Firewood Removal for Forest Stand Improvement in Transitional Hardwoods

1. Name - Yale School Forest Firewood Thinning

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The Yale Forests are maintained as working forests, which includes selling timber and non-timber forest products from the land while also providing educational, research, and professional opportunities. The Yale Myers Forest is certified by both Forest Stweardship Council and Sustable Forestry Initiative. The Yale Myers Forest covers 7,840 acres in northeastern Connecticut. The forest is set on rocky terrain cut by a number of parallel, small ridges that run from southwest to northeast. The elevation varies from 190 meters to 330 meters and slopes rarely exceed 40%. The most recent period of glaciation covered the metamorphic bedrock with glacial till soils, which are moderate to well-drained sandy loams. The forest is a mix of hardwood, pine, and hemlock that grew after the area had been cleared for agriculture in the late 19th century. Much of the forest is even-aged at about 100 years old. Although there are many stands of quality hardwoods and white pine, regeneration goals often require removal of low-value hardwoods.

This example comes from an 18 acre sale than included two stands: 1) a 55-year-old even-aged white pine stand in the midst of understory reinitiation, 2) a second-growth hardwood stand about 90 years old in the late stem exclusion stage.

The silvicultural goal for the first stand was to reallocate available canopy growing space to the white pine crop trees with the best form and vigor. In addition, the harvest aimed to promote white pine regeneration by releasing the existing suppressed understory of white pine saplings, destroying the striped maple subcanopy, and redistributing enough growing space to the groundstory to allow for the establishment of new regeneration. The harvest was a crop tree thinning with variable spacing on the crop trees. In order to reallocate growing space to the suppressed understory, spacing between retained trees was up to 60 feet. In areas where existing regeneration was sufficiently well-established, the overstory was removed altogether.

The silvicultural goals for the second stand were also to improve the growth of crop trees and promote the establishment of desirable advanced regeneration. Crop trees, mostly oak, were left at approximately 30-foot spacing. Trees removed included firewood- and sawlog-sized trees that were poorly formed, diseased, or stressed, or individuals that had been overtopped by crop trees competing for growing space in the same canopy stratum. Most sugar maples and other shade-tolerant species were left because they were not in direct competition with the intolerant or mid-tolerant crop trees.

The total harvest generated about 61 thousand board feet (MBF) and about 11 cords of firewood. The site was harvested by a contractor with a Timbco feller buncher and rubber-tired forwarder. Sawtimber was taken to a local mill and firewood was also sold locally. Harwood prices ranged from $30 per MBF for hickory to $220 per MBF for red oak. Firewood was priced at $10 a cord, which is about equal to the cost of sale administration and removal so firewood generated no income for the landowner. Firewood markets in the area fluctuate from year to year. In some years, removal of low grade trees is a cost to the landowner. During weak firewood markets, sale of sawlogs must subsidize removal of low-grade trees where silvicultural concerns require their removal. Alternatively, forest stand improvement projects have often been postponed until firewood prices increase.

Wildlife considerations in the sale included mast trees, snags, and group reserves. Mature, seed-bearing oaks, hickories, and wolf trees retained in the stand will provide a continuing source of preferred hard mast for wildlife. Snags were left to provide habitat for cavity-dwelling birds and small mammals. Four trees were converted into snags via either topping or girdling. Two small group reserves of hemlock and Norway spruce will provide undisturbed thermal cover for deer and lend species diversity to the future stand.

In both stands the ability to remove suppressed and poorly formed trees was crucial to achieving the silvicultural goals. About five trees per acre, for a total of 92 trees, were removed to open up growing space for crop trees to encourage advanced regeneration. Without markets for firewood, it is difficult to achieve the regeneration goals in the forest, because stands remain too shaded to encourage shade-intolerant or mid-tolerant species.

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