Frost Damage to Young Beech Leaves

 By Richard B. Primack

 

“In society you will not find health, but in nature.” Henry David Thoreau in Excursions.

 

Young leaves on beech trees growing along the Vale Stream in the Webster Woods of Newton are showing unusual signs of frost damage in early May.

Photo 1: A branch with damaged beech leaves.

The trees had leafed out earlier than usual in mid-April due to a mild winter and early spring conditions. Then freezing weather in late April, perhaps enhanced by cold air drainage into this low-lying valley, damaged the vulnerable unfolding leaves. 

Photo 2: A close up of a beech leaf damaged by frost. 

 

It remains to be seen if the damaged leaves will persist on the trees or if the trees will put out a flush of new leaves. 

This another indicator of the ecological effects of climate change. 

 

Two Climate Change Studies of Trees and Wildflowers Yield Different Results

By Richard Primack

 

“An honest misunderstanding is often the ground of future intercourse.” Henry David Thoreau in his Journal.

 

Five years ago, our research group examined field observational records started by Henry David Thoreau in the 1850s in Concord, Massachusetts combined with modern observations and found that trees are responding more rapidly than wildflowers to climate change. This represented a surprising and important example of “phenological mismatch.” 

Photo 1: Bloodroot (Sanguinaria canadensis) is one of the wildflower species in the study (CREDIT Anna Funk, Holden Forests & Gardens).

Using thousands of herbarium specimens to cover a wider geographical area, we confirmed that trees across North America are indeed more responsive to a warming climate than wildflowers. 

However, another research group, using observations contributed by citizen scientists to the U.S. National Phenology Network, found that wildflowers were more responsive to climate change than trees, the opposite of our results. 

Photo 2: Native wildflowers, such as these Dutchman’s Breeches, leaf out and flower early in the spring before trees leaf out (© Andrew Cannizzaro and licensed for reuse under Creative Commons License CC-BY-2.0).

Instead of ignoring or criticizing these conflicting outcomes, our teams decided to work together to figure out why we got such different results.

As described in a recent article, our combined team found that even though we both started with the same question, we had used different data types, plant samples from slightly different geographic ranges, and data analysis based on different statistical models. Taking these factors into account, we were able to reduce, but not eliminate, differences between the two studies. 

In the end, both groups recognize that trees and wildflowers are responding to climate change, and are leafing and flowering earlier over time. But our seemingly conflicting study outcomes demonstrated how important it is for scientists investigating climate change to be aware of the peculiarities of their methods and data sets.

Here is a link to the article: LINK 

 

Tara Miller Places Research within a Larger Context

 By Richard B. Primack

 

“Let every [person] make known what kind of government would command [their] respect, and that will be one step toward obtaining it.” Henry David Thoreau in Resistance to Civil Government.

 

 

In a recent post on the Journal of Ecology blog, Tara Miller, a graduate of the Primack lab, described the connections between scientific research and environmental policy.

Here is some of what she had to say:

“My work history has woven back and forth through science and policy. I am drawn to the intersection of the two – the nerdy, intellectual itch to dive deep into data and analyze problems, and the passionate, action-driven urge to find solutions and make the environment and society better for people.”

 

Photo 1: Tara Miller reflects on connections between scientific research and policy.

 

“Through the past decade, I kept a foot in community organizing and policy, sometimes as a job, but more often as volunteer work. This work has kept me grounded in the challenges facing many communities and fueled my motivation to improve people’s lives and the environment.”

Photo 2: Native wildflowers, such as these Dutchman’s Breeches, are not keeping pace with trees as they advance their leaf-out with warming temperatures ^{(© Andrew Cannizzaro and licensed for reuse under Creative Commons License CC-BY-2.0)}

“Our study highlights the impact that climate change may have by leading to mismatches between different groups of plants. We provided suggestions for land managers and wildflower enthusiasts, who may consider steps such as thinning overhead tree and shrub canopy, removing non-native species, and planting rare wildflowers further north to conserve native wildflower populations.”

“I am currently working as a policy researcher with the University of Virginia’s Repair Lab. I am supporting community partners in developing policy solutions to coal dust pollution in environmental justice communities. The breadth of my scientific background helps me understand complex scientific and industry documents across fields like air quality science, mitigation infrastructure, and public health, and my community organizing background helps me communicate this information to community members and integrate it into the policy process.”

Here is the full blog post: LINK

Pollinators in the Garden

 By Richard B. Primack

 

“The keeping of bees is like the direction of sunbeams.” Henry David Thoreau

 

This spring, we are starting a new project to determine the types of insects visiting flowers at the Arnold Arboretum. A first impression is that the garden has huge resources of flowers, but relatively few flower visitors.

Photo 1: In spring, flowers cover a sand pear at the Arboretum.

 

A key feature of this project is training and working with volunteers, many of whom were participants in the earlier Tree Spotter program.

Photo 2: Volunteers in front of a flowering yoshino cherry tree.

 

The most common flower visitors are European honey bees, collecting both pollen and nectar. Many of the flowering trees and shrubs had no flower visitors during our periods of observation.  

Photo 3: A honey bee collecting nectar from a cherry flower.

  

To help the volunteers, we prepared a guide to groups of flower visitors.

Photo 4: Guide for insect identification.