Project Overview
Commodities
- Nuts: Asian Pine Nuts
- Additional Plants: trees
Practices
- Crop Production: agroforestry, alley cropping, cropping systems, double cropping, forest farming, irrigation, multiple cropping, silvopasture
- Education and Training: on-farm/ranch research
- Production Systems: agroecosystems, integrated crop and livestock systems, permaculture
Summary:
Edible pine nuts are a nutritious high value crop that, once established, grows well on sandy soils in climate zones 3 or greater. Therefore, pine nuts could be a crop farmers in the North Central Region could use to diversify revenue, sequester carbon, a establish a multi-generational permanent crop. Pine nut trees native to Asia, like Korean Pine and Siberian Pine, have been established in the North Central Region because there are no pine trees native to our area that produce nuts large enough to market for human consumption. Unfortunately, in our personal experience and that of others, Korean Pine and Siberian Pine trees have be difficult to establish after transplanting. Because Korean and Siberian Pine trees are not native to North America, some hypothesize that the symbiotic microbial environment they need to thrive is not naturally present in North American soils and the lack of symbiotic microorganisms can limit establishment success. Others hypothesize that these pine trees need protection from wind and direct sunlight to during establishment. Therefore, we conducted an experiment to better understand best practices for pine nut tree establishment in the North Central Region by documenting establishment success of bare root Korean and Siberian Pine trees given varying microorganism inoculate treatments and tree shelter treatments and compared establishment success to native fir trees.
In the absence of any inoculate or shelter treatments, native fir trees exhibited the highest survival rates (98%), with Korean pine (88%) and Siberian pine (75%) being significantly lower that fir, but not significantly different from each other. Unexpectedly, commercial inoculation consistently was associated with reduced survival in both pine species, whereas shelters substantially mitigated this effect in Korean Pine but not in Siberian Pine. Regardless of treatment, surviving Korean and Siberian pine grew slowly. Average growth over two growing seasons was 1-3 inches, with inoculate or shelter treatments not explaining any of the variability in growth. Our experiment provides clear evidence that Korean and Siberian Pine are more difficult to establish than native fir trees and grow slowly after the first two years of establishment. The experiment unfortunately did not find any "silver bullet" for improving establishment success or growth after establishment; inoculate treatments nor shelter treatments produced higher survival and growth than the negative control (no inoculate and shelter).
Accordingly, this experiment provides no evidence that inoculant or shelters are worth the extra work and expense on our farm when planting bare root trees. Instead, we think it may be worth testing the establishment success of potted Korean and Siberian pine as means to minimize disturbance to the roots and any microbial communities associated with them . We also would like to see more nurseries in the North Central Region offering these pine trees. We had difficulty procuring Korean and Siberian Pine from a U.S. source and therefore needed to import our bare root pine trees from Ontario. The Ontario provider did everything in their power to expedite shipping, but shipping still took 7 days due to customs inspection. Therefore, we think it would be a great service to farmers in the North Central Region if more nurseries provided potted Korean and Siberian Pines because these trees would be highly preferred to purchase when we want to establish more.
Project objectives:
Objective: Determine how survival and growth of transplanted pine nut trees vary with soil inoculate treatment and tree shelter use.
Solution: We investigated what establishment tactics produced the highest survival and growth rates for two species of pine that produce edible nuts in the North Central Region. We conducted the experiment on two types of trees that produce large edible pine nuts and are hardy to Zone 3, Korean Pine and Siberian Pine. We varied inoculate treatments and tree shelter treatments. The inoculate treatments included (1) commercially available inoculate (https://www.nuttrees.com/edible-nut-trees/edible-pine-nut-trees), (2) inoculating with soil collected from under existing Korean Pine trees on our property, and (3) no inoculate. Inoculate from existing trees were introduced by collecting 1 cup of dirt from under our 6-year old Korean pines and placing the soil in the planting hole. The tree shelter treatments were a modified tree shelter for evergreens that we constructed from mesh material. The tree shelter provided shade and protection from wind, without producing the heat and confined conditions of a typical plastic tree tube. Therefore, the experimental design was a 2 x 3 x 2 factorial design (2 tree species, 3 inoculate treatments, 2 tree shelter treatments) with the following number of replicates per treatment: 100 Korean pine; 50 with commercial inoculate, 25 with inoculate from existing Korean Pine trees, and 25 with no inoculate. Of the 50 with commercial inoculate, 25 were a tree shelter and 25 were in a tree shelter. The same number of Siberian pine trees were planted with the same experimental treatment strategy. Treatments were systematically assigned throughout the planting field to minimize bias or artifacts from planting location. Pine nut trees were planted at a 35 foot by 40 foot spacing with drip irrigation provided. As a control, two conifer trees native to North America were planted between the pine nut trees, namely Fraser fir and balsam fir, so survival and growth of an industry standard conifer tree in the North Central Region can be compared to the pine nut trees. Fraser and balsam fir are also a good companion crop for pine nut trees because they can be harvested after 10 years for the wreath or Christmas tree industry as the pine nut trees are maturing. Fir trees were planted with no inoculate or shelters applied. The experiment occurred on a field with marginal hay production and loamy sand soils; a circumstance common on many farms in the Midwest that are on glacial till deposits. Soil tests occurred at the beginning and end of the experiment. Potash was applied to the field prior to establishment. Sheep were grazed in the aisles of the planting (35 ft spacing) to keep the land in production and soil nutrients cycling while the trees are establishing. Results were communicated through our website, our social media feeds, a conference presentation at the 8th Annual Underground Innovations Meeting, and a final report to SARE.
Illustration of experimental design and planting plan for pine nut trees under different inoculate and tree shelter treatments.
