Calculating the dollar value of trees

Heritage Canary Island Palms in Marrickville

Davey Tree Expert Company must be feeling really happy at the moment.  i-tree, a software program, they designed with the US Forest Service & released to the market in 2006 has become an item of huge interest over the last couple of months. Deservedly so too, as the program is a fantastically useful tool that can be downloaded by anyone free of charge. Instruction manuals can be downloaded free of charge as well.

Tree Hugger has recently written about the i-tree software as well as a number of other high profile green websites. There is much excitement in the media about i-tree. This surprised me because the i-tree software has been around for nearly 5-years.  The recent interest clearly demonstrates an attitude that is pro street tree.

i-tree can be used to calculate the value of a single tree or the value of the trees across a whole city.  It can be used a teaching tool by schools or as a professional assessment tool by councils, industry, arborists, landscape architects, anyone really.

“The i-Tree software suite v. 3.0 includes two flagship urban forest analysis tools & three utility programs.

• i-Tree Eco provides a broad picture of the entire urban forest. It is designed to use field data from randomly located plots throughout a community along with local hourly air pollution & meteorological data to quantify urban forest structure, environmental effects, & value to communities.

• i-Tree Streets focuses on the ecosystem services & structure of a municipality’s street tree population. It makes use of a sample or complete inventory to quantify & put a dollar value on the trees’ annual environmental & aesthetic benefits, including energy conservation, air quality improvement, carbon dioxide reduction, stormwater control, & property value increases.

• i-Tree Species Selector is a free-standing utility designed to help urban foresters select the most appropriate tree species based on environmental function & geographic area.

• i-Tree Storm helps you to assess widespread community damage in a simple, credible, & efficient manner immediately after a severe storm. It is adaptable to various community types & sizes & provides information on the time & funds needed to mitigate storm damage.

• i-Tree Vue (Beta) allows you to make use of freely available national land cover data maps to assess your community’s land cover, including tree canopy, & some of the ecosystem services provided by your current urban forest. The effects of planting scenarios on future benefits can also be modelled.”

To access the i-tree software program, go to – www.itreetools.org

The instruction manuals can be downloaded here – http://www.itreetools.org/resources/manuals.php

Stunning Fig tree in Dulwich Hill

There is another free computer modeling program developed by the United States Department of Agriculture Forest Service in the late 1990s called Urban Forest Effects or UFORE.  UFORE calculates the structure & environmental effects of the urban forest as well as the dollar value of the urban forest. http://www.ufore.org/

Then there is STRATUM designed by the US Forest Service & released in 2005 –

“STRATUM is a new street tree management & analysis tool for urban forest managers that uses tree inventory data to quantify the dollar value of annual environmental & aesthetic benefits: energy conservation, air quality improvement, CO2 reduction, stormwater control, & property value increase. It’s an easy to use, computer-based program. It allows any community to conduct a street tree inventory. The baseline data provided can be used to effectively manage the resource, develop policy & set priorities. Using a sample or an existing inventory of street trees, this software allows managers to evaluate current benefits, costs, & management needs.”

The New York City Parks Department used STRATUM to value their 600,000 street trees at US$122 million. This was 5 times the value of yearly maintenance.  The City of Pittsburgh calculated in 2005 that it received US$2.94 in benefits for every US$1 sent on its urban forest. The monetary benefit would likely have increased because, as trees grow, their benefits across all areas increase. For example, a tree with a 76 cm-diameter removes 70 times more pollution per year than does a tree with a 7.5 cm diameter trunk. Around 1.5 tons of CO2 are sequestered from the air & stored for every ton of new wood that grows.

CITYGreen, is another program. CITYGreen analyzes the ecological & economic value of trees in relationship to storm water management, energy conservation, carbon storage & air pollution. This desktop GIS software package requires a tree inventory as well as baseline data for each tree & the area, including impervious surfaces.

One of the many beautiful Fig trees in Marrickville Golf Course

GIS-based Trans-Agency Resources for Environmental & Economic Sustainability (T.R.E.E.S.) developed by Treepeople in Los Angles focuses not only on trees, but ecological stormwater management.

There are other urban forest software programs but these 5 give an idea of what is out there.  Urban forest computer assessment tools are a relatively recent development. Trees are being recognised as much more valuable than was realized in the past.

City planners & local governments are recognizing the many benefits of the urban forest.  This in turn will mean more trees will planted in the right place, looked after & not just planted in poor conditions & left to fend for themselves.  It will also mean that biophysical hazards as a result of urbanization, such as air, ground & water pollution, the Urban Heat Island Effect, carbon sequestration & storage & flash flooding will be managed in a sustainable manner.

Instead of trees being seen as just trees or even worse, pests that can be hacked into or removed at a whim, they will finally be recognized as the very valuable resources that they really are. That an increased canopy saves money for Councils will also be recognized & trees will be protected. Hopefully, this will also mean the deliberate increasing of not only the urban forest, but the planting or larger, shade producing trees as a preference, not just small trees that have limited value.

Mackey Park tree in the late afternoon

International tree news

1.     Not trees, but birds & too important to ignore .… in an X-File type event, more

What not to do to a street tree

than 4,000 Red Winged Blackbirds rained down dead on a small town called Beebe in Arkansas US on New Year’s Eve & for about a hour into New Year’s Day. The cause of the mass death is unknown at this stage, but fireworks are one of the theories.  Officials say the bird death “is not related to the 83,000 fish that died a few days earlier in the western part of the state, the biggest fish kill in Arkansas that anyone can remember.” 19-years ago, 2-dozen dead ducks fell out of the sky in the same place. http://www.nytimes.com/2011/01/04/us/04beebe.html?_r=1&partner=rss&emc=rss

And another article with video that also mentions “500 red-winged blackbirds, starlings & grackles were found dead in southern Louisiana in Labarre.” http://edition.cnn.com/2011/US/01/03/arkansas.falling.birds/index.html?hpt=C1

2.   Not trees either, but environmentally important …. Italy, which uses about 20 billion plastic bags a year & is responsible for 25% of plastic bag production in Europe has banned the single-use plastic bag from 1^st January 2011.  http://www.huffingtonpost.com/2011/01/03/italy-bans-plastic-bags_n_803686.html

3.     Finished with your live Christmas tree?  Want to dispose of it?  Instead of sending it to landfill or being made into woodchips if you are lucky, how about giving it to the fish?  An ingenious program by ‘Keep Bartow Beautiful’ uses discarded live Christmas trees to create fish habitat in Allatoona Lake in Cartersville Georgia. I could see a modified version working in a number of places next to the mangroves along the Cooks River. http://news.gather.com/viewArticle.action?articleId=281474978841747

4.     If you are interested in green architecture, the following is a 4-building educational complex designed by Gpp Architects for University College Nordjylland that will be built in Aalborg, Denmark. The buildings are fully sustainable with green roofs, real trees inside, a central green space connecting all buildings & uses natural sunlight.  It shows what can be done to create a large building, yet make it sustainable & very people friendly. I would call this a placemaking building in the true sense.  http://www.ecofriend.org/entry/gpp-architects-unveil-plan-for-a-sustainable-educational-complex-in-denmark/

5.    The UK went into shock last December 2010 when it was revealed that the

Brushbox trees in Marrickville

conservative government was seriously considering selling off “all state-owned English trees across the commission’s 635,000-acre Forestry Commission estate. This includes many royal forests, state-owned ancient woodlands, sites of special scientific interest, heathland, campsites, farms & sporting estates.” So far, 112,844 people have signed an online petition to stop the sale of the forests to private companies.  I hope the British government backs down on this plan. The forests, woodlands & heaths are integral to the beauty of Britain & it is unthinkable that they could be lost. Like there are war crimes, there should be government crimes.  http://www.guardian.co.uk/environment/blog/2010/dec/22/tory-privatisation-all-state-forests

6.   A number of Ornamental Pear trees were vandalized to preserve the view of the Sandia Mountains in Albuquerque.  “The top half of the tree is gone. This is not some kid – this is someone with a saw & a 10 to 12 foot ladder cutting the top of the tree off.” Vandalism for views seems to be increasing the world over. There is a short news video.  http://ht.ly/3sKGM

7.    This is a wonderful opinion piece about a healthy Torrey Pine at Ocean Beach,

Very dead

San Diego in the US that the authorities want to remove because it is leaning.   The tree is about 20 metres (80 foot) high & has a 1.2 metres (4 foot) girth.  A root is lifting up the footpath. It’s a great article as the writer brings up many good points trying to defeat the arguments to remove the tree which are mostly for convenience. “This tree needs to live because we need our trees. There is no compelling reason to kill this one. We can live around the trees. Our zeal for organization & straight lines needs to allow for some deviations, some curves. Beyond that, this is a living thing, & cutting it down would be killing it just to make our lives a little easier.” http://www.voiceofsandiego.org/peoplespost/nowthatsfunny/article_9bb7eb00-0147-11e0-9bce-001871e39ea8.html

8.     Muhammed Yousuf Jamil, a Lance Naik (Lance Corporal) in the Pakistani Army set a new Guinness World Record by planting 20,101 saplings in 18.40 hours.  It would have been higher except that 40 saplings were deemed poorly planted & disqualified form the count.  Amazing.  He must be so fit.  http://www.treehugger.com/files/2010/09/pakistani-soldier-plants-20101-trees-in-one-day-new-world-record.php

9.   A small, mummified wood uncovered by a melting glacier in the northernmost Arctic reaches of Canada is hoped to provide clue about how the Arctic will respond to global warming. The trees are at least 2-million years old.  Interestingly, the wood can still be burnt. http://www.livescience.com/environment/mummified-forest-arctic-climate-change-101216.html

10.  Wi-fi has been connected to the death of trees in the Netherlands, then unconnected. The verdict is still out. http://news.cnet.com/8301-1035_3-20025410-94.html

11.   The International Union for Conservation of Nature & other researchers have drawn up a world map showing 1.5 billion hectares where there are opportunities to replant degraded or cleared forests. The area if put together would be almost the size of Russia. “Three quarters of the world’s forests have been cleared, degraded or fragmented due to human activity, while a third have disappeared altogether, according to IUCN.” http://edition.cnn.com/2010/TECH/innovation/12/13/forest.restoration/index.html?hpt=C2

12.   Greenpeace & Finland’s indigenous Saami reindeer herders have won an 8-year battle to preserve 80% of 107,000 hectares of pine forests in northern Finland. The area is grazing land for the reindeer & includes tracts of old growth forest.   http://news.mongabay.com/2010/1215-hobbs_finland_forest.html

13.  Recent research by the US Forest Service found that “that areas with large trees, both in front & backyards, had lower levels of crime. We believe that large street trees can reduce crime by signaling to a potential criminal that a neighborhood is better cared for &, therefore, a criminal is more likely to be caught.” There you have it. Large trees lower crime. This has been found with other research & is just another reason why we benefit from larger street trees.  http://www.treehugger.com/files/2010/11/big-trees-may-make-communities-safer-says-study.php

14.  Sudden Oak Death has killed at least 1-million trees in California causing an imbalance in the ecosystem. This imbalance is thought to be linked to an increase in Lyme Disease. http://www.mercurynews.com/central-coast/ci_16898493?nclick_check=1

Here is an interesting fact to be held in the back of your mind for the time when the question comes up in Trivial Pursuit – Apparently Oak trees do not produce acorns until they are 50-years old.

Petersham tree and powerlines

Large trees reduce crime

Large areas of Stanmore are beautiful because of the presence of large trees

The internet has been buzzing over the last week or so about research by the US Forest Service who found there was less crime in areas that had large street & garden trees than in areas that had small trees.

They found that the presence of large trees sent a signal that the neighbourhood was well cared for & therefore it was more likely they would get caught. Smaller trees also were found to obstruct views & assist in the criminal behaviour.

This research matches other research that showed graffiti was less prevalent in areas where there were large trees, again because it was perceived that the community cared about the area.

The research about large trees reducing crime has been published in the Journal of Environment & Behavior. You can download the full research here – http://eab.sagepub.com/content/early/2010/09/16/0013916510383238.abstract

http://www.upi.com/Science_News/2010/11/01/Study-Urban-trees-can-reduce-crime/UPI-97191288646618/