Each year as Thanksgiving rolls around, I renew my gratitude for the special people in my life. But I usually don’t remember to give thanks for many of the things I just take for granted. So this year, I’m thankful for trees…for the many ecosystem services they provide — for FREE.
…for forests that enrich our lives and uplift our moods as we wander their winding paths.
…for vast tracts of unending vegetation that pump oxygen into our atmosphere and remove carbon dioxide, helping to manage the climate.
…for forests and other vegetation that filter runoff to maintain clean water in lakes and rivers and prevent soil erosion
…for trees that provide food and shelter for wildlife (and food and building materials for us)
…for forests that improve our urban landscape by providing shade, lowering the air temperature nearby, buffering noise, air, and light pollution, as well as providing a mental and physical escape from the urban jungle.
this post dedicated to daughter Becky, an ecosystem services specialist.
What do these animals have in common during the fall months?
The answer to the question above is that all of these (and many more bird and mammal species) exhibit excessive consumption of food in the fall, technically becoming hyperphagic.
There really are only a few viable solutions to surviving the long, cold winters of the far north: 1) get out of town — migrate! 2) build fat stores to last you several months and sleep as much as possible, and 3) stay active to search for what little food remains, tolerate the cold, but enter a starvation state by metabolizing a lot of of your muscle (when you run out of fat).
The temporary condition of hyperphagia is brought on by decreasing photoperiod — i.e., the continually declining number of daylight hours in the transition from late summer to fall — that triggers the change in an animal’s eating habits. Fortunately, this also happens to be when food is most abundant with the ripening of seeds, fruits, excess numbers of young, naive juvenile animals roaming the countryside, etc. So food is easy to come by and fattening is easily accomplished by overeating.
To take Black bears as a good example of this strategy, consider the following comparisons of its diet and caloric consumption from summer to fall.
In the summer Black bears consume about 5,000-8,000 kilocalories per day. If food and water are restricted at this time, they break down their muscles for energy, may accumulate too much nitrogenous waste in their blood, and may die. They cannot “hibernate” at this time.
In the fall, Black bears become voracious, begin consuming 15,000-20,000 kilocalories and drink gallons of water per day, excreting 1-2 gallons of urine as they metabolize all those calories into fat stores. Then, they stop eating and enter a lethargic, hypo-metabolic state of winter sleep, in which their resting heart rate of 80-100 beats per minute falls to less than 22 per minute and their breathing slows down to 2 or 3 times per minute. For the duration of their winter “sleep” they don’t eat, don’t drink, don’t break down any muscle, and females give birth to their cubs. It’s an amazing physiological transformation.
But have you ever wondered if we humans exhibit a similar response to the waning photoperiod and colder days of fall weather? It’s true that humans cannot hibernate the way small rodents do, but could they increase their consumption of carbohydrates and fatten up in the fall and then decrease their daily activity and sleep more in the winter to conserve energy — like bears do? [Side note: carb craving in the fall is a real thing for me — how about you?]
Well, here is the answer, in an article from the New York Times written more than a hundred years ago, back in November 1906. (Click on the image to enlarge it to be readable.)
Apparently, it has been common practice in some cultures (in the past?) that face temporary periods of starvation in winter to prepare multiple loaves of substantially nutritious bread in the fall, prior to beginning a routine of reduced activity and increased bouts of sleeping during long winters. Sleeping with farm animals for warmth was encouraged, I guess.
My favorite season of the year is almost gone now, but we did manage to see a part of the glorious color changes come through the Minnesota woods this fall. In addition to this year’s contribution (below) to my fall color postings, I wanted to share some of my past favorites as well.
In the northwest corner of Slovenia, the city of Bled has one of the most picturesque, postcard-worthy lakes in Europe, complete with its own tiny island (the only island in the entire country)! Like many cities founded in the Middle Ages, Bled has a castle dating to the 11th century that towers above the city on an imposing cliff. According to some, this is the oldest castle in Slovenia, and one of the most popular tourist attractions. Doubly fortified walls surround two courtyards (an upper and lower) providing beautiful views of the lake, the city, and the countryside.
After walking around the castle for a while, we boarded a small boat (gondola) to row out to the island. Motors are not allowed on Lake Bled, because apparently it is easily polluted. Lack of good water turnover from the few streams flowing in and out coupled with the lack of wind that could cycle water from the bottom to the top surface could make the lake water stagnant. Like some other glacial lakes formed in mountainous areas, Lake Bled is protected from wind by the surrounding mountain ranges.
I’ve visited quite a few famous caves in the U.S., but the amazing caverns carved from karst limestone near Postojna in southwestern Slovenia are the most spectacular I’ve ever seen. They are definitely one of the Wonders of the Natural World.
The Postojna cave system is notable because of all the animal life found there. Over 100 species have managed to survive in the dark, cold (45-50 F), mineral-rich water, including a cave beetle species, a jelly fish relative, crustaceans, pseudo scorpions, and a cave spider species. But the largest and most remarkable cave dweller in Postojna cave is the “baby dragon” or cave salamander or Olm (Proteus anguinus).
There was some excitement among the cave biologists several years ago when one of the large Olms began to lay eggs. It took quite a while but she eventually laid more than 50 eggs, about 20 of which hatched in about 5 months. The youngsters had normal eyes, but they regressed in size and skin eventually grew over them. When presented with small worms, Olms immediately go on the attack, hoovering them up (like a vacuum cleaner) with their elongate snout.
Our next destination on this trip was the laid-back, small beach town of Opatija (pronounced o-pa-ti-a). We had a free day to explore some of the area, while others on our tour were sampling the wines of the Istrian region (northwest peninsula of Croatia). It was perfect weather for a hike in the Učka (pronounced ooch-kah) nature park, about a half-hour drive northwest of Opatija. Park personnel recommended we hike to the highest peak of the park, Mt. Vojak (vo-yak) for the stunning views of the coast. Fall color was almost at peak in the beech forest, so we followed a well-marked trail from the Učka nature park visitor center to the summit of Vojak — about a 1500 foot climb.
Park personnel in the souvenir shop in the tower told us that Griffon vultures have nested in the park for the first time this year. Several pairs of the vultures (which are rare in the Balkans) have nested on a nearby island in last years, but park staffers make a concerted effort to rescue the fledglings that often fall into the bay and are not strong enough to fly out of the water.
Croatia’s largest national park, located in roughly the center of the country, features sheer limestone cliffs that tower above emerald green water and a bounty of large and small waterfalls and cascades that rush down a series of about 16 lakes.
A series of boardwalks at the park takes you around a few of the lakes and waterfalls where you can appreciate the amazing natural processes that create this landscape.
There were a few European or Eurasian representatives of the mammal fauna in the Zagreb zoo, but most of their mammals were native to Africa and Southern Asia. The zoo here has done an excellent job of providing as much natural habitat for the animals as possible, while still allowing them to be easily observed by zoo visitors. Enclosures with clean, clear glass facing zoo visitors allowed photographers up-close looks at the animals, and occasionally direct contact with them looking back at us. What a treat!
While we walked around the zoo, we could hear a male lion roaring intermittently. When we finally found the lion enclosure, the male was sleeping next to an old rubber tire — not exactly the perfect pose for the king of the jungle.
Zagreb, capital of Croatia, is a bustling city of old and new — ornate buildings dating to its boom period as part of the Austria-Hungary empire and sleek high-rise skyscrapers built after the Balkan War. There is a lot to explore in Zagreb, and many unique dishes to try, but yesterday afternoon was the time to explore the Maksimir Park Zoo. The zoo exhibits were spacious, nicely landscaped areas with glass separating animals from humans, which allowed me to get some good close-ups. Birds from Europe and Africa were pretty well represented.
Our Balkan adventure continued with a journey from Dubrovnik, Croatia north over rugged mountains and overgrazed valleys in Bosnia and Herzegovina to Sarajevo, the cultural, financial, and political capital of this country. The contrast between the two countries is quite stark.
Throughout its history, Bosnia-Herzegovina has been a melting pot of religions and ethnicities — catholic Croats, orthodox Serbs, and Muslim Bosnians — mostly living together in cooperative tolerance of each other, with many inter-faith marriages and mixed families. In our walk through the old part of the city we found a Catholic cathedral, an Orthodox Church, a mosque, and a Jewish temple within just a few blocks of each other.
Sarajevo was the site of the 1984 Winter Olympics, when the independent Balkan countries of today were united as Yugoslavia. Life was good, productivity was high, and people felt they had good lives following 40 years of rule by their benevolent dictator Josep Tito.
And then things fell apart as the influence of communism waned, Balkan countries began to assert their independence, and Serbia made an attempt to pull it all back together. Their troops surrounded the jeweled capital of Bosnia in early 1992, and began to pound away with shells and mortars fired from tanks that lined the hills above the city for more than 1400 days, the longest siege in the history of modern warfare. The Serbs were successful in cutting off water, gas, power, and food, and more than 14,000 people were killed in the city, one third of them children before the siege ended in early 1996. In addition to the shelling from the tanks, snipers picked off civilians as they attempted to forage for food, wood, water, etc.
Bosnian army soldiers began constructing a tunnel from houses in the Olympic village area (asterisk below arrow) under the airport runway to a village on the other side of the airport outside Serbian forces in spring 1993 in order to bring food and supplies into the city and as an escape route for some to leave the city.
When the war ended, the solution to representative governance of this mixed population in Bosnia-Herzegovina was the election of not one but three concurrent presidents (one Croat, one Serb, and one Muslim) who would rotate in the position every 8 months for four years, along with 14 parliaments and 136 ministries. A confusing solution to the problem of equal representation of all religious/ethnic affiliations to say the least!