Hair, Skin & Nail Vitamins Versus Prenatal Vitamins

Prenatal vitamins provide certain nutrients to expecting and breastfeeding moms. Photo Credit Spectral-Design/iStock/Getty Images

Certain vitamins, such as vitamin H or biotin, aid in hair and nail growth as well as skin health. There are claims that prenatal vitamins can help improve skin health and create longer, stronger hair and nails. Eating a healthy and well-balanced diet can ensure that your body is receiving the nutrients that it needs. Prior to beginning a vitamin regimen, consult with your health care provider for recommendations.

Hair, Skin and Nail Vitamins

B-complex vitamins consist of all of the B vitamins that your body needs. Vitamin H, or biotin, is a part of the group of B vitamins and is particularly responsible for longer hair, stronger nails and healthy skin, according to the University of Maryland Medical Center. Sardines, egg yolks, whole grains, nuts and bananas provide a plentiful source of biotin. Biotin is also available as a supplement. Adults who are healthy can safely consume up to 30 micrograms per day, according to the UMMC. Consult with your physician to see if this amount is right for you.

Prenatal Vitamins

Prenatal vitamins provide essential nutrients such as iron, folic acid and calcium, according to Drugs.com. Pregnant women and nursing moms need these additional nutrients to support healthy embryo growth and nourish themselves as well as the baby while breastfeeding. Folic acid helps ensure that the baby does not develop neurological defects such as spina bifida, while the calcium ensures strong healthy bones. The iron is required to ensure that the mother-to-be can produce enough red blood cells to support the increase of blood volume during pregnancy and supply the necessary amount of iron required for nursing.

Comparisons

Prenatal vitamins do not contain any nutrients that aid in hair, skin and nail growth or development, according to MedlinePlus. Biotin is simply not included in the formula because the primary function of prenatal vitamins is to deliver three essential nutrients: iron, calcium and folic acid. All of these nutrients, including biotin, folic acid, calcium and iron, are found in multivitamins. Prenatal vitamins deliver a higher dose of calcium, iron and folic acid than an ordinary multivitamin blend because pregnant and nursing women require higher doses.

Warning

If you are not pregnant, nursing or plan to become pregnant, taking a prenatal vitamin may not be in your best interest, according to Columbia Health. Since prenatal vitamins contain a higher concentration of iron, the iron could build up in your body. Too much iron can cause side effects such as nausea, vomiting, diarrhea or constipation. A severe build-up of iron in your system could possibly result in death.

Considerations

Only take a prenatal vitamin if you and your doctor decide it’s right for you. If you want to improve your skin or grow longer hair and stronger nails, opt for a biotin supplement. Certain cosmetic products, including fingernail polishes, shampoos and conditioners, are formulated with biotin to provide extra strength and support healthy growth, according to the University of Maryland Medical Center.

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How to Lose Weight If You Weigh 191 pounds

By dieting and exercising, that number on the scale will go down. Photo Credit Pixland/Pixland/Getty Images

If you're overweight at 191 pounds, weight loss can not only make you look better, but it can also improve your health. Being overweight heightens your risk of various health conditions including sleep apnea, stroke, heart disease, certain types of cancer and high blood pressure. Whether you need to lose 5 pounds or 50 pounds, the way to go about it remains the same -- you must burn more calories than your body uses every day.

Aim for Gradual Weight Loss

Although fast weight loss might be tempting, it's not recommended. According to the Centers for Disease Control and Prevention gradual weight loss at a rate of 1 to 2 pounds per week is easier to maintain in the long run. It also allows you to slowly get used to the lifestyle changes you're making to lose weight. Since there are 3,500 calories in 1 pound of fat, you must accumulate a daily deficit of 500 to 1,000 calories through exercise and diet to achieve this.

Incorporate Dietary Changes

Making healthy dietary changes can contribute to your daily caloric deficit. The National Heart, Lung, and Blood Institute recommends consumption of a diet consisting of a variety of fruits, veggies, and whole grains, such as brown rice and whole-wheat pasta. Lean meats, beans, skinless poultry, and reduced-fat dairy products are also recommended. Reduce your portions to lose weight. Limit sugar as well as saturated and trans fats, which are present in many baked and fried foods, fatty meats, hard margarine, lard and full-fat dairy products.

Burn Calories with Aerobic Exercise

Aerobic exercise, or cardio, burns calories that contribute to your daily caloric deficit. The American College of Sports Medicine states that doing between 150 and 250 minutes of moderate cardio a week can trigger weight loss. In 30 minutes, a 191-pound person can burn 219 calories by walking briskly at a speed of 3.5 mph; 462 calories by climbing stairs or bicycling at a speed of 12 to 13 mph; and 404 calories during a casual game of racquetball.

Build Muscles with Resistance Training

Resistance training promotes weight loss because it preserves and increases muscle tissue, which uses up a lot of calories to sustain itself. The University of Rochester Medical Center recommends resistance training on two to three days of the week. They suggest working your large muscle groups and continuously increasing the resistance so it's hard to do another repetition with perfect form after finishing a set. Exercises can include pushups, bench presses, lat pull-downs, crunches, squats, dead lifts and lunges. Always warm up with five to 10 minutes of light cardio before starting your workouts. If you're new to exercise or have an injury or health condition, get your doctor's consent before engaging in any physical activity.

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What Would Happen If Comet Swift-Tuttle Hit the Earth?

Author Bio

Greg Uyeno, Staff Writer

Greg Uyeno is a science journalist. He has studied cognitive science at the University of California, Berkeley and journalism at New York University. He’s always interested in the language of science and the science of language.

The Perseid meteor shower.

Credit: SKY2015 | Shutterstock.com

Shooting stars may fill you with child-like wonder, but these celestial showstoppers are also reminders that Earth is hardly alone in space, and some of those cosmic objects can be downright dangerous.

The Perseid meteor shower, which appears every year in mid-August, occurs when Earth passes through a trail of debris left by Comet Swift-Tuttle. In 1973, based on calculations about the object's orbit using limited observations, astronomer Brian Marsden at the Harvard-Smithsonian Center for Astrophysics predicted that Comet Swift-Tuttle could collide with Earth in 2126. The catastrophic prediction was later retracted, but what would happen if Comet Swift-Tuttle smacked into our planet?

"We have to be clear that it's not going to happen," Donald Yeomans, a senior research scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, and author of "Near-Earth Objects: Finding Them Before They Find Us" (Princeton University Press, 2012), told Live Science. [Perseid Meteor Shower 2016: When, Where & How to See It]

When Swift-Tuttle was last seen in 1992, Yeomans was among those who produced revised models for the comet's motion, making the complicated calculations to account for the gravitational effects of the sun and planets on the space rock's orbit. The 1992 sighting, along with data from 1862 and 1737, provided astronomers with enough information to rule out the possibility of a collision in 2126.

Even still, Comet Swift-Tuttle isn't just another space rock.

Comet Swift-Tuttle is "certainly one of the largest" objects that crosses paths with the Earth, Yeomans said. The cosmic object measures about 16 miles (26 kilometers) across, and when it passes close to the Earth, roughly every 130 years, it's hurtling through space at about 36 miles per second (58 km/s), or more than 150 times the speed of sound.

If the comet were to strike the planet, the impact energy would be about 300 times that of the asteroid collision that was thought to have caused the Cretaceous-Tertiary extinction that killed the dinosaurs about 65 million years ago, according to Yeomans. "It would be a very bad day for Earth," he said.

But the size of a comet or asteroid isn't the only thing to consider with cosmic collisions, said Gerta Keller, a geoscientist at Princeton University.

A comet strike on land or in shallow seas would be "rather destructive" regionally, but the real damage would likely come from gases put into the stratosphere, the part of Earth's atmosphere where the ozone layer is located, Keller told Live Science. Sulfur dioxide would initially cause cooling, and then carbon dioxide would lead to long-term warming, she added. An event like this would likely cause the planet's climate to change drastically, leading to mass extinctions around the globe. [Crash! 10 Biggest Impact Craters on Earth]

But Keller also pointed out that most of Earth's surface is covered in ocean. An impact in the deep ocean could trigger earthquakes and tsunamis, but based on what scientists know about the effects of underwater volcanic eruptions, the atmospheric effects likely would be mitigated by the ocean, she said. In this case, Keller said it's unlikely that a comet colliding with Earth would cause mass extinctions.

Scientists calculate that Swift-Tuttle's next approach to Earth will be on Aug. 5, 2126, when it will come within about 14 million miles, or 23 million km, or about 60 times the distance from Earth to the moon, Yeomans said. Current models don't expect the comet to ever get any closer than about 80,000 miles (130,000 km) to Earth's orbit, but as time passes, those predictions become less and less certain. So although Yeomans is sure that Earth faces no threat in 2126, he said 10,000 years from now, "you can't rule out the possibility, but it would seem to be very unlikely."

Part of that slim uncertainty is due to small influences on the comet that change its orbit ever so slightly each time it swings around the sun. For example, as comets pass near the sun and heat up, expanding gases act like jet thrusters, slightly altering the trajectory. For Swift-Tuttle, that effect is very small, likely due to the comet's tremendous mass, Yeomans said. But over thousands of years, these minute, unpredictable effects make it more difficult to predict the orbit of cosmic objects.

And there are plenty of other objects out there to be aware of, Yeomans said. "We have a long, long list of asteroids for which we haven't completely ruled out a collision, but the impact probabilities are so small that it's not really worth worrying about," he said.

Original article on Live Science.

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Natural Ways to Increase Serotonin & Endorphins

The endorphins released by vigorous exercise help fight pain and fatigue. Photo Credit running image by Byron Moore from Fotolia.com

Overview

Endorphins are opiate-like chemicals that produce feelings of euphoria and calmness in response to external stimuli like pain, excitement and physical exertion. Serotonin, the neurotransmitter implicated in mental disorders like depression, serves a similar purpose, affecting mood, sleep patterns and appetite. There are many natural ways to increase serotonin and endorphin production, many of which involve simple everyday lifestyle factors like diet and exercise.

Diet and Nutrition

Food is the fuel source needed for every action of our minds and bodies. The foods we eat influence physical health as well as brain functions like mood and cognition. Certain substances are required for the production of serotonin in the body. The serotonin precursor L-tryptophan can be found in a variety of foods, such as milk, turkey, soy and other high-protein foods. It can also be taken in supplement form as 5-hydroxytryptophan, or 5-HTP, and is more likely to increase actual serotonin levels when taken in this way.

According to a study by Felice Jacka featured in the January 4, 2010 edition of “The American Journal of Psychiatry,” women eating a healthy diet rich in vegetables, fruits and healthy fats were half as likely to experience anxiety and depression as those eating a typical American diet of processed and fatty foods, reinforcing the role of diet in mood and wellbeing.

Exercise

It has long been known that exercise increases the levels of endorphins in the blood, though these endorphins do not cross the blood-brain barrier to affect mood. According to The New York Times, long-distance running also triggers the release of endorphins in the brain. While the role of this response is not completely understood, it is believed that the body produces endorphins to help fight pain and fatigue, making it possible to continue in spite of physical discomfort.

Intense cardiovascular, weight-bearing and stretching workouts lasting 30 to 45 minutes are most likely to have a positive impact on endorphin production and physical fitness.

Sunlight

As the source of energy and life for all living things, the sun plays a vital role in every function of the mind and body. In humans, it provides essential vitamin D, which is needed for proper immune function, bone growth and calcium absorption. While too much sun exposure can cause skin damage, too little can lead to other problems like vitamin D deficiency and depressive disorders.

Seasonal affective disorder (SAD) is a form of depression caused by lack of natural sunlight during the winter months. The sun can have an impact on other forms of depression as well. A study by R.W. Lam and colleagues appearing in the June 30, 1999, issue of “Psychiatry Research” states that exposure to bright white light can effectively ease symptoms of nonseasonal forms of depression, such as PMDD, or premenstrual dysphoric disorder.

According to a study by Nicole Praschak-Rieder, MD, featured in the September 2008 issue of the Archives of General Psychiatry, lack of sunlight in the fall and winter months causes an increase in endogenous transporters that inhibits serotonin in the brain, explaining in part why depression, fatigue and lethargy are more common during colder seasons.

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How to Reduce Belly Bulge

Combining good exercise and nutrition habits is the best way to reduce belly bulge. Photo Credit Manuel Faba Ortega/iStock/Getty Images

Reducing belly bulge comes down to a combination of dietary and exercise strategies. Eating lots of junk food, drinking alcohol -- particularly beer -- and living a sedentary lifestyle inevitably leads to belly bulge. Even if you're active and try to be healthy, there are a number of key points you might be missing to reduce the fat around your abdomen. Keep in mind that spot reduction is a myth, and that making healthy lifestyle changes will reduce your overall body fat, not just your belly fat.

Step 1

Eat a healthy variety of foods, including a large selection of vegetables. Each meal should have a serve of protein, such as lean meats, eggs or fish; a small serving of carbohydrates such as whole grains, potato, fruits; and a small serving of fats, which could include nuts, dairy, coconut or olive oil. Additionally, each meal should include a liberal serving of fibrous vegetables, including broccoli, asparagus, celery, avocado, tomato, snow peas, spinach and beans. The fiber can help to reduce bloating in your belly and improve your digestion.

Step 2

Drink plenty of water. For most people, 2 to 3 liters a day will ensure that your body is functioning at an optimal level and not holding onto excessive levels of stress hormones. Stress hormones, such as cortisol, are released in response to physical, mental and emotional stress. This causes your body to store fat in the abdominal region, causing the "spare tire" effect. Keeping hydrated has the added benefit of improving your digestion, meaning that your body's nutritional needs are met more effectively. You will also feel fuller for longer after meals if you include a glass or two of water when you eat, reducing your chances of snacking on fattening foods.

Step 3

Exercise regularly. There's no getting around it -- if you want to lose fat, you've got to get moving. If you've been very sedentary for a long time, start with walking. Once you've done a couple of walks a week for around a month, look into joining a gym. Have a trainer show you around and teach you how to use the machines, and how to lift weights. Adding resistance training, such as weightlifting or bodyweight circuits, to your exercise routine will help you reduce your belly fat and tighten your core muscles for a flat abdomen. If a gym membership doesn't suit you, you can use bodyweight exercise routines, running, swimming, cycling or team sports to get in regular exercise.

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50 Million Pound Challenge Diet

Eat plenty of fruit if you're on the 50 Million Pound Challenge diet. Photo Credit Jupiterimages/Creatas/Getty Images

The 50 Million Pound Challenge is an invitation for the African-American community of the United States, to collectively drop 50 million lbs. of excess body fat. The campaign launched in 2007 and is headed by Dr. Ian Smith, who created the Fat Smash Diet. Dr. Smith also became known for helping celebrities lose weight on the "Celebrity Fit Club" TV show.

About the Challenge

The aim of the 50 Million Pound Challenge is to promote the benefits of a healthy diet and exercise plan, to help combat the risk of heart disease and diabetes in the U.S. According to the 50 Million Pounds website, two out of every three Americans are overweight, but the statistics among African-Americans are particularly alarming as almost 80 percent of women, and 67 percent of men are overweight. Therefore, the program is targeted at helping African-Americans, although anybody is welcome to join, regardless of race. After signing up for the challenge online, you can join a group of your choice which will provide support and motivation. Many groups hold local meet-ups and sporting events to combine weight loss efforts with social activity. You may track your progress online. The 50 Million Pound Challenge program focuses on reducing weight through a combination of exercise and dietary changes.

Breakfast

For breakfast, Dr. Smith advocates always eating at least one piece of fruit, even if you do not feel hungry. Along with the fruit, you can eat two eggs, or a 1 1/2-cup serving of cold cereal. Good cereals include bran, plain Cheerios or non-frosted shredded wheat. If you prefer a warm cereal, such as oatmeal or grits, your portion size should not exceed 1 cup of cooked cereal. You can also have waffles or pancakes, but no more than two, and they should measure no more than 5 inches across. Or, you can have 6 oz. of low-fat yogurt.

Lunch

Dr. Smith recommends eating no more than two servings of meat per day, and each serving size should not exceed 4 oz. Grill, bake or saute meat instead of frying it. Optimal breads to eat include whole-grain, whole-wheat, multigrain and rye pita bread, but have no more than two slices a day. Avoid white bread. A lunch example when on the 50 Million Pound Challenge diet is a rye pita bread, stuffed with 4 oz. of sliced grilled chicken and served with a large green salad. Dr. Smith encourages eating plenty of fruit, so a good way to end the meal would be to eat two or three pieces of fresh fruit.

Dinner

Dr. Smith recommends eating foods that have a low glycemic index, as these foods do not cause sharp rises in blood sugar levels, and the body converts them to energy more slowly. High GI foods, especially when eaten late in the day, are quickly converted to energy, and if the body does not burn the energy it will store it as fat for later use. An example of a low glycemic dinner is a 4 oz. fillet of grilled fish, served with a portion of brown rice and steamed non-starchy vegetables, such as cauliflower, green beans or broccoli. Dessert could include baked apples or pears, or homemade rolled-oat biscuits.

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Extreme Fat Smash Diet Meal Plan

Exercise is part of the Extreme Fat Smash Diet weight loss program. Photo Credit Wavebreakmedia Ltd/Wavebreak Media/Getty Images

The "Extreme Fat Smash Diet" by Dr. Ian K. Smith, is the follow-up book to his popular Fat Smash Diet used on VH1's television show, Celebrity Fit Club. The Extreme Fat Smash promises faster results in a shorter time period. If you have between 10 and 25 pounds to lose, this diet is designed for you. Consult your doctor before starting any type of weight loss program.

Extreme Fat Smash Diet Basics

Salmon and vegetables. Photo Credit rez-art/iStock/Getty Images

According to Smith, "Sometimes we must go through darkness to reach the light." The Extreme Fat Smash Diet, or EFSD, is a very specific diet plan that lasts three weeks. Follow each phase -- it's broken down into three one-week cycles -- exactly as written for best results. Smith emphasizes practicing portion control and high-fiber foods that score low on the glycemic index. Although it's a low-calorie approach, you can have meals and snacks every 2 to 3 hours to help keep glucose levels stable and avoid hunger -- and subsequent food binging. The plan calls for four to five small meals and two snacks daily.

The First Cycle

Swimming is excellent cardio exercise. Photo Credit Ingram Publishing/Ingram Publishing/Getty Images

Rotate through the three cycles as many times as needed until you hit your goal weight. The first cycle is the most restrictive. The book comes with a day-to-day menu, which you are expected to follow exactly -- there is no guesswork and no substitutions. Perform between 45 and 60 minutes of cardio exercise daily and keep a food log of everything you eat. Although the menu changes daily, a typical day might include 6 ounces of low-fat yogurt and a piece of fruit for breakfast, a small salad with fat-free dressing and 1 cup of vegetable juice for meal lunch, 4 ounces of chicken and 1/2 cup lentils for meal dinner, and 1 cup of rice with 2 cups of vegetables for a fourth meal. Choose two snacks from the list daily.

The Second and Third Cycles

Drink enough water. Photo Credit Jupiterimages/Pixland/Getty Images

The second week is less restrictive, capitalizing on your weight-loss momentum. You will start to add some fruits and higher-calories foods that were not allowed in the first cycle. Drink plenty of water each day. You may also drink two 6-ounce glasses of wine or two 12-ounce bottles of light beer during the week. Limit caffeine from diet soda, coffee and tea. Exercise continues daily for weeks two and three. The third week adds a variety of other food and drinks, including an additional mixed cocktail. All three cycles have a daily food plan and recipes. After you finish the third cycle, you have the option of moving into maintenance or repeating the cycles to lose more weight.

Dieting Types

Eating a healthy meal. Photo Credit George Doyle/Stockbyte/Getty Images

The EFSD takes different dieting types into account. Smith has three categories for those on a diet plan -- alpha, beta and gamma. Alpha types lose weight easily. Beta types have to work hard to see results and gamma types have to follow the diet perfectly and will still see milder results than alpha and beta types. There are adjustments throughout the program based on type; gamma types may need to add more exercise or remove a small amount of food on certain days. There are no adjustments based on gender, height or starting weight.

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A Meal Plan for Extreme Weight Loss

Small bowl of oatmeal. Photo Credit minadezhda/iStock/Getty Images

Any meal plan for extreme weight loss should have certain basic components. For example, caloric restriction and portion control are essential to weight loss. Following extreme diets in the short-term can help you achieve a healthy body weight, after which you can follow a less stressful maintenance plan that is more sustainable. Adding advanced dieting techniques to any weight loss program can dramatically accelerate your results.

Basics

The basic principles of an extreme weight loss program are reduced caloric intake and portion control. Simply put, you must eat less, taking in fewer nutrients than your maintenance caloric. It takes a deficit of 3,500 calories to burn a single pound of body fat. Reducing your daily caloric intake by 500 to 750 calories below your maintenance level, you can create this deficit over one week. See Resources to find your daily caloric maintenance level.

Components

According to “The Abs Diet”, successful weight loss programs stress frequent, smaller meals. Rather than the traditional three large meals (breakfast, lunch and dinner), eat six smaller meals. “The Fat Burning Bible” recommends a meal plan with three meals and two to three snacks. You also need to choose the right foods. Lean proteins (chicken, fish and turkey), low-glycemic carbohydrates (oatmeal, whole-grains and sweet potatoes) and healthy fats (olive oil, avocado, and nuts and seeds) can help you achieve extreme weight loss.

Benefits

An extreme weight loss program has many benefits to your health. Eating three large meals per day triggers large amounts of insulin. A necessary hormone for nutrient delivery, insulin drives fats and sugar into body fat cells for storage. Eating more frequently prevents fat storage and might keep you from developing Type II diabetes, according to “The Fat Burning Bible.” In addition, frequent meals and snacks suppress production of the stress hormone cortisol, which serves to shut down fat burning and encourage body fat storage, particularly in trouble areas.

Examples

Some examples of extreme weight loss plans include low-carbohydrate diets, moderate-carb diets and the 40-30-30 macro-nutrient ratio, which is recommended by “The Fat Burning Bible.” With low-carb diets you take in 30 to 50 grams of carbohydrates per day, the equivalent of ½ to 1 cup of oatmeal. This diet is very extreme and causes fast weight loss; however it is impractical and unhealthy in the long-term, according to “The Abs Diet.” A moderate-carb diet also can provide extreme weight loss. “Xtreme Lean” recommends that you take in 100 to 150 grams of carbs per day. The 40-30-30 diet recommends 40 percent carbohydrates, 30 percent protein and 30 percent fat as the best fat-burning ratio.

Advanced

Advanced dieting techniques can enhance your extreme weight loss program. Cheat meals can help you avoid dieting plateaus, according to “Combat the Fat.” Having cheat meals means eating whatever you want for one meal once a week, allowing you to relax and recover mentally, physically and psychologically from dieting. Another useful technique is carb-timing, or taking in most of your carbohydrates when they are more likely to be burned as fuel rather than stored. Examples include splitting your daily carb intake between pre- and post-workout meals and/or taking in most of your carbs during the day, rather than at night.

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Can the use of large, alternative nursery containers aid in field establishment of Juglans regia and Quercus robur seedlings?

Published Date
November 2015, Volume 46, Issue 5, pp 773–794

Title 
Can the use of large, alternative nursery containers aid in field establishment of Juglans regia and Quercus robur seedlings?

Author 

Barbara Mariotti, 

Alberto Maltoni, 

Pier Mario Chiarabaglio, 

Achille Giorcelli, 

Douglass F. Jacobs, 

Roberto Tognetti, 

Andrea Tani

Introduction

In Central and Southern European countries, plantations for producing commercial timber and for other agroforestry systems have steadily increased during the recent decades (Eichhorn et al. 2006) and have been established in ex-cultivated lands due to the financial incentives available through the EU Regulation. Such plantings have also important concurrent functions in restoring over-exploited and poor or marginal lands due to the reintroduction of forest ecosystems functions and services, such as: increasing biodiversity, carbon sequestration and enhancing landscape aesthetics (Eichhorn et al. 2006). In Italy, tree farming and agroforestry systems, including fine hardwoods oriented to high-quality products (veneer), have been most actively promoted (Colletti 2001).

Over the years, practices designed to improve productivity of fine hardwoods plantations have evolved. The rotation period has been shortened and pruning methods refined to provide high quality products (Balandier and Dupraz 1999; Bohanek and Groninger 2003; Ravagni and Buresti Lattes 2006). At the same time, establishment of plantations at relatively lower densities have been encouraged (Balandier and Dupraz 1999; Ravagni and Buresti Lattes 2006; Buresti Lattes et al. 2014). Nevertheless, in Italy, a high percentage of plantations designed over the last decades have failed to achieve the objective of enhancing forest resources of high quality (Cappelli et al. 2009), as well as restoring/rehabilitating abandoned or degraded agricultural lands, with the aim of providing a greater ecological balance in countryside management, and mitigating greenhouse effects (Stavi and Lal 2013). One of the reasons has been the lack of high-quality seedlings (Tani et al. 2007a; Maltoni et al. 2010), which has been often linked to unsuccessful hardwood afforestation and reforestation plantings (Jacobs et al. 2005; Salifu and Jacobs 2006). Preliminary plantation surveys (Tomat et al. 2005; Cappelli et al. 2009) have highlighted two critical phases: (1) delayed plantation establishment, implying a longer rotation, and (2) the lack of formative pruning from an early age, which is detrimental for tree form and value, downgrading the quality of the boles (required for veneer). In this framework, whatever the stock type, qualified seedlings should be tall and with suitable architectural features of the shoot (i.e., straightness and apical dominance) and root systems, such that the seedlings have a good probability of establishing and competing successfully in the field (Armand 1992; Drenou 2000; Fennessy and MacLennan 2003; Maltoni et al. 2010).

Nursery stocktypes (e.g., distinguished by bareroot/container systems and stocktype variations therein) have a large effect on resulting seedling quality (Wilson and Jacobs 2006; Pinto et al. 2011b). Containers currently used to grow seedlings for forest plantings have a wide range of shape and size (Landis 2009; Pinto et al. 2011a). Containers for hardwood seedlings generally have a volume ranging from 250 to 450 cm³ (Landis et al. 1990; Chirino et al. 2008), occasionally higher (to 800 cm³), and rarely deeper than 18–20 cm (Chirino et al. 2008; Morrissey et al. 2010). Usually, containers with larger volume or higher depth are used to prolong the cultivation time beyond 1 year (Howell and Harrington 2004; Chirino et al. 2008; Morrissey et al. 2010). In Italy, hardwoods are mostly container grown, using a range of types and sizes, generally from 400 to 1200 cm³ and the cultivation currently lasts 1 year.

Many studies have highlighted the need to examine the effect of container type and size on seedling structure, survival, and growth (NeSmith and Duval 1998; Pinto et al. 2011a). Containers influence growth and biomass allocation (Tsakaldimi et al. 2005; Gilman et al. 2010; Dumroese et al. 2011), root system development and architecture (Oddiraju et al. 1994; Heiskanen and Rikala 1998; Chirino et al. 2008). Therefore, container type can influence success and cost of planting programs (NeSmith and Duval 1998; Pinto et al. 2011a). According to the Target Plant Concept (Rose et al. 1990; Landis 2011), container type is an important factor in determining seedling quality (Ritchie and Landis 2010; Pinto et al. 2011b) and to refine quality assessments (Aphalo and Rikkala 2003; Wilson and Jacobs 2006; Pinto et al. 2011a). Studies have often shown positive effects of larger containers on seedling growth (Aldhous and Mason 1994; Ritchie and Landis 2010; Poorter et al. 2012). However, past research has generally emphasized conifer species under reforestation scenarios or use of hardwoods to restore degraded lands in arid or harsh conditions, while studies examining container effects on development of fine hardwoods meant for plantings designed to produce timber yielding high quality forest products (e.g., veneer) and/or for forest restoration are lacking (Wilson and Jacobs 2006; Maltoni et al. 2010).

The objective of this study was, therefore, to assess the influence of new and large containers, in combination with a cultivation period of 2 years, on seedling quality and early field development of Quercus robur L. and Juglans regia L. We hypothesized that the quality of seedlings propagated with new container types and after a longer cultivation period than usual (1 year) would favor successful early phases of plantation. The assessment included the analysis of root system morphology and shoot system characteristics that affect subsequent pruning operations and bole quality. Mariotti et al. (2015) compared the effects of a wide range of different sizes and shapes of forest nursery containers on quality indices of 1-year-old seedlings to be used in productive plantations of fine hardwoods. We took advantage of these results, evaluating two large sizes of the new container type (Superoots Air-pot^®) in comparison with a traditional large container (Plastecnic^®).

Materials and Methods

Nursery stock characterization

The studied species were Quercus robur (pedunculate oak) and Juglans regia (Persian walnut), which are used in multipurpose plantations for wood production in Europe (Ducousso and Bordacs 2004; Voulgaridis and Vassiliou 2005; Mohni et al. 2009; Bolte and Löf 2010). The stocktype for both the nursery and field trials included in this study were produced in the forest nursery “Centro Biodiversità Vegetale e Fuori Foresta” located in Montecchio Precalcino (45°39′20″N; 11°32′40″E) and managed by Veneto Agricoltura Regional Administration (Northeastern Italy). The site characteristics were described in Mariotti et al. (2015). Three container types were studied: two big sizes of the new container Superoots Air-pot® (AIR-3: 9800 cm3, 40 cm deep and 19 cm wide; and AIR-4: 15,500 cm3, 60 cm deep and 19 cm wide) and one big size of traditional container Plastecnic® (PL-2: 4900 cm3, 20 cm deep and 19 cm wide at top section). The Superoots Air-pot is a cylindrical container with a new air-pruning system that consists of perforated cones along its sidewalls and a grid at the bottom (Mariotti et al. 2015). There are no flat surfaces to deflect roots and promote the development of fine roots while also inhibiting root circling and spiraling (Amoroso et al. 2010; Gilman et al. 2010). In Italy, this container is frequently used to grow ornamental plants. The Plastecnic is a frustum of pyramid shape; the bottom is tapered with regularly distributed circular holes to minimize root deformation.

Seeds were obtained from Veja (Veneto, Italy) for Juglans regia and Palù di Moriago (Veneto, Italy) for Quercus robur. Seeds were sown at the end of winter 2012 in seedling trays into a substrate described in Mariotti et al. (2015). All containers were watered to field capacity at sowing. In both years, the containers were irrigated daily with 20 mm of water, from the sowing date to the end of June (from the end of March, the 2nd year), 40 mm from end of June to the beginning of September, and 20 mm from September to mid-October. During both years, substrate moisture was checked at different container depths (using Soil moisture meter PCE-SMM1) to ensure that seedlings were well watered. A total of 272 seedlings were grown, of which 162 were used in the nursery trial and 110 in the field trial.

Nursery trial

The nursery study included 27 seedlings, per species and container type, in a completely randomized design within the species. Twelve seedlings per each species-container combination were randomly sampled at the end of the first year (2012), and the remaining 15 at the end of the second year (2013), for morphological assessment. During both growing seasons (from March to leaf abscission in 2012, and from time of bud burst to leaf abscission in 2013), stem height was measured monthly on each plant. Year-end morphological assessment included the following: root collar diameter (RcD), first year and second year height (H), height/root collar diameter ratio (H/RcD), number of growing flushes (only for Q. robur), number of internodes (only for J. regia), and dry weight of stem and branches. The root system was divided into main root and first order lateral roots (FOLR), which were grouped according to the diameter at the junction with main root (<0.1 cm, 0.1–0.3 cm, and >0.3 cm). Moreover, FOLR were separated according to three 20-cm depth layers (from root collar to 20 cm, 20–40 cm, and >40 cm). The dry mass of the each below-ground portion was recorded; FOLR > 0.3 in biomass was calculated by adding the first order main root weight and its second and higher order roots. The number of FOLR > 0.3 and FOLR 0.1–0.3 was also counted (at each layer). The ratios between each measured portion of seedling biomass to the total biomass and between the root system biomass and the container volume were calculated.

Field trial

The field trial included a sample of 80 seedlings for J. regia and of 30 seedlings for Q. robur.For J. regia, the experimental design was a randomized incomplete block design due to lower number of AIR-3 seedlings. It consisted of 8 blocks with 4 plants x treatment x plot: 4 blocks were complete with the three stocktypes (AIR-3, AIR-4, PL-2) and 4 blocks where the AIR-3 treatment was missing. Thus, this experiment included 16 AIR-3, 32 AIR-4, and 32 PL-2 seedlings. A total of 30 seedlings of Q. robur (10 per each stocktype AIR-3, AIR-4, PL-2) were included in a completely randomized block design. The lower number of oak seedlings and the unbalanced experimental design for walnut were due to varying availability of seeds and to some seedlings mortality. Thus, the field experiment was planned differently for the two species, according to the number of available plants.

At the beginning of April 2014 seedlings were transplanted at a site managed by the Research Centre CRA-PLF (45°08′53″N, 8°30′55″E) located in the Po Valley of Northwestern Italy. The area was fenced to protect plants from wildlife. The mean annual temperature is 12.3 °C (1970–2005); the coldest month is January (average 3.1 °C), while the warmest is July (average 25.5 °C). The average annual precipitation is 772.2 mm and its monthly distribution follows a regime with minimum rainfall in June (average 7.0 mm), a maximum in May (average 154.4 mm), and with a secondary peak in October (average 71.2 mm). Dry periods typically occur from mid-June to the end of July. The lithological substrate is recent and results from gravelly-sandy or silty Holocene floods (Alluvium medium), (Servizio Geologico d’Italia 1969). Soil is loamy sand in the surface layers and sandy loam more in depth, and limestone is absent. The site phyto-sociological association is Querco (roboris)—Ulmetum minoris (Mondino 2007).

Stem height increments and physiological attributes (Chlorophyll a fluorescence and Chlorophyll Content Index) were measured on four different dates during the growing season (9 June, 27 June, 22 July, 2 September). Chlorophyll a fluorescence properties were assessed on the first two fully expanded leaves from the apex of all plants included in the field trial. For each date, sampling was conducted between 12:00–14:00 h on sunny days. Measurements were taken on each of two leaves per plant exposed to dark (30 min), using leaf clips placed on the middle part of abaxial leaf blades. Chlorophyll a fluorescence was induced by red actinic light (with energy of 1500 µmol m−2 s−1), and the first 3 s of transient fluorescence were registered with time intervals increasing from 10 µs within the first 300 µs of the measurement up to 100 ms intervals for times longer than 0.3 s; these data were analyzed and the so-called JIP-test was conducted using Biolyzer v.3.0.6 software (both developed in the Laboratory of Bioenergetics, University of Geneva, Switzerland) (Strasser et al. 2000). The fluorimeter used was a Plant Efficiency Analyser (Hansatech Instruments Ltd., King’s Lynn, UK). Measured parameters were: F o, chlorophyll fluorescence intensity measured when all PSII reaction centers are assumed to be open (minimal fluorescence, ≈F50 μs)—the measured value may be affected by several other parameters (at t = 0); Fm, maximal chlorophyll fluorescence intensity measured when all photosystem II (PSII) reaction centers are closed (=Fp); T FM, time needed to reach F m; Area, the area above the chlorophyll fluorescence curve between F o and F m (reflecting the size of the platoquinone pool). Calculated parameters were: F v, variable chlorophyll fluorescence (F m − F o); F v/F m, a value that is related to the maximum quantum yield of PSII; RC/ABS, density of reaction centres per PSII antenna chlorophyll; F v/F o, a value that is proportional to the activity of the water-splitting complex on the donor side of the PSII; (1 − V j)/V j, measure of forward electron transport, where V j is the relative variable fluorescence at time J (relative variable fluorescence at phase J of the fluorescence induction curve); PIABS, the performance index that is calculated as (RC/ABS) × (Π Po/(1 − Π po)) × (Ψ o/(1 − Ψ o)), where, RC is for reaction centre, ABS is for absorption flux, Π po is for maximal quantum yield for primary photochemistry, and Ψ o is for the quantum yield for electron transport, Π Po/(1 − Π po) is a ‘conformation’ term for primary photochemistry, and Ψ o/(1 − Ψ o) is a ‘conformation’ term for thermal reactions (non-light dependent reactions).

The values of parameters characterizing PSII functioning were shown in a “spider plot”, which enables to easily identify deviation (in positive or negative) from the typical shape. If fluorescence parameters overcome the threshold for undamaged PSII, this indicates that significant and permanent damage to the photosynthetic system has probably occurred (e.g., Ugolini et al. 2014).

Chlorophyll Content Index (CCI) was measured by CCM-200 Plus (Opti-Sciences Inc., Hudson, NH, USA) on the same leaves.

At the end of September, the plants were accurately excavated and stem height, root collar diameter, presence of apical dominance, and stem and branches dry weight, for the shoot system, and root depth, width, and dry mass separating main roots from FOLR, for the root system, were measured.

Statistical analysis

In the nursery trial the analysis of variance (ANOVA) was performed to determine differences among stocktypes, for each species separately, in shoot growth and in shoot and root biomass of the seedlings, considering treatments as source of variation (containers: AIR-4, AIR-3, PL-2). In the field trial, for Q. robur, ANOVA considered treatments in nursery cultivation (containers) as a source of variation; whereas, for J. regia, the sources of variation were blocks and treatments (containers). In case of significant results (p ≤ 0.05), Duncan’s post hoc test was used for multiple comparisons (α = 0.05). Percentage data were transformed using arc sine square root transformation to meet ANOVA assumptions, according to distribution of residuals. StatSoft Statistica 9 (Tulsa, Oklahoma, USA) was used to process all data.

Results

Nursery trial

For Q. robur, after 2 years of nursery cultivation, mean seedling height in both Air-pots exceeded 150 cm (Fig. 1a), and was significantly higher than in PL-2; greater increments at the end of the 2nd year were also observed in these containers (AIR-4 100.3 cm; AIR-3 78.9 cm; Table 1). Differences in seedling growth among stocktypes were evident from August of the 1st year, while during the 2nd growing season the gap began to increase from May onwards (Fig. 1a). Seedlings grown in Air-pots achieved also greater RcD and H/RcD (AIR-3, 2.1 cm and 82.8, and AIR4, 2.2 cm and 81.7, respectively) than PL-2 (1.7 cm and 68.6, respectively). In J. regia, only AIR-4 resulted in significantly higher seedlings that were taller than 150 cm at the end of the 2nd growing season (Table 1; Fig. 1b) and they had lower H/RcD values (AIR-4, 62.6 > AIR-3, 52.5, and PL-2, 43.2). RcD was not affected by stocktype. Container type influenced walnut seedlings growth beginning in July of the 1st year; however, in the 2nd year, growth rate dramatically slowed since June, similarly in all treatments (Fig. 1b; Table 1).

Fig. 1

Height (H) recorded during the two nursery growing seasons for Q. robur (a) and J. regia (b). Duncan post hoc test for height at the end of nursery cultivation is shown (PL-2: Plastecnic 4900 cm3; AIR-3: Air-pot 9800 cm3; AIR-4: Air-pot 15,500 cm3)

Table 1

ANOVA test results (p values) of above- and below-ground system main variables among containers for both species, at the end of the 1st and 2nd year in the nursery (in bold p ≤ 0.05)

ABOVE-GROUND
	Height		Height increment		RcD		H/Rcd
	1st	2nd	1st	2nd	1st	2st	1nd	2nd
Q. robur	0.0432	0.0005	–	0.0012	0.4200	0.0350	0.1251	0.0072
J. regia	0.0020	0.0051	–	0.9785	0.1496	0.1902	0.0010	0.0015

	Total biomass		Shoot system		Stem		Branches
	1st	2nd	1st	2nd	1st	2nd	1st	2nd
Q. robur	0.8232	0.0042	0.4714	0.0046	0.3638	0.0063	0.9572	0.0062
J. regia	0.9933	0.0033	0.2401	0.0018	0.2304	0.0035	0.2198	0.0462

	Shoot/total		Stem/total		Branches/total		Shoot/root system
	1st	2nd	1st	2nd	1st	2nd	1st	2nd
Q. robur	0.3773	0.2643	0.8206	0.4337	0.5597	0.4339	0.3358	0.1088
J. regia	0.0025	0.2110	0.0016	0.3270	0.1446	0.2740	0.0143	0.1664

BELOW-GROUND
	Root system		Main roots		FOLR > 0.3		FORL 0.1–0.3
	1st	2nd	1st	2nd	1st	2nd	1st	2nd
Q. robur	0.1164	0.0067	0.0755	0.0010	0.5447	0.4128	0.5887	0.2932
J. regia	0.7815	0.0076	0.8631	0.0039	0.0293	0.9663	0.0217	0.0100

	FORL < 0.1		Root system/total		Main roots/total		FOLR > 0.3/total
	1st	2nd	1st	2nd	1st	2nd	1st	2nd
Q. robur	0.9677	0.3079	0.3773	0.2643	0.2572	0.1862	0.9168	0.8076
J. regia	0.0015	0.4340	0.0025	0.2110	0.0489	0.5329	0.0026	0.2923

	FORL 0.1-0.3/total		FORL < 0.1/total		Root sytem/container volume
	1st	2nd	1st	2nd	1st	2nd
Q. robur	0.1361	0.1879	0.1820	0.0104	0.0029	0.4126
J. regia	0.0003	0.1280	0.0161	0.5488	0.7815	0.0009

After the 1st year, the container type did not affect oak biomass, while differences occurred in FOLR for walnut (Table 1; Fig. 2b). In the 2nd year, biomass sharply increased in all above- and below-ground parts, in both species (Fig. 2 a, b). After two growing seasons (Table 1; Fig. 2a), Q. robur seedlings in AIR-4 had higher biomass than those in PL-2 in all variables excluding all FOLR; in J. regia, seedlings in AIR-4 had more stem, main root, and FOLR 0.1–0.3 biomass than the other two treatments.

Fig. 2

Seedling above and below-ground biomass at the end of the 1st and 2nd year of nursery cultivation for Q. robur (a) and J. regia (b). Duncan post hoc test is shown. Percentages on 2nd year bars show the total increase in biomass (PL-2: Plastecnic 4900 cm3; AIR-3: Air-pot 9800 cm3; AIR-4: Air-pot 15,500 cm3 FOLR: first order lateral roots)

The container type did not affect plant biomass ratios in Q. robur except for the fine FOLR fraction in the 2nd year (Table 1; Fig. 3a). Oak seedlings, in general, had shoot/root ratio close to one in both years. Within-container comparison of biomass fractions between years showed notable differences in biomass allocation in both Air-pots (Table 2). In J. regia, container type influenced biomass ratios in the 1st year (Table 1; Fig. 3b); the seedlings grown in bigger Air-pot showed more changes in biomass fractions between years (Tables 2, 3). The shoot/root ratio in walnut was significantly higher in AIR-4 (0.63) than in PL-2 (0.47) and AIR-3 (0.39) in the 1st year, while no differences occurred in the 2nd year (about 0.50 across all stocktypes).

Fig. 3

Seedling above and below-ground biomass proportions relative to total plant biomass (%) at the end of the 1st and 2nd year of nursery cultivation for Q. robur (a) and J. regia (b). Duncan post hoc test is shown (PL-2: Plastecnic 4900 cm3; AIR-3: Air-pot 9800 cm3; AIR-4: Air-pot 15,500 cm3; FOLR: first order lateral roots)

Table 2

ANOVA test results of the comparisons of biomass fractions between the 1st and 2nd year seedlings within the containers (in bold p ≤ 0.05)

	PL-2		AIR-3		AIR-4
Q. robur
Stem/total	0.5912		0.0418	2nd > 1st	0.0138	2nd > 1st
Branches/total	0.7595		0.1278		0.9624
Main roots/total	0.3324		0.0378	1st > 2nd	0.0206	1st > 2nd
FOLR > 0.3/total	0.0210	2nd > 1st	0.0204	2nd > 1st	0.0168	2nd > 1st
FOLR 0.1–0.3/total	0.3858		0.0019	2nd > 1st	0.0008	2nd > 1st
FOLR < 0.1/total	0.0032	1st > 2nd	0.0001	1st > 2nd	0.0001	1st > 2nd
Root system/container volume	0.0098	2nd > 1st	0.0001	2nd > 1st	0.0000	2nd > 1st
J. regia
Stem/total	0.6683		0.6161		0.0260	1st > 2nd
Branches/total	0.0022	2nd > 1st	0.0761		0.0006	2nd > 1st
Main roots/total	0.4886		0.8266		0.1011
FOLR > 0.3/total	0.8641		0.9855		0.0167	2nd > 1st
FOLR 0.1–0.3/total	0.0033	1st > 2nd	0.0522		0.5058
FOLR < 0.1/total	0.7139		0.0002	1st > 2nd	0.0001	1st > 2nd
Root system/container volume	0.0000	2nd > 1st	0.0025	2nd > 1st	0.0002	2nd > 1st

PL-2: Plastecnic 4900 cm3; AIR-3: Air-pot 9800 cm3; AIR-4: Air-pot 15,500 cm3

Table 3

Mean value and SD of for the variables after one year in the field for both species

ABOVE-GROUND
	H increment (cm)	RcD (cm)	Shoot system (g)	Stem (g)	Branches (g)	Total biomass (g)
Q. robur
PL-2	12.8 ± 7.9 A	1.5 ± 0.8 A	75.7 ± 92.2 A	59.9 ± 72.6 A	15.8 ± 18.0 A	130.2 ± 155.9 A
AIR-3	26.0 ± 11.7 B	2.4 B	190.7 ± 89.0 B	145.8 ± 72.7 B	45.0 ± 28.1 B	340.4 ± 137.7 B
AIR-4	21.1 ± 10.7 AB	2.4 B	185.2 ± 127.5 B	151.0 ± 77.8 B	34.3 ± 36.1 AB	324.4 ± 222.5 B
p treatments	0.0011	0.0005	0.0425	0.0456	0.0468	0.0280
J. regia
PL-2	16.0 ± 10.2	3.1 ± 0.5	146.3 ± 57.1 A	126.8 ± 50.8	15.3 ± 19.8	376.5 ± 151.7 A
AIR-3	17.7 ± 11.1	3.1 ± 0.8	176.9 ± 92.6 B	157.7 ± 87.3	18.8 ± 23.7	504.9 ± 404.4 AB
AIR-4	11.2 ± 8.9	3.2 ± 0.6	197.1 ± 89.6 B	147.9 ± 84.6	15.1 ± 16.2	568.8 ± 249.5 B
p treatments	0.1790	0.5145	0.0158	0.3943	0.9813	0.0471
p blocks	0.1965	0.0176	0.2322	0.0771	0.1346	0.0220

BELOW-GROUND
	Width (cm)	Depth (cm)	Root System (g)	Main roots (g)	FOLR (g)	Shoot/root system
Q. robur
PL-2	29.5 ± 13.3 A	40.9 ± 12.2 A	54.4 ± 64.2 A	31.7 ± 35.0 A	22.7 ± 29.2	1.3 ± 0.8
AIR-3	42.6 ± 17.4 B	55.9 ± 12.1 B	149.6 ± 55.8 B	89.4 ± 32.3 B	60.2 ± 27.7	1.4 ± 0.3
AIR-4	45.7 ± 18.1 B	65.4 ± 11.8 C	139.1 ± 99.4 B	87.7 ± 46.9 B	51.4 ± 57.4	1.6 ± 0.8
p treatments	0.0079	0.0000	0.0217	0.0046	0.1287	0.5023
J. regia
PL-2	58.0 ± 13.8	47.5 ± 8.3 A	230.2 ± 102.5 A	143.0 ± 69.7 A	87.2 ± 44.3	0.61 ± 0.2
AIR-3	59.9 ± 12.1	62.6 ± 10.8 B	390.5 ± 333.6 B	272.6 ± 325.7 B	99.1 ± 42.6	0.58 ± 0.2
AIR-4	60.2 ± 11.9	72.5 ± 13.8 C	353.0 ± 205.4 AB	254.2 ± 19.2 B	73.8 ± 45.2	0.66 ± 0.2
p treatments	0.4757	0.0000	0.0471	0.0429	0.5589	0.4867
p blocks	0.4411	0.8498	0.2323	0.1498	0.0101	0.2581

Results of ANOVA (in bold p ≤ 0.05) among stocktypes and post-hoc test (homogeneous groups in capital letters). PL-2: Plastecnic 4900 cm3; AIR-3: Air-pot 9800 cm3; AIR-4: Air-pot 15,500 cm3

In all container types and for both species, the main root reached the bottom of the container at the end of the 1st year and the distribution of FOLR biomass along substrate layers (Table 4) highlighted the scarce presence of larger FOLR in the deepest layers (>20 cm) of both Air-pots. After 2 years of nursery cultivation, the proportional amount of the two bigger FOLR sizes passed in all substrate layers (Table 4). In the 2nd year, in Q. robur, root biomass increased significantly in the two Air-pots, both for the main roots and, more steeply, for the FOLR; in J. regia, only AIR-4 had a sharp increase in main roots and total FOLR biomass.

Table 4

Mean values and SD (g) of different sizes of FOLR biomass grouped according to container depth sections for both species, at the end of the 1st and 2nd year in the nursery (FOLR > 0.3—only first order root; secondary—including further orders roots—on FOLR > 0.3; FOLR0.1-0.3; FOLR < 0.1)

	Container depth sections	FOLR > 0.3	Sec on FOLR > 0.3	FOLR 0.1–0.3	FOLR < 0.1
PL-2	1st year
Q. robur	0–20	0.28 ± 0.52	0.09 ± 0.23	0.68 ± 0.67	1.32 ± 0.40
	20–40	–	–	–	–
	40–60	–	–	–	–
J. regia	0–20	1.91 ± 1.54	2.47 ± 1.90	4.29 ± 2.75	1.11 ± 0.66
	20–40	–	–	–	–
	40–60	–	–	–	–
	2nd year
Q. robur	0–20	4.25 ± 5.03	2.37 ± 3.07	5.24 ± 5.76	2.04 ± 1.78
	20–40	–	–	–	–
	40–60	–	–	–	–
J. regia	0–20	5.47 ± 3.04	6.24 ± 3.51	7.17 ± 3.91	4.21 ± 3.22
	20–40	–	–	–	–
	40–60	–	–	–	–
AIR-3	1st year
Q. robur	0–20	0.34 ± 0.83	0.04 ± 0.09	0.29 ± 0.60	0.61 ± 0.36
	20–40	0	0	0.16 ± 0.22	0.67 ± 0.62
	40–60	–	–	–	–
J. regia	0–20	1.46 ± 1.21	1.57 ± 1.11	1.79 ± 1.10	1.59 ± 0.72
	20–40	0.02 ± 0.08	0.01 ± 0.04	1.05 ± 1.00	1.14 ± 0.67
	40–60	–	–	–	–
	2nd year
Q. robur	0–20	4.43 ± 6.06	3.52 ± 5.57	5.32 ± 3.41	1.01 ± 0.57
	20–40	1.10 ± 1.19	0.85 ± 1.29	2.53 ± 1.83	1.31 ± 1.13
	40–60	–	–	–	–
J. regia	0–20	6.60 ± 9.06	5.37 ± 7.86	3.05 ± 2.05	1.71 ± 1.04
	20–40	0.49 ± 0.76	0.35 ± 0.58	2.27 ± 1.88	1.47 ± 1.76
	40–60	–	–	–	–
AIR-4	1st year
Q. robur	0–20	0.60 ± 1.06	0.15 ± 0.32	0.27 ± 0.32	0.52 ± 0.27
	20–40	0.02 ± 0.08	0.01 ± 0.03	0.19 ± 0.33	0.51 ± 0.38
	40–60	0	0	0.03 ± 0.12	0.33 ± 0.27
J. regia	0–20	0.90 ± 1.33	0.59 ± 0.69	1.05 ± 0.63	1.37 ± 0.91
	20–40	0	0	0.46 ± 0.37	1.06 ± 0.57
	40–60	0.01 ± 0.02	0	0.40 ± 0.42	0.42 ± 0.30
	2nd year
Q. robur	0–20	6.31 ± 6.57	1.94 ± 2.32	2.90 ± 2.44	1.08 ± 0.83
	20–40	1.45 ± 2.60	0.89 ± 2.10	3.61 ± 2.68	0.94 ± 0.53
	40–60	0.62 ± 1.36	0.64 ± 1.87	2.17 ± 1.75	0.91 ± 0.78
J. regia	0–20	5.26 ± 6.48	4.47 ± 3.91	4.51 ± 3.14	1.90 ± 1.67
	20–40	1.64 ± 2.35	0.99 ± 1.34	5.35 ± 4.84	1.48 ± 0.74
	40–60	0.12 ± 0.24	0.15 ± 0.32	2.46 ± 1.97	1.02 ± 0.66

PL-2: Plastecnic 4900 cm3; AIR-3: Air-pot 9800 cm3; AIR-4: Air-pot 15,500 cm3

In Q. robur, the root biomass/container volume ratio showed differences (PL-2 > Air-pots) in the 1st year, (Table 1), the opposite result occurred in J. regia (PL-2 > Air-pots in 2nd year). In the 1st year, in walnut, this ratio was more than double than that of oak.

Field trial

In Q. robur and J. regia, fluorescent transient analysis showed similar values of all parameters characterizing PSII functioning throughout the whole study period (Fig. 4). In particular, the maximal quantum efficiency of PSII (calculated from F v/F m) and the efficiency of the water-splitting complex on the donor side of PSII (as inferred from F v/F o) did not significantly decrease as the season progressed. The absence of marked stress on the photosynthetic efficiency of these seedlings was highlighted by the very few significant differences between averaged fluorescence parameters across the three container types. F omeasured at first sampling (with decreasing values from new to traditional containers in Q. robur, and (1 − V j)/V j in the second sampling (with decreasing values from new to traditional containers), in J. regia. ANOVA highlighted significant differences for CCI in the third sampling, in Q. robur, with increasing values from traditional to new containers (AIR-4 > PL-2) and in the first and second sampling, in J. regia (higher in AIR-4).

Fig. 4

A ‘spider plot’ of selected parameters characterizing behavior of Photosystem II of Q. robur and J. regia seedlings after 1 year in the field (See text for Nomenclature for the meaning of the symbols and the parameters). All values are shown as percent of PL-2 (PL-2: Plastecnic 4900 cm3; AIR-3: Air-pot 9800 cm3; AIR-4: Air-pot 15,500 cm3)

No mortality occurred for both species. In Q. robur, AIR-3 seedlings grew significantly more than those in PL-2, while no differences due to container type occurred in J. regia (Table 3). Oak seedlings in both Air-pots showed significantly higher values than those in PL-2 for almost all above-ground variables, with more than double the shoot biomass (i.e., by 216.3 % in AIR-4 and 251.8 % in AIR-3) by the end of nursery cultivation. Values greater than 1.3 were recorded for the shoot/root ratio, with no differences among stocktypes. Apical dominance was recorded in 22.2 % of the plants grown in PL-2, 45.5 % in AIR-3, and 66.7 % in AIR-4. Biomass increase was also observed in the root system for seedlings grown in both Air-pots, particularly in FOLR (at least +118.7 %); seedlings grown in Air-pot containers had also a greater root exploration capacity, in terms of width and depth, than PL-2; however, in relation to container dimension, the root system grew deepest in plants grown in PL-2 (+104.3 %), while the widest was recorded in both Air-containers (at least +124.2 %). Nevertheless, seedlings in AIR-4 had the deepest root system in absolute value (Table 3).

J. regia plants grown in the traditional container had the lowest values in biomass (Table 3). After 1 year in the field, above-ground biomass generally increased, slightly in AIR-4 (by 36.3 %) and dramatically in the other two types (by 122.0 % in PL-2, and by 140.0 % in AIR-3). Similar results occurred also in root biomass; concerning FOLR, the increase was by 151.3 % in AIR-4, 266.7 % in PL-2, and 365.2 % in AIR-3. All stocktypes showed similar root exploration capacity, with root systems being at least three times wider than the container width; concerning root depth, the highest increase in comparison with container size was observed in PL-2 (+137.5 %). Despite the positive response to planting of seedlings grown in PL-2, the deepest root system occurred for those grown in AIR-4 (Table 3). Apical dominance was present in 76.7 % of walnut plants grown in PL-2, 73.3 % in AIR-3, and 65.6 % in AIR-4.

Discussion

Nursery trial

The expectation that bigger and deeper containers would have a positive effect on seedling growth was confirmed in this study. For both species, in the traditional bigger container, the height after the 1st year in the nursery was similar or slightly greater than current one-year-old bareroot stock produced in Italy in the past decades (Calvo and D’Ambrosi 1995; Ciccarese 1998; Tani et al. 2007b) and generally in line with the standards indicated by Armand (1992) and Calvo and D’Ambrosi (1995) for bareroot stocktype for tree-farming purposes. The noteworthy results of both Air-pots proved that the larger volume size was effective in increasing: (a) the duration of the growing season through early October, which is an advantage in Mediterranean conditions where early frosts are uncommon; (b) the growth rate of seedlings, and thus (c) their final height and biomass. One-year-old seedlings in Air-pots were much taller than those observed in traditional and common container types for both species at the same age (Johnson 1981; Aldhous and Mason 1994; Brønnum 2004; Schmal et al. 2011). Chirino et al. (2008) observed that deeper containers (30 cm) produced taller seedlings in Q. suber. Pronounced effects of large containers have been observed in other hardwood species (Hathaway and Whitcomb 1977; Funk et al. 1980; Omari 2010; Morrissey et al. 2010; Dumroese et al. 2011).

Both Air-pots supported the semi-determinate growth pattern of Q. robur, which continued flushing until the early fall, as in favorable environmental conditions (Borcher 1975; Hanson et al. 1986; Harmer 1989). By contrast, in J. regia shoot elongation slowed or ceased growth in mid-summer, consistently with its monocyclic pattern of shoot growth (Solar and Štampar 2003). In this species, only the seedlings grown in the biggest Air-pot showed a considerably greater development of their height and biomass; notably, about 2/3 of seedlings sampled in this container were taller than average, and a few seedlings skewed the overall result. Often, the shape and size of containers exert serious constraints on the growth of roots and their function, especially in hardwood species (Wilson et al. 2007), adversely affecting seedling development. In walnut, which is characterized by a vigorous taproot, a smaller container volume would probably limit root development and plant growth (Le Dizes et al. 1997; Mohni et al. 2009). The bigger Air-pot strongly influenced seedling structure and development from one to two years of nursery cultivation, with the longer cultivation period resulting in a mean stem height that met the minimum standard of the highest quality veneer in Italy (Ravagni and Buresti Lattes 2006). On the other hand, in Q. robur, both Air-pots were effective in promoting growth and biomass accumulation. In both species, longer nursery cultivation resulted in a marked increase of biomass production over plant height; nevertheless, the relative biomass allocation to different plant portions was not affected by container size. The strong positive relationship between seedling biomass and container volume was expected for these uncommonly large containers (Poorter et al. 2012).

Our results highlighted that 1 year of nursery cultivation was enough for the main root of Q. robur and J. regia to reach the bottom of deeper containers, as observed by Chirino et al. (2008). Many studies have reported positive effects of container depth on root growth in other hardwoods (Chirino et al. 2005; South et al. 2005; Morrissey et al. 2010). The longer cultivation period was useful to enrich FOLR in all depth layers, in both species, highlighting that during the second year the root system colonized the container in width and, thus, in volume. Chirino et al. (2008) observed that in 30 cm deep containers Q. ilex seedlings developed deeper and more functional roots. Wilson et al. (2007) observed that, in small containers, Quercus rubra one-year-old seedlings developed FOLR both along the length of the main root and at the base of the main root, in a greater number than bare-root stocktype, which is partially in contrast with our results. The importance of a well-articulated root system is widely emphasized (Ruehle and Kormanik 1986; Davis and Jacobs 2005; Wilson and Jacobs 2006). FOLR are key aspect in seedling quality assessment because they play an important role in field establishment of hardwoods; FOLR are related to seedling transport functions, water and nutrient uptake (Wilson et al. 2007) and, thus, to the success in overcoming transplant stress (Kormanik 1986; Ruelhe and Kormanik 1986; Dey and Parker 1997). In both species, seedlings maintained a similar balance between shoot and root system during both years of nursery cultivation, with minor effects of container type. Walnut seedlings produced relatively more below-ground biomass, confirming the potential of this species for developing a vigorous root system, as also observed by Becquey (1997) and Picon-Cochard et al. (2001). Oak seedlings showed a good shoot–root balance, generally in line with values found in the literature (Lyr and Garbe 1995; Ammer 2003). Shoot/root ratio is an important attribute for hardwood seedling quality assessment (Wilson and Jacobs 2006), being linked to field performance in semi-arid environments (Leiva and Fernández-Alés 1998; Villar-Salvador et al. 2004).

Field trial

The absence of marked stress on the photosynthetic efficiency of all stocktypes in the early phases of field establishment was highlighted by very few differences between fluorescence parameters across the three container types. Chlorophyll fluorescence allows for rapid evaluation of seedling quality (Wilson and Jacobs 2012). In our study, planting stress, poor root-soil contact and limited root development did not deter the establishment of taller seedling, as reported in other cases (Burdett 1990). Seedling establishment is highly dependent on microhabitat, particularly in Mediterranean environments, where plant mortality during summer is the main factor limiting regeneration of many woody species (Villar-Salvador et al. 2012). In this sense, alternatively, or in parallel, to the use of large containers and plants (with operational difficulties), other cost-effective techniques (e.g., nurse crops and soil preparation) may support the establishment of the desired stocktype.

Despite the absence of evident stress, height increment was not fully satisfactory, especially for J. regia. In intensive hardwood plantings aimed toward high-quality timber production, about 50 cm of shoot growth is considered a threshold index for overcoming establishment stress (Ravagni and Buresti Lattes 2006). Height increments were also generally lower than those observed in the Po valley for fine hardwood bareroot stocktype (Tani et al. 2007b, c, 2008a, b). Among late-successional trees, stress-sensitive species (J. regia more than Q. robur) must withstand disturbances for a long time during field establishment. In particular, seedling size at planting has been found to influence responses to vegetative competition and plant survival in several oak species (Kormanik et al. 1998; Na et al. 2013). Proper functional balance and structural quality of plants grown in AIR-3 might have helped the seedlings of both species to overcome transplanting stress. The unexpected less satisfactory growth of seedlings in AIR-4 was probably related to the lower biomass of first order roots in relation to above-ground system development, which warrants further study. Adequate shoot–root balance is, indeed, an important issue in water uptake capability at the time of planting to avoid stress, especially from drought (Burdett 1990).

Positive results were obtained in relation to shoot system structure for growing high quality, productive plants; the branch biomass component was limited in both species, which is relevant to reduce early pruning and favor apical dominance. Quercus spp. tend to develop a shrubby structure in the first year (Buck-Sorling and Bell 2000; Drenou 2000) and, thus, seedlings lose apical dominance after transplanting (Harmer 1989; Drenou 2000; Barthélémy and Caraglio 2007). Root system establishment effects were particularly evident for Q. robur grown in both Air-pots, which showed increased FOLR; whereas, as much FOLR biomass increase was observed in J. regia grown in AIR-3. Root growth and soil exploration are critical to physiological performance during field establishment and longer FOLR have been associated with higher leaf gas exchange rates (Gazal and Kubiske 2004). In particular, well-developed FOLR in bigger seedlings would affect the capability of plants to absorb water and nutrients, increasing root surface (Davis and Jacobs 2005; Dey and Parker 1997; Grossnickle 2005; Thompson and Schultz 1995). Moreover, seedlings of both species grown in Air-pots provided soil exploration deeper than 56 cm and, therefore, they were able to reach more humid soil layers during the first year in the field. Sagrera et al. (2013) observed positive field performances in terms of root system development in Salix spp. grown in containers with similar volume and depth.

To provide a more complete evaluation of the tested containers we conducted a rough assessment of cultivation costs for nursery management. Cost per seedling, though preliminary and tentative, was maximum 20 times higher (about 0.25 € for one year current production in 1200 cm3 container versus about 4.5 € for two years of cultivation in AIR-4). Thus, this stocktype may have limited utility in practice, likely where production targets are focused on a limited number of high value plants per hectare (e.g., superior genotypes). A more complete economic assessment should consider the nursery stock market prices and entire planting rotation, including reduced pruning operations and a shortened rotation period due to the growth and structure of such a stocktype. Currently, EU funds are available for tree-farmers to sustain the purchase of the stocktype. Growing trees is a long-term investment for forest landowners and, thus, cost-share assistance for planting trees is critically important to many landowners. Indeed, most landowners converting land to tree plantations have taken advantage of government subsidies, which may facilitate the use of large and relatively expensive container types, as long as EU and the local government maintain direct and indirect subsidies.

Overall, results obtained using new bigger containers in combination with longer nursery cultivation provided an encouraging and relevant initial data set to implement indicators for successful plantings aimed at high quality timber. Plants grown in the nursery, in both new containers for Q. robur and in bigger Air-pot for J. regia, showed a good balance between the shoot and root system, as well as many potentially promising characteristics for future high-quality wood production. Seedlings taller than 1.5 m, with fewer branches and more apical dominance are suitable for reducing both the expected rotation length and the frequency of early pruning. Even though height growth in the field was not fully satisfying, early performance results did not show marked signs of transplanting stress. Three-year-old plants had reached a stem length close to 2 m and had well-structured root and shoot systems. It must be pointed out that, in tree farming in Mediterranean climates, 2 m is the maximum height generally reached by these species after at least 4 years in field. Although only early establishment data was reported here, the present results and additional sampling on plant performance during subsequent years should provide good initial information required to examine the relationships among nursery cultivation, outplanting techniques and seedling structure/function in the production of veneer quality hardwood timber. Nevertheless, the influence of such large containers on shoot and root system attributes can be beneficial wherever seedling shoot and/or root sizes confer an advantage in other reforestation and restoration scenarios, such as for resistance to competition and/or drought stress.

Acknowledgements

The research on nursery stocktype was funded by Veneto Agricoltura (Regione Veneto). The field trial was supported by Regione Piemonte. Fabio Bandini and Stefano Teri assisted with study maintenance and lab measurements. Massimo della Casa and Jaime Single provided containers. We appreciate the constructive comments of a Guest Editor and two anonymous reviewers.

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