The term “forestry” often evokes a myriad of images. From Smokey the Bear and Woodsy the Owl, to California’s current wildfire crisis, mechanized timber harvests, and majestic old growth forests, the term forestry encompasses as many concepts and issues as it does emotions. The definition of forestry is “the science of planting and taking care of trees and forests; the process of establishing and managing forests.” As humans we have long relied on timber and firewood as a basic and often readily available resource for energy, housing, warmth, and tools. As far back as Roman times, people realized the importance of trees and began practicing preservation and management techniques. Today, modern forestry has advanced to include not just forest management but genetic manipulation, wildlife preservation and monitoring, water quality control, biodiversity management, recreational considerations, and carbon sequestration surveying. There’s no doubt people and trees are patently linked in environmental, social, and economic ways.
Timber or lumber is processed wood that is ready for use in building and production. Foresters must be adept at predicting the amount of millable wood in a forest to determine its economic value. They use the tree’s board-foot volume as the means of measurement: a board-foot is 144 cubic inches – picture this as a 12×12 inch piece of wood that is one inch thick. Foresters start by measuring the trunk circumference at breast height (4.5 feet above the ground) to determine the tree’s diameter. Next, they measure the “merchantable height” – the height that can realistically be cut into lumber. This is the height of the tree, less one foot for the stump, to the height where tree tapers to 10 inches around. This measurement is then divided into units of 16-foot logs and 8-foot half logs. Once these two measurements are determined (the diameter and the number of 16-foot logs), foresters use a data table called the “International 1/4-Inch Rule” that calculates the viable board-feet. For example, a 12 inch diameter tree with 1 16-foot log has 60 board feet. Different species of trees then sell for differing prices, from around $3 per board-foot for poplar, or about $5 per board-foot for oaks, all the way to $40 per board-foot for teak. Learn more and see the 1/4-Inch Rule chart on Ohio State University’s School of Natural Resources.
The forestry industry has a significant economic impact in Wisconsin. According to the Wisconsin Department of Natural Resources, the forest industry accounts for over 59,000 jobs and an output of $22.9 billion. Wisconsin tops the US in paper production and wood furniture manufacturing, and several northern counties mark forestry as the number one employer. Find out where your county ranks in forestry employment, dollars of output, and acreage of forested land on the DNR’s Forestry Factsheet.
Most work with genetic improvement in forestry is focused on conifers. Scientists are striving to selectively breed pine trees that produce offspring with vigour, solid shape, and quality wood. Some programs also seek to breed species that are disease and insect resistant, or tolerant of drought or cold. One current project at the State University of New York’s College of Environmental Science and Forestry is working with genetics to help restore the nearly extinct American Chestnut tree – find out more from this article in Scientific American.
Did you know…
Pine trees grow a new ring of branches each spring. Each horizontal layer of branches, called a whorl, thus represents one year of growth. The next time you examine a pine tree, note how the branches grow in whorls and estimate the tree’s age by counting the number of whorls along the length of the trunk. Places where the whorls grow close together indicate a poor growing season.
Have you ever eaten a pine nut? Did you know pine nuts are harvested from the cones of pinon or Siberian pines? These trees are not grown on a plantation but grow wild, often in remote places, and the cones are harvested each year from the forest floor by local residents. This, in part, explains their high cost at the grocery store but some believe deforestation and climate change are also affecting pine nut harvests. Find out more from NPR.
To Do This Month:
There is so much happening at Nature Net sites this month. Keeping with the Forestry theme, you could take a Woodlands Walk or learn why leaves change color at the UW Arboretum’s Earth Partnership for Families program on October 11th. Or “Discover Madison’s Wild Side” on a Madison Conservation Parks’ guided hike of Owen Woods on Wednesday evening on the 14th. Or become adept at wielding a chainsaw at the Aldo Leopold Foundation. But there’s plenty of other topics to explore including fermentation, effigy mounds, good neighbors, badge work for scouts, and haunted hayrides. Enjoy the fall season and post your colored leaf pictures to the Nature Net facebook page!
LEAF Forestry Education
The Wisconsin K-12 Forestry Education Program, commonly known as “LEAF” provides professional development and curricula to help promote forestry education in Wisconsin schools. Because LEAF believes humans are dependent upon and connected to the earth’s systems, and that forests are life support systems, their mission is to provide a holistic teaching perspective that underscores the fact that we all use forest products and that sustainable forest management benefits us economically, ecologically, and socially. If students have an understanding of the diverse values of Wisconsin forests, they can make informed decisions and be engaged citizens.
To that end, LEAF makes it easy for teachers to integrate forestry education into their classroom routines: lesson plans are aligned to Wisconsin state standards in several areas, including Language Arts, Mathematics, Science and Social Studies; LEAF provides free on-line lesson plans, ideas, and instructional videos; and they offer workshops and presentations throughout the year. LEAF also coordinates the state’s 200+ School Forests (that’s over 28,000 acres of land) and offers ideas for time spent with students at your local School Forest, including environmental monitoring, estimating and graphing, patterns in nature, and soil or water studies.
Nature Net staff are big fans of some of the materials provided in LEAF’s Lesson Guide, including the real-life connections students are invited to make with world around us. They include forestry career profiles, and hands-on, get ’em outside field enhancements that can be used right outside the classroom door. PS there’s a workshop coming up in the Madison area in early November – sign up and get first hand information and training.
How Old is That Tree?
It’s safe to say that people of all ages will tell you the best way to learn a tree’s age is to cut it down and count the rings – and this would be true. However, with a little math and a secret formula (which we will reveal shortly) there is an alternative method that does not cost the tree its life.
Procedure: Find your favorite tree and measure 4.5 feet up the trunk from the ground. At this height, use a tape measure to determine the circumference around the outside of the tree – be sure to do this in inches so the formula works correctly. Now that you have the circumference, you can determine the diameter by dividing the circumference by pi – that’s 3.14 (see, your teacher told you geometry was going to come in handy later in life). Next, calculate the age of your tree by multiplying the diameter by the tree species factor (an expression of a tree species growth rate).
Since each tree species grows at a different rate, the species factor varies even within species. Here’s a few common Wisconsin trees and their respective species factors:
White Oak – 5
Red Oak – 4
Hickory – 7.5
Black Cherry – 5
Walnut – 4.5
Silver Maple – 3
Sugar Maple – 5.5
White Pine – 5
Red Pine 5.5
So, for example, one of our favorite walnut trees at Aldo Leopold Nature Center measures 37 inches around. Divided by pi, that’s 11.8, times a factor of 4.5 is 53 years!
Not sure which tree you’re trying to age – or how to tell a Silver Maple from a Sugar Maple? Check out this site from the Department of Natural Resources, or download the “Key to Woody Plants of Wisconsin Forests” from the app store.