I think all the "rules" allow most of us to go out by ourselves or in a small group......if so, it's a great time to observe some unique forest wildlife behavior in northern Michigan.....
Perhaps it's a good time to get out at dusk to hear/see American Woodcock males peent in an opening next to some young aspen?
Or go into some mature mixed conifer/deciduous woods to hear/see male Ruffed Grouse drum on a large, rotting log in the early morning?
Or see male and female Sandhill Crane unison call and dance in pine openings or in hayfields?
Or go to the eastern UP (when allowed) and see male Sharp-tailed Grouse dance in the morning in pine openings or hayfields?
Forest types are largely defined by the dominant tree species within the canopy of a stand. However, the under-story regeneration often varies, sometimes suggesting long-term forest type changes.
Bill Cook, Michigan State University Extension - March 16, 2020
Over decades, forests undergo somewhat predictable changes. Foresters call this “forest succession”. One of the best indicators of where a forest stand might be headed is from examining the regeneration. Without major disturbance, there’s a pretty good chance the seedlings of today will become the dominant forest type of the future.
Different forest types have various track records in their ability to reproduce themselves over time. Northern hardwoods can sustain themselves for centuries. Signature species, such as sugar maple, beech, and basswood, can grow in the shade and will take advantage of small canopy gaps as old trees gradually die.
On the other end of the spectrum, paper birch and red pine stands have very low percentages of their own seedlings in the under-story. These are sun-loving tree species. Without disturbance, other forest types will replace these forest types.
Paper birch stands are likely to become balsam fir or northern hardwoods. Red pine stands will trend more towards red maple, black cherry, and different species of oak. Similarly, aspen stands tend to be replaced by red maple or balsam fir. Aspen is particularly popular with most game species and a growing number of birds with declining populations.
Enter disturbance. Over the decades, the likelihood of a major disturbance increases. Such events as wind, wildfire, and pest outbreaks will open the forest floor to lots of sunlight and soils will warm somewhat. These conditions will favor the light-loving species, which tend to grow faster than the more shade tolerant tree species.
Forester and forest owners can mimic these events through management and timber harvesting. Practices such as clear cutting and shelter woods can help maintain forest types such as aspen, red pine, jack pine, and paper birch. Regeneration strategies of these tree species depend upon major disturbance.
In the bar chart, the green bars (lighter gray on the left) indicate a forest type’s ability to regenerate under its own canopy. There is a high percentage of signature species already in the under-story The red bars (darker gray on the right) suggest a need for a major disturbance in order to regenerate, as little regeneration of the signature species exists. Left alone, these “other” species will eventually replace the existing trees.
Most of the Lake States forests are adapted to natural disturbances. Since the glaciers melted about ten thousand years ago, the forest area has ebbed and flowed. Our forests have needed to be flexible. The region historically tends to have large sweeping storms, fires, and major insect outbreaks Native American intervention increased the role of wildfire.
As certain forest types matured, the trees served as host to widespread insect epidemics. Thousands of acres of fir-spruce would be killed by the spruce budworm. Large expanses of old jack pine fell prey to the jack pine budworm. Periodic outbreaks of forest tent caterpillar would defoliate and kill great swaths of aspen.
Wildfire would often result from the huge fire loads created by so many dead trees.
After these catastrophes, the fir, spruce, jack pine, and aspen forests would grow back Such is the way of natural cycles.
With human infrastructure spread nearly everywhere, these calamities came with unacceptable risk to people. Forest management has been developed to reduce the negative effects of natural disasters while maintaining those benefits that different forest types depend upon.
Red pine and paper birch still need major disturbances in order to maintain themselves. However, forestry has provided the solutions to help those forest types and humans coexist. So, the next time you see a clearcut jack pine stand, be grateful the jack pine is being regenerated without a forest fire.
This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).
What a simple word: science. Two short syllables, easily pronounced. Yet, to many, science is mystifying. As we cope with COVID-19, perhaps it is a good time to discuss how science works? According to the National Academies of Sciences, our most prestigious scientific organization, science is, "the use of evidence to construct testable explanation and prediction of natural phenomena, as well as the knowledge generated through this process." To practitioners, science is a process, a product, and a culture. As a human construct, science---by its very nature--is imperfect. But the scientific process acknowledges and addresses imperfections by specific actions aimed at improving data quality, reducing conflict of interest, and increasing repeatability. Science begins when curious individuals ask novel questions. These novel questions are then answered (imperfectly) through the structured collection of data, data analysis, and the preparation of a manuscript describing background, methods, results, and implications of findings. The manuscript is then subjected to peer-review. Peer-review is defined as, “the process of evaluating scientific work by a group of experts in the related field. It is also known as refereeing because the work or project must be critiqued before it is published, funded, or implemented.” Explicitly, peer-review takes into account conflicts of interest. Reviewers are expected to have no relationship with the authors of the submitted manuscripts, making peer-reviewed manuscripts quite different than a report coming from an individual organization or office. Reports often suffer by not being refereed by outside entities devoid of bias. Science is communicated among professionals in a written format. A good scientific moto is: beware what you hear, be skeptical of what you read. The product of peer-reviewed science is called a “paper”. Papers are published in “journals”. Journals, such as Forest Ecology and Management, The Journal of Wildlife Management, or the countless other journals in an array of disciplines compete for prestige either regionally, nationally, or internationally. Journals have a Board, an Editor, and a suite of Associate Editors. These scientists set the direction for the journal and oversee the selection of reviewers that evaluate the quality of submitted manuscripts. For some journals, acceptance rates (the proportion of submitted manuscripts done well enough to be accepted and represent the standards of the journal) can be as low as 20%. The more prestigious the journal, the higher its standards and lower its acceptance rate. For forest and wildlife ecologists, the entire process--from posing a question to seeing a paper through the peer-review process and published in a journal--may take years. Besides describing many aspects of the scientific process, papers also acknowledge the contributions of individuals and organizations. So, what are textbooks? One can think of textbooks as a compilation and summary of relevant papers on a topic. Because science changes, textbooks are updated fairly often. Each new version of a textbook summarizes and references recent papers and those whose findings have lasted the test of time. Science is a human enterprise aimed at serving society by advancing knowledge. Science does not make decisions, but allows decisions to be evidence-based. Not surprisingly, natural resources management guidelines change over time because the scientific foundation they are based on changes and the contexts in which the science is applied change. Natural resource management in 2020 is very different than management in 1950. If we think our knowledge of the natural world is complete, or if we think “one-size-fits-all” approaches apply, we may be fooling ourselves in many instances. Unfortunately, some decisions occur without the transparency of the science that is meant to guide the art that is management. This may occur because too few scientists are employed within our institutions or too few of our leaders are scientists. Scientists are needed to instill a culture of science. A culture of science encourages curiosity and rigorous debate based on data and methodology. At its core, a culture of science openly challenges dogma and rhetoric. Social vagaries, social sensitivities, group thinking, or politics can squash a culture of science. As a critical component of evidence-based decision making, the public should support a culture of science throughout all phases of society. While healthy skepticism is important, the public should also strive to be informed on the current state of science as it relates to issues that impact our lives. Always ask if findings being presented have been published and, if so, where. If interested, Google Scholar can be used to see what science is being done, where, and by which scientists (keywords can include topics of interest, locations, names of authors, or a combination). In science, process, product, and culture matter. Greg Corace is the forester for the Alpena-Montmorency Conservation District. For more information, including sources used in this article, Greg can be contacted via email (email@example.com) or phone (989.356.3596 x102).
The study of cyclic changes in the natural world based largely on climate’s effects on plants and animals is called “phenology.” In northern Michigan, many of us welcome the cyclic change we observe this time of year as the days get longer and warmer. And perhaps nothing is more a harbinger of spring than sap flow in our sugar and red maples, when cold nights are followed by warm days. But how does the process of sap flow work and what can a private landowner do to promote vibrant trees from which sap can be collected and syrup made? “Physiology” refers to the mechanical and chemical workings of plants and animals. Sap flow in maple trees is a physiological process driven by phenological change. To understand how and why sap flows in a tree one must understand how a tree produces and stores its energy and how it transports water and other materials from its roots to its leaves. Most green plants, including trees, produce energy through “photosynthesis.” Plants are called “phototrophs” because they use light energy (photons) to combine the gas carbon dioxide and water to produce sugars. In this process, oxygen is released. Without green plants, animals would not have oxygen they need to live. And without the sun, plants would not be able to produce energy. While all green plants need sunlight, some tree species need more sunlight than others. We refer to tree species that require less sunlight as “shade tolerant” species, and those requiring more sunlight as “shade intolerant” species. All native maples, as well as American beech, ironwood, and a few other of our deciduous tree species, are shade tolerants. These species are able to produce energy with relatively little sunlight. This energy (in the form of sugars) produced by photosynthesis is used to meet the demands of tree growth and maintenance. When excess sugars are produced, they are stored in the tree roots. Conversely, other tree species, such as aspen and oaks, are shade intolerant and need more sunlight. These tree species rarely produce extra sugars and do not typically store much energy. Tree sap is primarily a mix of water and sugars. Tree sap move in tubes in a manner slightly similar to the way blood moves in our arteries and veins. The tubes in which maple sap typically flows is called “xylem” tissue. Dead xylem is the “heartwood” of a tree and living xylem is the “sapwood”. Most of the material used in making lumber from a tree is xylem tissue. In other tree species, sap can also flow in the other tubes (phloem). Syrup made from other tree species has a distinctive taste quite different than maple syrup. During the spring of each year, sap flows from the roots, where sugars are stored in the winter, to the crown of the tree. Sap flows because of the pressure in the roots is greater than the pressure in the crown. What can a landowner do to promote vigorous maple trees form which syrup can be made? Tree vigor is the primary consideration for syrup production. Vigorous trees with large, healthy crowns tend to make and store more energy and produce more sap. Site (soil type) and location, as well as tree genetics, are factors that influence tree vigor. On sites with well drained, upland soils and plenty of sun (often south facing slopes), maple trees can thrive and be vigorous, especially if competition with other trees is reduced. When provided more sunlight, a maple tree will respond by growing more leaves and a bigger crown. This is the type of tree that if not impacted by disease or physical harm can produce sap for decades. Thinning a forest to produce trees of 10-25 inches in diameter separated by 20-25 feet is a good starting point. Removing diseased trees or trees of low vigor can promote more diameter growth on the retained trees. Do not, however, reduce overall stand tree diversity. Forests with more tree diversity tend to be healthier overall, and a vibrant maple stand (sugarbush) produces more maple sap. To capture sap, the general recommendation is that trees less than 20 inches in diameter should have one tap, while trees over 25 inches may have up to 3 taps in a given year. Just like all types of forest management, managing a sugarbush depends on many factors and involves a great deal of art guided by science. In the end, an understanding of how a tree, and a forest, forms and functions provides a solid foundation for planning and management. Greg Corace is the forester for the Alpena-Montmorency Conservation District. For more information, including sources used in this article, Greg can be contacted via email (firstname.lastname@example.org) or phone (989.356.3596 x102)
Dr. Greg Corace
Want to hear about what is new in the science world? Maybe get more information on the birds around us? Or maybe you want to keep up to date on what is happening in our current environment and with the natural resources we love. Check out some interesting articles shared by our Forester, Dr. Greg Corace.