Hugelkultur

Hugelkultur Background

  • Hugelkultur is German for “hill culture”
    • Raised permaculture beds that reutilize debris from deforestation and land development of property
    • Compared to burning wood from deforestation, hugelkultur beds reduce emissions by 98%2
    • Provide nutrient rich soil for cover crops & vegetation that can be planted on the property
      • Beds are NOT conducive for optimal growth of wine grapes, so they will not be used to grow grapes for wine
    • Retain water due to the "sponginess" of the materials contained inside
    • After ~20 years, hugel bed has lost its nutrients, and settles back down similar to the original soil
  • Created Hugel bed "blueprint" within AutoCAD
  • Utilization chart to determine bed number requirements, and account for variability within beds
  • Maximize ground surface volume: Adds ~2x amount of available area compared to standard ground

[2] J.A. Micales, K.E. Skog (1997). Decomposition of forest products in landfills. V 39, I 2-3, P 145-148

Hugelkultur Design

  • Currently, hugelkultur bed creation is more of an art than science
  • We based our designs off of "standard dimensions" found from hugelkultur expert
  • There are four main layers within hugel beds: Logs & large tree debris, ~2 in. Small tree debris (twigs, small branches), ~3 in. composting materials (leaves, leftover vineyard debris), and ~3 in. top soil
  • Optimal design was modeled in AutoCAD (figs. 6 and 7)
    • Model was then used to estimate amount of deforestation debris would be used in each bed
  • Due to variability in materials, and density of packing "material utilization" of beds was accounted for (Table 1)
    • We estimated the average hugel bed would utilize ~50% of its available volume
    • From there, we determined a ratio of space trees took up in forest compared to inside a hugel bed to be ~12 times to 1 (Goal ratio from advisor was 10 to 1)
    • We also accounted for spacing required in between beds (2 ft. total added to length, 4 ft. total added to width)
      • From there, an acreage "utilization" chart was constructed, and determined approx. 1/3 of each acreage would account for hugel beds and spacing around each bed
    • Combining calculations of each hugel bed size, utilization, and spacing around, we were able to finalize the total acreage required to completely repurpose all debris accumulated from 6 acres of deforestation & land development for winery
      • ~1.25 acres of land (which includes ~1000 hugel beds of dimensions above) are required

Fig. 6: Hugelkultur bed, front view with labeled layers & dimensions

Fig. 7: Hugelkultur bed, isometric view with dimensions

Table 1: Hugelkultur Bed Utilization Chart & Land Utilization Chart

Hugel Bed Utilization Table.xlsx

Hugelkultur Bed Placement

  • After calculations were completed to determine ~1.25 acres of land must be available for hugel bed placement and implementation, we used geospatial analysis (GIS) of winery and land to find ideal locations
  • Three pieces of criteria were used to assess plots of land best suited for hugel beds:
    • Aesthetic value - based upon owners request
    • Elevation change (<15% grade)
    • Rainfall and water accumulation rate
    • The combination of high elevation change, with large amounts of rainfall could lead to an issue with hugel beds. There is a concern of mudslides if enough water is gathered in a bed, and on a steep slope.
    • Beds were also required to remain at least 100 ft. away from the riparian buffer zone of the creek running through the bottom half of the property, and outside of the designated vine blocks (Fig. 9)
  • A three dimension elevation model was created (based upon topography in the area) to observe steep changes in elevation
    • Rainfall accumulation calculations were laid on top, to analysis both criteria simultaneously (Fig. 8)
    • From this model, two buffer zones (shown in green, fig. 9), were excluded because the land was too steep
  • From requirements of placement criteria, advisor request, and the 1.25 acre utilization prerequisite, three plots of land were selected for future implementation of beds (seen in Fig. 9)
  • The three beds totaled to 1.6 acres of available land, which also would help account for any additional bed utilization and spacing variabilities
    • With these plots, we will be able to fully offset all GHG emissions from deforestation, and repurpose debris to create nutrient rich soil beds

Fig. 8: Rainfall accumulation estimation of land plot, GIS

Fig. 9: GIS 3D topographic view of winery with bed placement