Chestnut Harvest Burr Management

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2014: $7,390.00
Projected End Date: 12/31/2015
Region: North Central
State: Michigan
Project Coordinator:
Carl DeKleine
Dekleine Orchards, LLC

Annual Reports


  • Nuts: chestnuts


  • Crop Production: agroforestry
  • Education and Training: demonstration, farmer to farmer, networking, on-farm/ranch research
  • Farm Business Management: whole farm planning, budgets/cost and returns, feasibility study
  • Natural Resources/Environment: soil stabilization
  • Production Systems: agroecosystems
  • Sustainable Communities: new business opportunities

    Proposal summary:

    Project Description
    Our project is to develop new systems and equipment for a more economical harvest of chestnuts by using more effective handling and management of burrs and trash, and to communicate our process to US chestnut growers.

    DeKleine Orchards, LLC, is a second-generation Michigan family farm that has been growing fruit for over 75 years. It currently grows cherries and chestnuts. We currently farm about 17 acres of chestnuts. This year we harvested about 20,000 lb of chestnuts.

    Our family has helped lead the establishment of a chestnut industry in Michigan, the state with the largest number of chestnut trees in the US, per USDA NASS.

    With the exception of a couple of lean years, our farm has hired local high-school students for summer work.

    We are members of the Chestnut Growers, Inc., a chestnut-growers cooperative. (CGI). We are also members of the Michigan Nut Producers Council (MNPC), the Chestnut Growers of America (CGA), the Northern Nut Growers of America (NNGA), and the Michigan Nut Growers of America (MNGA).

    Both Carl and Art were raised on the family farm when it was a 1200 tree peach operation. Both have been directly involves in the farm operation since 1985.

    Carl received college degrees in Engineering and Business Administration. Carl is a charter member and currently a Board member and Treasurer of CGI.

    Art received a PhD in Mathematics. He is currently a Board member and Treasurer of the California Rare Fruit Growers (CRFG, Inc.).

    Universally, chestnut growers face lost time and efficiency during harvest due to the huge volume of burrs, which are the large prickly seed cases of chestnuts. We, after 20 years of experience growing chestnuts, and other known growers, are reluctant to expand orchards until this problem is managed.
    Chestnuts grow inside a round burr of about 3 to 5 inches in diameter. When accumulated in a pile, the burrs become a ‘Velcro stuck” non-flowable mass. About Oct. 1, the burrs split open, dropping nuts to the ground.

    Each empty burr falls at about the same time. Previously sampled burrs and nuts indicate a 5 to 1 ratio of single burr volume to its nut volume. Adding to the bur problem, non-pollinated burrs drop from the trees several days prior to nut maturity, thus contributing to even more trash.
    When hand harvesting, the empty burrs conceal nuts resulting in additional labor and unharvested nuts. With the exception of a harvester designed at Michigan State University and an Italian machine, FACMA, there are no machines specifically designed for chestnuts that will efficiently separate nuts from the burrs. Even the two machines mentioned, drop trash and burrs into the orchard directly behind the machine. Unlike any other nut crop, chestnuts are very perishable and each tree needs to be harvested 3 to 4 times during the two week drop period. All harvesters are ineffective during the third time harvest with a nut to trash ratio of 1 to 15. At that point, either nuts are left in the orchard or expensive hand harvest is resumed.

    Our project is to manage burrs from separation of the nuts to removal from the orchard. We will redesign and rebuild a currently owned almond harvester to ensure burr separation after picking them off the ground. Burrs will be blown onto a specially designed trailer using the harvester blower. Nuts will be conveyed to a bin on the same trailer. The burr holding section of the trailer, a burr box, will allow removal and disposal of the burrs outside the orchard.
    Although this project has been a planning item for years, time has come to complete it. Harvest costs are increasing as our orchard matures and nut yield increases. We have done some testing and know the existing harvester will accomplish the task. Its manufacturer, Weiss/McNair, has agreed to advise us on changes. Air ducts and hydraulic fan motors need to be installed. The special trailer and burr box are critical items and involve design and metal fabrication. The trailer will be pulled behind the harvester. Considering that burrs form
    a non-flowable mass, the burr box will be designed to empty its contents as a bulk dump at the end of a row or as the box becomes full.


    • Jan. 2014 to April 2014 Design harvester modifications for efficient nut and burr separation. Design a nut and burr transportation trailer.
    • April 2014 to July 2014 Build separating and transport equipment.
    • July 2014 to Oct. 2014 Modify nut harvesting equipment.
    • Oct. 2014 to Jan. 2015 Experiment with the design and efficiency of the burr management and harvest equipment. Collect harvested burr and nut, volume and weight data.
    • Jan. 2015 to Oct. 2016 Write reports for publication and give presentations about our burr separation process.
    • Oct. 2016 Demonstrate the recommended burr separation process.

    (1)    We will write articles and share information about our burr separation process.
    (2)    We will provide slide and video presentations of our burr separation process to the Chestnut Growers, Inc. (CGI), the Michigan Nut Producers Council (MNPC), and other requesting organizations.
    (3)    We will make information about the design of the burr separation process public.
    (4)    We will invite chestnut growers to watch the burr separation process during the 2015 harvest season.

    Per USDA- NASS farm statistics, most American chestnut orchards are 5 acres or less and only a few are greater than 60. Consequently, typical chestnut harvest is accomplished by hand or using a wire basket collection tool. Many larger growers have purchased mechanical harvesters from Flory, Weiss-McNair, Savage, FACMA, Monchiero, Chianchia, or lesser known manufacturers. Michigan State University has designed its own machine and also purchased a FACMA machine for trial use. Also, Michigan State University has published a paper detailing the current status of chestnut harvest with consideration for applications and economics. This paper can be found at;
    Regardless of the harvest method employed, empty burrs are a roadblock to efficiency. Even hand harvested orchards, like our own, use some system for moving burrs out of the drop zone between collection days. With the MSU machine as the only exception, all mechanical harvesters are machines designed for other nut crops and perhaps modified for chestnut use. Many of the machines cannot effectively separate burrs from nuts and in every case the harvesters drop empty burrs back into the orchard to be harvested again and again.
    To alleviate the burr handling problems, several growers in Michigan, California, Missouri, and Washington collect nuts and burrs in bulk containers. Separation of the nuts and burrs is then accomplished at a central processing location. Because the burs do not flow, an  additional complex problem, a ‘Velcro stuck” non-flowable mass, is created that requires additional labor and specialized equipment.
    No known equipment manufacturer, University team, or private grower is working on solutions to the burr handling problem in the orchard. Today the nut production industry has defined harvest completed when the nuts are off the ground and separated from husks and trash. In order to find efficiency improvements, we’ve defined chestnut harvest as the collection and management of burrs and nuts.

    Our stated objective is to increase the efficiency of our chestnut harvest. Records from the last three years show DeKleine Orchards has paid $.40 per pound to have the chestnuts hand field harvested, and a sum total of $.57 per pound to harvest, process and move nuts to cold storage. The primary project evaluation will be a comparison between historical hand harvest costs and the costs associated with the new burr management system. We expect about a $.20 reduction in field labor costs. Reducing the cost of harvesting and the time required to harvest will make chestnut harvesting more sustainable.
    Other quantitative measurable goals are as follows.
    1.     We need to harvest a minimum 1500 pounds of nuts per hour in order to ensure fresh quality nuts. A record of total pounds harvested and hours worked will provide the final harvest rate.
    2.    Our current hand harvest provides an 85% yield and 15% are overlooked. We’ve previously documented this ratio by recording the weight of gleaned nuts after season end. With the new burr management system, all nuts are picked up but some good nuts may be inadvertently sent to the burr waste box. Samples will be taken and recorded to determine the efficiency yield rate.
    3.    We will design the system to allow unloading of burrs and nuts from the trailer within 3 minutes. Time records will be kept.
    4.    At a point when fan air flow is successfully removing burrs but still leaving nuts on the conveyor, air speed will be recorded along with notes on burr wetness and conditions.
    5.    In the 20 years of our chestnut production interest, we have not found data on the chestnut burr/nut ratio for weight and volume. These ratios are necessary for nut and burr container strength and size designs. An important part of our project is to include these ratio calculations, based on actual harvest data. They will be included in the final project report. Lacking any reliable data, we are planning to design a 1 yard / 1,000 Lb. chestnut bin and a 6 yard / 500 Lb. burr box to be built on the trailer. Adjustments may be need as field trials are

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.