Fruit and Berry Tree Crop Trial Program for Native Alaskan Rural Communities in Interior Alaska

Fruit and Berry Tree Crop Trial Program for Native Alaskan Rural Communities in Interior Alaska

Summary

This research project is investigating the potential for domestically grown fruit and berry crops on cold (zone 2) sites in Interior Alaska. Currently, we are evaluating fruit trees (primarily apples) identified to be cold hardy in other northern regions for survival, production and yield using high tunnel structures. We hope to be able to identify specific varieties of apple, cherry, plum, and pear that survive and produce fruit in zone 2 and explore the use of high tunnels for fruit production in interior and rural communities of Alaska.

Objectives/Performance Targets

We plan on continuing to collect climate data along with flowering, fruit set and harvest information for one additional season (fall 2009 through summer 2010). We believe three complete growing seasons will allow us to make confident recommendations on apple varieties and high tunnel usage in the interior and throughout Alaska. Our hope is to prepare a CES publication focusing on high tunnel construction, establishment and management. We also plan on developing a CES publication with recommendations for apple varieties suitable for the interior and other locations with similar climatic conditions.

Accomplishments/Milestones

We have constructed two high tunnels (42 x 96 feet) and planted more than 39 apple varieties. A total of 250 trees were planted inside or in the field adjacent to the structures. We have been monitoring climate and tree development such as flowering and fruiting since 2007. Our site is located on the Fairbanks Experiment Farm at the University of Alaska in Fairbanks, Alaska. For a full description of the site and our project please go to http://www.uaf.edu/ces/ah/fruit-tree-trials/.

Impacts and Contributions/Outcomes

There was significant snowfall during 2008-2009 compared to the 2007-2008 winter resulting in excellent insulation for the exterior plots. The soil temperatures remained above 0 degree Fahrenheit throughout the winter. We continued to use reflective insulation paper (one square meter in size) around the base of some trees inside the tunnels. However, the soil temperature remained similar independent of an exposed or a covered soil surface area around the tree.

Our second full growing season showed a slight difference in survival rates of newly planted trees (replacement trees were planted in 2008 for losses in 2007) between the tunnel and the exterior. The survival rate for our trees after 2 growing seasons was higher in the tunnel at 80 percent compared to trees in the adjacent field (30 percent). A similar trend was observed during the first season with slightly more trees surviving in the tunnel.

We were not expecting flowering and fruit set until the third full growing season. Still, a total of 12 trees in 2008 and 27 trees in 2009 flowered. The first open flowers in 2009 were observed on May 26 and flowering continued through the first week of June. Fifteen of the 27 flowering trees produced fruit. The two trees outside with flowers in 2009 did not produce fruit.

In 2009, we harvested apples from 15 trees starting in mid August until mid September. The apples were counted and weighed at harvest. The soluble solid content (SSC) was determined in samples of apples from each variety using a refractometer. The SSC level is an indication of the fruit sugar content expressed in °Brix.

The apples varied in size from 20 to 200 g with sugar contents between 8 and 20 °Brix. The harvest was small but more than exceeded our expectations. We are hoping for more complete flowering, fruit set and yield during the coming 2010 field season with an expectation of 80 to 90 percent of the trees producing fruit.

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