Birch Bark Canoe Workshop

Have you ever seen a birch bark canoe being built? Check out the upcoming Language Immersion & Canoe (Jiimaan) Building Project being held from 08 – 28 June at the Fond du Lac Reservation Cultural Museum. A team of master bark canoe builders and Ojibwe language experts will guide 8 students through the harvest of materials and creation of a birch bark canoe, a process that takes around 3 weeks. The daily workshops are open to the public and those interested can attend for as little or as much time as desired. The FDL Cultural Museum is located at the intersection of Big Lake Road and University Road off of Hwy 33 in Cloquet. Canoe building activities will occur outside under the wigwam. For information contact the Museum at 218.878.7582.

Saps and Syrups in Minnesota

Maple Syrup

It’s time to start tapping the sugarbush when we start to have warm days (above freezing) paired with cold nights (below freezing). Tapping Maple trees (Acer spp.) is a great spring activity for individuals, families, and friends. The ratio of sap to syrup is determined by the rule of 86 (86 / % sugar in the sap), and is roughly 45:1. Small producers, those with only a few trees, can freeze sap until sufficient quantity has been collected for processing. Maple sap is most often processed by reducing the sap to syrup through boiling or, more recently, through reverse osmosis. The resulting Maple Syrup can be consumed, traded, or sold. In some cultures, the sap is consumed without processing as a medicinal tonic. Putting a new twist on the old, Wind Tree Winery in Cloquet, MN produces a Maple Syrup wine. Demand has exceeded supply in the last few years and prices look to be great this year.

Each year, University of MN Extension offers Maple Syrup Clinics in different locations throughout the state. For those unable to attend, Extension has produced several publications on Maple Syrup and there is a MN DNR video on the process. There is also the MN Maple Syrup Producers Association. Ohio State Extension’s Maple Syrup Producers’ Manual (see image below) is a comprehensive resource for producers.

Birch Syrup

When spring peepers hail the end of the Maple Syrup season, a few hardy producers switch gears and collect birch sap. Tapping birch trees is much like tapping maple, but the similarity ends there. While maple sap contains sucrose, the natural sugar in birch sap is fructose.  Birch sap, collected from Paper birch (Betula paperifyera) also contains several vitamins and minerals including vitamin C, potassium, manganese, and calcium. Native American Indians have long known of its medicinal benefits and there are many cultures that bottle the sap for a health drink. Alaska has several major producers that create a variety of birch products. On average, 100 gallons of birch sap are needed to make a gallon of birch syrup.The sap is processed differently, with boiling techniques that evaporate water and avoid burning the fructose.

Connoisseurs also tap yellow birch (B. alleghaniensis) in early spring, before the leaves unfurl.  While yellow birch bark is a known source for ‘Wintergreen Oil” the sap is sweet with a slight wintergreen taste that is boiled to create syrups and flavor beer and wine.  Yellow birch sap is known to have a sweet flavor, with very low sugar content. Stay tuned for a forthcoming post about our yellow birch tapping trial!

For more information on NTFPs:

• University of Minnesota Extension: Dave Wilsey (dwilsey [at] umn.edu) or Julie Miedtke (miedt001 [at] umn.edu).
• Careful harvest brochure. (M. Demchik, J. Miedtke, K. Preece, and J. Zasada)
• Nontimber forest products and implications for forest managers. 2002. M.Reichenbach, J.Krantz, and K. Preece. University of Minnesota Extension.
• Nontimber forest products in the United States (book). 2002. E.T. Jones, R.J. McLain, and J. Weingard. University Press of Kansas, Lawrence.
• Plants used by the Great Lakes Ojibwa. (book). 1993. J.E. Meeker, J.E. Elias, and J.A. Heim. Great Lakes Indian Fish and Wildlife Commission (GLIFWC), Duluth.

Research report: Promoting birch in mixed stands

Want to grow quality paper birch in mixed aspen-birch stands?  An article in the September 2008 issue of the Northern Journal of Applied Forestry reports dramatic results from early birch release in mixed birch-aspen stands in Minnesota.

Sprout selection in paper birch: click for a better view

Study purpose and design: The research was designed to evaluate the impact of early timber stand improvement (TSI) in mixed stands at the Cloquet Forestry Center.  Before treatment, stands were 16-18 feet tall with 1500-3000 stems per acre of paper birch and trembling aspen.   Three different treatments were implemented.  In each case, birch stems were released.  This means that competing aspen or other stems were removed to give the birch more growing space.

The release treatments differed in intensity, with post-treatment stem densities from 250 to 750 stems per acre.  Preference was given to birch stems, but red maple and aspen were also retained where no birch was present to meet the spacing requirements.

Results and discussion: All three treatments led to major increases in the birch component relative to aspen.  In the control (untreated) plots, birch formed only about 14% of stand basal area six years post-treatment.  In the treatment plots, birch formed 77-87% of stand basal area.  There was little difference among treatment intensities.  The increase in birch basal area as a percent of the total basal area was due mostly to reduction in other species, but also to increased birch growth.

Relevance for woodland owners: If you’re trying to grow birch, this article should be of great interest.  With a brushsaw in a young stand, you can quickly release seedlings of birch or other species you want to promote.  This Minnesota study documents significantly reduced birch mortality and increased birch growth as a result of the treatment.

In different stand types, TSI could lead to other desirable outcomes.  For example, releasing oak or other masting species can enhance habitat quality for mast-eating wildlife like deer or wild turkey.

Brushsaw

What about financial outcomes?  Early and frequent thinning is usually the best way to optimize stand productivity and value.  Although these treatments may be expensive (and in some cases cost-prohibitive) with paid labor, well planned treatments can dramatically enhance the value of subsequent thinnings and the final harvest.  If you can do the work yourself or with family, your costs will be low and your return on investment greater.

Thinnings and TSI do not increase overall stand growth over time.  However, by focusing growth on a smaller number of the best stems in the stand, TSI can move stems into higher-value classes (e.g. sawtimber or veneer vs. pulp) more quickly.

For this study, trees were selected for retention based on the following criteria:  “(1) upper crown classes, (2) vigorous and healthy stem, (3) good bole quality, and (4) uniform spacing relative to other leave trees. Birch stump sprouts were thinned to one or two sprouts that werethe most vigorous and straight and that started low on the stump” (p. 125).  These same or similar criteria would apply to most TSI treatments.

TSI benefits can be quite variable, and there may be important reasons not to implement treatments like this in your woods.  Every site is unique, and it’s important to talk to a local forester about species selection, optimal spacing, and other considerations before heading to the woods with your brushsaw.

NJAF cover (c) SAF

More about the reviewed article:
Zenner, Eric K.; Puettmann, Klaus J. 2008. Contrasting Release Approaches for a Mixed Paper Birch (Betula papyrifera)-Quaking Aspen (Populus tremuloides) Stand. Northern Journal of Applied Forestry, Volume 25, Number 3, pp. 124-132.

Editor’s note: This is the first in a series of research reports. To comment or suggest topics, either click “leave a reply” below or email esagor-at-umn-dot-edu