Lake Sturgeon, Ice Coverage, and Tree Identification: this week in environmental news

lake-sturgeon

Juvenile lake sturgeon. Image: Michigan DNR.

Seasonal lake sturgeon releases put nearly 8,000 fish into Michigan waters (Michigan DNR): The Michigan Department of Natural Resources and several partners released more than 7,800 juvenile lake sturgeon into various public waters across the state this summer and fall in an effort to rehabilitate this culturally significant fish species. The juvenile fish were collected from the wild last spring and reared in streamside facilities until they reached at least seven inches or larger in size. Most fish were tagged prior to being released into their respective rivers to allow future evaluations of stocked fish.

ice-cover-graph

Ice Chart for Nov 28, 2013. Image: GLERL Digital Ice Database

How much ice should we expect to see on the Great Lakes this winter? (MSU Extension): Our last really big ice cover winter for the Great Lakes was 2013-2014 where over 92 percent of the Lakes were frozen over. So, during a really good ice winter, like that of 2013-14, how early did ice start forming in the Great Lakes? As early as Thanksgiving, 2013, (November 28) ice had already started forming and by December 31, 2013, there was significant cover. Now fast forward to 2016. There is no ice formed anywhere in the Great Lakes and we are past Thanksgiving. The reason is that all the Great Lakes are at their highest average temperatures for at least the past 5 years. As researchers continue to study and gather data on Great Lakes ice cover, we will begin to more thoroughly understand impacts, implications and ecological functions of Great Lakes ice cover.

Tree identification (MSU Extension): Michigan boasts around 100 tree species, depending upon how a tree is defined. There are about a dozen characteristics available to help identify trees. Learning which subset of characteristics to use for a particular tree is where practice and skill are needed. Some characteristics are seasonal, such as leaves, fruits, and flowers. Most others are more year-round, such as twig and branching patterns, buds, bud scars, bark, tree form, site, and tree associates.

Online tool combats sales of invasives (Great Lakes Echo): The Great Lakes Commission created a web tool designed to prevent sales of aquatic invasive species over the Internet. The software searches the web looking for sites selling plants or animals invasive to the Great Lakes and then records the data. The project’s director says most of the invaders purchased are aquatic plants. They make their way from homes into the environment. Being aware of what you buy is key to preventing accidental purchases of invasive species online.

Deciphering Michigan’s Snowy Forests

By Mitch Lex

As the heart of winter approaches and the beautiful colors of autumn are replaced by naked trees and blankets of snow, differentiating the many types of hardwoods in the mitten state becomes seemingly impossible. Separating conifers and deciduous trees (those that lose their leaves seasonally) might be the only observation one can think to make, but identifying trees like oak, maple and birch can be just as easy in the cold months of winter as it is in the heart of summer or spring—if you are looking for the right things. Although subtle, there are several defining characteristics that can be spotted on bare trees that will help you identify the many species we have here in Michigan.

The first distinctive characteristic to look for when classifying is the branching formation. Trees will have one of two formations—opposite or alternate. Opposite branching is when smaller stems are paired, with one on each side of the larger twig. Maple, ash, and dogwood are all examples of trees that exhibit opposite branching. Alternate branching occurs when the smaller twigs alternate on either side of the larger branch, such as birch, elm and redbud trees. These branching features are often more visible and easier to distinguish in the winter months than they are in warmer seasons when the leaves can disguise them.

Besides the more obvious alternate and opposite formation of twigs, there are a few more subtle differences that can be seen by those with a keen eye. The thickness of twigs, as well as how many there are, can be a telling factor in the tree species—maples and elms tend to have many smaller, thin twigs, while trees such as the walnut have fewer and thicker twigs. For those who are very observant, the buds at the tip of each twig vary dramatically between species and can differ in size, shape, color and texture. Basswood trees, found commonly in Michigan, have a unique bud structure that is a maroon red color and has two scales. Unique features on a branch like the thorns covering a hawthorn tree are also good indicators.

As the most visible and easy part to observe, the bark on trees can be one of the simplest ways to differentiate species all year round. Ridges, flakes, colors, textures and patterns are just a few properties of bark that can help distinguish tree species. The white ash, one of the most common trees throughout the state, has a distinctive diamond shape pattern throughout its ridges that make it easy to identify. Another common tree in Michigan, the paper birch, is known for its white-colored bark that peels in horizontal strips and has small black scars along the trunk.

Fruits, nuts or seeds can also be good species indicators. Animals, wind, or other factors can move these, so the seed or nut must still be attached to the tree unless you are certain of its origin. Nuts from the hickory tree and acorns from several different oak species are just a couple examples that are easy to identify.

These are just a few basic methods to help identify different trees throughout the state in the harsh months of winter. There are many tree identification books available that can help you more accurately classify species and their characteristics. With more than 100 different species and 18 million acres of trees in the state of Michigan, there is plenty of exploring and identifying to do in our forests. I hope this has been a good starting point for your winter adventures!

For more information on deciphering tree species, check out this dichotomous key!