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Forestland

Soil Health on Forestland

Forest soil health is essential for the vitality of our ecosystems. It defines the capacity of forest soil to function effectively, supporting not only a diverse array of plant and animal life but also fostering biodiversity, enhancing productivity, and maintaining environmental quality.

Soil Health for Sustainable Forestry

Soil Health Forestland graphic

As a cornerstone of sustainable forestry, soil health directly influences a forest's resilience to disturbances such as fire, pests, and extreme weather conditions. Implementing soil health practices—such as minimizing soil disturbance, strategically thinning forests, utilizing prescribed burns, and incorporating diverse tree species—can significantly enhance forest resilience. 

Investing in forest soil health is not just an ecological necessity; it is an imperative for a sustainable future.
Soil health as defined by NRCS is “the continued capacity of the soil to function as a vital living ecosystem that sustains plants, animals and humans”. Soil health in forestlands is maintained or achieved through optimizing continuous living roots, disturbance, soil cover, and biodiversity. Assuring healthy forest soils begins with identifying whether any soil health resource concerns are present.

For more in-depth guidance and best practices, explore Soil Health Technical Resources for Forestland. 

Soil health in forestlands is maintained or achieved through application of four principles:

  1. Optimize Disturbance
  2. Optimize Soil Cover
  3. Optimize Biodiversity
  4. Optimize Continuous Living Roots

By embracing these strategies, forest managers have the power to cultivate thriving, robust forests that can deliver a multitude of invaluable ecosystem services, including pristine water and air quality, sustainable timber production, and effective carbon sequestration. 
 

The Principles of Soil Health on Forestland

Trees in a forest with pine needs, pine cones and branches on the ground.

Healthy forest soils reduce the effects of minor disturbances and are essential for  recovery from major storm events. Natural disturbances like wildfire, flooding, or windthrow can cause varying degrees of damage to forests. When the events are minor or infrequent, these disturbances are a typical part of the forest growth cycle. When these events are severe or frequent, however, it can take years or decades for the forest to recover. Soils with high water holding capacity and available nutrients enable rapid forest regrowth in damaged landscapes. 

Forest soils that are healthy enable the forest ecosystem to respond quickly to disturbances. Foresters us managed disturbances like prescribed fire, tree thinning, and control of invasive understory species to keep forests healthy and productive. Strategic use of managed disturbances can help prevent catastrophic events. For example, tree thinning and prescribed fire reduce the risk of catastrophic wildfire. These practices also create openings that encourage regrowth of preferred native species and improve wildlife diversity.  

Forest with leaf litter on the ground and saplings with green leaves.

Like cropland soils, exposed soils in forests are vulnerable to erosion. Plant litter on the forest floor acts like crop residue, protecting the soil surface from raindrop impact and soil movement. Runoff water can carry sediment into streams and rivers, impacting water quality. Healthy soils protected by leaf litter can absorb more water and store it for later use by the trees and other forest plants. 

Unlike crop soils, too much plant residue on the forest floor can present a risk of damaging wildfire. Management practices like prescribed fire can reduce the amount of litter and the risk of severe wildfire without damaging soil health. An optimal amount of soil cover balances soil protection against increasing wildfire risk. 

Leaf litter, bark, twigs, and an insect on the forest floor.

Forest soils with healthy roots that are protected from severe disturbances and have optimal cover, support a healthy soil biota community. Small animals, insects, and microbes living in the litter layer and soil consume dead leaves and branches, creating a network or pores in the soil, building soil organic matter, degrading chemicals, and recycling nutrients. Root secretions also feed soil microorganisms and fungi that extend the reach of roots and increase the availability of water and nutrients. 

Careful and planned inclusion of livestock into forest systems can have soil health benefits. Grazing animal depositions help recycle and redistribute nutrients and organic matter. Livestock can also be used as a tool in controlling undesirable vegetation. However, unrestricted or prolonged livestock access is generally detrimental to forest health and should be avoided due to the potential for compaction by animal treading and soil exposure from overgrazing.  Unrestricted or prolonged livestock access is generally detrimental to forest health and should be avoided. However, the careful and planned inclusion of livestock into forest systems can have soil health benefits. Examples include using livestock as a tool in maintaining rangeland or savannas or managing livestock as an integral component of silvopastures.

Soil, pine needles, and exposed roots.

Trees and understory plants of forests need healthy root systems to take up the water and nutrients they need to grow. Healthy soils store more water and gradually recycle nutrients into plant-available forms. Natural factors like a shallow water table or bedrock may limit rooting depth, making healthy soils even more important. Avoiding management practices that restrict root growth by damaging shallow roots or compacting the soil will help maintain healthy root systems.

Soils with strong structure and stable aggregates provide a firm anchor for large tree roots. These large roots support tall trees against high winds. Healthy soils without restrictive soil layers allow deeper rooting, helping prevent windthrow(trees tipping over in high winds). Living roots also help hold soil in place on steepslopes, reducing erosion by preventing soil eroding downslope.