerations for establishing forest farming and are somewhat independent of where you may wish to deploy forest farming, although the examples I provide are regionally-specific to the Pacific Northwest of North America.
Options for Establishing Forest Farming
1. Optimize Existing Potentials. Often the simplest establishment option is to cultivate adapted understory species or manage and harvest non-timber components from existing trees or shrubs in a closed-forest setting. The advantages to this type of forest farming include the minimal need for establishment inputs and labour (i.e. the natural tendency of the forest will be towards full occupancy of the site), and the stand structure maximizes tree density, so no changes to stocking standards needed. This is a potentially important consideration where forest stocking is set by regulation. The primary disadvantage is the lack of control over balancing overstory and understory resource sharing which limits the range of NTCs that can be grown.
But that being said, these systems are good for NTCs that thrive with a full overstory (e.g. wild ginger, ginseng, and ferns). It is also good for producing non-timber products from trees (e.g. sap or nuts), where management and health of the tree is generally proportional to a healthy yield of the non-timber components.
2. Manage Stand Density and Tree Form. This option is established by thinning forest stands to a lower density and pairing that management with pruning to open up the understory. This set-up is highly flexible to balance overstory and understory and therefore can be tailored to suit a wide range of tree-understory crop mixtures. The thinning and pruning can provide direct tree growth benefits and increase log value on the timber crop. And indeed for some tree species, without pruning following the thinning, they can become much more ‘branchy’ and with tapered stems, both of which tend to reduce wood value. The boughs and thinnings may also have economic value, adding extra income from the system to offset the costs of the silvicultural work.
These forest farming systems are good for NTCs that thrive with a partial overstory (e.g. huckleberries). The reduced canopy can work well in semi-arid regions where partial shading slows evaporation from the soil, but is not blocking solar input to the extent that it significantly depresses photosynthesis in the understory crop.
3. Modify Spatial Patterns. The third general option for establishing forest farming involves manipulating the grouping of trees or tall shrubs on a site through either planting or thinning to create patches with gaps or small openings between. Creation of larger patches is good for species that like ‘life on the edge’, (e.g. saskatoon, hawthorn and soopolallie) with their leaves in full sun and their roots in the shade. Indeed many permaculture systems are created to maximize edge as well, recognizing how productive these environments can be. Smaller gaps are suitable for more shade-tolerant understory cultivation, including many of the same species that are growing in either of the preceding forest farming options.
This type of forest farming system is good for overstory trees that either don’t respond well to thinning or aggressively self-thin or self-prune (making the silvicultural work of dubious value). These set-ups of patches and gaps may also mimic the natural patterns of open, fire-maintained forests. They therefore can be used as an ecosystem restoration option which is much needed throughout western North America where fire suppression has created millions of hectares of unhealthy, in-grown forests at a high risk of succumbing to catastrophic wildfires.