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Evaluation of Nurse Log Planting for Agroforestry Practice

Michael Culbertson

2016-Present

This project evaluates an experimental method of planting that attempts to simulate the rotting “nurse log” or “pit and mound” effect in a forest. It will measure this practice in comparison with a control group of common agroforestry plantings in terms of tree growth (germination rates/timing, aerial structure, roots, health/disease, production) and soil conditions (aeration, moisture, carbon, fungi, and microorganisms).

 

Nurse log planting:

  1. Laying seasoned compost to simulate pre-existing decomposition and accelerate regeneration. Or laying fresh, scrambled organic materials into a pile and permitting them to begin decomposing into a mound over winter then planting in spring.

  2. Setting the tree seed or bare root sapling into the mound.

  3. Surrounding it with sticks, leaves, and brush to simulate debris, deter browsing, and feed wildlife.

  4. Sowing native, herbaceous, pioneer species into it.

 

​Potential Benefits:

  • There is anecdotal evidence that decomposing wood of nurse logs forms ideal germination conditions for many species.

  • Simulating natural regeneration conditions for ecological benefits, but in a controlled manner to determine stand composition.

  • Possible enriching of soil as material is pulled down through gravity, rain, roots, and soil organisms.

  • Possible interaction of elements to create increased benefits across the growing system.

  • No digging, which reduces labor costs and benefits soil, roots, fungi, microorganisms, nutrient cycles, and food web.

  • No artificial fertilizing necessary.

Common Planting methods include seedling dibble, hoedad, auger-hole digging, and shovel digging with soil amendments.

 

This practice is unique in simulating decomposition, being reduced to a single tree, repeated for the establishment of a stand, using on-site materials, sowing co-evolved herbaceous/tree species, and focus on ecological benefit. This may therefore produce a series of compounding benefits on site compared to other methods.

 

This is inspired by Native American practices like growing in small mounds and concern for ecological systems (Anderson, 2013). However, it is applied to perennial forestry rather than annuals.

 

This practice may be similar to Sepp Holzer's Hügelkultur method. However, it does not bury large amounts of wood with domesticated species around the tree for maximized production; does not require the associated machinery, risk, and skill; and does not so significantly and immediately alter geology/water features.

Further information on design, implementation, and discussion available upon request.

Nurse Stump.jpg
Nurse Log Goodwin Forest.jpg
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