Old Trees Trap More Carbon and Fight Climate Change

This article is reprinted with permission from SutroForest.org, a website fighting to save the century-old forest on Mount Sutro in San Francisco, CA.

The older a tree grows, the more carbon dioxide it grabs out of the air and sequesters, thus fighting climate change. Cutting down these large old trees releases this carbon back into the atmosphere.

tree-x-ed-out-jan-mt-davidson-2017

An article published in the Nature Journal summarizes the results of a huge research project by the US Geological Survey. This directly disproves the myth that young trees sequester carbon rapidly, but large old trees do not.

“The trees that are adding the most mass are the biggest ones, and that holds pretty much everywhere on Earth that we looked,” says Nathan Stephenson, an ecologist at the US Geological Survey in Three Rivers, California, and the first author of the study, which appears today [i.e. 15th January 2014]  in Nature.

“Trees have the equivalent of an adolescent growth spurt, but it just keeps going.”

The study, which looked at over 673 thousand trees of more than 400 species, found it was universally true.  This confirmed the results of a 2010 study that had focused on redwoods and on a eucalyptus species.

Former trees in a pile of woodchips sm

All the huge old trees that are cut down in San Francisco were fighting climate change – but now, whether as mulch or as rotting logs, they are contributing to it.

DETAILS OF THE STUDY

Here is the abstract of the study, from the NIH website [formatting and emphasis ours]:

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Rate of tree carbon accumulation increases continuously with tree size.
Stephenson, Das, Condit, Russo, Baker, Beckman, Coomes, Lines, Morris, Rüger, Alvarez, Blundo, Bunyavejchewin, Chuyong, Davies, Duque, Ewango, Flores, Franklin, Grau, Hao, Harmon, Hubbell, Kenfack, Lin, Makana, Malizia, Malizia, Pabst, Pongpattananurak, Su, Sun, Tan, Thomas, van Mantgem, Wang, Wiser, Zavala.

Abstract
Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle–particularly net primary productivity and carbon storage–increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age.

Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree.

The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree’s total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.

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And here is a link to the study itself in Nature: Rate of tree carbon accumulation increases continuously with tree size.

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Rally for Trees & Against Pesticides in Our Parks!  Feb 28, 2017

rally-and-hearing-feb-2017

Rally for Trees & Against Pesticides in Our Parks!

Join Our City and San Francisco Forest Alliance to demand that the San Francisco Board of Supervisors vote to reject the Environmental Impact Report (EIR) that allows the Recreation and Park Department to cut down over 18,000 trees and spray toxic herbicides to ‘manage’ our public parks.

After the rally we will assemble in the City Hall Board of Supervisors chamber, room 250, to speak in favor of the appeal to block Rec & Park’s plan.

Rally
WHEN:       1:00 pm Tuesday February 28th
WHERE:     SF Civic Center Plaza (across from City Hall, Polk St. steps

Hearing
WHEN:       3:00 pm Tuesday February 28th
WHERE:     Board of Supervisors Chamber, SF City Hall, Room 250
(come early to get a seat)

Map – http://tinyurl.com/SFCityHall-Plaza-BART
Directions – http://sfgov.org/cityhall/directions-city-hall

More information: https://sfforest.org and https://sfforest.org/blog-updates/

See you at City Hall!

San Francisco Forest Alliance

Public opinion does make a difference!

Thank you for your support

The San Francisco Forest Alliance is a non-profit 501(c)4 environmental organization working to protect urban forests, reduce pesticide use, and preserve access to our parks.

 

San Francisco – More Public Trees Destroyed

We recently received this report from a long-term member of the Fort Mason Community Garden. More trees have been destroyed, shocking those who cared about them.

More bad news about the trees we have enjoyed for many, many years. The entrance to our beautiful Fort Mason Community Garden was lined with plum trees that flowered magnificently in the Spring and then had burgundy colored leaves when the flowers dropped (see photos below). The Park Service has chopped them all down and plan to plant native stuff in their place. [Webmaster: No trees.] As most of you know, native plants remain brown most of the year so now our entry way is completely ruined, in my opinion, and those of many other garden members.

Below are before and after photos of the entry way, and then a report on how the Park Service tries to justify why they did this horrible thing. They claim that the trees were beyond their life span and beginning to die off. However, the below photo was taken this past Spring and these plum trees sure look very healthy and beautiful to many of us. None of the garden members knew anything about this until all the plum trees were chopped down — a big shock to most of us.

plumblossomsfortmason

There seems to be an epidemic of chopping down trees in this city that is contagious, and it is very sad and terrible for our environment and the esthetics of San Francisco. It is happening all over the city (200 coming down on Van Ness alone and many more in other neighborhoods). However, I was not expecting this horrible epidemic to affect the once very lovely entry to our beautiful Fort Mason Community Garden—which is a haven in the middle of a busy city.

(Signed) A Very Sad and Frustrated long-term FMCG member

ornamentalplumsgone-at-fort-mason-san-francisco-12-28-16

THE PARK SERVICE JUSTIFICATION

Plum Tree Removal at Fort Mason (SF) – Dec 2016

November 18, 2016 Posted by: GGNRA Public Affairs

GGNRA will remove the plum trees at the Fort Mason entrance and replace with drought tolerant native plants.

The tree removal will begin in December with planting to follow early in the new year.

Plans for adding the Purple Leaf Plum (Prunus cerasifera) trees were developed early in the park’s history, 1974, but following the historic period of significance. These trees typically have much less than the 42 year life span we’ve enjoyed. Within the last 5 years, the plums have begun to die back and shed limbs, indicating they are well into decline.

Removing the trees will re-establish a historic view to the Chapel along Franklin Street. Overgrown yews that flank either side of the Chapel entrance door will also be removed and replaced. The project will also remove about 7,000 sq ft of turf.

Native, drought tolerant plants are coming from our Presidio nursery, grown from local seed.

By establishing this low water plant community at the park’s headquarters entrance, we are signalling our commitment to environmental sustainability. We will also replace the irrigation system with a much more efficient model and expect to be able to stop all watering in the entry area within 5 years.

These before-and-after renderings were developed by the Olmsted Center for Landscape Preservation as a treatment recommendation included in the 2012 Cultural Landscape Report Volume II.

fort-mason-after-tree-removal

Before and After from NPS. (Our notation.)

Disturbing Story of the Mt Davidson Bench

Here’s the story of the Mount Davidson Eagle Scout bench, from its sudden removal by the Natural Areas Program, to the silly lie included in the Environmental Impact Report on the Natural Resource Areas Management Plan.  The Natural Area Program’s disregard for the public is illustrated at every twist and turn along the way.

Once upon a time, there was a nice little bench on Mt. Davidson.  It was built by Boy Scouts.  It wasn’t much, but people liked it and it was well used.

benchphoto1

THIS IS THE BENCH THE SCOUTS BUILT

Then one day the bench disappeared.  Who were the vandals?

It turns out it was actually the work of our RPD Natural Areas Program.  When people complained they received this response from NAP management:

To: XXXXXXXXXXX
CC: XXXXXXXXXXXX; Lisa.Wayne@sfgov.org
Subject: Re: Bench missing on Mt. Davidson
From: Christopher.Campbell@sfgov.org
Date: Thu, 27 May 2010 08:42:45 -0700

Hello XXXXXX,

The bench that you’re referring to was installed by the Recreation and Park Natural Areas Program. It was installed a number of years ago on this site to take advantage of the views, beauty and serenity of the plateau. We monitored the use of the bench and it unfortunately became an attractive nuisance. The secluded location was a draw for night time drinking and smoking. Bottles were thrown down the hill slope and most often broke, causing a hazard for both animals and people. Secondly the bench became a draw for commercial dog walkers, at times with more than 12 dogs in the area at once. This activity resulted in trampling of this sensitive slope, disturbance of wildlife and the creation of trails around the bench. One of the trails remains in the grassland below the bench location. After consideration we concluded it was best to remove this bench.

Over the coming year we will evaluate the installation of benches city-wide. This will be done in correlation with a natural areas trail project . Due to the activities associated with this bench we unfortunately do not have intentions to re-install one on the lower plateau at Mount Davidson.

Sorry for the disappointment this may bring,

Christopher Campbell
Natural Areas Program

 

Why does NAP management take credit for installing this popular bench?  They had nothing to do with it.  Why did they remove it?  Because people liked it and it attracted them to this area of the park. Clearly the NAP does not want us in their Natural Areas.

storyphoto2

THIS IS THE BENCH THAT WAS UNDER THE TREE THE NATIVISTS KILLED

After much pressure, the NAP finally installed a replacement bench a bit higher up the mountain.  For some reason they sited it right under a dead tree.  In fact, it was a tree they had killed by girdling some years earlier.  Given the NAP’s zeal for removing even slightly hazardous trees along its “trail Improvement” projects, it seems especially odd they would site a popular amenity directly under this tree.

Can you guess what happened next?  The tree fell over right across the bench.  Thankfully no one was sitting there at the time.

benchphoto3

In the photo below you can see where a wide ring of bark was cut away to kill the tree.

benchphoto4

It appears when the facts don’t suit the writers of the EIR, they substitute other “facts.”

That brings us to today.  The final Environmental Impact Report for the Significant Natural Resource Areas Management Plan (SNRAMP) has been released.  In the section addressing public comments made during review of the draft EIR the bench makes another appearance. (page 4-340)  In response to questions raised by the public about the removal of benches from NAP areas, some specifically citing the Mt Davidson bench, the NAP offers the following response,

“These comments refer to prohibition benches and the removal of a bench at Mt. Davidson Park. In 2011, SFRPD removed a bench on the northern portion of Mt. Davidson because it was rotting and unsafe for sitting. In late 2012, SFRPD installed a replacement bench close to where the unsafe bench had been located.”

“rotting and unsafe for sitting”?.  That is a bold lie.  How many other items in the SNRAMP EIR are based on fabrications like this? (Quite a few)

Claiming the original was unsafe and installing a replacement right under a tree they purposefully killed – That is disturbingly ironic.

benchphoto5

 

This little story is just the tip of the iceberg.

See the rest of the problems with the SNRAMP EIR at:
https://sfforest.files.wordpress.com/2016/12/arguments-against-certification-of-snramp-eir.pdf

Additional coments against EIR organized on CA Environmental Quality Act Criteria

Felling Trees Will Harm Rare Frogs in Sharp Park

The Natural Resources Department (NRD -formerly called the Natural Areas Program) is planning to cut down more than 15,000 trees in Pacifica’s Sharp Park, mostly on hillsides east of Highway 1. This is supposed to benefit the two species that live around there – the threatened red-legged frog and the endangered California garter snake. It will most likely threaten them still further.

THE LAKE OF THE RED-LEGGED FROG

4 Lake and trees in Sharp Parkcalifornia-red-legged-frog-the-frog-book1906

This lake is red-legged frog habitat. And it’s not just good for the endangered frog, and presumably the endangered snakes that preys on it. All kinds of other wildlife use it. Observers have seen everything from bobcats to quail to rabbits in the area.

The lake, which lies to the east of Highway 1 in Sharp Park, was made by damming a seasonal creek. On the left of the picture above, you can see the earthen dam covered with greenery. Now a naturalized pond, it was originally part of the irrigation system for the Sharp Park golf course, and was fed water through pipes and a cistern. Now the golf course gets its water elsewhere, the cistern has been filled in, and the pipes in disuse or gone.

Where the old tank was in Sharp Park Archery Range

This is where the old cistern was filled in. It’s invisible now under wildflowers and shrubs.

All the water in the lake now comes from the watershed created by the forested hills around.  Since this park lies within the fog belt, the tall trees catch the water and rain it down into the pond, even in summer. As a result, the pond has water through the year. (The photos here were taken in June last year. Everything was lush and green and there was no sign of any drought.)

7 Idyllic forest in Sharp Park archery range

So what happens when the trees are felled? We expect two adverse impacts on habitat.

  • First, and immediately, there will be an increase in erosion, bringing mud and debris into the lake and affecting its water quality.
  • Longer term, the lake will start to dry up in summer, since without the surrounding trees it will no longer get the water from the fog. What water it gets will evaporate more quickly without the tree shade cooling its surroundings. In dry years, it may not even get much water in winter. Its function as habitat would be severely degraded.
  • The area will become a lot dryer and warmer in summer, just the time when the red-legged frogs are changing from tadpoles to frogs. According to the National Wildlife Federation, the California red-legged “frogs do not like very hot temperatures and will seek shade within tall grasses and reeds.”

OTHER NEGATIVE ECOLOGICAL IMPACTS

Besides damaging the habitats of endangered species, the tree-cutting plan is environmentally damaging in many ways.

  • Carbon sequestration: Trees sequester carbon, and preserving trees and thus fight climate change. Once they are cut down, they release this carbon back to the atmosphere. With 15,000 trees, the impact will be significant.
  • Trees fight pollution, especially particulate pollution. With Highway 1 running through it, and the city of Pacifica nearby, these trees are fighting the pollution that would otherwise drift into populated areas.
  • Trees prevent erosion. The trees help to prevent erosion on these steep hillsides, and reduce the likelihood of landslides.
  • Trees help water regulation. These trees not only increase the water available by precipitating water from the fog, they also help to store in by slowing evaporation and encouraging the growth of plants that slow run-off. This provides a green environment year-round.

There’s more about the plan for Sharp Park HERE in an article we wrote last year. In the map below , the red percentages show the percentage of trees to be felled at each site. In most places, it’s 75% of the trees. (You can click on the map to make it larger.)

snramp - sharp park- plan A

Imagine this hillside as a bald mountain with a few scraggly trees, brown and dry in summer.

7 a forest on the hillside - sharp park

What we wrote then in conclusion:

Aside from the beauty of the place, and the undisturbed wildlife habitat that would both be destroyed, we think it is environmentally irresponsible. Eucalyptus, with its dense wood, its size, and its 400-500-year life-span, is particularly effective at sequestering carbon. In foggy areas, it captures moisture from the fog and drops it on the ground below, allowing for a dense damp understory that fights drought and resists fire. It cleans the air, especially fighting particulate pollution, by trapping particles on its leaves that eventually get washed onto the ground. It stabilizes hillsides with its intergrafted root system that functions like a living geotextile.  SNRAMP would require the use of large quantities of poisonous herbicides to prevent resprouting of the felled trees – herbicides that are likely get washed down the hillsides and into surface and ground water.

Pacifica actually has an ordinance prohibiting logging (removing more than 20 trees in a year). NRD’s answer to that is to see if the ordinance applies, and if it does, to try to get permission.

Hands Off Mt Davidson’s Forest – Take it Away from NAP

San Francisco Recreation and Parks Department’s Natural Areas Program (NAP) plans to remove 1/3 (10 acres) of the mature and healthy forest on Mount Davidson. We think the 30-acre forested area of the mountain should be removed from NAP’s control to prevent this destruction. The forest should be managed by professional foresters, like those in the Presidio, not gardeners.

In June, 3 years ago, U.C. Berkeley Forestry Management Professor Dr. Joe R. McBride (pdf link: MtDavidson_McBride_Ginsburg(06-29-13)) wrote about his inspection of the Mt Davidson forest, concluding that the Natural Areas Program’s  Significant Natural Resource Areas Management Plan (SNRAMP) for the removal and thinning of different portions of the eucalyptus plantation on Mt. Davidson is NOT justified.

He noted that the forest serves an important role in the history and visual characteristics of the city. Trees and the existing understory provide habitat for wildlife and wind protection for walkers.

mt davidson forest - hiker on trail

Summary of Dr. McBride’s letter to Phil Ginsburg, General Manager of the SF Recreation & Park Dept (parent Department of Natural Areas Program (NAP)):

1) Historic importance and Visual Value.
The eucalyptus forest on Mount Davidson was planted under the direction of Adolph Sutro, philanthropist and former Mayor of San Francisco. The hilltops covered in eucalyptus trees and Monterey cypresses are a distinctive feature of San Francisco’s landscape. They’re been there for a hundred years and are an important historical heritage.

2) Eucalyptus is not invasive.
The Plan frequently refers to these trees as “invasive.” Prof. McBride’s studies indicate that eucalyptus does not invade adjacent grasslands; and this is also obviously true on Mt Davidson, where a stable boundary exists between the forested and unforested areas. [In fact, the California Invasive Plant Council, which had earlier considered eucalyptus as moderately invasive downshifted this classification in April 2015 to “Limited.]

3) Eucalyptus groves are biodiverse.
Eucalyptus groves are richer habitats for vertebrates than either redwood or Monterey cypress/pine forest; and are similar to dry chaparral and grasslands.

4) More Pesticides.
Removing the number of trees shown in the Plan will expose the ground to more light than existing understory plants can tolerate. In the disturbed ground and increase light conditions, existing exotic species will proliferate and will have to be controlled by using even more pesticides.

5) Increased wind-throw and breakage of remaining trees.
Removing trees in this windy area will affect the trees that remain, which are not wind-hardened. More trees will go down.

6) Reducing a wind-break.
This is a very windy part of the city, with winds blowing in straight from the ocean. Walking recreationally on Mt Davidson will be a less pleasant experience.

7) Reduction in habitat.
The Plan’s assumption that birds will quickly adjust to removal of 1600 trees is unfounded. Many birds return to the same nesting site each year. Cutting down large numbers of trees displaces these birds, and also causes a great deal of disturbance. Bird protection plans usually call for a 300-foot radius of protected area around a nest.

Girdled tree Mount Davidson

Girdled tree Mount Davidson

8) The forest is healthy.
The dead trees in the forest have been girdled by someone/s with a vendetta against eucalyptus; few trees – if any – have died naturally.

9) Ivy is not a problem.
English and Algerian ivy climbs up the trees, but cannot smother the trees by growing into the canopy. The only snags covered in ivy were those that had been girdled.

10) Regeneration is a 22nd Century issue.
It’s been argued that the understory of ivy, Cape ivy, and Himalayan blackberry may restrict the establishment of eucalyptus seedlings. If so – and it’s possible – this is a problem for the next century. The forest, though 100 years old, is comparatively young. This could be revisited in another 100 years or so. Meanwhile, the understory provides an excellent food source and cover for wildlife.

Mt Davidson 2 - fuschia flourishing despite drought, watered by the trees catching the fog

 

Below: Mt Davidson map shows where 10 acres of healthy, mature trees will be removed if the  SNRAMP plans for maximum restoration are approved.  The red, green and yellow notations highlight the information contained SNRAMP plans (as per notes on the lower, bottom left).

SNRAMP. p. 6.2-10, F-14

Source: SIGNIFICANT NATURAL RESOURCE AREAS MANAGEMENT PLAN p. 6.2–19, F-14

Trees Matter: Mc Laren Park and Environmental Justice

This is one of our park visitor posts, written by a neighbor of McLaren Park. The Natural Areas Program targets over 800 trees in McLaren Park for destruction.

TREES MATTER by Ren Volpe

My San Francisco neighborhood is surrounded on three sides by freeways. Interstates 101 and 280 are busy spewing exhaust all day and most of the night. Breezes and fog from the ocean help dissipate some of the smog, but on windless days the air hangs heavy and dense. The only thing saving our air quality is the trees.

The Excelsior is not your typical rich San Francisco neighborhood. It is mostly families and working class folks. The tech buses have not found their way down our streets and our main retail corridor is filled with nail salons, dollar stores, pot clubs, and boarded up storefronts. Despite having nearly 40,000 residents, sometimes it feels like we are a forgotten neighborhood. Tourist maps often omit the entire south end of San Francisco and visitors have been known to ask whether they are still in The City.

The wealthier a neighborhood, the more trees it has. Rich people have trees, poor people get cement. This is especially true in the Excelsior, Visitacion Valley, and the Portola, where the single-family homes are modest and many front yards are paved over and littered with old cars. Our sidewalks are “tree poor” compared to wealthy Noe Valley and posh Pacific Heights. But the working class neighborhoods on the southeast side of San Francisco have one thing going for them : McLaren Park.

McLaren Park San Francisco copyright Ren Volpe

McLaren Park is the second biggest park in San Francisco, after Golden Gate Park. It is as wild and isolated as Golden Gate Park is manicured and visited. It is possible to hike miles of trails without seeing another person. I have seen foxes, coyotes, red-tail hawks, and great horned owls on my daily walks. In many parts of the park birdsong drowns out the constant drone of the freeways and the tree canopy blocks the cityscape. McLaren is our little piece of paradise in this urban corner of the City.

McLaren Park sunrise copyright Ren Volpe in San FranciscoRecently I found out that San Francisco’s Rec and Park Department has big plans for this urban oasis: the Natural Areas Program. The plan calls for cutting down many hundreds of healthy trees in an attempt to recreate the native scrubland that existed in the 1700’s. The trees slated for removal are not only eucalyptus, but mature and healthy Monterey Pine and Cypress, among others. Millions of our tax dollars have already been spent on this boondoggle, while maintenance in our park is practically nonexistent.

The “Natural Areas Plan” claims about ⅓ of San Francisco’s city parks, but Rec and Park’s biggest conquest yet may be McLaren Park. Could it be because the southeast corner of the city is the least rich, the least white, and the least likely to oppose this butchering? Almost 50% of the population in adjacent neighborhoods are foreign-born and speak english as a second language. People on this side of town don’t have the same political clout and connections as those living in wealthier neighborhoods. Even chopping down dying trees in other parts of the city creates a community uproar. When it comes to environmental justice, our hood is just not rich enough and not white enough.

Trees clean the air, absorb traffic noise, and provide respite from our hectic city lives. As the Bay Area becomes more populated, we all need more access to public green space. John McLaren created the park in 1927 in order to save the area from development. Now we have to save it from clearcutting.

McLaren was originally mostly coastal shrubland. Three-quarters of lush Golden Gate Park was originally sand dunes. Sutro Forest was desolate, sandy and wind whipped. Whether you agree with “native plant restoration”, the bigger question here is, should a beautiful yet neglected city park surrounded by freeways and adjacent to tree-poor neighborhoods be slated for such a project?

san francisco sand dunes

Sand dunes in Golden Gate Park – source: sfbotanicalgardens.org

SF Rec and Park maintain that they just don’t have enough money to pay for proper garbage cans and trash pick ups, trail and tree maintenance, repairing crumbling playgrounds, and other upgrades that McLaren desperately needs. But the department apparently has enough money for spraying cancer-causing herbicides like glyphosate (Roundup), cutting down healthy trees, and fencing off large parts of our park to visitors. The Natural Areas Program may have a different budget category within the Rec and Park department, but it all comes from our tax money.

Our city and our neighborhoods need more trees, not less. San Francisco has the smallest tree canopy of any major U.S. city. Poor children and children who live near freeways have higher rates of asthma, and studies show that a dense urban tree canopy can decrease these high rates of childhood asthma. Children in the southeastern part of San Francisco have the highest asthma rates in the city, and all the residents this side of town on experience high rates of air pollution.

Graph showing urban tree canopy cover in major US cities

San Francisco Has the Least Canopy Cover of any Major US City (data source: socketsite.org)

Tree-filled parks don’t just beautify our neighborhoods, they also improve our psychological well-being. Green urban neighborhoods with plenty of trees actually improve our health, according to several recent studies. Our 49 square-mile city is the second densest in the country, right behind New York. Attempting to return large swaths of our urban parks into the treeless landscape that they once were doesn’t make sense in present day San Francisco. Urban trees do more than just improve air quality; they improve our quality of life. Living in a city can be stressful, hectic, and cramped. We all need access to open, public, forested green space.

McLaren Park's Flowered Grassland and Forest

McLaren Park’s Flowered Grassland and Forest