Why Trees are Green

Why are trees green? After all, if plants wanted to absorb the maximum amount of sunlight, they’d be black.

You can see the answer in lakes and oceans that have a purple tinge to them. Purple is a tricky colour - it’s actually a mixture of red and blue. Complimentary colours are tricky. Purple is white light with the green colour removed. Green is white light with the purple colour removed. I think the French impressionists were the first to paint the shadow under green trees as purple, not black.

Andrew Goldsworthy, a British botanist, has worked out a theory. Modern green plants appeared on the planet late in the scene, and he reckons that the best colour had already been picked. So plants are green because something else isn’t.

The original non-green plants can still be found in some Australian salt lakes. While sea water is only 4% salt, some salt lakes can be reach 20%. In many of these salt lakes you’ll find a bacteria called Halbacterium halobium, a living fossil. It thrives, where other creatures would die from the high salt levels and heart attacks. But if the salt level falls low enough for other creatures to grow - it dies.

Halobacterium lives in a salty world by itself - a world free of competition - so evolution has passed Halobacterium by. Some scientists are sure that Halobacterium , or at least its very close relatives, have been found in fossils 3,000 million years old - so it’s been around a very long time.

Halobacterium was one of the first solar powered creatures. It discovered photosynthesis - being able to get energy out of sunlight.. Halobacterium does not have any green chlorophyll in it. Instead, it is loaded up with a purple chemical - but why is purple a better colour for solar energy collectors?

White sunlight is made up of many different colours - from red to green to blue. But the Sun puts out most of its energy in the middle of the visible spectrum - green. So for a solar-powered leaf to work at top efficiency it should suck out most of green light. When you suck away the green out of white light, you end up reflecting red and blue light which mix to make purple.

So purple Halobacterium spread across the planet, because of its free energy supply. But it had one great weakness. It could not use carbon dioxide from the atmosphere to make simple sugars. So even if it had a free energy supply, it had to eat up big if it wanted to get bigger.

Andrew Goldsworthy’s theory says a new creature evolved to fill this ecological niche. Not only did it have a free energy supply from the Sun, it could turn air into new leaves. Green photosynthesis kick-started the oxygen atmosphere, stabilised the temperature, and made life as we know it possible.

This creature turned out to be the mother of all plants - the green algae - but why green ?. Think back to our Halobacterium floating on the surface of the water, absorbing all the green light. The mother of all plants, the new intruder, was floating down below, waiting in the wings. Only blue and the red light would have filtered down through the water. It wasn’t the light with the most energy, but it was all there was at the time, and the new plants had to make the most of it. So they invented chlorophyll - which is green.

But why didn’t the green algae choose to be black. After all, black is the most efficient absorbing colour of all. Well there’s another factor - temperature control. The best temperature for leaves is between 10 and 30°C. A tree can control the temperature of its leaves using a number of tactics - absorbing or evaporating water, the shape of the leaf, the depth of the canopy and the colour of the leaves. When you look at a tree, you’ll see that the leaves at the bottom of the canopy are much darker in colour than the leaves at the top. They are not at risk for overheaing, because they are shaded by the upper leaves.

So that’s probably why the plants didn’t undergo a further evolution to be black - because they’d overheat in summer. Just think if things had been different - it wouldn’t be Greenpeace out there saving the whales, it would be Purplepeace!

Park plans create controversy

The fountain. The steam engine. Now, the trees. Plans to redo Mount Pleasant’s Central Park have caused public outcry over the last six weeks after citizens learned nearly half the park’s trees might be removed and replaced with new.

Designs for the park’s $1.2 million renovation, approved by the Mount Pleasant City Council in May, included taking out 23 mature trees spread across the park and planting 24 new around its perimeter.

Concerned residents voiced disapproval for cutting down full-grown trees, citing shade, ambiance and memorials as reasons they should not be removed.

“I just don’t believe cutting healthy, mature trees to put in young trees that will take years to grow to that size is right,” said Mount Pleasant resident David McCoid.

Some trees were removed in the plan to make way for wider sidewalks, others because of sickness and disrepair.

“If they are diseased or damaged I understand. But I think it is a shame to cut down those trees,” said resident Marilee Donnolly.

To ease their concerns, the LINCS Committee, a consortium of community representatives responsible for the plans, is reviewing ideas with its architect to keep every branch possible in its current place.

The LINCS committee was formed in 2003 to improve the city’s economy through development and includes representatives from the city, Iowa Wesleyan College, Midwest Old Threshers and the Mount Pleasant Chamber Alliance, among others.

“We’re definitely going to keep as many trees as we possibly can,” said Lisa Oetken, director of Main Street Mount Pleasant and member of the LINCS Committee.

At least four large trees near the center of the park must be removed. These trees’ leaves lead to clogs and high maintenance costs for the Edd King Memorial Fountain. Two dying pin oaks and several trees suffering from ice and storm damage also will be uprooted. The park now houses 52 trees, one was removed last month after being marred last winter by ice.

To replace the trees, landscape specialists from Shive-Hattery Architecture suggested planting thornless locusts around the edge of the park, Oetken said. Instead of planting saplings, 8 to 10 foot trees will be inserted in the ground with a tree spade.

The controversy surrounding the trees can be blamed on the LINCS committee for not communicating the plans well enough to the public, Oetken said.

Two other Central Park issues became hot topics for citizens during Central Park’s design phase, which was commenced in August 2005.

When plans looked at replacing the fountain, dedicated in 1988 to the city’s slain mayor, public outcry caused the designs to be altered ensuring it remained the focal point of the park.

In January, when word spread plans included moving the steam engine off the square, petitioners gathered 1,105 signatures asking to keep the relic put. Despite the petition, plans moved forward to relocate the iron horse elsewhere.

Current renovation plans call for moving the steam engine to the northeast corner of the courthouse lawn. Across the street, a landscaped area with a “Welcome to Mount Pleasant” sign and four-sided clock would be added as part of the Central Park overhaul, too.

Though a petition couldn’t stop its move, the steam engine has continued to be a subject of discussion for Mount Pleasant residents.

Blocking the view of the Henry County Courthouse and taking out a blue spruce hospice tree are the main concerns of rural Henry County resident Carol McCulley.

“I was county auditor for 16 years, so I care very much about the appearance of the courthouse lawn,” said McCulley. “Adding the steam engine would take away from its beauty.”

The LINCS Committee believes the move to the courthouse lawn would be beneficial.

By placing the steam engine across the street welcome area, visitors would enter downtown through a framed entrance on Washington Street, Oetken said. She added the committee did not want to subtract from the beauty of the lawn, but felt it would add to the feel of the new entrance welcoming people to the area.

“It will be a great entry to downtown,” Oetken said. “It’s kind of like a front porch — we have to welcome people into the square.”

Right now, the steam engine move is only conceptual and has not been approved by the Henry County Board of Supervisors.

Plans for the Central Park, the steam engine and the welcome area will further after committee secures its funding. So far, the project has a $400,000 pledge from the city council but also requires a $400,000 Vision Iowa grant and $400,000 from local donors to come to fruition.

The large gift campaign for the project began at the beginning of this month, and if all of the necessary funding comes through, the project will be completed in summer 2010.

About Dutchman Industries

Dutchman Industries is the equipment manufacturing division of Dutchmaster Nurseries.

Since 1970, Dutchmaster’s specialty has been wholesaling large caliber trees to the commercial and industrial landscape trades. Digging trees has always been both a pleasure and a challenge for us. Dutchmaster currently ships over 90,000 trees per year. To support our principal business, optimum production in the digging and transplanting methods remains our constant focus as the industry changes from year-to-year.

In the early 1980’s, Dutchmaster began to development and manufacturing of the “Dutchman Tree Spade”. Continual design upgrades over the past two decades have resulted in a number of models that can deal with trees of all calipers while maintaining our reputation for efficiency and dependability. In the early 90’s we implemented a total re-design of all our models and continue to refine and upgrade our products in an effort to better serve the nursery/landscaping industry.

Today, the Dutchman Tree Spade defines the equipment standard in the North American tree transplanting industry.

Dutchman can increase landscaping and nursery productivity with a proven performer.

University of Guelph Arboretum

The Arboretum at the University of Guelph is somewhat modeled after the Arnold Arboretum of Harvard University which is 100 years older.

Plantings started in 1971 and are now maturing to produce a beautiful landscape, within which The Arboretum continues to develop specialized gardens, botanical collections, and gene conservation programs. Labels are maintained at the base of all woody plants in the collections that are listed on The Arboretum map.

The Arboretum spans 165 hectares (408 acres) with 8.2 km of signed trails. Observed at The Arboretum are 38 species of mammals, 188 species of birds, 39 species of butterflies, 18 herptiles (reptiles and amphibians) and 1,700 types of trees and shrubs. Almost every tree and shrub indigenous to southern Ontario is growing at The Arboretum.

The Arboretum offers a pleasant stroll or a study of the fabulous diversity in plants. It is a great place for weddings, dinner theatre or memorial services and dedications. The Arboretum offers Docent-led tours as well as naturalist / horticulturist-led tours throughout the year. A wide array of adult and children’s educational programs are also offered covering art, botany, gardening and wildlife.

Without the efforts of over 150 volunteer auxiliary members from the City of Guelph, the University, and financial support of hundreds of people, The Arboretum could not be what it is today. The Arboretum is a significant visitor attraction as well as an important amenity for the citizens of Guelph and Ontario.

Plant Family Collections:

Maples, oaks and beeches, serviceberries, crabapples, birches, viburnums, dogwoods, lilacs, rhododendrons, and the conifers (pines, spruces, firs, cedar, junipers and larches) are presented as a more in-depth display of the genera. In these collections, the emphasis is still on species diversity and includes a range of cultivar selection. The map of The Arboretum will orient you to the location of these detailed plant collections.

Horticultural collections:

Roses, lilacs, serviceberry and dwarf conifers display the extent of horticultural plant selection. The rose collection is significant in that no insecticides or fungicides are used to sustain any plants. This allows visitors to consider which roses would manage well in a pesticide free landscape. The dwarf conifers are presented in their natural form and growth rate and the sculptural variation is quite stunning.