Krummholz: life at the edge

How extreme can environments be before life can no longer hold on? The quaking aspen (Populus tremuloides) trees I study seem to cope well with all sorts of extremes – they are found as far north as boreal Canada and as far south as Mexico. Normally when I see an average aspen clone, it looks happy and healthy, as in this subalpine Colorado meadow.

low elevation

But averages are boring. The interesting biology happens at the extremes. We’re interested in carbon economics, and want to understand if aspen clones in very extreme environments are almost at the point of negative carbon economics, where more carbon is lost through respiration than is gained through photosynthesis. So off we went in search of a very unhappy aspen clone – myself and a post-baccalaureate student in charge of this project named Richard.

bellview

A few years ago I climbed Mt. Bellview, the brown peak in the background, and recalled seeing some very small trees growing near its summit. So off we went to find them, and then measure them.

climb

About 1500′ of scrambling later, Richard and I found ourselves on a dry scree field, covered in small and sharp rocks. Shifting these rocks revealed bedrock just a few centimeters down. Yet somehow, more than a few aspens were growing out of this substrate.

find aspens

They didn’t look very happy. In good conditions, aspens will grow easily ten meters high, with lush dark green leaves; here, each stem was no more than knee-high, with small and tortured looking stems. This kind of vegetation is typical of alpine krummholz where plants are exposed to extreme temperature and wind. The plants have no choice but to hunker down.

aspen roots

The slope was loose, but we measured some aspects of growth rate, and then installed light-loggers in the trees’ upper branches.

leaf length

light loggers

In a few weeks we’ll climb the mountain again, this time with a portable gas analyzer able to measure photosynthetic rates in these plants. By merging these measurements with the growth rate and light data we are now collecting, Richard will be able to understand how well these plants are growing at this upper elevational extreme. To me it doesn’t look like that great of a place to live – we were happy to downclimb the slope and head home – but maybe the aspens see it differently. We’ll find out soon.

bellview bottom

Knowing when to go

camera

For the past few days I have been testing an infrared camera for a study on temperature variation across environments. My assistant and I have been carrying approximately fifteen thousand dollars’ worth of non-waterproof equipment into the mountains to make some preliminary analyses. This gets interesting when the sun disappears, then wind picks up, the view across the valley changes quickly from blue sky to heavy dark clouds, and thunder echoes among the peaks.

home

It’s hard to know what to do in these scenarios. Taking instruments up a peak requires extensive preparation and hard physical work, and it is a waste to give up and go home too early. But tarrying too long means the risk of heavy rain, or worse – a lightning strike.

Sometimes a storm passes easily, leaving blue skies behind.

clear2

But other times, clouds descend, and the storm is everywhere.

clouds

Today I decided the risk wasn’t worth it, so we hastily packed our gear and rushed down the slope away from the storm, accompanied by the sounds of thunder. As we reached home, the sky cleared and then the storm was gone. We gambled – and lost – and then went back to work in the sun.

clear

I don’t know if one can ever know perfectly when to go, and when to stay. But we probably still made the safe decision. The risk on any one day is low, but the cumulative risk over hundreds or thousands of days in the field is high. Better to live to do science another day!

rain2

A snowy burial

1 base

When is the snow going to melt? The alpine plants I study will not begin seriously growing until the ground is bare and the soil is unfrozen. I want to examine how the microclimate around these plants changes through this transition and into the growing season, but it’s hard to know what’s going on from deep in the valley below.

2 slope

Installing a weather station next to my research site would solve this problem, but it’s been too dangerous and difficult to do it – until yesterday.

3 assembly

My assistant and I spent some of the past few days in the shop building a small temporary near-ground frame for a datalogger and a set of probes that will provide information on the light, moisture, and temperature conditions at my site, and then some more time thinking through all of the tools and computers we would need to set up the instruments. Then I recruited one more scientist, and we headed up a nearby mountain road as far as a vehicle could travel.

4 up

We climbed up with our gear on snowshoes, through a magical landscape of soft and packed snow, some tinted red by high-elevation algae.

5 up2

6 arrival 2 (1)

An hour later we gained the final ridge line and were there, nearly on top of the world. Thunderstorms were forecast for late in the day, so we quickly set to work putting the station in the ground. My site is on a south-facing slope, so I had hoped it would have been snow-free by mid-June. Unfortunately it wasn’t, but fortunately we brought along a large shovel.

7 digging

We started into the ground and quickly made it through the top layer of fresh snow, an icy layer likely from a May melt-refreeze, and then deep through many more layers. We took guesses on the snowpack depth – Sean thought waist-deep; Rozalia, navel-deep; and I, chest-deep. We were all wrong. We cut through at least eight feet of snow before finally scraping bottom and seeing the rocky substrate that constitutes the soil on this mountain. A hammer and soil knife served to break through the soil to make space for buried instruments.

8 bare ground

We then unloaded our instruments, screw-mounted everything to the frame, weather-sealed the data-logger and programmed it for interval logging with a field laptop, then put the whole apparatus into the ground.

9 logger setup

10 logger

We anchored the whole system into the rock with metal screws. It was very difficult for me to maneuver in such a small space, but we didn’t have the enthusiasm or time to make the hole any larger!

11 logger

Once everything was set and secured, we began back-filling the hole with snow with me standing in the bottom to redistribute snow and ensure that the instruments would not be crushed. It felt very much like being buried alive.

12 buried

Disturbing the snowpack in this way of course will change the melt dynamics, but I am sure that this weather data will be more accurate than if we had left the system exposed. The manufacturer has assured me that the system will survive these conditions, and I very much hope they are correct.

Now the final product is buried and waiting for the summer to arrive. It’s hard to imagine bare soil and growing plants, like in my memories of last year’s plot setup, but I am sure they are there under the eight feet of snow. Waiting.

A muddy day in the field

A stormy few days – snow at high elevation and heavy rain lower down. I have abandoned my alpine project until conditions improve, and have temporarily refocused on a low-elevation aspen study. It proved to be an interesting day in the field, especially after helping a few fellow researchers who were also caught out by a heavy mid-day rain. This time I’ll let the photos tell the story of four unexpected inches of mud, a steep dirt road, and a non-atypical day in the field…

almont 1

almont 2

almont 3

almont 4

almont 5

almont 6

almont 7

almont 8

Too much snow

I spent today waist-deep in snow because of the interactions between the climate system and the airfare pricing system. A long time ago I planned a summer of fieldwork meant to focus on how alpine plant communities changed over a growing season – the followup to last year’s project installation. Alpine plants begin seriously growing – producing leaves, growing stems making flowers – once the snow has melted, although a few species manage to start growing under the snowpack. That meant I needed to plan an arrival at the field site that was early enough to catch the beginning of the growing season, but not so early I would waste time waiting for meters of snow to melt.

summer start 0

So a few months ago I made a gamble. The California drought was symptomatic of a very dry climatic pattern over the Rocky Mountains, so I imagined a dry winter with an early snowmelt. And I imagined rapidly increasing airfares from Europe. So I took a chance on an early June arrival. All perfect until May turned out to be one of the wettest on record, with extensive snowfall at high elevation – and fresh snow too, not covered in a whole winter’s worth of dark-colored dust that would hasten the melt.

summer start 1

You can see my research site in the upper right of this photograph – to the left of the dark-colored ridgeline, apparently well-covered. But sometimes aerial photographs distort the truth, and local variation in substrate and sun exposure lead to faster melts. I knew that my site was on a south-facing ridgeline, and not too far away from one of the dark patches indicating bare rock. Maybe its growing season might be underway.

Today I took my field assistant on a long hike into the mountains to scout out the area. We were aiming to reach 11800′ elevation.

summer start 3

Unfortunately the snow was exactly where the aerial photo showed it to be. We spent a fruitless afternoon falling waist-deep into loose snow on forested steep slopes before giving up at about 10500′. Too dangerous, and very little chance that anything would be growing.

summer start 2

Tomorrow we build instruments, assemble gear, and find snowshoes. Then we wait. And finally we will head up the mountain again, ready to welcome our plants to the summer.

top

Towards fossil fuel divestment

I think that universities can play a unique role in leading public conversations on controversial issues. A university is a city on a hill, a place where light cannot be hid. It is a place that can lead by example and set precedent for others.

I have been thinking about this role because two institutions I have been closely associated with have now taken divergent paths. The issue in question is fossil fuel divestment. Should a university’s endowment and other funds be used only to maximize long-term returns to support the overall institution, or instead to also be used as instruments of social change and leadership? In particular, should a university with goals of building a more just and verdant future be supporting investments in an unsustainable industry that directly causes both economic growth and harm to people and the environment? There are clearly good arguments on either side, but I do think that some social issues stand out from others in terms of their generality and urgency – and climate change and the role of fossil fuels should be one of them.

speaker

Right now I am working for the University of Oxford, where an active student campaign has been pushing for divestment for some time now. Since moving to England I have been following their actions, but had been surprised by the limited level of support and awareness the cause has found among students and the community. The photo above is from Radcliffe Square on the day of a protest and awareness event; aside from a wonderful and dedicated group of organizers, hardly anyone appeared. Compare the same location two weeks earlier, when thousands of people populated the square to celebrate nothing more important than the first day of May. But in the wider community, many prominent academics have signed on, including several in my own research group.

radcliffe

Earlier this week, the university’s Council took a decision on their investments. Despite student pressure, I didn’t expect that anything would come of the meeting. But I was pleasantly surprised that the students’ hard work had been worthwhile. The university re-affirmed their commitment to socially responsible investing. They are committed to a policy of no direct investment in coal or oil sands, and to minimizing overall exposure to the energy sector. But they did not divest from extant holdings in these sectors, and as far as I can see have made only vague statements with regard to engaging on the issue in the future, or with regard to making more direct changes. It is a good start, and one that generated some international press coverage, but not one that conclusively resolves the issue. I am cautiously optimistic about the university’s commitment to leadership on this point.

I was much more disappointed by the choices made by my own undergraduate institution, Swarthmore College. It is a Quaker school, one whose founders included many prominent abolitionists and suffragists, and one whose ethos is ostensibly committed to moral leadership. It is also the birthplace of the fossil-fuel divestment movement and the alma mater of the United Nations’ climate chief, Christiana Figueres. Students had been putting pressure on the administration to make a similar commitment to divestment, but the institution’s board of managers took a decision in early May to not divest, and only to offer a chance for future donations or income to be allocated to fossil-fuel-free funds. The decision was covered by several international news outlets, but too late to effect change. It was a disgraceful retreat, and in my opinion a lost opportunity for leadership.

I have added my name to campaigns at both institutions, and have committed to withhold any donations to the latter until this policy changes. In my personal life, my savings are invested in broad market-tracking funds, but this summer I plan to sell them and change that. These are small nudges, but small nudges can lead to big changes, just as university divestment can encourage public conversations about the topic in the broader world.

tractor

Citizen science in the woods

wytham bluebells

A few miles distant from Oxford are Wytham Woods. This forest has become one of my favorite places to visit, a quiet place reachable by a few miles’ cycling over canals and country lanes. In spring the woods are painted with the flowers of bluebells (Hyacinthoides non-scripta). It is perfect for a solitary walk, but it is much more than that. Wytham is also home to a compelling set of research programs and citizen science initiatives.

Last Thursday I headed out in the early evening to go badger watching. Researchers have been studying the population dynamics of the badger (Meles meles) since the 1970s, providing a unique long-term record of thousands of individuals constituting a carnivore population’s dynamics, and of the social behavior of a charismatic species.

badger 1

Every spring the public is invited to go badger-watching in solidarity with this research.

badger 3

Badgers are charismatic icons of the English countryside, and have special status under the 1992 Protection of Badgers Act. They are the icon of a local conservation group I volunteer with, and our leader on this evening even happened to have a stuffed one with him.

badger 2

We piled into cars and made our way through the golden light of the day’s end, then picked our way into the forest.

badger 4

Badgers live in setts. These are large sets of underground tunnels and rooms that accommodate many individuals, and which are used year after year. From the surface they look like large mounds, with nearby trees used for scratching, and nearby forest sites used for toilets. They very clearly look like well-maintained homes. I settled in next to a pine tree on the downwind site of the sett, and began to wait.

badger 6

Badgers are predators of earthworms, insects, and most any other sort of grub or egg that can be found on the ground. They hunt at night, and have a keen sense of smell but a fairly limited sense of vision. I had no sight of any badger at all until the sun began to disappear over the horizon, and the day began to change into night.

badger 5

And then one made a first appearance, its head surveying the land above a tunnel entrance. I had never seen a live badger before – sadly only dead ones on roadsides. It had a very friendly and quick way of moving, almost playful. And then it was gone back underground, perhaps waiting for darker night, or for me to leave. Over the next few hours I was lucky enough to see glimpses of several more before the chilly air and my own hunger took me away. Being unable or unwilling to predate earthworms, I headed back to the city, happy for this small glimpse of the life of another species.

What impressed me most about the night was the large turnout of people who felt strongly enough about badgers and forests to spend a night shivering in the darkness looking for them. I have never seen such an enthusiastic turnout for this kind of citizen science, or this kind of bridge-building between researchers and the public. I think there is a lot of power in this kind of low-effort, high-fun engagement. Admittedly the the group was not very diverse – mostly older people and younger parents with small children, and nearly all white – but it was still a large one. Inclusivity and diversity seem to be challenges that span nations. Regardless, the night was an inspiration and a challenge for my own future outreach work.

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