Justin Heavey

Willow and poplar short rotation woody crops (SRWC) have shown promise with regards to environmental benefits and rural development but wide adoption lags due to underdeveloped markets and supply systems. High costs associated with harvesting, handling and transportation (40-60% of delivered cost) have impeded expansion. A better understanding of these systems will create opportunities to improve efficiency, reduce costs, and realize environmental benefits and impacts. The project’s goal was to lower the delivered cost of hybrid poplar in the Northwest and willow in the Northeast by optimizing harvesting and logistics supply systems while maintaining or improving biomass quality along the supply chain. Over 3,400 Mg of biomass and 300 ha of willow and poplar were monitored over a range of crop and field conditions. Feedstock quality as affected by storage and preprocessing were shown to improve or maintain feedstock quality. Modeled harvesting costs ranged from $38–61 Mg-1 dry; when including delivery and preprocessing feedstock costs ranged between $79-83 Mg-1 dry for willow and $106-116 Mg-1 dry for poplar. Costs for willow minimized when hot water extraction and high-moisture densification preprocessing were used. Models also suggest that social and regional factors could further reduce costs. Results will give guidance to feedstock growers, harvesting and logistic operations, biorefinery project developers, and policy makers developing SRWC to support a growing bioeconomy.

Driven by the challenges of rural development, energy independence and environmental sustainability, research on willow biomass crops for renewable energy and environmental applications has been ongoing at SUNY College of Environmental Science and Forestry (ESF) since 1986. SUNY-ESF has teamed up with more than 20 universities, commercial partners and non-profit organizations throughout the U.S. and Canada to conduct research and facilitate the commercialization of willow biomass crops.

Living snow fences require care and monitoring for several years after planting. The length and type of care varies based on the plant species, site conditions, and the quality of site preparation. Once plants are well established and have achieved sufficient height growth, care and monitoring can be reduced or eliminated. Plants of the same age and height are needed for effective and continuous snow control along the roadway. Monitoring of snow fences is essential so that problems with dead or slow-growing plants are quickly identified and solutions can be developed and enacted.

Coppicing is a form of management for certain woody plants that has been used for centuries. The process involves cutting stems near the ground and allowing new stems to grow from the part of the plant that is left behind, which is referred to as the stool. Coppicing living snow fences is a maintenance practice that increases the number of stems on each plant. A larger number of stems on each plant increases “density” of the living snow fence, lowering the optical porosity and allowing fences to become functional more quickly. Coppicing improves the vigor of many species, and has been shown to accelerate the overall aboveground growth of shrub-willow. The information and techniques described in this fact sheet are primarily intended for coppicing shrub-willow plants, but may be applicable to other species with coppice potential as well.

After the site assessment and design phases, it is important to properly prepare the site before planting a living snow fence. Investing adequate time and resources in thorough site preparation will improve growth rates and long-term survival. Site preparation will minimize the time it takes for a living snow fence to become effective, and maximize the return on investment. The practices listed in this fact sheet are considered best management practices that can be applied to all types of living snow fences. This includes all species of evergreen trees and woody shrubs recommended for living snow fences. The site preparation tasks summarized here can be followed in the order they appear to achieve sufficient site preparation and improve the health and vigor of living snow fences. Roadside environmental conditions can be stressful to plants in a number of ways. Site preparation improves site conditions as much as possible to give living snow fences an advantage over competing species in stressful roadside conditions.

Two general categories of plant materials, rooted and unrooted, can be used for living snow fences. The planting techniques used with rooted plant materials are different from the techniques used with unrooted plant materials. Types of rooted planting stock include balled & burlapped (B&B), potted, bareroot, and seedlings. Types of unrooted planting stock include species that can be planted as single stem cuttings without pre-formed roots such as shrub-willows. Step by step planting techniques for both rooted and unrooted stock are provided in this fact sheet in the general order they should be performed.

The design of living snow fences involves several components. This fact sheet offers a general protocol for the basic elements of design: Fence Orientation, Snow Fall, Fetch Distance, Snow Transport, Required Height, Selecting a Design Age, Optical Porosity, Fence Capacity, and Setback. The general guidelines presented here are adapted from “Controlling blowing and drifting snow with snow fences and road design” (Tabler, 2003), and “Climatological analysis for snow mitigation in New York State” (Tabler, 2000). It is recommended that these sources be consulted to supplement the basic information provided in this fact sheet. After the site assessment phase has sufficiently identified the blowing/drifting snow problem at a site (see Fact Sheet #2 of this series and Chapter 4 in Tabler 2003), the steps in this fact sheet can be followed in the order in which they are presented to create a basic living snow fence design to address the problem. A case-study example from a real living snow fence designed using this step-by-step protocol is provided at the end of the fact sheet.