Secondary Compounds in Willow: Measuring Levels and Seasonal Variation of Tannins and Salicin for Livestock and Human Health

Project Overview

FNE26-146
Project Type: Farmer
Funds awarded in 2026: $29,978.79
Projected End Date: 09/30/2028
Grant Recipient: Wellspring Forest Farm LLC
Region: Northeast
State: New York
Project Leader:
Steve and Elizabeth Gabriel
Wellspring Forest Farm LLC

Commodities

  • Additional Plants: trees

Practices

  • Animal Production: animal protection and health, feed management, herbal medicines
  • Crop Production: agroforestry
  • Education and Training: on-farm/ranch research
  • Sustainable Communities: new business opportunities

    Proposal summary:

    Willow (Salix spp.) is widely recognized for its ecological benefits, yet farmer adoption in the Northeast remains limited because its economic potential, particularly for livestock health and medicinal bark products, is poorly quantified. This project measures seasonal levels of two key secondary compounds: condensed tannins in willow leaves, which support parasite control and animal performance, and salicin in bark, the precursor to salicylic acid and the basis of willow's medicinal uses. We will sample six willow varieties in the spring and fall of two growing seasons across two farms in different climate zones to document how compound levels vary by species, season, and environment.

    Our objectives are to:
    (1) collect standardized bark and leaf samples over two seasons for six varieties;
    (2) quantify salicin and compare spring versus fall values;
    (3) quantify tannins and compare spring versus fall values;
    (4) evaluate salicin content in spring and fall tinctures;
    (5) synthesize trends to identify optimal harvest windows and preliminary economic projections; and
    (6) develop practical outreach materials.

    The project integrates field sampling, laboratory analysis (HPLC/LC-MS), tincture production, and analysis to generate a regional dataset that will help farmers determine when to harvest bark or leaves for maximum potency, and how willow can serve as a dual-purpose crop for fodder and value-added products.

    Outreach includes two on-farm field days (2026, 2027), a regional webinar (2028), and a suite of farmer-oriented educational materials-including harvest guidelines, bark processing instructions, tincture workflow notes, enterprise budget templates, and variety profiles-distributed through regional agroforestry networks, Substack articles, and the SARE website.

    Project objectives from proposal:

    Objective 1

    Collect seasonal bark and leaf samples from six willow varieties across two farms over two years to generate a dataset for salicin (bark) and condensed tannins (leaves). Sampling will follow standardized protocols and include spring/fall bark collections and early-/late-season leaf collections.

    Objective 2

    Quantify salicin concentrations in spring and fall bark samples for two seasons using HPLC or LC-MS through Cornell or SUNY-ESF laboratories, which have confirmed capacity to support the project.

    Objective 3

    Quantify condensed tannins in early- and late-season willow leaves for two seasons using HPLC or validated colorimetric methods through Cornell or SUNY-ESF labs.

    Objective 4

    Produce willow bark tincture from two sample per year; one in spring and one in fall, over two growing seasons. Analyze salicin concentration and extraction efficiency across six willow varieties, generating 24 tincture tests for comparison.

    Objective 5

    Compare compound data from bark, leaf fodder, tinctures, across species, sites, and seasons to identify peak harvest windows and evaluate economic implications for fodder use, tincture production, and winter feed strategies.

    Objective 6

    Translate research findings into farmer-friendly tools: harvest guidelines, value-added product pathways, enterprise budget templates, and willow management recommendations. Share results through field days, written guides, website and Substack articles, a regional webinar, and partner distribution networks.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.