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!

Monday, November 21, 2011

Life of an Oak Part 3: seedling to canopy

This is part three of a four part series titled "Life of an Oak".

Root Before Shoot
Oak seedlings thrive in recently disturbed areas.  Whether the disturbance was a result of logging, fire, or diseased caused death of larger trees, oaks establish themselves by taking advantage of the lack of competition with other plants and the abundance of sunlight.  Most oaks start off rather slowly compared to other trees.  Willows, birches, aspens, or cottonwoods put most of their energy into quick above ground growth.  However, these trees later suffer the consequences with a shortened lifespan, maybe 100 years, partially due to smaller root systems.  Oaks however are in it for the long-hall, say three to five hundred years in some instances, and order their life strategy accordingly.  Immediately upon germination oaks begin with this long-term view by putting all of their energy into root establishment.  Even after above ground foliage appears on seedlings or saplings, much of their energy goes into root establishment at the expense of above ground growth.  Extensive well established root systems later in life will benefit the oak with strong hard wood, capable of surviving all but the worst ice storms, fires, winds, and droughts.  Faster growing trees with weaker root systems and softer woods, such as cottonwoods, suffer dramatically from these same natural events.  When an oak sends roots out it claims the soil as its own for the long run.

Slow determined growth emphasizing root and long term establishment is an excellent life strategy.  This strategy is not however without consequence.  Slow growth makes oak seedlings easy targets for Whitetail Deer who love to munch on the new sprouts.  Unfortunately, over population of Whitetails in much of the eastern United States has partially resulted in poor establishment of oak seedlings over the past several decades.  Faster growing trees can quickly out grow young oaks and shade them out.  Fortunately, though oaks prefer lots of sunlight, most are fairly tolerant of some shade.  Too much shade will however, kill an oak.  When partially shaded by faster growing trees, oaks don't change life strategies and try to compete by growing faster.  Rather, in tortoise and the hare like fashion, the slow growing oak continues according to plan.  By slowly out growing and out living the faster growing, weaker, and shorter lived tree the oak eventually prevails.  The oak may suffer in the short run due to faster growing trees, but oaks have a long term perspective.  Often, if low intensity ground fires are present, oaks will not need to wait long to overcome other trees.  While other trees may be killed by fire the thick bark of oak insulates from and resists fire.  Even if a young sapling is killed by the fire the roots remain alive underground ready to sprout soon after the fire.  Very few tree species have both the ability to resist flames as well as resprout from roots.
Fire killed oak sapling.  This young trees roots still survive underground and will sprout next spring.
Fire and Resprout
Young oaks can be killed back by fire and resprout many times.  The larger an oak grows the thicker its bark becomes making it increasingly resistant to ground fires.  With time, oaks overcome both competitor trees and fire.  As the oak continues to grow it continues to take advantage of ground fires as they eliminate competing trees and replenish the soil with nutrients.  Once an oak is around five years old it is very likely it will survive to old age, only a fraction of a percent survive even to this age.  At this stage the tree has earned the ground it has slowly but surely taken, as most of the predators, fire, insects, and competing trees have been overcome or will be overcome in a matter of years.  The slow but steady path of growth will continue and the oak tree will become increasingly a landscape landmark.

After twenty or so years, the young acorn sprout makes its way back to the canopy.  The severe struggle against the forces of nature are overcome and the oak enters the next stage of life.

Friday, November 18, 2011

Life of an Oak Part 2: from acorn to sprout

These charred branches are evidence of ground fires in this Oak Savanna.
Fire and the Young Oak
Just prior to and after winter, oak woodlands historically experienced another form of harsh natural selection.  Just when life appears to be as hard as it gets, fire enters the picture.  In the fall before snow fall and early spring after snow melt, the ground is covered with a large supply of flammable dead vegetation.  Oak trees themselves contribute significantly to this fuel with their crunchy leaves covering the ground.  This dead vegetation historically has supported low intensity ground fires across the prairies and bordering oak savannas and woodlands.  Amazingly, most oaks are highly adapted to this type of fire, and anywhere you find fire disturbance you will typically find oaks.  Native Americans and many early European settlers throughout the eastern United States liberally utilized fire for a number of purposes.  In-fact, prior to any European impact Native Americans utilized fire so frequently and on such a large scale that essentially none of the Eastern or Midwestern landscape can be considered without human disturbance.  The general attitude seems to have been when in doubt, burn it.  The thinking went something like this: I want an open forest, lets burn this area.  I want more berry and fruit production here, lets burn it.  I want to create a fire break for the village, lets burn the area surrounding the village.  It would be easier to gather nuts or wild ground bird eggs if there wasn't so much vegetation, lets burn it so we can find these easier.  Prairie and forest floor fires had the added benefit of cooking the eggs also, making them ready to eat.  I want to create better habitat for game animals, burn it.  We need to herd some animals to make the hunting easier, lets round them up by burning them out.  Lets clear the land so we can plant a garden, better burn it.  There are too many snakes and ticks in this area, lets burn it.  And the list goes on.  Scientists have found that fire returned to areas anywhere from every two to 11 years.  Most of this burning was human started for the purpose of benefiting the landscape.  Very few of these fires were "natural" lightning started fires.
A recently burned oak savanna in Eastern Iowa.
Fire was amazingly effective in accomplishing all kinds of positive effects on the prairies, woodlands,and savannas; and oaks always followed right behind these fires.  As fire goes, so goes the oak, or any other tree for that mater.  While most trees are killed by fire, many upland oaks greatly benefit from ground fires.  Shortly after fall fires, Bluejays will begin caching acorns from nearby forests in newly burned areas.  Even if caches are made just before an area burns, low intensity ground fires cause very little harm to these acorns being they are protected underground.  Insect predators, such as Acorn Moths and weevils, are nearly eliminated in burn areas, greatly increasing acorn viability.  Fires also clear thick overhead vegetation, decrease surface soil moisture, and kill seeds deposited on the surface.  This allows for the full sun oaks require for establishment as well as lack of competition they thrive on.  Other tree seedlings typically require higher soil surface moisture for establishment or are killed by fire while oak acorns are safely buried just under the surface, and have access to soil moisture.  Even with very little soil moisture, the large acorn seed is capable of sprouting and sending out a thick strong taproot to search for moisture.  Very few plant seeds have this ability to germinate and survive such low moisture conditions.
This young oak tree has four stems coming from one original stem that was burned in a fire during a previous year.  The four stems showing in this picture were killed by a surface fire this fall but the root remains alive and will sprout next spring.
The cache is an ideal acorn hiding spot where they can snugly wait the winter out.  A few acorns, such as those from White Oaks, will sprout within weeks of falling of the tree in the fall and occasionally even sprouting on the tree.  This gives them a head start come spring and helps them avoid seed predators.  Bluejays or squirrels returning to a cache for a dinner of White Oak acorns, will likely be very disappointed when they find unappetizing sprouting acorns.  Most acorns however wait for snow melt and spring temperatures before germination, requiring exposure to cold before they are even able to germinate.  Once germination starts the seedling immediately puts all its energy into producing a thick taproot that can grow to six inches or more before any greenery sprouts above ground.  Establishing a healthy root system helps ensure the longevity of the plant as well as prepares it for future fires.  When fire does burn through an area, established seedlings may be top killed but thick healthy roots remain safe underground and can quickly sprout new stems.  In general, the thicker and larger a root system the more likely it will survive a top killing fire.  Quick recovery and growth after fire allows oak seedlings to out compete other plants, ensuring survival.
Fall in an eastern oak woodland.

Monday, November 14, 2011

Life of an Oak Part 1: life as an acorn

A White and Red Oak forest in Eastern Iowa.
This is the first of a four part series on the life cycle of oak trees in the eastern upland deciduous forest.

Hiking though the cathedral like upland forest normally gives us no impression of the journey those trees took to where they are today.  Towering trees give the impression of quiet permanence, as though they have always been there and always will.  This path operates on a different time frame from what we do, years or perhaps seasons as apposed to our hour and minutes.  Very very few people actually are privileged and patient enough to observe this process, let alone live long enough.  The journey from seed, to seedling, to sapling is not survived by many.  It is a long, difficult journey back to the canopy.  Each tree species has a particular preferred route from the ground to the canopy programmed into their DNA.  Any deviations from this DNA program prove fatal for the vast majority of seeds, seedlings, and saplings.  Even when everything follows pre-programmed genetic pathways, the vast majority do not survive, falling to predators or the abundance of natural hazards filling the woods.  But slowly and surely, some do survive, and some do produce seed to start the whole cycle over again.
Pin Oak leaves and acorn.
The Mighty Oak and Vulnerable Acorn
Mighty oaks are revered in every culture they are found as symbols of strength, royalty, high rank, endurance, and even deity.  It is easy to see why when gazing upon a mature oak tree, and it is easy to forget this oak was once an acorn among thousands or millions of similar acorns.  Life as an acorn is quite simple, growing on the mother oak for a year or two, depending on the species, and then making the short quick journey from mother to ground.  This fall is quick and easy but the return is long and difficult, exceedingly few survive.  Once on the ground the acorn finds itself in a rather non-ideal location under its mothers canopy.  Shade from the mother plant can limit growth of young oaks and competition of roots between the plants can end up hurting both mother and child, but primarily child.  So what's an acorn to do?  It can't roll itself to another location and its too heavy blow in the wind.  At the same time often 90 or more percent of these acorns will become infected by insects, bacteria, or fungi, causing them to rot long before they ever have the chance to germinate.  On top of that, deer, turkey, chipmunks, squirrels, and birds of all types literally flock to oak trees each fall, gorging themselves on calorie rich acorns in preparation for winter.  From a practical standpoint none survive this magnet like attraction to acorns.  Literally, searching a forest floor the following spring or even a few months after the initial fall, likely not a single viable acorn will be found.  The food source is simply too valuable for wildlife to leave alone.

The Blessing and Curse of Predators
But with the curse of wildlife gorging themselves comes deliverance.  While deer and turkey consume acorns as soon as they find them, this is not true of all wildlife.  Chipmunks, squirrels, and certain types of birds gather and hide huge numbers of acorns in caches to get them through winter.  Squirrel and oaks seem to be particularly fond of each other.  Squirrels sneak around under oak trees hiding from predators, searching out acorns.  Often acorns hidden under foliage are the first to be gathered.  Foliage that hides acorns also hides squirrels from hawks flying overhead, thus oddly, hidden acorns are not hidden at all from seed loving rodents.   But as squirrels eat they also gather and hide many acorns by burying then in secret locations for winter feasting.  Oddly, Red Oaks appear to encourage both eating and caching of acorns by squirrels at the same time.  Top portions of Red Oak acorns are sweeter while bottom portions have higher proportions of bitter tannins.  Squirrels will bite in, eat the top portions, but leave the bottom behind.  Interestingly, these bottom portions contains the embryo, and even without a top portion the seed can easily germinate and grow, so both oak and squirrel have their nut and eat it too.  Cached acorns are often buried in location away from trees and in open areas ideal for oak seedling growth.  The often forgotten caches later germinate, potentially growing into trees.
Bluejay, picture from
Acorn Snobs
Bluejays and oaks also have a particularly close relationship.  These loud and aggressive birds are like snobbish connoisseurs of the acorn world.  Nothing gets in the way of a Bluejays acorns, and if something does the bird lets it be known loud and clear.  Depending on their mood, nothing is too big for the Bluejay to squawk at or try and chase off.  These birds are quite opinionated, and quite entertaining to watch, as long as you are not the one they are squawking opinions at.  Jays are excessively efficient at what they are designed to do, which is gather and cache large seeds.  Jays have the ability of gather nearly all acorns fallen from a tree within days, without the help of other wildlife.  And true to their connoisseur title, only the best, most viable acorns are gathered.  Jays examine, peck, shake, and weigh acorns in their beaks.  Acorns meeting their high standards are then stored temporarily in their expandable esophagus.  Several acorns can be stored this way and transported quickly to distant locations for caching.

The Bluejay cache is the ideal location for acorns.  High quality seed, buried in the dirt, hidden from predators, in areas away from other trees, like any master gardener would do it.  Most caches will be relocated by the jay and eaten during winter, but many will be forgotten or simply not used.  Some oaks such as the white, prevent their acorns from being eaten by germinating within days of being cached.  Others survive the winter hoping they are lost or not needed by the jay to get through the winter.  Come spring however, the acorns readily germinate, potentially expanding the oak forest.  Very few acorns actually get to the stage of germination, and of the few that do germinate most don't continue much past seedling stage.  Life as an acorn is passive and easy, if survived.  No real work is ever done by the seed.  But with germination begins the work as the tiny oak begins its climb back to the canopy.

Friday, November 11, 2011

Sonoran Desert Rain: El Nino and La Nina

If anything is consistent in the desert, it is its consistently variable rainfall and drought.  Though still a desert, portions of the Sonoran Desert are considered some of the wettest deserts in the world.  Rainfall ranges between three and twelve inches annually, depending on location, and is split roughly between summer monsoon season and winter.  Between these "rainy" seasons there are two annual droughts, one in spring and one in fall.  Resulting from "abundant" rainfall compared to other deserts, and both warm and cool rainy seasons, the Sonoran Desert is likely the botanically richest desert in the world.  Other deserts receive less rain and only have one rainy season, if any at all.  Despite this so called abundance, rain is still sparse and variable.  I have seen years with three inches of rain and others with 20 inches.  Trace rain showers are the most common type of shower, but I have seen storms that drop eight inches, an entire years worth, in one storm over a few days.  Months often pass without even a trace of rain, then drought is broken by a storm dropping two inches in a single day, followed by more months without rain.  Variability is the rule, and much of what controls this variability is connected to ocean temperatures thousands of miles away.

Amazingly, the Pacific Ocean off the coast of South America can have huge effects on weather in the Sonoran Desert.  Within the Pacific Ocean, along the equator, water temperatures vary from season to season and year to year.  These temperatures cycle above and below the average temperatures on a seemingly an unpredictable basis.  This cycling is called the El Nino Southern Oscillation, or ENSO.  The weatherman is still trying to figure all this out but does know that both above and below ocean temperatures produce predictable weather patterns.  When equatorial ocean temperatures off the coast of South America are below average it is called a La Nina event.  When ocean temperatures are above average it is an El Nino event.  Weathermen watch for these and make long-term predictions based off of them.

El Nino, top map, with red and orange representing warmer ocean temperatures along the equator off the coast of South America.  La Nina, bottom map, with blue representing cooler ocean temperatures. 

Check out this link with lots of ENSO information, including an animation that tracks Pacific Ocean temperature change over the past three months.

Link to current National Weather Service ENSO observations: ENSO Diagnostic Discussion 

La Nina's lower ocean temperatures results in less evaporation from the ocean and therefore a weak pacific jet stream bringing moisture to the Sonoran Desert.  Typically this means winter rainfall is lower than normal.  El Nino's higher ocean temperatures results in greater evaporation from the ocean and therefore a stronger Pacific Jet Stream bringing in moisture to the Sonoran Desert.  So typically La Nina means less winter rainfall, while El Nino means more winter rainfall.  Summer rainfall patterns seem to be less controlled by ENSO.  However, La Nina does seem to occasionally increase summer rainfall but El Nino seems to have the opposite.  

Even with this information, predicting rain in the desert just about drives me crazy.  As always, even when all forecasts align, the exact opposite often happens.  Though El Nino and La Nina often do accurately predict rainfall, they also are often wrong.  The driest years I remember where always strong La Nina's.  The wettest, El Nino's.  But I have also seen wet La Nina's and below average rainfall during El Nino's.  

This winter we currently have strengthening La Nina conditions, which typically would mean less rainfall.  However, we have already had about a half inch of rain for November in the Phoenix area.  More rain is predicted in the next week or so.  This is unusual, but for the desert, the unusual is expected.  As a result of this rainfall, temperatures have been slightly below what is typical.  If even a little more rain does come in the short term, and temperatures do stay cooler, the soil will stay moist and cause an abundance of dormant wildflower seeds to germinate.  Then, if rainfall continues, say one decent rainfall every month through March, massive blooms of wildflowers will display themselves in the spring.  We will all have to wait and see, but predicting good spring desert wildflower displays is even more difficult than predicting desert rain.  
A spring desert wildflower display after a winter of above average rain.  Picture from Arizona-Sonoran Desert Museum. 

Monday, November 7, 2011

Sonoran Desert Fall: October and November

Fall in the Sonoran Desert is a return to paradise.  After the long endured scorching summer, redemption comes to desert life.  October begins with average highs in the 90's and ends with highs in the low 80's.  But throughout the month summer isn't quite sure if it wants to stay or go.  The mornings and evenings can be quite beautiful but afternoons will often hit 100 degrees.  Other days temperatures will only hit the low 80's though.  But eventually, by the end of October cooler temperatures win out and day after day beautiful temperatures will be the rule through April or early May.  Typically, fall in the Sonoran Desert is quite dry but fortunately not nearly as dry as May and June.  This year we are especially dry around Phoenix due to a very disappointing monsoon season.  We have had a little rain in October and early November, but only just enough to help keep things cool and prevent things from being completely bone dry.

Fall is not quite as exciting in the desert as it is in deciduous forests (desert dwellers are absolutely ecstatic about cooler temperatures though!).  For colorful leaf displays through, riparian areas that support cottonwoods, willows, sycamores, or ashes will produce ribbons of yellow across the desert landscape.  Often, if summer rains were decent, an abundance of fruits available for migratory birds.  Prickly pear fruit, wolfberry, and hackberry are often available for these birds providing both nourishment and hydration.

The most notable event of the fall is the arrival of migratory birds from the cold north.  Hawks of many types are often seen soaring through the sky.  With a little closer observation a great diversity of song birds can also be found.  I have often come across small flocks of out of place birds passing the winter in certain localities.  While Northern Cardinals can be found in the desert through out the year, they are by far most common during the winter months.  In one particular year I frequently came across a small flock of Eastern Bluebirds living on a mountain slope.  Areas with an abundance of water will typically host large flocks of many species of waterfowl, quite an unusual site to the desert.  A part from birds, mule deer are preparing for their rutting (mating) season which begins in November.  During the rut, bucks scrape the velvet of their antlers in preparation for mating sparing competitions.  If you are fortunate enough to observe mule deer bucks this time of year you will often observe them running around and acting like they are crazy.  Once, I was even charged by a large buck, which luckily changed his mind when he was about ten feet from me!  Snakes are also commonly found due to the cooler temperatures which make them more sluggish.  By November, nearly all reptiles will be hidden away in hibernation waiting for warmer temperatures.

In rare years, maybe once or twice a decade, El Nino in the Pacific Ocean will bring an abundance of rain in the fall.  These El Nino storms will cause masses of wildflower seeds that lay dormant in the soil to germinate and begin to slowly grow through winter months before they bloom in spring.  Typical dry fall weather though usually ends early December with gentle winter rainstorms blowing in from the Pacific Ocean.  The first storm quite reliably hits during the first few weeks of December bringing the next big annual changes in the Sonoran Desert.

Thursday, November 3, 2011

Simply Unique Seaweed

Seaweed is one of the simplest, most unique, and interesting plants.  But calling seaweed a plant is a slight misconception.  Technically, seaweed is not like the land plants we commonly encounter, seaweed is actually an algae.  What's the difference between plants and algae?  Land plants are much more complex, they absorb nutrients and water through extensive root systems, and have vascular systems to distribute these through out the plant.  Algae on the other hand have no root system, instead they have a holdfast, which simply anchors them to the ocean floor.  Instead of a stem, algae have a stipe, which is like a stem but does not contain woody vascular tissue.  Lastly, algae may have what looks like leaves but actually are called lamina because they also lack vascular tissue.  Nutrients, instead of being absorbed from the soil, through the roots, and then transported to the leaves through the stem like land plants, algae directly absorb everything they need directly from the ocean.  Nutrients move from the ocean directly into lamina where it feeds the algae.  One major function land plants and algae have in common though is both harvest light using photosynthesis to produce sugar for energy.

All kinds of algae grow throughout the ocean, the largest and most interesting grow in the tidal zone.  These are distributed by elevation within or near the tidal zone.  Some species are located just above the tidal zone gaining nutrients from wave spray or splash.  Other species only like to be covered with with water for a short time each day so are in the highest portion of the tidal zone.  Others like weak waves and others very strong waves.  Each has their specific preference of conditions.  The largest are the furthest out from shore.  Bull Kelp, for example, can grow in water 100 feet deep with their highest lamina floating on the surface.  Kelp grows with amazing speeds of up to 20 inches in one day during the summer.
An underwater kelp forest.
The following video is great, showing how seaweed is harvested and the type of environment it is typically found it.  I have spent a decent amount of time in tidal areas like this and they are truly amazing places.  Typically, places like these are only accessible during low tide.  A few locations where deeper water algae grow may only be accessible during the lowest low tides which only happen a few days a month or a few days a year.  The waves, ocean, rocks, and great abundance of sea life in these areas is both beautiful and amazing.  At the same time these areas are extremely dangerous and only highly skilled and informed people can experience these areas on a relatively safe basis.  I say relatively because the constantly pounding waves, the rocks, and currents can be quite unpredictable, even to the most experienced.  Larch Hanson, the person harvesting the seaweed, is amazing at how he handles this dangerous environment, making it appear quite easy.

The Perennial Plate Episode 76: Seaweed Man from Daniel Klein on Vimeo.

Seaweed is truly remarkable for the number of things it can be used for.  Of course, most people know that sushi is wrapped in seaweed, specifically Porphyra.  Seaweed salads available in Japanese restaurants are typically made from Wakame.  Agar and other gelatinous materials are also produced from a variety of different alga.  It is also an excellent source of many different nutrients that are not typically present in other foods, but especially iodine.  This great diversity of available nutrients also makes it an excellent organic fertilizer.  Research is also being done on how to efficiently use seaweed to produce bio-fuels.  This all makes for a booming but relatively small seaweed agricultural industry that is still in its infancy having only started about 50 or so years ago.

More information on seaweed: Maine Seaweed: the Seaweed Man