Richard Waring

Richard Waring

Richard Waring is emeritus Distinguished Professor of Forest Science at Oregon State University. In his long career, he has held guest and visiting professorships at leading institutions around the world, and has served as administrator of a NASA program exploring land-atmosphere interactions and as a long-term consultant to NASA on forest modeling projects.
Photo Credit: Shutterstock

Determining When Trees Are Drought Stressed

Unlike most annual crops, the roots of long-lived trees can penetrate through soils to great depth to reach water (Figure 1).  If we can’t tell how deeply roots penetrate, how do we determine when trees run out of water?  One way is to monitor...

Unlike most annual crops, the roots of long-lived trees can penetrate through soils to great depth to reach water (Figure 1).  If we can’t tell how deeply roots penetrate, how do we determine when trees run out of water?  One way is to monitor the moisture status of leaves and twigs, because these are connected through the sapwood in branches, stems, and roots to water deep underground. Water in the tree’s conducting system is under tension; when a molecule evaporates from pores in the leaves, another molecule moves upward to maintain the integrity of the water column.  The tension on the column during a typical clear day is often equivalent to a tension of 15 atmospheres (14.7 pounds per square inch) or more. At night, when dew accumulates on the foliage and there is no transpiration, the tension on the water column falls to as low at 1 atmosphere when water is readily available to the roots. Similar values would be recorded during a foggy day. As water is depleted from the soil, tension in tree’s vascular system increases, sometimes exceeding values of 40 atmospheres. Such high values result in breakage of the water column that can, if maintained for long, kill trees.

Fig. 1. In western Australia, the roots of one species of eucalyptus extends downward 28 m (92 feet). Photo by Keith Smettem, University of Western Australia

Collecting twigs from tall trees at night is a dangerous job.  A shotgun loaded with buckshot is handy for sampling, although ones shoulder suffers (Fig. 2).  Once a twig is severed, the tension is released on the water column.  To determine how much tension the water column was under, the twig is inserted through a rubber stopper into a pressurized chamber, and the value recorded that is necessary to force water upward to the cut surface (Fig. 3).  Before the effects of climate change became obvious, forest vegetation in arid parts of the western U.S. separated along defined water-stress gradient with native oak woodland at one extreme and subalpine forests at the other (Waring and Cleary 1967).  

Fig. 2. The smile soon disappears.     

                                     

Fig. 3. Severed twig being inserted into cap of a pressurized chamber.         

Since 2000, much of the forests in the western U.S. has experienced prolonged drought. Process-based forest growth models have been used to predict areas where trees might be expected to succumb to drought (Fig. 4) and aircraft carrying sophisticated remote sensing gear have confirmed the cumulative effects of sustained drought (Fig. 5).  With the combination of modeling and ever-improving remote sensing tools, we have reached the stage where danger from wild fires can be predicted with increasing accuracy.  The extent that damage from wildfires can be reduced by thinning stands of trees and through fuel reduction will soon be analyzed using these methods.

Fig. 4. Areas in red indicates places in northern California where forests were predicted to be under sustained drought (Waring & Coops, 2016). 

            

Fig. 5.  Airborne surveys with remote sensing instruments are able to validate (and improve) model predictions (Asner et al., 2015).

       

References

Asner, G.P., P.G. Brodrick, C.B. Anderson, N. Vaughn, D.E. Knapp, and R.E. Martin. Progressive forest canopy water loss during the 2012-2015 California drought. Proc. Nat. Academy Sci. Dec. 28, 2015: E 249-E255.

Waring, R.H., Coops, N.C. 2016. Predicting large wildfires across western North America by modeling seasonal variation in soil water balance. Climatic Change 135:325–339.

Waring, R.H. and B.D. Cleary.  1967.  Plant moisture stress:  Evaluation by pressure bomb.  Science 155:1248-1254.

Island Press

Offsetting the Environmental Impacts of Trump

Island Press authors share their creative ideas for offsetting the damaging environmental impacts of the Trump administration.

This summer, three environmentalists banded together to counter Trump’s inaction on climate by planting trees. So far, the crowd-sourced forest is at 840,000 trees pledged and growing.

We asked Island Press authors to reflect on the idea of Trump Forest and offer their own suggestions for offsetting the damaging effects of the Trump administration. Their ideas—from Twitter-based fundraising to more walkable neighborhoods—are below. Have your own creative idea? Share it in the comments.

How about the Trump Military-Industrial Parks Funding Bill: for every dollar that the Trump administration's EPA saves for corporate polluters, a dollar is transferred from the budget for Defense Department and applied to funding for National Parks. 
—Emily Monosson, Natural Defense

BadlandsView3
Badlands National Park in South Dakota, via Wikimedia Commons

Planting trees for—or, more accurately, against—Trump and his policies is a great idea. We know that it’s not going to solve the problem of climate change, although every tree helps a little, and if we plant enough trees they will have a significant effect. But, perhaps just as important in the short term, every little gesture against the awful Donald contributes to the tide of protest by millions of people saying  “we will not accept the attitudes of this president and we will not go along with his agenda."

Continue reading the full post here.
Joe Landsberg and Richard Waring, Forests in Our Changing World

I suggest creating an online platform where everyone who voted for Hillary (all 68 million of them) can sign up and pledge to give 1 cent—which would be automatically deducted from their bank accounts (if they have one)—every time Trump tweets. This money would then go to combating climate change denial organizations/agendas, which are (demonstrably) incredibly well-funded.

If even half of everyone who voted for Hillary did this, we could generate $3.4 million in one day alone. (34 million votes equals 34 million cents multiplied by 10—the amount of times he tweets daily, on average.) The environmental cause he donates to could change every day. Even changing the monetary amount to half or a quarter of a cent for every tweet would still generate a lot of money.” 
—Michael Carolan, No One Eats Alone

The best way to offset the environmental impacts of the Trump administration is to advance smart policy at the state level and be prepared to do the same at the federal level once Trump leaves office… or if he changes his mind while in office! I am very worried that the GOP’s “Obamacare repeal” moment will be repeated in climate policy in a few years, and I speak from experience: 2016’s pioneering I-732 carbon tax ballot measure campaign in Washington State (which I founded and co-chaired) lost in part because of opposition from the “environmental left,” including the Sierra Club and Washington Conservation Voters. The same dynamic played out in California earlier this year, with the Sierra Club and 350.org opposing the extension of California’s cap-and-trade system.

And you can watch it happening again in Washington State as the groups that splintered with the grassroots I-732 campaign are now splintering with each other about a 2018 ballot measure. So: If you’re on the right side of the political spectrum then there’s lots of work to do getting conservatives to pay attention to the risks of climate change (Bob Inglis and his compatriots at RepublicEn are one great resource), and if you’re on the left, well, as the Washington Post editorial board put it, “The left’s opposition to a carbon tax shows there’s something deeply wrong with the left.” Fix it. 
—Yoram Bauman, Cartoon Introduction to Climate Change

Upper State4.jpg
Restaurants on East Rock's main commercial strip in New Haven, CT, via Wikimedia Commons

A good place to plant many of those trees is along the streets of America’s cities, towns, and villages. It’s been shown again and again that a canopy of street trees can significantly lower the air temperature of a block or a neighborhood or a larger area during the height of summer. That makes for more comfortable living. It reduces the need for air conditioning. It encourages people to walk or bike to nearby destinations rather than drive a car. Moreover, street trees make a place more beautiful. They persuade people—at least some people—that living in a somewhat dense neighborhood is not a sacrifice—it’s an advantage. 

Along with planting trees, we should put more emphasis on making the street network safer for pedestrians. Especially important is what happens at intersections, the most dangerous parts of the street network. Some intersections need to be narrowed, to get motorists to slow down and to reduce the distance that pedestrians have to cross. On long or especially busy blocks, segments of the planter strips could be extended into the street, causing vehicles to move at a more reasonable speed and helping people to cross the street safely. 

Follow examples from cities like Portland, Oregon, where centers of many neighborhood intersections have been planted, moderating the speeds on residential streets. In front of some neighborhood shops, encourage merchants to create patios where people can come together, eat and drink, and get to know one another. On Orange Street in the East Rock section of New Haven, Connecticut, where small stores are interspersed among houses and apartment buildings, patios of this sort have been created, giving the neighborhood a more congenial atmosphere than previously existed. 

Making a greener, more beautiful, more sociable environment benefits people in many different ways.
—Phil Langdon, Within Walking Distance

There's no lack necessary actions we can take. But where to start? Or perhaps better asked: How can I channel my outrage into something that's constructive but also as satisfying as ripping out part of my sink? (After all, outrage is an itch best scratched soon lest you turn into a humorless crank.)

Seed-bombing Trump golf courses with wildflowers and edibles immediately comes to mind, though admittedly that ranks high on "satisfying" and not much else. Punching literal Nazis on the street is constructive, in a way, though it's not a skill I currently possess. Keeping up with my curated Twitter roster of political and environmental experts is more important than it sometimes feels (especially when the underrated Sarah Kendzior has a new post) but it's also far from satisfying.

Of course, anything that makes a whit of difference is generally going to be neither easy nor quick. Meaningful changes take time, time spent in setting intention, executing action, and curating results. I think this holds true whether you're raising a garden, starting an activist organization, or making a footprint-reducing lifestyle change.

Continue reading the full post here.
—Daniel Lerch, Community Resilience Reader

Island Press

Forests Against Trump

Wouldn’t it be a splendid irony if reaction to Trump’s short-sighted stupidity led to an increase in tree planting that might otherwise be difficult to achieve?

Most sane and sensible people accept the reality of human-induced climate change. Yet the Trump  administration not only denies it, but is working to reduce  actions that will help slow the process and mitigate its effects. The EPA, and other government-funded agencies are not even allowed to mention climate change.

Planting trees for—or, more accurately, against—Trump and his policies is a great idea. We know that it’s not going to solve the problem of climate change, although every tree helps a little, and if we plant enough trees they will have a significant effect. But, perhaps just as important in the short term, every little gesture against the awful Donald contributes to the tide of protest by millions of people saying  “we will not accept the attitudes of this president and we will not go along with his agenda."

The contribution of trees and forests to the maintenance of a pleasant and livable global environment is well known and understood. However, as we know, forests around the world are under unprecedented pressure and are being destroyed at a horrifying rate. Clearance and illegal logging, particularly across southeast Asia, are rapidly reducing the area of tropical forests there. Brazil’s business-friendly government has recently proposed reducing the protected areas of the Amazon forests and has also announced plans to allow mining and development in protected areas. These activities will result in more clearance and forest degradation.

Amazon Manaus forest
Amazon rainforest, near Manaus, Brazil, via Wikimedia Commons

Clearing forests releases vast amounts of CO2 into the atmosphere, adding to the emissions from power generation, transport, factories, aircraft, and the rest, produced by modern human societies. Clearing also contributes directly to global warming because forests help reduce air temperature: when solar energy strikes green canopies much of it is used to evaporate water (transpiration from leaves), but when solar energy strikes bare surfaces those surfaeces become heated and the heat is transferred to the air, leading to more global warming. (This is what happens in cities, causing what’s known as the heat island effect.)

The droughts that are becoming more common and severe in some parts of the world are affecting forests directly, and also increasing the likelihood that they will burn. Across the western US huge areas of coniferous forests, dried out by drought associated with the changing climate, have burned this summer. All indicators suggest that droughts will continue and fire frequency will increase, raising the possibility that many of those forests will be destroyed in the not-too-distant future. They will not be able to regenerate after repeated burning.

Wildfire in California
A wildfire in California, via Wikimedia Commons

In Portugal, Spain and France, the record heat of this summer, combined with drought, has resulted in unusual numbers of destructive forest fires, in which lives and property have been lost. Australia has just had an exceptionally warm, dry winter. Modelling and data analysis indicate that these conditions have been made 60 times more likely by climate change. The probability of damaging and destructive fires, always high in summer in Australia, has been significantly increased.

So back to Trump and tree-planting. We know that this irrational, materialistic, bombastic and unreliable president is not likely to acknowledge the nature and causes of climate change, and is not likely to encourage or support programs aimed at saving existing forests and increasing the area of forested land on our beleaguered planet. But wouldn’t it be a splendid irony if reaction to Trump’s short-sighted stupidity led to an increase in tree planting that might otherwise be difficult to achieve?