Friday, December 30, 2011

Miracle Under the Oaks

Oak woodland where management practices similar to what is discussed in the book "Miracle Under the Oaks" have been implemented.
Recently, I read William Stevens’ book “Miracle Under the Oaks.”  This is an absolutely fantastic book of the scientific drama a group of non-scientists experienced as they learn how to, and restore prairies and oak savannas along the Chicago river.  Beginning in the late 70’s, Steve Packard lead a group of volunteers to restore the tallgrass prairies in north east Illinois.  These volunteers were composed of ordinary citizens who really had no idea how to restore a prairie.  Carpenters, doctors, pharmacists, people from all walks of life with no formal scientific background, self educated themselves and learned through trial and error how to restore the prairie.  As things began to pickup with the restoration projects, the general public and scientists began to take notice, becoming increasingly involved.  In the process of prairie restoration the volunteers rediscovered and helped define the Midwestern oak savanna, an ecosystem that once encompassed 30 million acres during pre-settlement time but today only 0.02% remains.  As a result, a movement has begun where thousands of acres of tallgrass prairie oak savannas are being researched and restored throughout the Midwest today.  This ecological restoration movement has not been isolated to oak savannas however, many other similar movements are taking place throughout the world in many different ecosystems as diverse as deserts to grasslands to forests.  Similar to the story in this book, these restorations are largely spearheaded by ordinary people without scientific backgrounds.  These ordinary people work together with the scientific community and often become experts in some portion of these projects.  Here is a great quote from the book showing how ordinary people can become valuable experts in a scientific subject through experience and self education:

“...I think there’s a lot of knowledge out there we haven’t taken advantage of.  One of the things that bothers me is the degree of arrogance you see among the so-called scholars and researchers who have gotten the notion that they have all the answers and who often look down with disdain at people who are just walking encyclopedias of bits of knowledge.”  Allen Harvey in Miracle Under the Oak

So the average non-scientist can become through self education and experience a sort of lay-scientist.  Where these types of people work together with the scientific community huge strides can be made in restoration of damaged ecosystems and habitats.  I truly believe common people can become experts on a subject if they have the desire to.  Formal education does not need to limit this, though it can help.  Formally educated scientists will always play a major role in science but the informal, lay-scientist expert can and should be playing a much larger role in science.  Yes, the application of lay-scientists will be different but their overall roll can and should be an important one in many areas of science.  The lay-scientist often has better access to land for ecological work and is not limited by availability of grant money.  They do it because they love it.  I love to encourage people to pursue things they love through self or formal education and become an expert of some type, the results are often amazing.  

Here is a link to one of the preserves Steve Packard’s group worked on:

More information on Midwestern oak savannas:

Red oak leaves and acorn.

Monday, December 26, 2011

Easy Enzyme Experiment: Rennet and Cheese Making

Curds separating from whey after being mixed with rennet.

Learning about cheese can be an amazingly diverse education in history, culture, as well as science.  Cheese making beautifully integrates both art and science, one without the other will result in a mediocre cheese at best.  Of course milk of all types is the primary ingredient in making cheese.  Along with milk though many combinations of bacteria, enzymes, aging processes, moisture, humidity, and other factors are controlled in the cheese making process.  Most cheeses found in the supermarket utilize a specific enzyme (or rather a complex of enzymes) called rennet.  Typically, rennet is one of the first things added to milk in the cheese making process.  Once added, it immediately starts separating curds and whey.  Rennet acts on the milk protein casein by making it non-soluble.  Milk is normally white because casein protein is dissolved and floating around in it.  However, when casein is made insoluble through the action of acids or enzymes like rennet, it precipitates out forming white clumps called curds.  For a few of the most basic cheeses only rennet is utilized.  Most cheeses found in the supermarket however utilize a combination of bacteria and rennet.  For this cheese making experiment we will only use rennet in order to display its function.

As with the history of yogurt, the history of rennet goes back many thousands of years.  And similar to how most great discoveries are made, rennet was likely discovered by accident.  Presumably, we can imagine, thousands of years ago some dairy worker ran out of milk containers.  The dairy worker also had probably just butchered a young animal and found a left over stomach.  Thinking the stomach would make a good milk container, filled it up and let it sit.  When the worker came back at a later time he would have been surprised to find the milk was now separated into curds and whey but not rotten smelling.  Then by draining off the whey the curds would have made the first cheese.  This would have been the first known accidental use of rennet.  

Being rennet begins the process of digesting milk it makes perfect sense that it would be found in the stomach of a young animal from the dairy herd.  This is in-fact where most rennet historically has come from.  Today however, rennet is often created by bacteria in a laboratory or derived from plant based products.  Various plants, for example stinging nettle, have enzymes in them that have effects on milk similar to rennet.  From what I have heard, animal based rennet works best.  But each cheese maker has their preferred and even secret type of rennet, and boy can they be opinionated!  I personally have used Junket rennet tablets with what I consider good results.  Junket and other rennets can be found and purchased on Amazon and occasionally in the supermarket.

How to make rennet cheese:

Materials: Spoon, stainless steel pot, thermometer, and strainer

Ingredients: Milk, water, salt and rennet

1. Heat the milk to 180 degrees Fahrenheit.  This pasteurizes the milk so no bacteria cause it to spoil.  Slowly heat milk and stir gently every once in a while to ensure milk does not burn.

2.  Depending on the directions on the type of rennet you purchase, mix up the rennet.  For Junket dissolve your tablet in ¼ cup of cool water.  I prefer to mix ½ tablet with ¼ cup water.

3. Let milk cool to about 100 degrees Fahrenheit.  Add the rennet solution and mix by st iring for about 1 minute.  

4. Let milk/rennet mixture sit as close to 100 degrees as possible overnight.  Let the mixture sit absolutely still, do not disturb!

5. The next day the curds should be separating from the whey.  Simply dump these through a strainer to separate.  The curds left in the strainer is the cheese.  Transfer the curds to another container and salt to taste.
Curds after straining and salting.
The body temperature of a cow is about 100 degrees, so it makes sense that rennet would work best at this temperature.  At cooler temperatures rennet either will not work or will work very slowly.  Warmer temperatures will break down, or denature, the enzyme so it won’t work at all.  

After the curds and whey are separated the resulting cheese will be very soft and will taste like milk.  Unfortunately, at least for this cheese, most taste is derived through bacterial metabolism.  What this basic rennet cheese is known for though is adding things into it.  It is often used as a cheese for making spicy dips also when mixed with chili peppers.  Other fruits, veggies, and herbs can also be mixed with it and it can be used as a cream cheese. You can experiment and come up with your own recipe.

Friday, December 23, 2011

Chestnuts Roasting on an Open Fire: What Ever Happened to this Christmas Tradition?

The American Chestnut.  Whatever happened to the American tradition of, "Chestnuts roasting on an open fire..."????
Everyone knows how the song goes, "Chestnuts roasting on an open fire..."  But how many people really have roasted chestnuts over an open fire for Christmas?  I can't think of a single person.  Of course nuts are part of Christmas tradition today as we can find walnuts, pecans, almonds, pistachios, and of course the corresponding famed nutcrackers in stores.  Chestnuts also can be occasionally be found but these are always the Chinese variety as opposed to the traditional American variety.  It has been said that roasting chestnuts on an open fire was such a common tradition in the eastern United States that its distinctive smell could be found throughout towns in the east this time of year.  Part of this was because the American Chestnut tree was extremely abundant prior to the early 1900's.  But no more.  So what happened to this once nearly universal American tradition?  The answer can be found in the plight of the American Chestnut beginning in 1904.

The Asian chestnut trees have grown for millenniums with chestnut bark fungus, resulting in strong resistance.  American trees, however, were never exposed to this fungus and therefore could not easily survive infection.  Beginning in 1904 the first american tree infected with the bark fungus was found in the Bronx Zoo.  The disease had been accidentally transported to the United Stated from Asia on an imported Chinese Chestnut tree.  After the initial infection in the Bronx, the disease spread rapidly through air-born fungal spores.  American Chestnut trees were killed by the billions.  The disease quickly became known as chestnut blight, and by the early 1940's had made the american chestnut tree exceedingly rare.  During this 40 or so year span the chestnut tree also was aggressively logged in forest areas and cut down in residential areas.  This aggressive removal of trees was done simply because it was thought they were all going to die anyway.  As a result, the blight made this once abundant tree has today been wiped out from the landscape and with it, the tradition of roasting chestnuts at Christmas time.
Chestnuts roasting on an open fire...
But there is hope for the return of the chestnut tree and therefor the roasting chestnuts at Christmas.  While it may appear that the American Chestnut is extinct, a handful of small areas with surviving trees have been discovered.  It has been estimated that less than 100 have survived that are greater than 24 inches in diameter. Many more, but still not a lot, survive as roots in the ground that send up sprouts that never reach more than a few inches in diameter before the blight kills them.  If it were not for the aggressive logging of chestnut trees in response to the blight many, but not a lot, more likely would have survived.  Unfortunately, some of these surviving trees could likely still be killed by the blight.  Fortunately, however, many of these survivors likely are resistant to the blight and can be propagated to reintroduce and repopulate chestnut trees in eastern North America.  Geneticists and plant breeders are also working to identify and place genes that are resistant to the blight into American Chestnuts.  They are using both the resistant Chinese chestnut and the surviving American Chestnuts to find genes and breed new resistant breeds of American Chestnuts.  Many non-scientists who are interested gardeners, naturalists, and landscapers are taking a large part in this though aiding scientists in breeding, growing, observing, and finding resistant chestnut trees.

Check out the American Chestnut Foundation for more information on efforts to restore this species:

Fifty or so years ago we may have thought that the American Chestnut was extinct, or at least doomed to extinction.  Today however, there is great hope for the tree.  While still possible, it is unlikely that the tree will not go extinct.  We can currently say it really can't get much worse for this species and recovery is a very viable option.  Only time will tell, and as with most trees it will take a long time to grow these trees to see if they are able to grow and resist the blight.  Our efforts as humans often result in environmental destruction as we see with the american chestnut.  But the american chestnut also shows that hopefully, our careful efforts can also restore and benefit the natural world.  And there is great hope that song words, "chestnuts roasting on an open fire" can once again be experienced by Americans.  Merry Christmas!

Monday, December 19, 2011

Pack Rat Middens and History of the Sonoran Desert

A pack rat midden in the Sonoran Desert.
Ever wonder what the life would have been like during the Ice Age or shortly after?  During that time period humans were busy running around chasing mammoths or being chased by the saber toothed tiger.  Unfortunately, no one took the time to record what life was like or what the landscape looked like.  Besides that, they didn’t know how to write anyway.  So the glacial age is literally gone with the ice.  Fortunately for us enlightened modern humans who do know how to write, a lowly unintelligent creature did make records of sorts in Western North America to what Ice Age life might have been like.  This lowly creature is otherwise known as the wood or pack rat and because of its compulsion to pack away everything it finds of interest, has literally packed away thousands of years worth of plant materials within their multi-generational middens.

You might think, “The Ice Age ended about 10,000 years ago, are there really 10,000 year old pack rat middens?”  Yes, there are.  In-fact some seem to be considerably older.  You see, these middens are passed down from one generation to the next, some surviving very long periods of time.  Middens are simply debris piles of things the pack rat collects, the first important activity of the rat as an Ice Age historian, and boy do they collect.  Within 100 or so meters of their midden, the rat will collect anything they find of interest, and carry it back to be deposited on the pile.  Pack rats earn their name by collecting anything, leaves, cactus pads, seeds, sticks, animal dung, rocks, even watches or buttons.  Hiking through the desert southwest middens are fairly common, and are often several feet high and wide.  Middens are rather gross, for besides them depositing all kinds of things on them, the rats also use them as a restroom, which results is the pack rats second important activity as an Ice Age historians.  As materials are deposited on midden piles, the pack rat also urinates on the piles.  This urine dries out, crystallizing around items within the midden so they are protected from decay.  As a result thousands of years of materials can be protected within a midden.  Though interesting, they sure aren’t pretty and they sure aren’t something normal people would want to dig into.  

When I say that “normal” people would not typically want to dig into a midden I exclude scientists, because scientists are simply not normal.  So of course scientists decided they should dig into these middens to see what they could find.  I am sure this wasn’t even fun for the scientists but they did it anyway and what did they find?  Large chunks of crystallized urine that contained preserved portions of plants that grew near the midden thousands of years ago.  The scientist then carbon date each of these urine chunks and break them down to see what is inside.  Then based on the age of the urine crystal and what was inside, the plants that lived near the midden could be determined for certain time periods.  If enough crystals were found from enough different time periods, a continuous timeline of how plant communities changed over time can be made.  This has been done many different times in many different locations in the Southwestern United States.  For that reason we can get a pretty good feel for what plants lived where and when over the past 10 or more thousand years, and therefore what life might have been like during and after the Ice Age.  
Central Arizona Pinyon-Juniper woodlands, possibly similar to what the Sonoran Desert looked like during the Ice Age.
Several of these middens have been examined within the Sonoran Desert and we are able to give a fairly accurate description of how vegetation has changed since the Ice Age.  Pack rat urine crystals from during the Ice Age show that the Sonoran Desert was dominated by woodland plant species typical to higher elevations further north.  These woodlands were composed of singleleaf pinyon pine, juniper trees, shrub live oak, and joshua tree.  This plant community indicates much cooler temperatures and more cool season precipitation.  At the lower elevations where it was hotter and drier, these species were far less abundant and creosote was more common.  As the Ice Age ended, the weather warmed-up and dried-out, and species more typical to what we see today in the Sonoran Desert began to increase.  First, saguaro cacti and brittlebush occupied the area, followed by palo verde and ironwood.  In all, it took many thousands of years of changing temperatures and rainfall patterns for the present day mixture of plants to develop here in the Sonoran Desert.  This transition from woodland to desert could be compared to (but not exactly like) the transition of plants as you travel from 5000 feet in central Arizona down to around 1000 feet.  Central Arizona at 5000 feet is characterized by pinyon pines, junipers, and shrub live oak.  Moving down in elevation the weather warms up and dries out, similar to how the weather transitioned after the Ice Age until today.  As the weather changes downslope we see an increase in Sonoran Desert plants. 
Modern day Sonoran Desert.
Today's plant communities within the Sonoran Desert are determined by the hot dry weather with both a cool and a warm season rainy periods.  But the climate continues to change and therefore plant communities will continue to change.  We as humans will do our best to keep track of these changes and so will the pack rat.  With the variable nature of humans though it is easy to think we might somehow loose track or forget about our records overtime.  Even so, the pack rat with its innate drive to pack things away will continue to do so and therefore continue to be the Southwests most consistent historical record keeper.  

Friday, December 16, 2011

Winter in the Sonoran Desert

A winter rain shower in the Sonoran Desert.

Seasons in the Sonoran Desert don’t follow the typical patterns found further to the north.  At the very beginning of December though we make a rather predictable transition from dry and warm fall weather to cooler and wetter winter weather.  The start of the Sonoran Desert winter is almost like clockwork with temperature and rainfall.  Within the last few days of November through the second week of December low temperatures begin to dip close to the freezing mark and a very predictable winter rain shower waters the desert.  The cooler and wetter conditions will continue through February before the desert begins to warm-up again.  

Usually the first indicator that winter has arrived is the arrival of freezing temperatures.  Of course you can identify freezing temperatures by looking at your thermometer, but there are also some biological indicators you can look out for.  Some desert plants such as Ironwood cannot tolerate temperatures very far below zero.  Freezing temperatures will cause Ironwood leaves to yellow and fall off.  This is not spectacular in any sense compared to how deciduous trees in the east change color.  To me the tree just looks like a sickly yellow.  Other plants may also show evidence of freezing with similar yellowing.  Another indicator of cold temps is the lack of reptile activity with many in hibernation.  Most “cold-blooded” organisms require the desert heat to stay active but come the end of November temperatures are just too cold.  
Winter rain shower soaking the ground.
One of the most exciting signs of the start of winter is the very predictable rain shower that happens anywhere from the last few days of November through the second week of December.  If my memory is correct we have received this rain shower six out of the past seven years.  The year we didn’t receive it we had not even a trace of rain from October through March.  The rest of those years we typically received about one-half to two inches over a one or two day period.  This is the one time of year that you can expect the dry washes to flow for a few hours during the peak of the rain and this year has been no exception.  About one inch of rain fell on December 12th and 13th causing most of the washes to run.  Water running through these washes quickly is absorbed into the sediments so washes only run for a very short period of time.  The water is not lost however, but is rather stored in the sediments for many months.  The larger the flow the larger the volume of water is that is stored in the sediments.  This water can persist through many months of drought helping deep rooted plants survive high temperatures and bone dry conditions on the surface.  The denser vegetation around dry washes are typically there because of this water stored deep in the sediments.  

Rain this time of year will also saturate the soils and the cooler temperatures will prevent the soils from drying out too quickly.  If about one-half inch or more of rain is received a massive number of seeds that lay dormant in the soil will germinate.  These seeds will often wait years and even decades, simply waiting for the right conditions to germinate.  Seeds from different plant species require specific temperatures and amounts of moisture in order to germinate.  Amazingly, these seeds are not tricked into germinating with rain coming at the wrong time of year.  Winter ephemerals, as they are called, wait for cooler temperatures and a significant rainfall in order to germinate.  With one inch falling across most of the desert we should see a profusion of tiny green plants within a few weeks.  These tiny plants could possibly result in a major spring wildflower bloom.  The trick however is that rain must continue to fall at regular intervals through March so these new sprouts survive.  Without rain the sprouts will shrivel-up and die.  A typical winter has at least one rainstorm to germinate a large number of wildflower seeds but does not have enough rain in the following months to allow them to survive until spring when they can produce spectacular displays.  Desert ephemeral wildflowers are highly adapted to this, having the ability to produce tiny flowers very quickly to made seed under dry conditions.  And as the name ephemeral suggests, these flowers are here today with wet conditions and gone tomorrow once dry conditions return.  It has been six years since we had a good spring wildflower bloom.  Right now conditions are good for another spring bloom but only if we receive rain every few weeks for the next several months.
A hedgehog cactus, common to the Sonoran Desert.

The cooler temperatures makes large animals and birds more active during the day when it is warmest.  Wetter conditions also provide more water across the landscape for larger animals.  With dry conditions in most Octobers and Novembers most mule deer will stay close to water holes in the mountains.  However, with washes flowing and forming new waterholes further away from the mountains the deer will venture further out making them easier to find.  Some of the best places to look for deer and javelina are along dry washes being these are sort of natural trails for these animals.  Rain will also be good for helping the survival of young gambles quail and if rain persists the overall population can grow significantly, simply because there is more water and more food as a result of the increased moisture.  

So winter in the Sonoran Desert is a little like Paradise.  We have rain and beautiful temperatures which make a day in the desert very enjoyable.  Quite different from what northerners are experiencing this time of year.  However, northerners, don’t complain too much when winter and spring end in the desert the nearly intolerable heat and dryness of summer will return to the desert.  But of course, the grass is always greener somewhere else...  So enjoy your weather no matter what it is.  I’ll be enjoying the deserts winter while I can.

Monday, December 12, 2011

Mississippi River Louisiana Creole Plantation

Laura Plantation along the Mississippi River in Southern Louisiana.  
Farms are always full of all kinds of interesting biological subjects.  For me, the traditional Midwestern farm is pretty familiar but still a very interesting place to do some “scientific” exploration.  Recently I visited the Laura Plantation on the Mississippi River in Southern Louisiana, which was a totally new experience for me.  This particular plantation is Creole, which is different from the English plantations we more traditionally think of.  English plantations have a culture like what we can see in “Gone With The Wind” with a big white house.  Creole plantations are much more colorful and are French in origin.  

All of the plantations in Southern Louisiana are located on the Mississippi River being it was a natural highway through impenetrable swampland that expanded in every direction.  The Mississippi was essential for bringing supplies into the plantation and sending products out.  Without the river there really wasn’t any reliable mode of transportation
Sugar cane field. 
The primary product of these plantations was and still is sugar cane.  Sugar cane is a tropical grass that produces a large amount of sap that is rich in sucrose, otherwise known as table sugar.  This grass can grow up to a half inch a day reaching up to 15 feet and can produce an amazing 20 pounds of plant material per square meter as long as their is plenty of sun, heat, and water available.  Unlike most crops, sugar cane only needs to be planted once every three to ten years being even after it is harvested the roots survive underground and will sprout the next season.  During the 1800’s these plantations were worked by slaves until the Civil War.  After the Civil War however, slaves were freed but plantation owners kept the African American workers through debt slavery...  And so slavery continued in another form until the chopper harvester, or combine was developed.  Once invented, the combine could do the same amount of work as about 100 slaves, thus ending the need for slavery in the sugar cane industry.  
Chili peppers 

Besides sugar cane, Creole plantations are full of all kinds of other interesting plants.  I found citrus, bananas, papyrus, and all kinds of tropical flowers.  Also common to these plantations were pecan trees which of course grow the common pecan nut found in stores.  Interestingly, pecan trees are a type of hickory tree very similar to the shagbark hickory further north.  Pecans however consistently produce large quantities of nuts making them agriculturally superior to other hickorys.  In this area of the south, pecans are cooked with sugar to make the famed praline snack.  Chili peppers are also traditional Creole plants.  There are many varieties that have their origin in Southern Louisiana, including the tabasco chili from which Tobasco Sauce is made.
Southern live oak draped in spanish moss.

Lastly, no description of the south would be complete without mentioning the southern live oak.  On these plantations, the oaks can be absolutely massive and are often hundreds of years old.  On one particular English plantation called “Oak Alley”, 300 hundred year old live oaks line the quarter-mile long sidewalk that approaches the front of the house.  These trees are strong giants with trunks over four feet in diameter and massive crowns draped with spanish moss.  It is amazing to think, many of these oaks witnessed the entire history of the plantation from before its establishment, through its growth and production, until today.
300 year old southern live oaks lining the walk up to the Oak Alley Plantation.

Friday, December 9, 2011

How to Make Yogurt

Make your own yogurt!
Around 4000 years ago or more the first milk maids probably accidentally invented yogurt.  Likely, some forgetful maid filled a bucket with fresh milk from a cow, goat, camel, sheep, or yak and simply forgot about it.  When the maid finally got around to remembering the milk bucket a day or two later I am sure they were quite surprised at finding not a bucket of not rotten milk, but rather a fresh smelling, thicker textured version of the milk.  They were probably further surprised to find the newly formed yogurt tasted good.  Today, the same process is used with the same ingredients more or less, resulting in the same final yogurt product.  The smell, texture, and taste of this first yogurt would have been similar to the yogurt we purchase today in the grocery store.    

Purchasing yogurt in the store can be quite expensive, maybe one dollar for eight or so ounces.  Milk however, the main ingredient for yogurt, is much cheaper, maybe three dollars a gallon.  In other words, simply buying yogurt can be about three times more expensive then purchasing the milk that goes into making it.  The fact that yogurt is so simple to make, especially if you eat lots of it, makes making  your own extremely economical.  And not only economical, an extremely simple, interesting, and tasty experiment anyone can do at home.  You simply need two ingredients, milk and a starter culture, just like the ancients.  

When people of ancient time, and up until the mid 1800’s wanted to preserve their milk for longer then a half day or so, they simply let it develop into yogurt.  Prior to refrigeration, and even today, milk directly from the cow is known as raw milk.  Raw milk contains a healthy bacteria known as Lactobacillus which when given the right conditions can proliferate in the milk and turn it into yogurt.  The problem with raw milk however is that it can’t be transported far before it turns into yogurt or spoils.  So in the mid-1800’s the process of pasteurization was developed to kill unwanted bacteria and allowing the milk to remain milk for longer periods of time.  This happened with the industrial revolution when masses of people moved into cities and no longer had close access to a dairy, so milk had to be transported into the city.  Pasteurization allowed for milk to keep in order to transport it into the city for consumption, the same is done today.  Pasteurization simply was heating the milk up to about 180 degrees Fahrenheit and then letting it cool down for refrigeration.  This process kills all the bacteria that could spoil the milk.  All milk in the grocery store today has been pasteurized so that it could be transported for you to buy.  

To make your own yogurt you will simply need to purchase a gallon of milk from the store.  But, because this milk is pasteurized you also will need to buy a starter culture.  A starter culture simply is the bacteria, specifically Lactobacillus, which will process the milk, making it into yogurt.  This starter culture can be purchased as a dry yogurt starter, buttermilk, or a living yogurt.  Dry yogurt starters can be purchased through Amazon while buttermilk or yogurt can be purchased through the local grocery store.  Most yogurts sold in the store have been pasteurized and therefore no longer have any living bacteria in them. Therefore, yogurt cannot be made from them.  Buy an unflavored, plain yogurt that is labeled as “natural” or as having living culture in it can be used.  Once you start your first batch of yogurt you will never need to purchase another starter again.  You can simply use the yogurt you make as the starter for your next batch.  

To start your yogurt you first should do your own pasteurization.  Be sure to do this in a stainless steel container being the process of yogurt making can be ruined by other potting materials.  Using a meat thermometer, simply heat up the milk on the stove to about 180 degrees.  Stir frequently and heat slowly to ensure the milk does not burn to the bottom of the pan.  Once 180 degrees is reached let the milk cool down, making sure to keep it covered.  Covering the milk will prevent outside contaminates from entering and potentially spoiling your yogurt.  Allow the milk to cool to about 100 degrees, then stir in a few ounces of starter.  After stirring in the starter, the milk must incubate in order to allow the Lactobaccillus bacteria to ferment lactose in the milk into lactic acid which preserves the milk as yogurt.  Incubation simply means keeping the milk at a constant temperature for 12 or so hours undisturbed until yogurt is made.  For buttermilk the milk can be kept at room temperature while yogurt starter requires a temperature of 100 degrees.  I prefer to use buttermilk starter at home simply because you can keep the pot sitting out on the counter.  I have used yogurt starter when I can incubate outside in hot weather or in a warm oven.  Then after the yogurt comes to the consistency you would expect it is ready to eat.  Different starter cultures and different types of milk will produce different tasting yogurts.  Experiment and see what you like best.

How to make yogurt:
Materials: Stainless steel container for pasteurizing milk and meat thermometer.

Ingredients: Milk and starter culture (Dry starter, buttermilk, or yogurt)

1.  Slowly heat milk to 180 degrees being sure to stir frequently to ensure it does not burn to the bottom of the container.
2.  Cool the milk to about 100 degrees, then mix in your starter.
3. Let the milk incubate undisturbed for 12 or more hours so the yogurt can form.  Temperature of your incubation depends on your starter.  Buttermilk requires room temperature, yogurt requires about 100 degrees, and follow directions on the box for dry powder starter.  
4.  Once the milk reaches yogurt consistency it is ready to eat.  You can mix in fruits, flavors, or sugar according to your taste.

Monday, December 5, 2011

Louisiana Wetlands and the Mississippi River Delta Part 2

A floating Louisiana marshland.  This wetland is characterized by thick mats of semi-floating grasses, sedges, rushes, and a few small shrubs and are important to alligators for hibernation   
Also within these areas is the famed alligator of the south.  The abundance of water and bird life of these swamps and marshes feed these gators, allowing them to grow to large sizes.  The wild gator grows about one foot a year until it reaches six feet, then growth slows considerably.  The longest lived gators can survive up to 90 years in extremely rare instances and reach 15 feet in length.  Gators over six feet are uncommon but gators less than this are often found in abundance.   During warm summer months when water temperatures are over 70 degrees gators can be found throughout the swamps and marshes, anywhere there is enough water.  However, in November water temperatures drop below 70 degrees and gators go into hibernation until early spring when the water warms up again.  Typically, water levels in these wetlands fluctuate with ocean tides and floods coming from upstream.  This is a problem for hibernating gators who need to hibernate in wet areas but cannot be submerged with flood waters.  Because of this, gators hibernate in floating grassy marshlands that float up and down with fluctuating water levels.  Gator hunting is a rather common practice in Southern Louisiana.  The game management agency allows one gator to be harvested per twenty acres of wetland.  I've been told this is a major meat source for rural Louisianans.  I personally have eaten gator fried, as jerky, and as sausage.  Fried gator is rather chewy, but the jerky and sausage are great.  I love both of them.  In-fact, I may like gator jerky better than beef jerky.
A Louisiana alligator found in a bayou.  
Underneath all these wetlands in the sediments is an abundance of oil and natural gas.  Over past decades these natural resources have been drilled and mined out of the sediments, resulting in the wetlands sinking and flooding with more water.  This flooding has killed wetland vegetation and caused the disappearance of  this habitat.  According to some sources an entire football field of Louisiana wetland is disappearing as a result of this every 38 minutes.  Historically, the Mississippi has also snaked its way back and forth across southern Louisiana depositing sediments in low laying areas everywhere it went.  Today, the Mississippi is highly channelized and controlled by the Army Corps of Engineers, preventing this nature controlled movement and deposition of the river.  So when wetlands sink, sediments from the river is not available to raise them back up again.  People from all professions and industries are still searching for solutions to this problem.

The red area of the ocean indicates areas of low oxygen known as the dead zone.  This dead zone is a result of  water pollution brought into the gulf by the Mississippi River.  Picture from Wikipedia.
As the muddy waters of the Mississippi pass through the Midwest and the South, some of the richest agricultural land in the world, sediments and fertilizer are washed into and pollute the river.  The vast wetlands of the Mississippi River delta capture much of this pollution.  As wetlands naturally do, they capture and filter out pollutants from water in an amazingly efficient manner.  However, as some of these wetlands disappear, and being the levels of pollution are so extremely high, much of the pollution works its way through the delta and is deposited into the Gulf of Mexico.  This immediately has the effect of "fertilizing" the Gulf, which may seem a good thing at first.  Fertilization of water by pollution is known as eutrophication, and results in large algal blooms.  Once this algae dies however, the decompose and consume all the available oxygen in the water.  As a result of these low oxygen levels, very little ocean life can survive in these areas, giving it the name "dead zone."  The dead zone in the Gulf where the Mississippi ends currently is the size of New Jersey and has had huge effects on sea life, including the fishing industry.
Sediment pollution causing the dead zone (right side) next to oxygenated waters (left side).
Despite the negative, the wetlands of Southern Louisiana are still a vast, amazing, and relatively healthy functioning ecosystem.  Even in their impaired state these wetlands are still intact and functioning as they should.  Of course, they could function better if the Mississippi was allowed to flow as it pleased rather than be controlled.  With the many towns and small settlements in the area, letting the Mississippi flow back and fourth across the delta would likely destroy many of these communities.  Controlling the Mississippi is also important to the shipping industry.  So simply restoring natural flow is not such as simple task.  Still, even in their present state these wetlands absorb and filter much of the pollution that is carried down the Mississippi as well as provide huge areas for wildlife and recreation.  Without these functions the current dead zone in the gulf would be much larger and have enormous impacts on the fishing industry.

While I was only able to spend one day exploring these wetlands, it made me hungry to experience them more.  These wetlands are an amazing place to which so many people, cultures, plants, birds, and animals call home.  All of these different aspects are tied together forming the diversely rich creole culture.  In the near future, I will be talking more about this creole culture with a post about a historic Mississippi river plantation.

Friday, December 2, 2011

Louisiana Wetlands and the Mississippi River Delta Part 1

A Louisiana bayou in the Mississippi River Delta.  
Louisiana boasts an amazing 40 to 45 percent of the continental United States wetlands.  Flying into, and driving through Southern Louisiana gives you a good sense of the vastness of these wetlands, miles and miles of unbroken soggy earth everywhere.  Water is literally everywhere, there is of course lots of open water, and where there isn't open water there are sopping wet grassy marshes, and where there aren't mashes their are soaked forests.  The air is always full of humidity with a faint marshy smell, no matter where you are at.  I have visited many wetlands in my life, but none compare to the expansiveness and diversity of these subtropical wetlands.

A part from the sopping wet nature of southern Louisiana, the next most obvious feature is the perfectly flat nature of this landscape.  This soaked flat landscape is a result of the Mississippi River reaching the Gulf of Mexico and depositing massive amounts of water and sediment as the river slows before dumping into the ocean.  The Mississippi begins as a small clear stream at Lake Itasca in Northern Minnesota, which I have personally walked across in only a few short steps that only went up to my knees.  Growing up, I also fished the Mississippi River in Iowa where it is a mighty and muddy river.  Flowing southward, the river continues to grow in volume and accumulate more muddy sediments making it "The Big Muddy."  All this water and mud however has to end up somewhere and is deposited in a delta entering the Gulf of Mexico in southern Louisiana.  This deposition and delta forming process has been taking place for thousands of years since the end of the last ice age.  The entirety of Southern Louisiana was at one time deposited by the Mississippi, and today, over one mile of sediment covers the underlying bedrock.
Oak trees draped with Spanish Moss along a higher, drier portion on a bayou.
Along the Mississippi and other distributary rivers flowing out of it, heavier sandy sediments are deposited along the bank.  These sediments form a sort of natural levee elevated above the rest of the alluvial plain.  On these natural levees many species of oaks are commonly found including the Southern Live Oak, Water Oak, and Swamp Laurel Oak.  These Oaks can only tolerate temporary flooding and need to be on dry land adjacent to lots of water, such as next to a river or swamp.  A short distance from the river, the natural levee slopes slowly down, away from the river.  As the slope moves downward, away from the river, the ground becomes increasingly wet.  Maples and Ash grow on this wetter back-slope along with some oaks.  Lower on the back-slope the ground becomes increasingly saturated, often with standing water, here Baldcypress and Water Tupelo grow.  These areas are still high enough on the slope so that they are not flooded for extended periods of time.  Cypress trees can grow for over 1000 years on these sites and grow large "buttress" roots around the base of their stump in order to stabilize themselves for these long periods of time in these soggy loose soils.  All of these trees are draped with often thick clumps of Spanish Moss.  This moss, is technically not a moss at all but rather more closely related to a pineapple, very odd considering they look nothing alike.  These draperies of Spanish Moss are normally tan colored, except for after rainfall when they turn green.  Hanging from trees and blowing in the wind the moss gives the narrow bayous a romantic southern feel, as they decorate the majestic oaks and cypress trees.
Baldcypress trees found in wetter portions of the wetland then the oaks.  
A floating marsh wetland characterized by grasses, sedges, and rushes.  These types of marshes are important locations for alligator hibernation.

Away from the natural levee and closer to the mouth of the river where the water is always flooded, floating marshlands exist which are dominated by grasses, rushes, sedges, and cattails.  Historically, these floating marshes were far more common and widespread.  As they were settled, channels were dug through these marshes and the sediments piled adjacent to the channel.  These new channels formed what are known today as bayous with the adjacent piles of sediments forming vegetation similar to the natural levees along rivers.  These marshes and bayous can have brackish water (slightly salty) or freshwater and are filled with an abundance of life.  Brackish waters have crabs, while crayfish are found in fresh, both of which are trapped for the great seafood the area is known for.  Bass, crappies, drum, gar, and catfish are in abundance in these areas.  A guide told me there are so many fish in these wetlands that if you don't catch any fish, you don't tell anyone.  In other words, there are always fish to be caught, and to not catch any is not typical, and embarrassing.  Birds also fill these areas including waterfowl of all types, herons, and ibis.

This concludes part one of the Louisiana Wetlands.  In our next entry we will cover the famous alligator of these wetlands as well as some of the ecological issues they face today.  

Monday, November 28, 2011

How to Make Farmers Cheese

Farmers cheese final product, a soft crumbly cheese.
Cheese making is both an art and science, around which all sorts of cultural significances have developed.  Historically, cheese has been a highly localized food item where a specific type of cheese could only be found in one specific region of the world.  The reason for this is because these regions would have certain types of foods for cows, goats, or sheep to eat, resulting in a milk with a unique taste and ability to make cheese.  Local climates and the microorganisms present also played a major role in regional cheeses.  And of course, each region or family would have their own secret cheese recipe.  Unfortunately today, much of this localized specialty cheese has vanished with modern milk pasteurization laws and large cheese factories.  The laws make it difficult for cheese makers to sell their products in many cases and the factories are difficult to compete with.  Fortunately, some of these localized cheeses still exist today and if you have access to milk you can make your own cheese.  Grocery store milk is almost excursively pasteurized and homogenized, which is unfortunate for cheese makers but necessary to increase its self-life.  Unprocessed milk makes the best cheese, but for the rest of us who don’t have a cow in the backyard, store bought milk will still produce great tasting cheese.  There are many very complex cheeses, some of which take many months to make.  This particular cheese, known as farmers cheese, is probably the easiest of all.  

What you will need:
Pot you can heat milk on the stove with
Spoon for stirring
Cheese cloth, strainer or pantie-hose

1 gallon milk
¼ cup white or cider vinegar, lime juice, or lemon juice (each will produce a different flavored cheese)
Salt to taste

Heat milk slowly on the stove top, stirring gently making sure not to burn milk to bottom.  Heat milk only to about 180 degrees Fahrenheit, any hotter will curdle or burn milk.  Once milk reaches 180 degrees, add the vinegar or juice by gently stirring in and take of the heat.  The milk should almost immediately separate into curds and whey.  Once the two are mixed let it cool for a while, then strain the mixture to separate the curds from the whey.  Allow to strain for about an hour or more in the refrigerator.  After straining mix salt with the curds to taste, it doesn’t take much.  After this the cheese is ready to eat.  It can be eaten plain or have fruits, vegetables, or herbs mixed in with it.  Onions, garlic, strawberries, apricots, rosemary, chives, or a variety of other things can be mixed in to make your own unique cheese.  

Curds and whey after adding an acid such as vinegar, lemon or lime juice.  The curds are the white part while the whey is the whitish yellow liquid part.
In this recipe an acid (vinegar, lime or lemon juice) causes the milk protein casein to precipitate out of the whey.  Casein is the white chunky curds that make up cheese while whey is the whitish liquid the casein separates from.  Using an acid to make cheese produces a soft crumbly cheese being the casein proteins weakly stick together.  Other cheeses use an enzyme called renet to precipitate casein out of milk whey.  Renet produces much stronger bonds between casein proteins and therefore stronger curds or hard cheeses such as cheddar.  In the near future I plan on having a post covering the use of renet in making hard cheeses.

Friday, November 25, 2011

Life of an Oak Part 4: the Eastern Forest Tree of Life

Life of an Oak part 4 of 4

After twenty or so years of slow continuous growth, the oak tree enters the next stage of life.  At this age most oaks begin bearing their first large harvests of acorns.  Ground fire disturbance during decades leading to mast production help the acorn bearing process along.  Native Americans knowing this would purposely burn oak woodlands to increase production.  While most oaks produce some acorns every year, years of large mast production typically happen every two or three years.  A few oaks, such as the White Oak, will only have large mast productions every five or so years.  Large mast production typically depending on spring weather conditions that affect pollination of the trees flowers.  During the spring flowering period for oaks, freezing temperatures will kill flowers or overly wet conditions will prevent pollination, both of which prevent large acorn crops from being produced.  Further complicating this matter is the fact that some oaks require only one summer to produce acorns such as White Oaks, while Red Oaks require two summers to mature acorns.

Mother of the Forest
Once mature, the open canopy of oaks allow flecks of sun to pass through the tree and across the forest floor.  Greater amounts of sun reaching the forest floor allows for a greater diversity of plant-live and
greater total plant production.  As a result, the oak tree not only feeds an abundance of animals with acorns in the fall, but by aiding thicker more diverse vegetation on the forest floor an abundance of organisms are fed through spring and summer.  Spring in an oak woodland is filled with a variety of delicate beautiful flowers such as Bloodroot, Dutchmans Breeches, Trillium, and Wild Geranium.  During the summer a thick green blanket of vegetation covers the forest floor.  Where oaks are more spread out such as in savannas or open woodlands even prairie plants can begin to establish themselves.  Other trees such as Maples have such thick canopies that forest floors under mature trees can often be quite bare.
These fallen pin oak leaves resist decay because of the chemical tannin within the.   By resisting decay and curling up like these leaves, oak leaves encourage low intensity ground fires in the fall.  
The Oak doesn't stop here however.  At the end of each summer and through early spring an abundance of dry curly leafs fall from the tree.  Other trees typically produce leafs that lay flat against the ground, absorb water, and rot quickly.  Oaks however produce hardy leafs that curl-up, resist decay, and remain dry.  These fallen leafs, as well as additional ground cover as a result of the oaks open canopy, produce an abundance of ideal fuel for a low burning ground fires. These fires clear forest floors, befitting both the oak tree and the overall community, as well as encouraging the growth of new oak seedlings.  And so the oak forest or savanna is perpetuated with its own help.

Cycle of Forest Life
The oak is truly a mother and nurturer of the forest, part of a larger cycle involving humans providing fire, wildlife being fed and dispersing seed, and the forest community being structured by the presence of this magnificent tree.  The mature mother oak produces an abundance of seed feeding forest wildlife.  Light is let through the tree canopy growing more plants that provide more food for wildlife.  Fallen leafs and thicker ground vegetation encourage fire that clears invading plants.  Forests cleared by fire encourage the tree to grow stronger and produce more acorns.  Wildlife, fed by the oak, disperse and plant acorns in new areas.  Fire in-turn produces ideal locations for acorns to sprout and grow into new oaks which will again nurture a healthy forest habitat.  And so the oak comes full circle.

Thursday, November 24, 2011

Happy Thanksgiving!!!

Happy Thanksgiving!  Here on the Practical Biology Blog we try to take a biological perspective on things, turning the ordinary into interesting biological education.  And of course, eating is biology, so Thanksgiving is an easy lesson in biology.  What we consider today as a traditional Thanksgiving meal really is no reflection of what the original Thanksgiving meal looked like.  If we do our history, however, we can come pretty close to figuring out what the original 1621 Thanksgiving meal looked like at Plymouth.  History tells us that the original Pilgrims, especially during their first year in the New World, were primarily farmers, gardeners, hunters, and gatherers.  Some of these skills, such as gardening and farming, they would have learned in England.  Most of them they would have had to learn from the Native Americans.  Even skills they learned in the Old World would have had to be relearned in the context of the new conditions in America.  

A little more history.  When the original Pilgrims landed in Plymouth in 1620 they barely survive the winter.  If it were not for them finding a large stash of hidden corn in an abandoned Wampanag Native American village they all might have died.  I must add here, the Pilgrims were a peaceful Christian people, they did not kill the Native Americans and did not steal their food.  In the year to come the Pilgrims and Wampanag people developed a peaceful relationship through which the Pilgrims learned much about how to survive in the New World.  Remember at this point, the New World was nothing like it is today.  In 1620 and 21 the New World was a very hostile place to Europeans.  The winter was far harsher then anything they had encountered, there were no markets for food or established agricultural system, no stores for supplies or tools, no houses, and no buildings.  It was pretty much what we would consider wilderness and everything they needed had to come from the land or the little they carried over from England.  These Pilgrims had no clue how to survive with meager supplies in a wilderness they had never encountered before.

So that first year was extremely difficult.  In-fact, it was so difficult that normally modestly dressed Christian Pilgrims were described as being dressed in rags or nearly naked.  They had virtually nothing that first year.  But after a peaceful relationship with the Wampanag people was developed they began to learn how to hunt, fish, trap, grow food, and gather food from the forest plants.  During that first year, the Pilgrims learned to live on the land so well that by fall they had an abundance of food.  During that first year they went from having next to nothing and no real idea of how to survive to learning how to survive and having an abundance of food.  Anything could have easily wiped the entire Pilgrim group out during that first year but it didn’t, and they did as every good Christian should, they thanked God.  A big part of this thankfulness took place with a three day celebration full of food, games, and just having a thankful good time among themselves and the Native Americans they befriended.  This celebration became known later as the first Thanksgiving.

So the first Thanksgiving meal would have been composed of food items grown and gathered by hand, not bought from a store.  The meal also would have been heavily Native American influenced being that is who taught them how to gather their food.  Some of you may be wondering at this point, what does all this have to do with biology?  Much in every way.  Of course gardening is biology as well as living off the land.  All of this had its context in the Eastern Deciduous Forest ecosystem of New England.  So all of the plants and animals they gathered would have only come from the local environment.  We do know the Wapanag people contributed five deer to the first Thanksgiving.  The Pilgrims also hunted a huge number of what they called fowl.  Fowl likely was duck, goose, turkey, and other birds.  Other than that we really don’t know exactly what was on that first menu.  We can take clues from the local environment of what probably was on that menu through.  It is also very likely that they ate eel, lobster, mussels, and fish.  As for plant products there were also probably nuts such as acorns, walnuts, hickory nuts, and chestnuts.  Fruits and berries gathered from the forest would have been out of season during the late fall when the celebration took place.  There would have also been an abundance of garden produce including squash, pumpkin, corn, leeks, carrots, parsnips, cabbage, and turnips.  Some of these plants were given to them by the Native Americans while others would have been brought over as seed from Europe.  Also interesting is that the corn would not have been sweet corn, it would have been ground up and served as cornbread, mush or pudding.  There was also very little or more likely no sugar.  So no sweet desserts except for what could have been sweetened with molasses.  No pies, no cranberry sauce, and no sweet potatoes with marsh mellows on top.  Maybe a little wine and beer but most likely only water (The Pilgrims didn’t have a problem with moderate consumption of alcohol).  

If you think about it, this would be quite an interesting meal.  I mean, who wouldn’t want lobster and eel for lunch three days in a row! Have a happy Thanksgiving!