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But while much is known about the growing process, there remains a layer of mystery around the mechanisms within these small plants. Now, a new study by a University of Georgia researcher sheds some light on the microscopic tissues that help tree seedlings grow. The results could change how researchers and growers view the first weeks of a tree’s life.

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Q:  This past week the trees on the edge of my yard started looking a bit droopy and some of the lower leaves are yellowing and dropping off. Should I be fertilizing them? I planted them a couple years ago and they have been doing well up until this past couple weeks.

A:  Without further information I cannot be completely sure of your problem, but it sounds like water stress. Are the trees getting regular water? If so, have you checked recently to make sure the system is working properly? And are the trees getting water in addition to what the lawn is getting? Trees need a deeper watering than most lawns receive.

At some point in the past few hundred years, human activities became a dominant force influencing Earth’s climate, affecting natural hazards such as drought. But it’s difficult to pinpoint exactly when this tipping point occurred. A new study tracking temperature seasonality—the difference between summer mean temperature and winter mean temperature—has found that major indicators of global warming were present as early as 1870.

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Bart Fusco certainly knows which way the wind blows on the East End when it comes to the do’s and don’ts of winter tree care. 

What types of trees can be trimmed in the colder months?
For most clients, I like to prune in the fall or very early spring. Fruit trees should be pruned when they are dormant, and many fruit production farms prune all winter.

What’s the difference between “trimming” and “pruning?”
Pruning is a way to enhance a tree, shrub or other woody plant’s structure and esthetics. The word “trimming” is more often used to describe the cutting of a plant’s foliage using hedge trimmers or small hand tools.

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and rot active in the tree. Some tree folks say that nothing can be done and that the tree is going to die. I do not agree with that.

If these growths have been present for several years and the rot inside has been allowed to spread through a large percentage of the trunk, the tree might not make it. On the other hand, if a procedure I recommend is used soon after the growths appear, the tree can be saved and brought back to complete health and vigorous growth.

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But there are a few exceptions. Some cracks in trunks, dead limbs releasing, peeling and falling bark, and unseasonal leaf drop may indicate tree health problems.

How can we tell the difference? Examine the base of the plant. If the tree is too deep in the ground, the investigation is pretty much over. Trees with straight trunks at ground level, that look like telephone poles, fence posts or straws stuck in the ground, indicate that the tree is planted too deeply or the soil and/or mulch has been piled on.

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local climate. So reports a new study that analyzed more than 23,000 tree cores to investigate how adult trees respond to changes in climatic conditions. Results were published this week in the journal Ecosphere.

Charles Canham, a forest ecologist at Cary Institute of Ecosystem Studies, led the research team, which included several collaborators from the USDA Forest Service. He explains, "By looking at data in tree rings, we were able to reveal how individual trees responded to variations in climate during a roughly 40 year period. There is evidence of pervasive local adaptation."

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previously thought, new research in Ecology Letters suggests.

By analyzing stores of carbon in temperate and boreal forests, researchers found that tree diversity does influence the amount of carbon stored in a given part of an ecosystem. But in a departure from previous research, researchers found biodiversity's role was relatively small when compared to other forest traits and environmental factors -- and even can decrease carbon storage in some cases.

The research team, led by Carol Adair of the University of Vermont and David Hooper of Western Washington University, found that climate, site topography, time since fire, and characteristics of the tree species in each plot explained most of the variation in forest carbon storage across temperate and boreal forests in Québec, Canada. Alain Paquette of Université du Québec à Montréal and Bruce Hungate of Northern Arizona University co-authored the study.

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Sweden's oldest oak tree is fighting for survival, with concerns raised over its deteriorating health.

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You may think that trees and other plants are stationary and passive organisms that just stand around all day.  So long as they get sufficient sun and water, everything is fine.

But the reality is far more complex.

We have known for a long time that plants act differently at night than during the day. Last year, Jeffrey C. Hall, Michael Rosbash, and Michael W. Young, won the Nobel Prize in physiology for their work on the molecular mechanisms that control circadian rhythms of animals and plants.

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The orange growths are nothing new, according to Sharon Yiesla, plant knowledge specialist at The Morton Arboretum in Lisle. They’re the most visible stage of a common fungal disease called cedar-apple rust, with a complex life cycle that involves both junipers and apple trees. “We’re seeing a lot of it this year because we’ve had so much rain,” she said.

The fungus that causes cedar-apple rust — so titled because some kinds of junipers are often erroneously called cedars — reproduces more readily in wet spring weather.

The disease usually does no lasting harm to the juniper tree or shrub, she said, but it can be a somewhat more serious matter for apple trees, including ornamental crabapple trees. Infected leaves get spots and may shrivel. Rust also can cause spots on apples, and may keep the fruit from developing or cause it to drop.

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International scientists have discovered that most of the oldest and largest African baobab trees have died over the past 12 years.

They suspect the demise may be linked to climate change, although they have no direct evidence of this.

The tree can grow to an enormous size, and may live hundreds if not thousands of years.

The researchers, from universities in South Africa, Romania and the US, say the loss of the trees is "an event of an unprecedented magnitude".

Revealing the findings in the journal Nature Plants, they say the deaths were not caused by an epidemic.

"We suspect that the demise of monumental baobabs may be associated at least in part with significant modifications of climate conditions that affect southern Africa in particular," said the team, led by Dr Adrian Patrut of Babes-Bolyai University in Romania. "However, further research is necessary to support or refute this supposition."

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Trees planted in cities, towns and along roadways tend to live decades shorter than those that grow in forests due to many potential sources of stress to which they can be exposed.

Younger trees tend to be more vulnerable to mechanical bark damage, be it environmental or human-caused, said Gena Lorainne, horticulturist and plants expert at Fantastic Services.

“Some species of trees are also more sensitive to rapid climate change than others,” Lorainne added.

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High-precision three-dimensional surveying of 21 different species of trees has revealed a yet unknown cycle of subtle canopy movement during the night. The 'sleep cycles' differed from one species to another. Detection of anomalies in overnight movement could become a future diagnostic tool to reveal stress or disease in crops.

One of the most important processes sustaining life on Earth is the transport of water from the ground and into the leaves where the photosynthesis and capture of the sun's energy take place. The process has fascinated scientists for centuries and is still debated in plant physiology. Scientists generally agree that water transport is driven by light and consequently occurs in 24 hours cycles.

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A new analysis is shedding light on drought in Mongolia, both past and future.

By studying the rings of semifossilized trees, researchers constructed a climate history for the semiarid Asian nation spanning the last 2,060 years — going 1,000 years further back than previous studies.

It was suspected that a harsh drought from about 2000 to 2010 that killed tens of thousands of livestock was unprecedented in the region’s history and primarily the result of human-caused climate change. But the tree ring data show that the dry spell, while rare in its severity, was not outside the realm of natural climate variability, researchers report online March 14 in Science Advances.

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Plants do not have immune systems like animals. Instead, they have evolved an entirely different way of dealing with infections. In trees, this process is known as the "compartmentalization of decay in trees" or "CODIT." CODIT is a fascinating process and many of us will recognize its physical manifestations.

In order to understand CODIT, one must know a little something about how trees grow. Trees have an amazing ability to generate new cells. However, they do not have the ability to repair damage. Instead, trees respond to disease and injury  by walling it off from their living tissues. This involves three distinct processes. The first of these has to do with minimizing the spread of damage. Trees accomplish this by strengthening the walls between cells. Essentially this begins the process of isolating whatever may be harming the living tissues.

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Old magnolias never die, they just fade away. That seems to be the fate of the most historic tree at the White House, a Southern magnolia planted by Andrew Jackson and now so ancient and fragile that part of it was dismantled last month.

The decision to take down or at least dismember an old tree is neither easy nor always objective, but professional arborists are guided by a risk assessment protocol that brings a rationality to the process. The evaluation assesses the tree's vigor, the thickness of its sapwood shell, its disease stresses, the state of the roots and the like. Arborists also consider its location and the proximity to what they call "targets" -- property and people.

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For the seventh year in a row, Napa “citizen scientists” participated with the UC Berkeley Forest Pathology and Mycology Lab in an ongoing effort to track Sudden Oak Death (SOD), the exotic disease that has killed hundreds of thousands of oaks and tanoaks in California.

The Napa SOD Blitz was held on May 6 and the results came out in October.

The disease is caused by Phytophthora ramorum, a microscopic organism that spreads during periods of relatively warm, rainy weather in late spring in northern California, according to the lab’s website.

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