The last plant to leaf out at the Arnold Arboretum: Makino Rhododendron

Post by Richard Primack

Every spring for the past three years, we have been monitoring the leaf out times of over one thousand species of trees, shrubs, and vines at the Arnold Arboretum of Harvard University. We try to survey the entire collection at least once a week, recording when the first flush of new leaves are produced for each species.

The work is important for ecosystem research in determining when the growing season begins, when new leaves are available as food for animals, and when plants start to absorb atmospheric carbon dioxide. This work is also important in determining the ability of plants to respond to a warming climate. And lastly, the variation among species in leaf out is a rich area of natural history that has been surprisingly neglected.

At the Arnold Arboretum in 2013, the first plants began to leaf out in mid-March. These were mainly species of honeysuckles (Lonicera), gooseberries (Ribes), and privets (Ligustrum). The last species did not leaf out until 2 to 3 months later, and these were mostly species of pine (Pinus), fir (Abies), and spruce (Picea), along with a few evergreen rhododendrons. The last species to leaf out at the Arnold Arboretum in 2013 was the Makino Rhododendron (R. makinoi), which did not produce its new flush of leaves until mid-June, three months after the first species.

Rhododendron makinoi, the last plant species to leaf out at the Arnold Arboretum. 

(This photo was taken in mid June of 2013) 

We are currently cooperating with botanical gardens from around the world to monitor leaf out times on a larger scale. Our goal is to determine the relative advantages and disadvantages of early and late leaf out times.

For further reading, see http://arnoldia.arboretum.harvard.edu/pdf/articles/1976.pdf

Acadia National Park Update: Using transplant gardens to investigate climate change.

Caitlin McDonough MacKenzie

Greetings from Maine!

The view from a mountain transect, Acadia National Park

In Acadia National Park, we are investigating how climate change, and specifically warming spring temperatures, affect flowering times, and possibly the population sizes, of wildflower species.  We are currently monitoring flowering times along  transects that run up and down the slopes of three mountains, including Cadillac Mountain.  On the southern ridge of Cadillac, the transect begins in Northern hardwood forests and climbs through a pitch pine-jack pine community to open granite dotted with shrubby subalpine species.  A hiker starting out in a T-shirt will soon pull long-sleeved layers from her pack she ascends into the increasingly cool and windy microclimate above treeline.

A white Rhodora flower on Sargent Mountain,  May 28, 2013

Later this year we will use a common garden experiment to explore the relationship between temperature and flowering times.  To this end, we will create a series of transplant gardens at elevations from sea level through the summit of Mt Cadillac (1500’) using widely distributed species such as Rhodora and Low bush blueberry.  Each garden will be filled with transplants from the different elevations in Acadia, as well as plants of the same species from Concord.  In these elevation-created microclimates, we can test the roles of local spring temperatures versus the original home of each plant species in controlling its leaf out and flowering dates.  For a certain species, such as Rhodora, if all the plants in a garden bloom at the same date, regardless of their original source, then temperature is a more important factor than where the plant came from and its genetic characteristics.  But, if there is a difference among flowering dates of a particular species within a garden depending on where the plant came from, perhaps populations at different elevations (or different locations, such as Concord) have genetically adapted their flowering response in relation to local conditions.  We’re looking forward to using the common garden approach to dig into these questions on the interaction of climate change, temperature, flowering times, and local adaptation.

When you are in Acadia, please join me for a hike up the mountains!

Back to Borneo: Richard Primack helps a team of scientists research the impacts of climate change on Malaysian rain forests

Posted by Richard Primack

Figure 1. The field team poses for a photo at Bako National Park.

At the end of April 2013 I left behind my fieldwork on flowering times in Concord, MA and flew across the Pacific to re-connect with my old research project in the rain forests of Sarawak in Malaysian Borneo. 

A little background information is necessary first: In 1965, Prof. Peter Ashton (now a retired Harvard professor) and the Sarawak Forest Department established permanent research plots in primary forest to investigate factors affecting tree species diversity. These forests have exceptionally large numbers of tree species, with many of the biggest trees belonging to the economically important dipterocarp family. In the 1980s and early 1990s, my students and I helped in the 5-year re-censuses of plots at Bako National Park and Lambir National Park, using the data to calculate growth rates and mortality rates of trees which we could compare with nearby selectively logged forests and tree plantations. 

Presently, these forests are being re-censused by scientists from Leeds University in the UK and the Center for International Forestry Research in Indonesia and local forestry workers to gain insight into the impacts of climate change on tropical forests:  Are trees now growing faster due to the fertilizing effects of higher atmospheric levels of carbon dioxide? Or will trees have a slower growth rate and increased mortality rate due to higher temperatures and increased drought stress? 

My key task was to show them how we took measurements in the past, so they could replicate our methods. The results of the current study will affect ongoing governmental and scientific discussions about the value of tropical forest conservation in lowering atmospheric carbon dioxide levels.  The study also illustrates the importance of well-documented, long-term studies to address contemporary issues. 

Figure 2. Field biologist takes a measurement of tree diameter at a painted point. Note that this measuring point has been moved up to about 2 m to avoid buttresses.

Caroline Polgar in the hood

Today Dr Caroline Polgar was hooded by Dr Primack at the BU hooding ceremony! Caroline defended her dissertation on the effects of climate change on spring phenology last autumn. All of the students who received a PhD from the graduate school of arts and sciences this year were ceremonially dressed in hoods matching those of their academic advisors. Dr Primack and the dean of arts and sciences hooded Caroline. Congratulations, Caroline!

Primack Lab Goes to Washington

Caitlin McDonough MacKenzie

Caitlin & the cherry blossoms (photo credit: Matt Berg)

One of the major tenets of the Primack Lab is an emphasis on communicating our research beyond the scientific community.  From the Concord Museum to the pages of the New York Times to this very blog, we are committed to public outreach and education.  Following in this tradition (and inspired by our newly minted lab blog!) I applied for an Ecological Society of America Graduate Student Policy Award, and then I blogged about the experience.

The opportunity to travel to Washington DC for two days and talk science, policy, and research funding with ecologists and Congressional staffers was amazing.  Every time I entered a Congressional office, I talked about my work studying the effects of climate change on plant communities in Acadia National Park, the importance of ecological research, my experience as a graduate student whose funding had been sequestered on March 1, 2013.  And, when I returned home, the opportunity to blog about this trip at Early Career Ecologists was truly icing on the cake.  Read an excerpt below & click through for the full post!

In April, I had the honor of visiting the Congressional offices of my home state Massachusetts to lobby on behalf of science funding. I spent Monday morning tromping between snow drifts off the coast of Maine, but by Tuesday evening I was wandering under cherry blossoms along Washington DC’s tidal basin in a T-shirt. I was a week into my field season monitoring flowering phenology in Acadia National Park, but I had traded my down jacket and LL Bean boots for a pencil skirt and pumps, hopped on a tiny eight-seated Cessna at the Bar Harbor airport, and flown to Washington DC as an Ecological Society of America (ESA) Graduate Student Policy Award recipient.

The ESA’s Graduate Student Policy Award (GSPA) is actually a two-day experience. There’s a hint of career-fair, a crash course in suit-wearing, a steady shuffling of business cards, and a challenging exercise in communicating your dissertation at a middle-school-science-fair level. The agenda, of course, doesn’t list those activities. Instead, it reads: “Science Policy at Federal Agencies,” “Training Program for All Participants,” and “Orientation for Congressional Meetings.” That is Day One – the preparation for the migration of scientists to Capitol Hill, the lead in to the Congressional Visit Day.  Continue reading →

Caitlin & other grad students on Congressional Visits (photo credit: Julie Palakovich Carr)

Record warm temperatures and cherry blossoms in Japan

Libby Ellwood

While the spring weather in New England has been unremarkably "normal", Japan has experienced a record warm spring. March was the warmest on record for 35 of the 140 weather observatories around Japan that have been recording weather since 1953. Regular readers of this blog will not be surprised then that the cherry blossom season was record early. I know of no culture as fascinated by signs of spring as the Japanese, and the flowering of cherry trees is a greatly anticipated national event.

Hanami, or cherry blossom viewing, is a popular Japanese pastime and has been for many hundreds of years. Each spring authorities attempt to predict the date of peak cherry flowering so that people can plan parties under the ephemeral blossoms. This spring, cherry flowering was 10 days earlier than predicted in Tokyo and was 15 days earlier than last year. Summer-like temperatures in March, including an astonishing 25.3˚C on 10 March, are to blame for the early flowers that are tied with 2002 for the earliest on record.

Of course this early spring did not stop large crowds of people from enjoying the flowers. Throughout Tokyo, parks and temple grounds were overflowing with groups of families, friends and co-workers eating and drinking under the dense canopy of beautiful blooms.

Early Spring: Henry Thoreau and Climate Change

Post by Caroline Polgar and Richard Primack

Over the past few years Primack Lab members have been collaborating with folks from the Concord Museum on an exhibit showcasing our work in Concord over the past 10 years, as well as historical artifacts focused on the long history of natural observation in Concord.  After years of planning, brainstorming, and meetings, followed by several months of intense preparation, we are pleased to announce that the exhibit is now officially open!

On April 11 the museum hosted a fabulous party to celebrate the opening of the exhibition. The party was well attended, and many of the notable contributors to the exhibit were there. The exhibit will be open until September 15th, so if you are in the area make sure to stop by and check it out!

There have been a number of articles about the exhibit in the press, with more expected in the next few weeks.  Below is a link to a Boston Globe area that came out a few weeks ago.

http://www.bostonglobe.com/metro/regionals/west/2013/03/10/the-detailed-records-plant-and-animal-life-concord-create-treasure-climate-change-data/PoIqx9GvOOZmEUgP1tZ7GK/story.html