Part 2: Bark beetles threatening more than just lodgepole pines
This article is the second of a two part series on the book "The Insatiable Bark Beetle" by Dr. Reese Halter. The first article covered the grand sweep of our rapidly warming forests and the attacking strategies of the bark beetles. This second article gives a taste of Dr. Halter's tours of several magnificent forest types and the dire future awaiting them if we continue to overheat our planet.
For a few years I've been reading a lot -- and writing occasionally -- about the mountain pine beetle's epic attack on BC's lodgepole pines. All this time I've been bothered by the lack of discussion about: "what comes next?"
The media and politicians talk as if BC's epic beetle kill is a one-time event that is now winding down. But how can that be if the climate continues to warm rapidly, humans are doing nothing effective to slow it down, and the bugs certainly aren't going away? Clearly there is more to this story that isn't getting reported or discussed.
Fortunately I finally stumbled upon this tiny gem of a book -- "The Insatiable Bark Beetle" by Dr. Reese Halter. Dr. Halter spent months reading "a couple thousand scientific papers and several dozen books." He compiles all that into an extremely readable and engaging series of chapters devoted to many different kinds of conifers in harm's way:
- Lodgepole Pines
- Spruce Forests
- The Piñon Pines
- The Whitebark and Limber Pines
- The Bristlecone Pines
I have read this book three times now, amazed at what I'm learning about our magnificent forests and the threats our native bark beetles pose in a rapidly warming world. Finally someone has laid out for the general public the larger picture of "what comes next?"
Here are a few insights and excerpts from the book's later chapters on specific tree species.
The Lodgepole Pines
The shocking tale of how the tiny mountain pine beetles devoured half of BC's lodgepole pine forests in just the last decade is fairly well known. (see: Half of BC pines dead from fossil fuel pollution. Is it over?)
Dr. Halter tells that story briefly and goes on to make it clear that it is much larger than just in BC:
Mountain pine beetles have also been on an epic all-you-can-east smorgasbord in the US, across eastern Washington, Idaho, Montana, Wyoming, Colorado and South Dakota… mortality rates in excess of 90 per cent, as many smaller-stemmed trees have also been killed from intense infestations.
What is much less well known is that the remaining BC lodgepole pine forests in our colder northeast are next on the menu as the climate warms. Even worse, they lack a critical "terpenoid" resin defense mechanism because they have never faced mountain pine beetles before. Global warming is now allowing the bark beetles access to these "naïve" and unprepared forests.
Any subsequent temperature rise of between 1 and 2C will be endgame for many lodgepole pine forests; the species would likely survive in only 17 per cent of its current range.
And the wholesale destruction doesn't stop with lodgepole pines. As this chapter makes gruesomely clear, when lodgepoles are in short supply the mountain pine beetles are happy to attack and devour:
- western white pine
- ponderosa pine
- whitebark pine
- limber pine
- eastern white pine
- pitch pine
- red pine
- jack pine
- true firs
As we warm the planet, vast new landscapes are becoming accessible to these insatiable bark beetles:
There is every reason to believe that jack pines, red pines and eastern white pines along the lake states in the northeastern United States will, with rising temperatures, also face mountain pine beetles incursions.
This chapter tells the story of six rugged and long-living species of spruce that have thrived where the climate has been cold enough to prevent the Spruce Bark Beetle (Dendroctonus rufipennis) from reaching dangerous levels.
Over the past two decades, though, something appears to have gone very wrong. Not only have there been massive beetle outbreaks far beyond any historical records, but the infestations are also occurring across larger, regional networks of forest – on a regional scale. Moreover, vast tracts of moisture-starved mature spruce have stopped growing. A warming climate is disassembling the far northern boreal forests at a pace that is truly alarming.
Piggy backing on the warming-driven chow fest,
...the western spruce budworm is also on a feeding frenzy. This aggressive defoliator is eating its way through Alaska, Oregon, Washington, Idaho, Montana, British Columbia and the Yukon.
Already the spruce-rich boreal ecosystem in Alaska has started dying faster than it is growing. It has switched from a carbon sink to a carbon source. Meanwhile, over in a climate-warming Europe the European Spruce Bark Beetle (Ips typographus) has erupted into killing sprees covering millions of hectares of Norway spruce.
The Piñon Pines
Slow growing piñon pines can live hundreds of years, constantly pumping out large nutritious seeds that are a staple food for local humans and wildlife.
[T]he incredible piñon pines and their constant companions the junipers spread across the American Southwest … the third largest wooded ecosystem in the USA ... revolves around the health and well-being of the piñons, as they nourish life throughout the Southwest.
Dr. Halter tells the remarkable history of the piñons and their co-evolution with the intelligent jays and nutcrackers. Sadly, like the other ancient forest ecosystems he covers, the piñon-juniper forests are being unraveled by our fossil fuelled climate changes:
Nowhere in North America better exemplifies the effects of a global-change type of drought than the US Southwest. In 2002 the region experienced an extreme drought, and in many areas 90 per cent of the trees were killed. Water-starved, heat-stressed piñon were completely incapable of fending off the onslaught of Ips bark beetles, which during outbreaks can breed at least three generations in a year.
Global warming is now cooking up a particularly deadly combination of drought plus extreme heat. Many plants, including many of our major crops, succumb quickly. Death rates multiply rapidly:
…when temperatures increased by 4 degrees, piñon pines died five times faster. When the climate is warmer, it takes a much shorter drought to kill trees.
As this chapter closes, Dr. Halter describes what in my view is the most significant -- yet rarely reported -- threat to our forests. Fossil fuelled warming is not just killing today’s forests, it is also turning the landscape deadly for future forests.
The new hotter and rapidly changing climate favours both more bark beetles and more competition from short-lived, weedy plants. Beetles are breeding faster allowing an exponential increase in their attacking populations. In addition, new species of bark beetles are being welcomed north to join the killing:
Elevated temperatures have also enabled bark beetles that live in more southerly regions to march north into Arizona, southern Utah and Colorado. The round-headed pine beetles have attacked a number of pine species in the southwest, including ponderosas. Populations of southern and Mexican bark beetles have an extraordinary ability to produce in excess of five generations within one year.
Conversion to simpler, weedy ecosystems:
…not only did at least 100 million mature trees die but invasive species like cheatgrass muscled into the ecosystem. Overall, woodland forests are dramatically changing, in some cases reverting to prairie.
A new study just out shows that the invading cheatgrass is significantly increasing the size and ferocity of wildfires. It gains a competitive advantage by helping burn down its forest competitors.
As these forests -- and others such as BC's lodgepole pine forests -- try to grow back they face a long-term regime change that often excludes them from the landscape. The weeds and the bugs are winning.
Whitebark and Limber pines
Talk about tough. These “tenacious” trees live for over a thousand years in the brutal high-elevation climate of the Rockies, Sierras and Cascades. Their ancestors migrated very slowly from the old world across the Bering Strait land bridge. Along the way they have formed an ongoing partnership with one of nature’s most amazing birds: the Clark’s Nutcracker.
One Clark’s nutcracker can easily place 98,000 whitebark or limber seeds in over 30,000 caches and later recover half for food for themselves
These birds literally plant the next generation of these forests. The “Insatiable Bark Beetle” tells the page-turning story of how these remarkable pines and birds survive and thrive to anchor and feed a massive ecosystem. In just one of the anecdotes, we learn
In the tree’s lifetime, say 700 years, it can provide over 504,000 individual seeds …[an] imperative food source in Yellowstone National Park for interior grizzly populations. [These seeds] determine the fate of the bear population … three times as many grizzlies die in bad whitebark pine years as good ones
Like the repeated tolling of a funeral bell, the story eventually shifts to the bleak future our fossil fuelled warming is bringing these keystone species:
[T]heir very existence is perilously close to its end, as rising temperatures have enabled their predator – the mountain pine beetle – an opportunity to wipe them off the face of the Earth.
…whitebark pitch is loaded with myrcene, which appears irresistible to the ravenous bark beetles.
…the whitebark’s only refuge was in the high mountains forests, where they could survive but the beetles could not…the protective cold barrier has lifted.
Mortality rates in the whitebark and limber pines are as high as 90 per cent.
As in other chapters, Dr. Halter uses the unfolding story of one particular tree species to explain a larger climate threat. Here we learn that long lived organisms -- like trees -- can not adapt as quickly to climate changes as short lived competitors.
At least one theme is applicable across the gameboard of biology: long-lived organisms are in no hurry to reproduce. Whitebarks, for instance, do not produce their first cones until they are about half a century old.
Bark beetles however can produce fifty to a hundred generations in the time it takes whitebark pines to produce just one. No contest. In a rapidly changing climate the short-lived bugs and weeds will adapt first.
I've often heard people say they aren't overly concerned about our forests and other ecosystems because the earth has seen big climate changes in the past, and yet the plants and animals adapted. For example, Canada used to be covered from coast to coast with a mile-thick sheet of ice that melted away and yet the forests survived and thrived.
What these people don’t understand is that the threat this time isn't the size of the climate change but the unprecedented speed it is happening at. As NASA climate scientist James Hansen points out, we are pushing the climate 100 times faster than what it took to end the last ice age and melt the great ice sheet from Canada. Scientists have never found any warming in the Earth's past even close to the pace our fossil fuel pollution is currently causing.
Yes, when past climate changes slowly crept across the landscape some forests were able to move and adapt at that slow pace. It took thousands of years to melt the ice caps. Today we have seen half of the arctic sea ice disappear in just eight years. The jaw-dropping disappearance of spring snow cover in the northern hemisphere has been more rapid than that. As late snow cover disappears, summer droughts increase. Global temperature records show that extreme heat now covers fifty times more of the planet during the summer months than just few decades ago. Droughts, extreme heat, freak weather … rapid climate changes are now sprinting into ancient, slow-to-adapt, forests.
Here is a conservative view of what awaits BC if we keep burning up fossil fuels as we have been doing:
I say these maps are conservative because the latest data shows that the actual fossil fuel consumption path we are on will lead to a far more rapid climate shifts than these maps from a few years ago envisioned. As Natural Resources Canada says about the climate threats to our forests: "One thing is clear: the future will not be like the past."
Whether the future will still include large landscapes full of healthy forests depends on how rapidly we reduce our climate pollution.
The Bristlecone Pines
The three species of Bristlecone pines include the oldest living trees on earth. Individual trees have been living for an amazing 48 centuries. The habitat they live in is improbably ferocious. I think "The Insatiable Bark Beetle" is worth the price for this chapter alone. I'll leave you with just two teaser quotes about these trees:
Unlike any other known living thing, these trees and the ancient cliff cedar of the Niagara Escarpment show no signs of degenerative aging. [They are the] gatekeepers to the Holy Grail: the secret to eternal life.
The fact that the most exquisite trees on Earth, the Great Basin bristlecone pines, are in a perilous position due to rising temperatures and an emerging onslaught of bark beetles has kept me awake for far too many nights.
Beyond the beetles
At one point Dr. Halter steps back to survey the other damages our fossil fuelled warming is inflicting on the world's forests. Increasing drought, extreme heat, freak storms and expanding wildfires are battering forests around the world.
All forest types are suffering from a deadly combination of at least three factors: insects and diseases associated with elevated temperatures; the drying out of plants; and carbon starvation, that is water stressed trees unable to photosynthesize, or make food….both old and young trees are affected.
Here is just a sample:
- Extreme droughts in North Africa are killing Atlas cedar from Morocco to Algeria.
- Heat and drought are battering the high-elevation tropical moist forests in Uganda, mountain acacia in Zimbabwe and centuries-old aloe plants in Namibia.
- Drought as also lambasted the tropical dry forest of northwest and southwest India, fir in South Korea, the junipers of Saudi Arabia, and pine and fir in central Turkey.
- Australia has seen widespread death in acacia woodlands and eucalypt and Corymbia forests.
- Oak, fir, spruce, beech and pines across Western Europe are dying too.
- Quaking aspen [are] dying en masse….warmer temperatures and dry weather have proven again to be lethal for these remarkable trees.
In Canada, quaking aspen (aka trembling aspen) is the most abundant deciduous tree in our boreal forest and the primary tree in the vast parkland zone bordering our prairies. It is an extremely important tree, both ecologically and commercially.
The recent die off of these aspens has been so extreme and so widespread that the Canadian government has started a multi-province study -- the Climate Impacts on Productivity and Health of Aspen -- in the hope that something can be done to save these iconic and valuable ecosystems.
Even this book's long list of climate damages to the world's forests is far from complete. For example, a favourite tree of mine -- our yellow cedar -- is being killed off as its rapidly warming habitat becomes deadly. (See: Freezing to death in a warming climate: yellow-cedars in trouble)
As Dr. Halter urges, consider that all this is happening with only 0.8 C of global warming. Institutions like the World Bank, the International Energy Agency, the United Nations and the Massachusetts Institute of Technology have all recently warned that we are on course for a "catastrophe" of 4.0 C to 6.2 C during the lives of today's children. This is five to eight times the amount of warming we have seen so far. Beyond 2.0 C the climate science and the nations of the world have said human civilization faces dire threats.
Forests in particular require centuries of climate stability to develop and thrive. They move and adapt very slowly. Yet the warming we are now unleashing by burning coal, oil and natural gas is far faster than anything science has uncovered in our planet's past. The future for our forests is indeed grim unless we act with haste to leave most of the world's known fossil fuels in the ground. Our rapid transition to a sustainable renewable energy system is the forests' best hope.
Despite the dire threats, Dr. Halter preserves his optimism that a solution can be found in time:
Humans are exceptional problem solvers – it’s what we do best.
Knowing what is happening in our wild ecosystems empowers us to embrace change and make an effort to adapt in our own lives. Change is opportunity…
There is hope if each of us lends a helping hand.
For me this short book opened a clear window into the ancient splendour and recent fragility of our forests. It helps explain "what comes next?" I've only scratched the surface of what it serves up. I recommend it to anyone interested in the future of our magnificent conifer forests in North America.